Ceramics- inorganic polycrystalline materials obtained from molded mineral masses (clays and their mixtures with mineral additives) in the process of high-temperature sintering.

The ceramic composition is formed by a multicomponent system, including:

• - crystalline phase (more than 50%) - chemical compounds or solid solutions;
• - glassy phase - layers of glass, the chemical composition of which differs from the chemical composition of the crystalline phase;
• - gas phase - gases located in the pores.

The properties of ceramics are determined by its composition, structure and porosity. Ceramics are classified according to their material composition, crystalline phase composition, structure and purpose.

According to the material composition, the varieties of ceramics are earthenware, semi-porcelain, porcelain, terracotta, cermets, corundum and super-hard ceramics and the so-called stone mass.

Based on the composition of the crystalline phase, they are distinguished ceramics made of pure oxides and oxygen-free.

Based on their structure, ceramics are divided into dense and porous. Porous ceramics absorb more than 5% of water, and dense ones - 1...4% by mass or 2..8% by volume. Brick, blocks, tiles, drainage pipes, etc. have a porous structure; dense - floor tiles, sewer pipes, sanitary products.

Ceramics are classified according to the nature of the structure, the degree of sintering (density) of the shard, types, types and varieties, and the presence of glaze.

Based on the nature of their structure, ceramics are divided into rough and fine. Products of coarse ceramics (pottery, bricks, tiles) have a porous, coarse-grained shard of heterogeneous structure, colored yellowish-brown by natural impurities.

Fine ceramic products are distinguished by a fine-grained white or light-colored, sintered or finely porous shard of uniform structure.

According to the degree of sintering (density) of the shard, ceramic products are distinguished between dense, sintered with water absorption of less than 5% - porcelain, thin stone products, semi-porcelain and porous with water absorption of more than 5% - earthenware, majolica, pottery.

Types, types and varieties of ceramic products

Main types of ceramics - porcelain, fine ceramic products, semi-porcelain, earthenware, majolica, pottery ceramics.

The type of ceramics is determined by the nature of the materials used, their processing, especially the fineness of grinding, the composition of the masses and glazes, the temperature and duration of firing. The composition of masses of all types of ceramics includes plastic clay substances (clay, kaolin), waste materials (quartz, quartz sand), fluxes (feldspar, pegmatite, perlite, bone ash, etc.) When firing molded products as a result of complex physico-chemical transformations and interactions of the components of masses and glazes, their structure is formed. The structure of the shard is heterogeneous and consists of crystalline, glassy and gas phases.

The crystalline phase is formed during the decomposition and transformation of clay substances and other components of the mass. The crystalline phase and especially mullite give the shard strength, thermal and chemical resistance.

The glassy phase arises due to the melting of fluxes and partially other components. It connects particles of mass, fills pores, increasing the density of the shard; in amounts up to 45 - 50% increases the strength of products, with a higher content it causes fragility of products and reduces their heat resistance. The glassy phase helps reduce water absorption and makes the shard translucent.

The gas phase (open and closed pores) has an adverse effect on the physical and chemical properties of products; reduces strength, thermal and chemical stability, causes water absorption and water permeability of the shard.

The difference between individual types of ceramics is due to the specifics of their internal structure, that is, the composition and ratio of individual phases, the composition and structure of the glaze.

Properties of ceramics

Ceramic products and materials are classified according to their purpose and properties, according to the main raw materials used or the phase composition of the sintered ceramics. Depending on the composition of the raw materials and the firing temperature, ceramic products are divided into 2 classes: fully sintered, dense, shiny products with water absorption not exceeding 0.5% and porous, partially sintered products with water absorption up to 15%. A distinction is made between coarse ceramics, which has a coarse-grained, non-uniform fracture structure (for example, building and fireclay bricks), and fine ceramics with a homogeneous, fine-grained fracture and uniformly colored shard (for example, porcelain, earthenware). The main raw materials in the ceramic industry are clays and kaolins due to their wide distribution and valuable technological properties. The most important components of the initial mass in the production of fine ceramics are feldspars (mainly microlin) and quartz. Feldspars, especially pure varieties, and their intergrowths with quartz are extracted from pegmatites. In ever-increasing quantities, quartz-feldspathic raw materials are extracted from various rocks by enrichment and purification from harmful mineral impurities.

According to the method of preparation, ceramic masses are divided into powdery, plastic and liquid. Powdered ceramic masses are a mixture of crushed and dry mixed initial mineral components, moistened or with the addition of organic binders and plasticizers. By mixing clays and kaolins with lagging additives in a wet state (18-26% water by weight), plastic molding masses are obtained, which, with a further increase in water content and with the addition of electrolytes (peptizers), are transformed into liquid ceramic masses (suspensions) - foundry slips . In the production of porcelain, earthenware and some other types of ceramics, plastic molding mass is obtained from slip by partial dewatering in filter presses, followed by homogenization in vacuum mass grinders and screw presses. In the manufacture of some types of technical ceramics, the casting slip is prepared without clays and kaolins by adding thermoplastic and surfactants (for example, paraffin, wax, oleic acid) to the finely ground mixture of the initial raw materials, which are then removed by preliminary low-temperature firing of the products.

The choice of ceramic molding method is determined mainly by the shape of the products. Products of simple shape - refractory bricks, facing tiles - are pressed from powdery masses in steel molds using mechanical and hydraulic press machines. Wall building materials - bricks, hollow and facing blocks, tiles, sewer and drainage pipes, etc. -- molded from plastic masses in screw vacuum presses by squeezing the timber through profile moldings. Products or blanks of a given length are cut from the timber by automatic machines synchronized with the operation of the presses. Household porcelain and earthenware are formed mainly from plastic masses in plaster molds using semi-automatic and automatic machines. Sanitary-building ceramics of complex configuration are cast in gypsum molds from ceramic slip on mechanized conveyor lines. Radio- and piezoceramics, cermets and other types of technical ceramics, depending on their size and shape, are manufactured mainly by pressing from powdered masses or by casting from paraffin slip in steel molds.

Products molded in one way or another are dried in chamber, tunnel or conveyor dryers.

Firing of ceramics is the most important technological process that ensures a given degree of sintering. Exact observance of the firing regime ensures the required phase composition and all the most important properties of the ceramics. With rare exceptions, sintering of crystalline phases occurs with the participation of liquid phases formed from eutectic melts. Depending on the composition of the ceramic mass and the firing temperature in porcelain, steatite and other tightly sintered products, the content of the liquid phase during the sintering process reaches 40-50% by weight or more. Due to surface tension forces arising at the boundary of the liquid and solid phases, the grains of crystalline phases (for example, quartz in porcelain) are brought closer together, and gases distributed between them are forced out of the capillaries. As a result of sintering, the dimensions of the products are reduced, their mechanical strength and density increase. Sintering of some types of technical ceramics (for example, corundum, beryllium, zirconium) is carried out without the participation of the liquid phase as a result of volumetric diffusion and plastic flow, accompanied by crystal growth. Sintering in solid phases occurs when using very pure materials and at higher temperatures than sintering with the participation of a liquid phase, and therefore has become widespread only in the production of technical ceramics based on pure oxides and similar materials. In accordance with the set of requirements, the degree of sintering of different types of ceramics varies widely. Products made from electroporcelain, porcelain, earthenware and other types of fine ceramics are coated with glaze before firing, which melts at high firing temperatures (1000-1400 °C), forming a glassy water- and gas-impermeable layer. Glazing increases the technical, decorative and artistic properties of ceramics. Massive products are glazed after drying and fired in one step. Before glazing, thin-walled products are pre-fired to avoid soaking in the glaze suspension. In some ceramic industries, the unglazed surface of fired products is ground with abrasive powders or an abrasive tool. Household ceramics products are decorated with ceramic paints, decalcomania and gold.

Table 1. Classification of ceramic products

Coarse ceramic materials

Large-pored, coarse-grained ceramic materials are used for the manufacture of large-sized products in construction, small-form architecture, etc. These varieties can withstand high temperatures and thermal fluctuations. Their plasticity depends on the content of quartz and aluminum (silica and alumina - Ed.) in the rock. The overall structure contains a lot of alumina with a high chamotte content. The melting point ranges from 1440 to 1600 °C. The material sinteres well and shrinks slightly, so it is used to create large objects and large-format wall panels. When making artistic objects, the temperature should not exceed 1300°C.

Stone ceramic mass

The basis of these raw materials are fireclay, quartz, kaolin and feldspar. When wet it has a black-brown color, and after wet firing it has an ivory color. When applying glaze, stone ceramics are transformed into a durable, waterproof and fireproof product. It can be very thin, opaque or in the form of a homogeneous, densely sintered mass. Recommended firing temperature: 1100-1300 °C. If it is disturbed, the clay may crumble. The material is used in various technologies for making pottery from lamellar clay and for modeling. Products made from red clay and stone ceramics are distinguished depending on their technical properties.

Porous ceramic mass

Clay for ceramics is a white mass with a moderate calcium content and high porosity. Its natural color ranges from pure white to greenish-brown. Fires at low temperatures. Unfired clay is recommended, as for some glazes a single firing is not sufficient.

Technical ceramics

Technical ceramics include electrical and radio ceramics, cermets, abrasive ceramic materials, foam ceramics and others.

Based on their electrical properties, ceramics are divided into electrical ceramics proper, used at frequencies up to 20,000 Hz, and radio-technical ceramics, used primarily at high (more than 20,000 Hz) frequencies.

Electrical ceramics by area of ​​application are divided into insulator (installation), capacitor (ferroelectric) and piezoceramics, quality examination.

Insulating ceramics must have low losses, good electrical insulating properties and strength. Insulating ceramics must have high dielectric constant, low losses and low temperature coefficient. The basis of capacitor low-frequency ferroelectric ceramics are solid solutions of barium, calcium, zirconium titanates and calcium and magnesium stannates, etc. The use of capacitor ceramics increases the operational reliability and heat resistance of capacitors and reduces their size.

Piezoceramics are ceramic materials with piezoelectric properties. The structure of piezoceramics is solid solutions based on barium titanite, barium niobate and lead niobate and titanate.

Abrasive ceramic materials (abrasives) are substances of increased hardness used in a massive or crushed state for mechanical processing of other materials. Natural abrasive materials - flint, emery, pumice, corundum, garnet, diamond, etc.; artificial abrasive materials - electrocorundum, silicon carbide, borazon, elbor, synthetic diamond, etc. In descending order of abrasive ability, these materials are arranged as follows: synthetic diamond, cubic boron nitride, silicon carbide, titanium carbide and electrocorundum. Currently, new abrasive materials are being developed based on borides and carbides of transition metals, as well as the belboron type.

Main characteristics of abrasive materials: hardness. Strength and wear, size and shape of abrasive grain, abrasive ability, granularity. As the strength of these materials increases, their resistance to cutting forces improves, since their compressive resistance is several times greater than their tensile resistance. The tensile and compressive strength of abrasive materials decreases with increasing grinding temperature.

The crushed and classified abrasive material is called grinding material. The grain size of grinding materials is determined by the size of the abrasive grains, i.e. group of materials according to GOST 3647-80: grinding grains, grinding powders, micro-grinding powders and fine micro-grinding powders. The designation of grain size is supplemented with indices B, P, N and D, which characterize the percentage content (mass fraction) of the main fraction (36...60%).

Abrasive ceramic materials are used both in unbound form (powders, pastes, suspensions) and in bonded form (brushes, abrasive cloths, wheels, heads, etc.).

Ceramic vases, pots, tea sets, candlesticks, plates, whistles and even musical instruments - you can create all this yourself.

To learn how to make ceramics with your own hands, the main thing is desire. Before becoming a ceramicist, try making a simple trinket out of clay, and you will understand whether it is worth spending money on buying equipment for the work. If something doesn’t work out, it doesn’t matter, soak the scrap and make a new figure out of it; before baking, the product can be modified endlessly.

What is ceramics made from and where to get materials for work

Ceramics is fired clay, which is the main material in the work of a ceramist. In contrast, natural is of natural origin; it is extracted from the bowels of the earth without subjecting it to chemical or other types of processing.

Experienced craftsmen, in order to save money, extract and prepare raw materials themselves. This process involves several stages and is unlikely to deserve attention if you are just starting out and live in the city.

Clay for making ceramics must be greasy and free of pebbles and other debris, otherwise the craft will crack during baking. The finished mass is stored under certain humidity conditions.

Natural clay happens different types:

• White is the most common, initially has a grayish tint, and after heat treatment it acquires a pleasant ivory shade.
• Red – contains iron oxide, which gives the raw material a greenish tint. The main color of the raw material is brown, after firing the products become red. It lends itself well to modeling, does not crumble, and is ideal for sculptures and large items.
• Porcelain – gray when raw and white after baking.
• Blue - more often used in cosmetology and folk medicine.
• Black or dark brown ceramic mass is the hardest clay, taking on an ivory hue after being kilned.

Also clays for ceramics classified by temperature processing for low-melting, medium-melting, refractory.

It is most convenient to buy ready-made pottery clay, focusing on the fraction size, color after firing at different temperatures and other characteristics and quality indicators. The cost depends on the manufacturer, packaging, texture. There are ready-made masses with additives for various tasks - modeling, molding, potter's wheel.

In addition to clay, you need glazes and enamels to coat products, pigments to give hand-made ceramics the desired shade, special additives to improve properties and heat treatment.

Used for gluing parts slip mass- a kind of glue made from diluted clay. If you simply connect the elements, they may fall off when heated. All this is sold in specialized stores for ceramists.

Methods for making ceramic products

There are several ways to transform clay into a beautiful ceramic product.

Modeling- the most affordable way to make ceramic products with your own hands at home. Souvenirs, sculptures, dishes, toys or other crafts are sculpted by hand, as if from plasticine, helping themselves with special stacks or improvised devices.

Pottery requires a rotating circle. With the help of this ancient craft, vases, jugs, pots, plates, and cups are still created today.

Cooldown– the easiest option for making ceramics for beginners. The work uses a plaster mold, into which soft clay is placed, and after hardening, the figured product is removed. Plaster molds are attractive because they absorb excess moisture, helping the clay product to harden and dry.

Casting– forms are also used here, but of a different type. The diluted clay is poured into molds, the blanks are dried, removed and painted.

Clay crafts gain strength only after firing - processing in pottery kilns at temperatures from 900 to 1300 degrees. Finished souvenirs are coated with acrylic paints or a special glassy glaze for ceramics. In the case of glazes, another firing is required after coloring.

If you want to get a natural shade, use milking - cover an unpainted baked ceramic figurine with milk in several layers and bake again at lower temperatures.

Pottery kiln - types and preferences

Previously, kilns for firing ceramics were furnaces dug in the ground and heated exclusively with wood. Modern pottery kilns come in gas, electric and wood. The latter, as a rule, are made by hand and are suitable for use in private households. In apartment conditions, it is most convenient to work with electric ovens; for larger volumes, you can choose a gas oven.

The metal body of such furnaces contains a refractory brick or other material that retains heat and is not afraid of heat. Ventilation holes are provided to remove moisture; the ceramic firing process is controlled by a program controller. Electric pottery kilns are not a cheap pleasure. The price depends on the manufacturer, volume, power.

There are models with vertical and horizontal loading and bell-type ones on sale. According to the type of location of the heating element, pottery kilns are divided into muffle and chamber kilns. IN muffle it is located around a container made of refractory material (muffle). In chamber heaters, the heater is located inside, which reduces heat loss and makes the equipment more economical.

With a little effort, you can make a kiln for firing ceramics at home with your own hands, using refractory bricks and something for the body, for example, an old washing machine.

Baking is the most important process that does not forgive mistakes. Sometimes even experienced craftsmen see a worthless defect instead of the expected masterpiece. The products are never taken out immediately; they must cool in the oven.

How to choose a pottery wheel

Pottery wheels are needed for sculpting round objects, so you don’t have to buy this tool right away. If you are just learning ceramics, start with sculpting or kneading. Circles come with manual, foot and electric control.

Ceramics

CERAMICS-And; m.[Greek keramikē]

1. Pottery production, pottery art. Specialize in ceramics.

2. collected Products made from baked clay. Antique room Ceramics exhibition.

3. Specialist. The mass from which such products are made. Ceramic products.

◁ Ceramic, oh, oh. K products. Kth vase. K-th tiles. K. plant, workshop. Ceramic, oh, oh. K-th production.

(Greek keramikē - pottery art, from kéramos - clay), products and materials obtained by sintering clays and their mixtures with mineral additives, as well as metal oxides and other inorganic compounds (carbides, borides, nitrides, silicides, etc.). Based on their structure, they distinguish between coarse ceramics (building bricks, fireclay bricks, etc.), fine ceramics with a uniform fine-grained structure (porcelain, piezo- and ferroelectric ceramics, cermets, etc.), porous ceramics with a fine-grained structure (faience, terracotta, majolica, etc.), and highly porous ceramics. (thermal insulating ceramic materials). Based on their application, ceramics are divided into construction (bricks, tiles, facing tiles, etc.), household and sanitary ceramics (dishes, art products, washbasins), chemically resistant (pipes, parts of chemical equipment), electrical engineering, radio engineering, thermal insulation (expanded clay, foam ceramics, etc.), refractories. Ceramics have been known since the Neolithic era (the first finds were in the 8th millennium BC in Ganj Dar, Iran).

CERAMICS (Greek keramike - pottery art, from keramos - clay), an extensive group of dielectric materials, united by a common technological cycle. Currently, the word ceramics refers not only to clay-containing materials, but also to other inorganic materials with similar properties, the manufacture of products from which requires high-temperature firing.
Ceramics composition
Ceramic material consists of several phases. The main phases are crystalline (one or more) and glassy. The crystalline phase determines the characteristic properties of the ceramic material and represents chemical compounds or solid solutions of these compounds. The basic physical properties of ceramics - electrical, piezoelectric, magnetic, temperature coefficient of linear expansion, mechanical strength - largely depend on the characteristics of the crystalline phase. The glassy phase is found in the ceramic material in the form of interlayers connecting the crystalline phase. The amount of glassy phase and its composition determine mainly the technological properties of ceramics - sintering temperature, degree of plasticity of the ceramic mass during molding. The density, degree of porosity and hygroscopicity of the material also depend on the content of the glassy phase. The presence of the gas phase (gases are in closed pores) is determined by the method of processing the mass and leads to a decrease in the mechanical and electrical strength of ceramic products, and also causes dielectric losses at increased field strengths due to the ionization of gas inclusions. Pores worsen the properties of ceramics, especially at high humidity.
The advantage of ceramics is the ability to obtain predetermined characteristics by changing the composition of the mass and production technology. Ceramic materials, due to such properties as high heat resistance, the absence of hygroscopicity in most materials, good electrical (piezoelectric, ferroelectric) and magnetic characteristics with sufficient mechanical strength, stability of characteristics and reliability, resistance to high-energy radiation and the use of fairly cheap and accessible raw materials have provided their wide application in various fields.
Depending on the purpose of ceramics, obtaining the specified properties of products is achieved by selecting raw materials and additives and by technology features. The main raw materials in the ceramic industry are clays (cm. CLAY) and kaolins (cm. KAOLIN) due to their wide distribution and valuable technological properties. The most important component of the initial mass in the production of fine ceramics is feldspars (cm. FELDSPARS)(mainly microlin) and quartz (cm. QUARTZ). However, the increased and sharply differentiated requirements placed on ceramics by metallurgy, electrical engineering and instrument making have led to the development of the production of various types of technical ceramics based on pure oxides, carbides and various compounds.
Ceramics production.
The technological scheme of ceramic production includes the following operations as mandatory:
- fine grinding and thorough mixing of the starting components;
- plasticization of the mass and formation of a molding semi-finished product;
- molding blanks from plasticized mass;
- sintering of products (high-temperature firing).
Grinding and mixing of raw materials is carried out in ball and vibration mills. Grinding can be “dry” or “wet”. All crushed ceramic masses, according to technological features, are divided into three groups: plastic masses (materials whose charge contains a significant amount of clay substances), low-plastic masses (materials with a small amount of clay substances), non-plastic masses (materials from a clay-free charge). Blend composition (cm. CHARGE) determines to a large extent the technology for preparing the mass for molding.
The resulting mixture is plasticized with an organic plasticizer (cm. PLASTICIZERS).
The molding of products is carried out by pressing, plastic drawing (extrusion) through a mouthpiece or hot injection molding. The choice of molding method is determined by technical, economic and technological factors, the main of which are the shape, size and accuracy of the part, the number of parts produced and the technological properties of the masses used.
For example, large-sized products with complex configurations are molded by casting liquid ceramic mass (water slip) into plaster molds, which are broken when the blanks are removed. Household porcelain and earthenware are predominantly molded from plastic masses in plaster molds on semi-automatic and automatic machines. Sanitary-building ceramics of complex configuration are cast in gypsum molds from ceramic slip on mechanized conveyor lines. Radio and piezoceramics (cm. PIEZOCERAMICS), cermets (cm. CERMETS) and other types of technical ceramics, depending on their size and shape, are manufactured mainly by pressing from powdered masses or by casting from paraffin slip in steel molds.
Pressing involves obtaining a product from a granular mass under the influence of external pressure. Pressing can be “semi-dry isostatic”, “wet”, “hydrostatic”, “hot”. Hot pressing is used to produce non-porous products with controlled grain size (up to 0.1 microns), characterized by increased strength and density, which improves, for example, in the case of ferroceramics, magnetic characteristics: magnetic permeability, induction, magnetization reversal time. This method is especially suitable for the production of ferrites for magnetic heads of devices for magnetic recording and playback of sound and video signals, microwave ferrites and piezoceramics, which cannot be produced by conventional methods. Products molded in one way or another are dried in chamber, tunnel or conveyor dryers.
Sintering of products is carried out in muffle or tunnel electric furnaces at a temperature of 1300 o C and above. During sintering, the plasticizer is burned out and chemical reactions between the components are completed. Due to the merging of particles, the shape of the product is fixed, the material acquires the necessary mechanical strength and specified physical and electrical properties. Depending on the composition of the material, sintering (firing) can be carried out not only in an oxidizing, but also in a neutral and even in a reducing environment. Firing of ceramics is the most important technological process that ensures a given degree of sintering. Precise adherence to the firing regime ensures the required phase composition and all the most important properties of the ceramic. During the firing process, due to the evaporation of moisture, burnout of the plasticizer and compaction of the material, shrinkage of the products occurs, i.e. their size decreases, but their mechanical strength and density increase. In accordance with the set of requirements, the degree of sintering of different types of ceramics varies widely. Products made from electroporcelain, earthenware and other types of fine ceramics are coated with glaze before firing, which melts at high firing temperatures (1000-1400 o C), forming a glassy water- and gas-impermeable layer.
Based on application, ceramics are divided into building ceramics, household and sanitary (dishes, art products, washbasins) ceramics, chemically resistant ceramics, electrical ceramics, radio engineering ceramics, heat-insulating ceramics (expanded clay (cm. Expanded clay), foam ceramics (cm. FOAM CERAMICS) etc.) and refractories.
Based on their structure, there are coarse ceramics (construction ceramics, fireclay bricks, etc.), fine ceramics with a uniform fine-grained structure (porcelain (cm. PORCELAIN), piezo- And ferroelectric ceramics, cermets etc.), porous with a fine-grained structure (faience (cm. FAIENCE (ceramics)), terracotta (cm. TERRACOTTA), majolica (cm. MAJOLICA) etc.), highly porous (thermal insulating ceramic materials).
HISTORY OF CERAMICS Ancient ceramics
The first clay figurines appear in ancient Paleolithic times (cm. PALEOLITHIC)(about 27 thousand BC). Somewhat later, clay vessels appeared in which water and food were stored. At the same time, there were attempts to use baked clay.
Already in the Neolithic era (cm. NEOLITHIC) Roasting is widespread. In different parts of the Earth, similar products are created, still clumsy, sculpted with fingerprints, mostly open forms, with thick walls. The original vessels generally had a sharp or rounded bottom and were placed between hearth stones. In the Late Paleolithic, vessels with a flat bottom appeared. The products are decorated with sculpted ornaments. Gradually, ceramics from different areas acquired a variety of shapes and patterns. Ceramics of this period are an important archaeological feature of cultures, which are often named by the predominant type of ornament.
In 6 thousand BC. e. in a number of regions painted ceramics predominate (Samarran culture in Central Mesopotamia, Aegean ceramics). Polished ceramics of excellent quality appear (brown and red, strictly black tones). Ceramic figurines in the Aegean world perfectly convey the grace of kor girls. During the same period, ceramics were used as a building material.
In the Bronze Age, in the states of Mesopotamia and Egypt, artisans began to use the potter's wheel, making ceramics became a hereditary profession. Thanks to the opening of the glaze (cm. GLAZE) porous vessels became waterproof, and the variety of colors and decorations produced by colored glazes turned pottery into works of art. In China, thanks to the use of high-quality white clay - kaolin (cm. KAOLIN) already in 2-1 thousand BC. e. thin-walled glazed dishes were made. In Ancient Egypt in 2 thousand BC. e. faience appears (cm. FAIENCE (ceramics)).
Fine fired pottery is used to decorate buildings (Ishtar Gate (cm. ISHTAR) in Babylon (cm. BABYLON)). Harappan civilization (cm. HARAPPAN CIVILIZATION) uses brick tiles for paving floors.
Antique pottery
Painted ceramics of Ancient Greece had a huge influence on the development of the entire world of decorative and applied art. Various types of ancient Greek vases (amphoras, hydrias, kylixes, craters) are widely known, decorated with elaborate floral patterns, which are then replaced by carpet, or orientalizing (cm. ORIENTALIZING STYLE), style - ornament with polychrome belts of images of animals and fantastic creatures.
In the 6th century. BC e. The so-called black-figure (black-varnish) style developed, in which silhouette images were painted with black varnish on yellow or red clay, and details of clothing and ornaments were painted with white and purple paints.
The composition of the painting was based on the expressiveness of black silhouettes outlined by a thin generalized line. A little later, red-figure vase painting appeared, preserving the natural color of the clay in the images of the figures when filling the background with black varnish. This technique gave the master the opportunity to draw forms in more detail, conveying the natural movement of the figure.
Greek ceramic art also reached a high level of development. Expressive female figurines made of terracotta (cm. TERRACOTTA) in Tanagra, they recreate the images of ancient Greek women, their daily activities, and the exquisite fashion of ancient Greece.
Roman ceramics did not reach such heights as ancient Greek, but left its mark on the art of ceramics. Not painting, but relief was a favorite technique of the craftsmen of Aretium, the center for the production of ceramic tableware in Ancient Rome. Vessels with relief ornaments, covered with transparent glaze, were widespread here. Roman builders widely used ceramics to create complex architectural details.
Ceramics of the Far East
The oldest clay products found in China date back to 3 thousand BC. e. Already in the 4th-5th centuries. Earthenware products were made in China. But China became famous primarily for the invention of porcelain (cm. PORCELAIN), which appeared as a result of improving ceramics manufacturing technology in the 6th century. From the 14th century Jingdezhen, the region where kaolin and feldspar occur, became one of the main centers for the production of Chinese porcelain (cm. FELDSPARS), as well as especially clean sand. Chinese vases and dishes are distinguished by technical and artistic perfection, and an extraordinary richness of forms and decoration. They served as a model for later European products.
In the 14th century Korean ceramics, decorated with inlays of black and white clay, as well as porcelain products with reliefs and plant patterns, also flourished. With the formation in Japan in the second half of the 14th century. During the cult of the tea ceremony, porous vessels and Raku-yaki bowls made of heavy ceramic mass appeared here. Among the Japanese ceramic centers, Seto stood out, where they produced products with transparent glazes. Japanese porcelain was particularly delicate.
Ceramics of the Middle and Near East
The impetus for the development of artistic ceramics in the countries of the Middle East most likely came from Chinese porcelain products imported at the turn of the 8th-9th centuries. In Mesopotamia, Egypt, Turkey and especially Persia, excellent ceramic utensils were created. The vessels were especially notable for their chandelier paintings. (cm. CHANDELIER), finely turned objects with turquoise glaze from the Persian city of Kashan, complex items in the “Minai” style from ancient Raga (now Rey in Iran), blue and white ceramics from the Turkish city of Iznik.
Western European ceramics
In Western Europe, ceramics began to develop intensively during the Renaissance. (cm. REVIVAL (Renaissance)). Pottery from Arab countries, especially from the Moorish part of Spain, had a great influence. Influenced by Spanish pottery with tin glaze, known as Hispano-Moorish ware (center of manufacture - Valencia), at the end of the 14th century. in Italy (in the cities of Faenza, Urbino, Gubbio) the production of similar ceramics began to develop intensively, but under the name “majolica” (cm. MAJOLICA). Covering the pieces with white pewter glaze created the perfect backdrop for painting. In turn, Italian majolica had a significant influence on the development of majolica in Germany in the 15th century, as well as in France (especially in Nevers) in the 16th-18th centuries, where it began to be called “faience”.
In the Netherlands (in Delft) similar ceramics were made from the mid-16th century. English pottery with a tin glaze in the spirit of Dutch ware, produced during the 17th and 18th centuries, was called "Delft ware". Later, more utilitarian products were produced by the English Lambeth ceramics factory - apothecary jugs, wine bottles, water flasks.
Ceramics with lead glaze, which can be easily painted in various colors, have also become widely known. It reached its peak in France in the 17th century. - famous fine vessels from Saint-Porcher and “rural clays” - decorative dishes covered with glazes by Bernard Palissy (cm. PALISSI Bernard).
Another technological type of ceramics of that time was stone mass (cm. STONE MASS). The primacy in its invention belongs to German potters of the 14th century. The centers for the production of stone products were Nuremberg, Hoechst, Nymphenburg, and Ludwigsburg. German ceramics came to England. Staffordshire craftsmen improved the stone mass and obtained a more durable shard.
The greatest success was achieved by the English ceramist J. Wedgwood (cm. WEDGWOOD Josiah), who, based on the stone mass, invented higher-quality earthenware masses - a basalt shard, a cream mass and a “jasper mass”, from which the famous blue vases with white relief in the style of classicism were made (cm. CLASSICISM).
A real revolution in the history of Western European ceramics was the invention at the beginning of the 18th century. German chemist Johann Bettger (cm. BETGER Johann Friedrich) porcelain. Soon a manufactory was opened in the Saxon town of Meissen, which began producing one of the most valuable porcelains in the world - Meissen (cm. MEISSEN PORCELAIN). Porcelain from Meissen became famous for its elegant subject figurines, sets, vases, and toiletries.
From the middle of the 18th century. Sevres porcelain began to excel in Europe (cm. SEVRES PORCELAIN), produced in the French city of Sevres. The predecessor of the Sèvres manufactory was a small factory in Vincennes near Paris, which specialized in casting porcelain flowers in the Rococo style. (cm. ROCOCO). In 1756, the Vincennes factory moved to Sèvres, where the exquisitely sophisticated style of Sèvres porcelain finally took shape. Along with painted gilded plastic, figurines were created from white unglazed porcelain - bisque (cm. BISCUIT).
High-quality English porcelain has also gained worldwide recognition. In the 18th century Britain almost excelled in the number of ceramic factories: Worcester, Chelsea, Derby, Spode, Coalport, Bow, Minton. Each of them had its own handwriting and style.
Russian ceramics
After the decline during the Tatar-Mongol yoke, Russian ceramics in the 14th-15th centuries. is reborn again. In the 18th century Along with pottery handicrafts, majolica dishes with painting on raw enamel began to be produced, in particular at the Moscow factory of A. K. Grebenshchikov, founded in 1724. The production of tiles was established (cm. TILES)- first embossed, then smooth with painting.
In 1744, the Porcelain Manufactory was founded in St. Petersburg, where three years later D. I. Vinogradov (cm. VINOGRADOV Dmitry Ivanovich) production of Russian porcelain began. In 1765 the manufactory received a higher status and became known as the Imperial Porcelain Factory. (cm. IMPERIAL PORCELAIN FACTORY), where from the end of the 18th century. beautiful sets, vases, portrait busts were produced in the style of early classicism, and later in the Empire style (cm. AMPIRE). From the day of its foundation, the plant worked on orders from the imperial court. For more mass production in 1766 in Verbilki F. Gardner (cm. GARDNER Franz Yakovlevich) founded a private factory, famous for its genre figurines and high-quality tableware. In the village of Gzhel (cm. GZHEL) in the Moscow region in the 1830-1840s. Many businesses are springing up to take advantage of local clay. At the end of the 19th century. the largest private factories pass into the hands of entrepreneur M. S. Kuznetsov (cm. KUZNETSOV Matvey Sidorovich)(including the Gardner factory). His factory in Dulevo produced mass production of earthenware and porcelain of fairly good quality.
20th century ceramics
Already from the end of the 19th century. The works of ceramists in most countries are marked by the search for a new style: the desire to expose the natural beauty of the ceramic mass or, conversely, to give it a sophisticated urban feel. Art Nouveau porcelain became famous (cm. MODERN), manufactured at a plant in Copenhagen.
In a number of countries, the stylization of folk art characteristic of Art Nouveau and a return to handmade products appeared. Many artists and sculptors turn to ceramics. In Abramtsev's workshops (cm. ABRAMTSEVO) ceramics takes on new forms, a new color (primarily in the works of M. A. Vrubel (cm. VRUBEL Mikhail Alexandrovich)). The attention to decorative and applied decoration characteristic of Art Nouveau leads to the widespread use of ceramics in the decoration of buildings and interiors.
Functionalist designers, beginning in the 1920s, sought new, simple forms, stripped of excessive decorativeness and suitable for mass production. Particular attention was paid to identifying the texture of the material. Technologies are developing: new types of glazes and enamels are appearing. Large panels and small sculptures from ceramics are made by almost all major artists of the 20th century. Particularly famous are the panels of F. Léger (cm. LEGER Fernand). Ceramics are becoming an important part of interiors.
The development of technology and the rise in living standards lead to the fact that ceramics is becoming a fairly widespread hobby; many have their own kilns. In the works of many ceramic artists, there is a noticeable desire to combine Western styles with Eastern traditions and technologies. In the USSR, the Baltic republics were especially famous for their ceramics.
In 1953, the International Academy of Ceramics was organized in Geneva (Switzerland).

Ceramics (from the Greek word keramos, which means clay) are products that are produced by sintering clays and mixtures of clays with mineral additives. As a result of heat treatment, ceramics acquires properties that determine its widespread use in a wide variety of sectors of the national economy. In terms of the totality of physicochemical, mechanical, artistic and aesthetic properties, ceramics has no equal among known materials. It is used in everyday life (dishes, ceramic figurines, vases, paintings), used in construction, and in art. The main types of ceramics can be distinguished: terracotta, majolica, earthenware, porcelain.

Types of ceramics

Pottery can be divided into two groups: unglazed and glazed ceramics.

Unglazed ceramics : Terracotta and pottery ceramics are the most ancient of all types of ceramics.

Terracotta- in Italian “baked earth” - unglazed ceramic products made of colored clay with a porous structure. It is used for artistic, household and construction purposes. Terracotta is used to make dishes, vases, sculptures, tiles, tiles, toys, facing tiles and architectural details.

Pottery ceramics requires additional processing. To make it waterproof, it is smoothed before firing with any smooth object (“polished”), compacting the outer layer of clay until a peculiar shine appears. “Staining” involves keeping clay products for a long time in the smoke of a slowly cooling oven. A very ancient method of processing is “steaming”, or “scalding”: the product removed from the oven is dipped into water with flour. At the same time, beautiful scorch marks are formed on its surface, and the dishes become waterproof. Currently, pottery ceramics have become very widespread. It is used to make pots, cups, jugs and other household items. And they are valued no less than porcelain and glass. Pottery ceramics

Glazed (or glazed) ceramics:majolica, earthenware, porcelain, fireclay.

The ceramics are covered with a layer of glaze and enamel and fired a second time. Thanks to the glaze, the products become waterproof. The glaze also allowed the product to be decorated: a matte, velvety surface alternates with flows of shiny glaze. Under the glaze, painting with engobes (painted in different colors with liquid clays) looks good. Engobing is an ancient type of processing of clay surfaces, but is still widely used.

Majolica- the closest relative of pottery ceramics. This word comes from the name of the Mediterranean island of Mallorca, where this type of ceramics originated. Majolica is the name given to products made from pottery clay, coated with colored glazes - enamels. Using the majolica technique, decorative panels, frames, tiles, etc., as well as dishes and even monumental sculptures are made.
Jug, jug, plates, brother. Majolica, enamel painting.

Gzhel. Late 18th century
Faience(from the name of the Italian city of Faenza, where faience was produced) - ceramic products (cladding tiles, architectural details, dishes, washbasins, toilets, etc.), having a dense, finely porous shard (usually white), coated with a transparent or dull (opaque) glaze. Its basis is white clay. An earthenware jug is easy to distinguish from a majolica one, you just have to pay attention to the bottom: pottery ceramics have dark protrusions on it, while earthenware ones have white ones. What distinguishes faience from majolica brings it closer to porcelain, but faience does not have the whiteness and transparency of porcelain, its shard is porous and less durable. Earthenware products have thick, opaque walls of soft, streamlined shapes.

Tea-set. Faience

Porcelain differs from other similar decorative materials in its high strength parameters, resistance to chemical and temperature influences.

Depending on the proportional composition of clay and related substances, porcelain can be divided into two categories: soft and hard. The main difference between these categories is not the hardness of the composition, as one might think, but the behavior under the influence of high temperatures. In addition, soft porcelain contains a greater variety of substances that give it additional qualities - for example, translucency. Soft porcelain more often used in the manufacture of decorative ceramic objects, and solid– for dishes and appliances. A variety of soft porcelain - bone china. Among other things, it contains bone ash, rich in calcium, which gives products made from such porcelain additional strength, whiteness and translucency.

If porcelain is made without any coating and remains matte, it is called "bisque", although it is much more common to find porcelain that has had a layer of glaze applied to it. When painting porcelain they use two technologies– underglaze painting and overglaze painting. Overglaze painting looks more vibrant due to the wide range of available colors. When painting porcelain, oxides of various metals, including noble ones (gold, platinum), are often added to paints.

Today, porcelain figurines, dishes, dolls, and other interior decorative elements are valued no less than they were several centuries ago. It is still a beautiful and sophisticated material that can become a real decoration for your home and delight its visitors for many years.

Service.Porcelain
Both porcelain and earthenware differ in price, composition and production technology. In order not to confuse noble porcelain with practical earthenware, you need to know the following differences.
Porcelain contains less clay and more various additives: feldspar, quartzite, kaolin. These additives give porcelain whiteness, glassiness, resistance to high temperatures and less porosity compared to earthenware.
It is not difficult to distinguish porcelain from earthenware. Hold the dishes up to the light - thin-walled porcelain should be translucent. It is thin and translucent, whereas earthenware does not transmit light at all and is usually covered with glaze.
If you need to determine what material the figurine is made of, turn it over and examine the bottom. Porcelain has a bottom that is not glazed. This is due to the firing technology - higher temperatures are used in the production of porcelain than in the production of earthenware. To prevent the porcelain from sticking to the stand, the glaze is cleaned off before the second firing stage.
When choosing dishes, pay attention to the rim on the bottom. In earthenware, it differs from the glaze of the dishes themselves and can be either light gray or beige. If the rim is white, then most likely it is porcelain.

Chamotte(from the French chamotte) is a ceramic fight mixed with clay. Chamotte has a coarse-grained composition, the glaze on its surface spreads in spots without covering it completely, which gives the chamotte product a special originality. It is highly valued by artists who introduced it into the field of decorative and applied arts.

Amphora with satyrs (chamotte)

Fireclay is a type of frost-resistant ceramics fired at a temperature of 1250 degrees. Products made from fireclay clay can remain in your garden for the winter; they are not afraid of frost and temperature changes. But it is important that moisture does not get on the product; to do this, it must be covered with plastic film before the first frost.

Fireclay ceramics are used to make garden and interior lamps, bases for fountains, flowerpots and craters, pots with trays, cache-pots, animal figures, vases and amphorae.

Making ceramics is easy! Once you know the basics, you can start creating your piece in no time. The process may seem daunting at first, but once you gain enough experience and knowledge, you will become proficient. Here's almost everything you need to know to get started making ceramics.

Steps

Basics

Select a method. It's important to do this first because the method determines the type of clay you'll be working with. Don't rule out choosing clays that require a kiln - if you're serious about this hobby, you can buy a small home kiln. The following is a summary of the methods and their corresponding clay varieties:

1. Choose your clay. Once you've chosen the method you'll use, you can choose the type of clay. Most clays require kiln firing, but most new brands can be fired in the oven. If you just want to play with the wet clay, don't even worry about firing it. Basic rule: wet and dry clays will not work together - be sure to make sure the clays are the same consistency.

   • If you are going to fire clay, make a choice between high-temperature and low-temperature firing.
     • Low temperature firing is most suitable for vibrant colors and detailed designs. Glazes are very stable at this temperature, the colors remain bright and do not shift during the firing process. The disadvantages are that the pieces are not completely vitrified (the clay does not completely fuse), so you will have to rely on a glaze to make the piece waterproof. This makes such products less suitable for use as cookware or for storing water. Since the glaze did not interact with the ceramic, as happens during high-temperature firing, there is a high probability of glaze chipping. However, when using the right clay and glaze, the latter can be quite durable. The clay used for low-temperature firing is called pottery clay.
     • Medium and high temperature firing uses clays called finestone or porcelain. Vibrant colors can still be achieved in oxidizing atmosphere (electric) ovens, and to a lesser extent in reducing atmosphere (gas) ovens. After firing at temperatures where the product itself is waterproof, greater strength is achieved and such products can be used as tableware or ovenware. Porcelain can be made very thin and still have sufficient strength. At these temperatures, the glaze interacts with the clay shard to create colorful and unique pieces that many people find interesting. Typically the glaze will move (either a lot or slightly), so the detailed design will be blurry.

2. Prepare yourself and prepare your work area. Working with clay can be messy, especially if children are involved. Cover areas you don't want to get dirty by placing a tarp or newspaper on the floor, or working in a garage or outbuilding.

   • Never work in clothes that you are afraid of getting dirty. If you have long hair, tie it back. This way they will become less dirty and will not get into your eyes.

   Shaping on a potter's wheel

   Prepare the clay. Air bubbles on an otherwise perfect piece can have disastrous consequences, so get rid of them before you begin. Knead or roll out the clay with your hands in small portions - start with a portion that fits in both of your palms.

   • Knead the clay like dough, form it into a ball and hit it, placing it on the plaster (it absorbs moisture well). Repeat the operation several times until the bubbles disappear. If you are not sure whether there are any bubbles left, split the ball in half using a wire and inspect it.

3. Start the circle. Using a little force, drop the clay into the center of the circle. Since you are just starting out, use no more than a large handful of clay at this time. Wet your hands in a plate of water, which should be placed close, and begin to shape the clay.

   • Begin to pull the clay mass upward. Grasp the clay with your hands and begin to squeeze upward.
     • At each stage of working with clay, make sure that your elbows are pressed against your inner thighs or knees, whichever is more comfortable for you. This will help you keep your hands steady when you work.

4. Center the clay. Using this method, the clay is spun to a perfectly smooth state, without bumps or beatings. Once you have the cone, you are ready to work further.

   • Push the tower with one hand and hold it with the other. If you are right-handed, then press the tower with your right hand: the main force is directed from above.
   • Once the clay looks like a wide piece at the surface of the circle, begin to level the sides by applying pressure to them. There may be some clay on your left hand - just set it aside.

5. Form the product. Specific instructions end at this stage - each product (plate, pot, etc.) needs to be shaped differently. But regardless of the type of product, make deliberate and slow movements - the circle should make about 5 revolutions before you complete each movement. All clay in 360 degrees must receive the same treatment to ensure the product is round. Remove accumulated water with a sponge.

   • When you're finished, scrape the piece with a wooden knife and smooth the surface with a scraper.
     • Please note: if everything goes wrong and you mess up the clay mass, then you should not try to make a ball out of it and try to repeat everything. The clay will not take on the desired thickness the second time and will not be moldable in the future.

   Modeling by hand

   1. Make sure there are no bubbles in the clay. If you put a clay piece with bubbles in the oven, there is a chance that it will explode. As outlined in Shaping on the Potter's Wheel, hit the clay on top of the plaster (it absorbs moisture) and roll it out like dough.

      • If, to be sure, you want to check the mass from the inside, then take a wire and cut the mass in half. If the bubbles do not disappear, continue working.

   2. Use the pinching, tape or sheet technique. There are three techniques you can use to sculpt ceramics. Products obtained using each technique have their own characteristic appearance. The sheet method is best suited for large items.

      Applying glaze

      1. Fire the clay at least once. After that you can apply icing on it! Get access to a kiln if you don't have your own and let the professionals take care of the rest. If you have your own oven, be sure to double check that you can operate it correctly and find out what the requirements of your product are.

         • Different clays react differently to heat. Read the instructions on the clay package and do a little research online. Also take into account the dimensions of your product.

      2. Choose your frosting. As with any step, there are many options. Each type of glaze will have its own distinct look.

         • Slip: You can buy glazes and underglazes in slip form, which are usually created for brush application. All you need to apply this glaze is a brush. Some glazes are difficult to apply with a brush to achieve a smooth layer; As a result, marks will remain on the product. Others will melt well enough that the brush marks will disappear.
         • Dry: You can purchase glazes in powder form, which are usually created to be applied by dipping, pouring, or spraying. In addition to a brush, you will need a bucket, some water, something to stir and a mask to avoid inhaling dust. The benefit of dipping is that you can get a more even glaze coverage, and you can do interesting techniques that you can't do with a brush, like double dipping, which allows you to get different colors on the same piece. More advanced people apply glaze by spraying, since it requires good ventilation, a spray gun, a compressor, an application booth, etc.
         • Do it yourself: This is the most advanced form of icing work. Guided by recipes, you buy the raw materials yourself and mix them. Among other things, you will need recipes, which can be found in books and on websites. You will also need the chemicals used to make the glazes, a scale, a sieve, and an experimenter's spirit. Sometimes your glazes won't come out quite right. You will need to learn how to modify these glazes to solve problems that get in your way. Sometimes the results will be amazing.
      3. • Be sure to dry the clay completely before firing it. Otherwise, cracks may appear in it or it may explode.
         • When carving designs into the clay, wait until it becomes as hard as leather. Also, don't "scratch" by making deep, thin cuts. Make the cuts wide enough for their depth.
         • If you are working on a piece for several days, store it under a plastic bag overnight to prevent it from drying out too quickly.
         • Clay forgives mistakes, but working with it during prolonged contact with water or with significant manipulation can cause you to get tired and lose your mood.
         • Always dry the clay completely before firing. The moisture in the clay turns into steam, which when released from the clay causes the pot to explode.
         • An easy way to make small animals is to make small balls and connect them, then smooth out the attachment points.
         • Sometimes colleges will give you enough clay to play with for a bit. They may even let you work in their studio.
         • Ideally, you'll want to find someone who has at least a little experience to teach you. This is a very practice-based process, so it's important to have someone around who can lead by example and interact with you. This guide is intended as a reminder or rough instruction, but in reality, the position of the hands is different for each sculptor.