Ceramic material: properties, production technology, application

The first ceramic products appeared long before people learned how to smelt metal. Ancient pots and jugs, which archaeologists find to this day, are a confirmation. It is worth noting that the ceramic material has unique properties that make it in some areas simply irreplaceable. Let's consider with you the features of ceramics, let's talk about its production and characteristics.

General information

Ceramic products are obtained by sintering clay and mixtures with organic additives. Sometimes oxides of inorganic compounds are used. The first such products appeared 5,000 years ago. During this time, the production technology has been substantially improved, and today we have high-strength ceramic products available. They are used in construction for facing facades, floors, erection of walls, etc.

There are ceramic products with a dense and porous shard. The key difference between them is that the dense shard is waterproof. This porcelain products, floor tiles, etc. Porous crock - tile, ceramic stone, drainage pipes and more.

History of occurrence

The word "ceramics" in Greek means "clay". Naturally, for the manufacture of any product a kind of mixture was used. The necessary materials were added to it depending on what was to be obtained eventually. The first time, manually, and a little later and on a special machine, a special form was made of clay. Further ceramic products are fired in furnaces at high temperature.

Many countries used their own production technologies. This applies to pottery, painting and glazing. The first state to achieve significant development of this industry is Egypt. It was the production of ceramics there that was set in the first place. The products were of rough and poorly mixed clay, but in the future the technology was improved. Today, they find bricks of yellow clay, which were allegedly used in the construction of the Memphis pyramids.

The appearance of porcelain

For a long time in China, such material as jade was used. It was beautiful, but quite fragile and difficult to process. After many years of searching, a solution was found. Porcelain is easier to make. Nevertheless, there were some nuances. For example, mica and zwaoku, which were found in "porcelain stones", were rubbed into fine powder and stored for more than 10 years. This was done in order to make the material as plastic as possible. The first porcelain products in China were tall and elongated vessels. They had a polished surface and a blue or dark green color. The last were most appreciated.

Today it is believed that it is China that is the state where porcelain was most widely distributed. This is true, although it was popular in Europe, but appeared there later, and its production developed longer.

The main types of ceramics

At present, clay products have a wide classification. Thus, pottery can be divided into two main groups:

• Unglazed ceramics (terracotta and pottery);
• Glazed (majolica, faience, porcelain, chamotte).

Terracotta - from the Italian "burned land." Products are made of colored clay and have a porous structure. From the terracotta make vases, dishes, as well as toys and shingles.

Pottery is also more difficult to process. In order to make it waterproof, it is necessary to glaze. Then the product is exposed to the sea. To do this, it is left in a hot oven in the smoke until completely cooled. Today many kinds of ceramics, in particular pottery, are extremely popular. It is used in the home for storing milk, loose materials or as a decoration.

As for the second type - glazed pottery, then the most popular porcelain and faience. The first is more expensive and labor-intensive in production, the second is practical and cheap. They differ among themselves in that porcelain products contain less clay and more special additives. In addition, porcelain is translucent in the light, unlike faience.

About Refractories

Products from mixtures of clay are refractory. Depending on the purpose, they can withstand temperatures from 1,300 to 2,000 degrees Celsius, and even higher. A special furnace for ceramic firing is used. Refractory materials in the largest quantities are used in the metallurgical process. There they are used to construct blast furnaces and aggregates.

It is quite logical to say that as the temperature rises, the strength of the refractory is not lost, but, on the contrary, increases. This is achieved due to the presence of refractory oxides, silicates and borides in the composition. They are used almost everywhere, where high-temperature processes take place. Very often they occur molded, that is, in the form of a specific product, say, a brick. Less often it is necessary to use unshaped refractories in the form of a powder.

Ceramics in construction

The advantages of ceramic materials are that their reserves are practically unlimited. Along with the simplicity of production and high durability of such a product, today it is indispensable in the construction sector. If you take the wall materials, then the leading position here is exactly clay brick.

The same applies to ceramic tiles, which, despite the appearance of polymers, does not give up position. It is still used to equip rooms with high humidity and temperature. Among the facing materials, claydite takes the first place.

Over the past few years, the production of a hollow ceramic block and brick increased by 4%. For their manufacture, minimal changes are required at brick factories and factories, with costs paid off in the first year of sales. Abroad, hollow ceramics has long taken a leading position and is sold much better than conventional bricks.

Special ceramic materials

These products include sanitary and sewage pipes. The first are divided into three large groups:

• From solid faience (porous crock);
• Sanitary porcelain (baked crock);
• Half-porcelain.

The main requirements put forward for sanitary products are resistance to mechanical damage, heat resistance. The recipe must be observed in strict order, the same applies to technology. Only a professional ceramic kiln and high-quality raw materials are used. Sanitary equipment includes washbasins, toilet bowls, bathtubs, radiators, etc. The correct way to check the quality of the product is an easy tapping on the body. The sound should be clean and without rattling. This indicates firing at the correct temperature and no cracks.

As for the sewer pipes, they should have a dense caked crock. Ceramic pipes are produced in diameter of 150-600 mm. Usually covered with glaze both inside and out. Such products are characterized by high resistance to aggressive environment and wandering electric current. They have a moderate cost, which makes them more affordable.

Physico-chemical properties of ceramics

As already noted above, all products can be divided into two broad groups: dense and porous. Dense have a water absorption coefficient of less than 5%, porous - 5% or more. The last group includes the following products: clay bricks (porous and hollow), hollow wall stones, facing tiles, roofing tiles. Dense ceramic products - road bricks and floor tiles. In the sanitary industry, both porous and dense ceramics are found.

Speaking about the physicochemical properties, it is necessary to note the key shortcoming of ceramics. It consists in increased fragility in comparison with other materials. Nevertheless, high availability and universality make this material one of the most popular in many industries and even in everyday life of a person. Modern technologies make it possible to obtain a smooth surface immediately after firing. If it is required to achieve a certain color, then iron or cobalt oxides are added.

Features of microstructure

When heated, the ceramic gradually turns into a liquid state. It is distinguished by a large number of simple and complex connections. During cooling, crystallization occurs. It appears in the precipitation of pure crystals, which increase in size. When the mass hardens, a microconglomerate is formed in the structure. In it, the mullite grains are cemented with a solidified mass. It is worth mentioning that the oxygen atoms form a kind of matrix. It contains small atoms of metals, which are replaced in the voids between them. Consequently, ionic and slightly less covalent bonds prevail in the microstructure. Chemical stability and stability are achieved due to the presence of strong and strong chemical compounds.

As noted above, the use of ceramic materials is limited. This is due to the fact that the crystals are not ideal. Crystalline lattices have many defects: pores of an atomic size, deformation, etc. All this significantly worsens strength. However, there are here their own nuances. For example, while observing the technology during the manufacture of a ceramics, it is quite possible to achieve good strength results. For this, it is extremely important to observe the temperature regime and the duration of the firing of the product.

Characteristics and properties of clay

Clay is a sedimentary rock, which forms a plastic material, when mixed with water, regardless of composition and structure. After baking, the stone body. Usually the mixture is dense, mostly consists of aluminosilicates. Quite often in clays are found such rocks as quartz, spar, sulfur pyrite, and also hydroxides and carbonates of calcium, magnesium and titanium compounds.

Kaolins are the purest clays that are known to date. Almost completely composed of kaolinite. After calcination, they become white. The plasticity required for processing is achieved due to the presence of a clay substance (0.005 mm) in the structure of fine grains. Naturally, the more in the composition of such a substance, the greater the plasticity, and vice versa.

The main ceramic properties of clays are:

• Plasticity - deformation without disruption of integrity;
• Connectedness;
• Air and fire shrinkage;
• Fireproofness.

Today, various depleting and enriching additives are used, which allow changing the properties of the material in one direction or another. This leads to the fact that ceramic products become even more popular and affordable.

Technological scheme of production

The characteristics of ceramic materials indicate the possibility of using clays in various industries. This led to the fact that there was a great demand, and, consequently, the supply increased. Production plants in most cases operate according to the same scheme:

• Extraction of raw materials;
• preparation;
• Formation and drying;
• Roasting and release of the product.

To minimize costs, factories are usually built in close proximity to the clay deposit. The extraction is carried out by an open method, that is, an excavator. The next stage is the preparation of the mass. Raw materials are enriched, crushed and mixed until homogeneous. Formation of the future ceramic product is carried out by wet and dry methods. In the first case, the mass is moistened to 25%, and in the second - no more than 12%.

Previously, natural drying was often used. However, the result depended for the most part on the weather. Consequently, in the rain or cold the plant stands. Therefore, special dryers (gas) are used. The most important stage is firing. It is extremely important to comply with technology, which is quite complicated. Much depends on the cooling of ceramics. Do not allow a sharp temperature drop, which can lead to a curvature of the plane. Only after that you can sell ceramic materials. The technology of production, as you see, is not simple, consists of several stages. Each of them must be observed. If this does not happen, then on the shelves of the store we can meet a marriage.

A little about the shortcomings of ceramics

As already mentioned, the composition of ceramic materials is not ideal. In particular, this affects the strength of the clay product. Any mechanical damage can appear as a chip, crack, etc. This is the key drawback. But there are other factors that restrain the widespread dissemination of the material we are considering. One of them is high cost. For example, ceramic tile for the roof of a country house is a beautiful solution from an aesthetic point of view, but it will cost such a pleasure very much.

At the same time, its appearance will last no more than 5 years with proper care. Further fading occurs, the appearance of moss on the surface, etc. Along with this, brittleness and brittleness lead to the fact that any mechanical damage can lead to the flow of the roof, and this is very few people like. Of course, modern ceramic material looks very impressive, which is achieved through a broad texture of colors and high quality workmanship. But it is still expensive, which often makes us think about the advisability of such a choice.

Let's sum up the results

We examined the main properties of ceramic materials. Proceeding from all of the above, we can conclude that such products have some uniqueness. It consists in the fact that in the absence of mechanical damage they will last very, very long. In addition, the ceramic material for casting liquid metal in factories is also indispensable, because it withstands high temperatures.

As for everyday life, then ceramics are very handy. Special dishes for cooking in the oven, although it changed its appearance over many years, but it is still made of this material. Porcelain, despite its high cost, has an elegant look and is simply pleasing to the eye. This applies to faience, which, with proper execution, is difficult to distinguish from porcelain.

In any case, it is necessary to use ceramic material. First of all, this is due to the large reserves of natural clay. It really is a lot, and every year more and more new careers are being developed for the extraction of this natural resource. The second important factor is ecological cleanliness. Previously, people generally did not have the opportunity to use any harmful additives to improve the strength characteristics of the product. Today the situation has changed, albeit not too critical. Ceramic tiles, unlike synthetic materials, do not harm health. This also applies to pottery made from ceramics, which, in comparison with plastic, especially if the latter is heated, does not cause harm at all.