Ceramic tiles This finishing material is a product of clay, quartz sand and other natural ingredients, fired in a kiln at high temperatures, varying depending on the type of tile. The choice of ceramic tile type is determined

A ceramic mass is a mixture of kaolins, different types clay and other minerals. These masses are the basis for the creation of various ceramic products and determine its properties. Other names that are found in the literature and the Internet are plastic materials, clays, fireclay, slips. Also ceramic masses include faience and porcelain.

It is necessary to choose the mass taking into account the technique of formation and decoration, the type of product, the firing conditions. If the workshop has special equipment for the preparation of clay mixtures, it is possible to adjust the firing, drying, molding properties of the mass with any parameters.

The most efficient equipment are pug grinders with a vacuum function. Devices for the dissolution of lamellar, dry materials in water are indispensable in workshops. A complete set of equipment includes filter presses, ball mills, vacuum pug mills, devices for storing and mixing liquid masses.

Processing technologies for ceramic masses

Plastic masses go on sale in the form of layers or wads wrapped in polyethylene film; the mass of a unit of goods, as a rule, varies from 1 to 30 kg. The slip can be supplied in powder form or already diluted according to technical requirements liquids.

Clay products are processed using molding, drying, decoration and firing. Plastic shaping techniques include stuffing, rolling, sculpting, drawing on a circle - these are the most popular options. In principle, the mass can be molded in any way - the main thing is that the ceramist has enough skill. Slip casting is used for small volumes of ceramic production. Most effective way molding of ceramic products in mass production is pressing.

Drying of ceramics must be uniform, that is, all parts of the product are dried at the same speed. If necessary and technically possible, thin quick-drying edges or parts are isolated from contact with air. The faster the drying process takes place, the lower the percentage of shrinkage will be. The thick walls of the products dry for a long time, so it is recommended to dry them on bomz.
Decoration involves the application of ceramic paints, glazes and other materials. Engobe painting is allowed on the raw material, glazes are applied to the salvage-fired product.

Continues for 5-20 hours at maximum temperatures. Start processing slowly to avoid explosions of products as a result of contact with water vapor.

Characteristics of clay masses

Consider the main parameters of clay masses:

• – this characteristic must be taken into account, especially in cases where there are restrictions on the temperature treatment of products. The minimum indicators include those indicators at which a strong shard is obtained. Below them, marks are set only in cases where the process is carried out for clarity - for example, you need to show how ceramics are fired to students in a creative studio. The maximum allowable temperature is the one above which the product begins to swell and deform.
• The color of the shard - terracotta is made from red clays, majolica from white and light, porcelain, faience only from white-burning masses.
• The textural features of the shard are usually the surface of clay is smooth, while that of fireclay is granular or smooth. The masses meet appearance which, after firing, resembles granite, marble, sandstone.
• Forming technique - some types of ceramic masses that are optimally suited for sculpting, others for, and still others for stuffing products with thick walls. The differences between them are conditional and are determined to a large extent by the experience of the master. Casting masses (slips) are suitable only for casting into plaster molds.
• Water absorption (or density) is a characteristic that indicates the number of free pores in an already fired shard. The lower the water absorption rates, the more durable and dense the shard will be. Porcelain products have water absorption below 1%, an indicator of 20% is acceptable only for decorative majolica.
• Shrinkage - the degree of reduction in the size of the product in the process of firing or drying. The smaller the shrinkage, the higher the probability of deformation of the final product. Fireclay masses have minimal shrinkage.
• relation to drying. Thin masses that contain a large number of clays, can hinder the exit of water vapor from the thickness of an already molded product, have significant air shrinkage, and are highly sensitive to the drying regime. Skinny clays pass water better, give minimal shrinkage and are practically insensitive to drying. Fireclay is best tolerated by temperature effects - they can be used to make products with very thick walls, so they are used for the manufacture of large forms and landscape gardening sculptures. .
• Frost resistance is a characteristic of the product as a whole. Many masses are frost-resistant themselves by seed, but the glazes on them peel off already after 2-3 winter seasons.
• Thermal expansion coefficient - the indicator indicates the parameters of the relative expansion of plastic masses when heated per degree. It is not so much the KTR itself that is important, but its relationship with the glaze.

Rules for working with ceramic masses

The main danger that arises when working with clay and other ceramic masses is dust. Therefore, clean your workplace regularly and wash your clothes more often. Since most casting masses contain soda ash and water glass, allergic reactions are possible, although they are extremely rare. With regular and large-scale post-fired processing and glazing, the use of a respirator is recommended. If the performance of work is associated with the active release of gases, high-quality ventilation must be organized in the premises.

CERAMIC MASSES

Ceramic masses are mixtures of various clays, kaolins and many other minerals. Masses are the basis of any ceramic product and determine almost all of its properties.

Often, plastic ceramic masses are simply called "clays", plastic masses containing large chips - "chamottes", masses in liquid form - "slip", and, finally, masses in dry form - "powder".

If there is mass preparation equipment in the workshop, it is possible to adjust the forming, drying, firing properties of any mass, as well as compiling your own recipes based on the available masses and starting materials. It is desirable to have a pug grinder, ideally with a vacuum. A good help is a device for dissolving dry or plastic materials in water. A complete set of equipment includes ball mills, a filter press, a vacuum pug mill, devices for dissolving, as well as mixing and storing liquid masses.

Ceramic masses have many characteristics. Some are important for shaping products, others for obtaining the desired properties of the final product, there are those that are "hidden" in nature and manifest themselves in special cases or after a long time.

FIRE INTERVAL - this characteristic is important if there are restrictions on the firing temperature in production. The minimum temperature is such, below which a strong shard will certainly not be obtained. Below the lower temperature, firing can only be carried out for "educational" purposes, such as in a children's studio. Maximum temperature- such a temperature above which noticeable deformation of the product, swelling, etc. begins. phenomena.

SKULL COLOR - color after firing (original clay often has a different color). Terracotta is made exclusively from red-burning clays, majolica - from red-, light- and white-burning clays, faience and porcelain - only from white-burning clays, the color of the shard does not matter for stone products.

SKULL INVOICE. The so-called "clays" usually have a flat smooth surface, "chamottes" - smooth or granular. There are masses, the surface of which after firing resembles sandstone, marble, granite. Some weights allow burnishing.

FORMING TECHNIQUE. There are clays that are extremely convenient for modeling, or for molding on a potter's wheel, or for stuffing thick-walled products. The differences here are largely arbitrary and determined by experience. Slips (casting masses) are only suitable for casting into plaster moulds.

WATER ABSORPTION (shard density) is a numerical characteristic indicating the number of open pores in a fired shard. The lower the water absorption, the denser and stronger the shard. The porcelain shard must have exactly less than 1% water absorption. The stone mass must be the same dense. It is extremely rare that water absorption exceeds 20%, which is acceptable for decorative majolica.

SHRINKAGE. Reducing the size of the product during drying (air shrinkage) and firing (fire shrinkage). The smaller the shrinkage, the less likely the product to deform. Chamotte masses have, as a rule, a slight shrinkage.

ATTITUDE TO DRYING. Thin masses containing significant amounts of clay make it difficult for water vapor to escape from the thickness of the molded product, and often have large air shrinkage. Such masses are sensitive to the drying regime. Skinny masses pass water more easily, shrink less, and therefore are less sensitive to drying. Fireclay masses are the easiest to tolerate drying; they can be used to mold products with thick walls.

FROST RESISTANCE. This characteristic applies to the product as a whole. Many masses are frost-resistant on their own, but the glazes on them may begin to peel off after 2-3 winters.

COEFFICIENT OF THERMAL EXPANSION (CTE) characterizes the relative expansion when heated by 1 degree. It is not the CTE itself that is important, but its relationship with the CTE of the glaze. Most icings will come out without a caulk if the crucible has a CTE of 60-65 (10 to the minus seventh power). CTE is determined by the composition of the mass and the conditions of its firing.

White-burning masses
White-burning masses are necessary to obtain products white color or products on which colored painting and colored glazes look especially rich and bright.
Main characteristics.

MASS TYPE - some conditional name that characterizes the general set of mass properties. The widely accepted types are:

- "White clay"

The concept of porcelain currently covers a very wide range of materials based on white-burning clays, kaolins and feldspars. The ripening temperature ranges from 1200 to 1350C. General - a dense, almost vitreous, almost white shard. Thin-walled porcelain is translucent.

Faience is a mass that looks like porcelain, but gives a white shard with residual porosity after firing. There are hard faiences (without fluxes at all) and feldspar faiences. The term "faience" is adopted in Russia and may be perceived differently by ceramists in other countries.

The so-called "white clays" are special compositions with very different firing temperatures, determined by the manufacturer.

Some chamotte masses, according to the color of the shard after firing, can also be classified as white-burning.

The main supplier of ceramic masses for Ceramics Gzhel LLC is Ceramic Masses of Donbass LLC

At the request of consumers, the mass brand can be subdivided into additional sub-brands within the limits of the requirements for the physical and chemical properties of this brand, which is indicated by the addition of a digital and (or) letter index. Requirements for subgrades: the number in the name indicates the physical and chemical properties of the subgrades, the letter in the name indicates the recommended method for manufacturing products from this mass (L-for slip casting, I - for isostatic pressing, P or F - for plastic molding) - are indicated in the specification to the contract. An example of recording the designation of semi-porcelain mass for slip casting PF when ordering and in other technological documentation: “Ceramic mass PFL-1, TU U 14.2-32359731-001:2006”

Ceramic-metal is a technological combination of two materials - a metal alloy and dental porcelain or glass-ceramic, in which the first serves as a frame, base, and porcelain or glass-ceramic - facing. Ceramics is a product obtained by sintering a raw mass of various components fired in a vacuum, as a result of repeated firing, they turn into a strong ceramic mass, chemically stable in many environments, with the exception of strong hydrochloric acid, in which it dissolves. The clinic uses domestic and foreign-made ceramic masses for veneer of cast metal frameworks of non-removable dentures. Domestic mass of CS APPLICATION: CS is used for facing metal frames of non-removable dentures made of cobalt-chromium alloy. Represents current-crushed powders. PROPERTIES: mass products do not irritate the tissues of the oral mucosa. FORM OF RELEASE: release: a set of 11 colors of ground and dentin masses and 2 transparent masses. The clinic is widely known and popular masses "Ivoklar" (Liechtenstein), which is constantly improving and expanding the configuration of these products. At the same time, it should be noted that, in addition to the usual production of masses in the form of powder and liquid, the company produces ready-to-use paste-like materials, the consistency and excellent stability of which ensures high covering power when applying the material in thin layers. The exact composition of the components that make up the IPS-Classic masses allows you to control the basic properties of the ceramic masses, such as the coefficient of thermal expansion, crystal growth, etc. This makes it possible to mix all Ivoclar ceramic materials. The main assortment of IPS-Classic is represented by the following components: powder of an opaque "primer" mass "primer - filler" for filling the hollow frame of the intermediate part of the bridge, obtained using standard wax blanks; 20 pastes of various shades of opaque "primer" and dentine masses that can be applied in a thin layer; a set of "5 color options" of a paste-like, intensely colored, opaque "ground" mass, which is applied "if necessary" before the second ground mass firing; a set of "9 colors" of paste-like intensely colored dentine mass, which is applied "if necessary" before the second dentine firing; a set of transparent masses "4 colors" to achieve various effects, as well as creating an incisal edge (5 colors), which makes it possible to imitate natural tooth enamel; pasty glaze mass - to give the lining a natural shine. In addition, the assortment includes: means for isolating with gypsum from the ceramic mass (Model Separator liquid, which dries up within two minutes after application) and for separating the layers of the ceramic mass “Ceramic Separator liquid”; three modeling liquids: "N" - for applying a small amount of ceramic mass with a brush, "L" - a slowly drying liquid, "S" - for applying the mass with a spatula, followed by condensation and drying, i.e. for fast modeling. An undoubted advantage is that the Ivoclar company, in addition to the main set, produces: IPS-Classic masses of the six most common colors that are most often used in the clinic; a set of individual masses (IPS-Impulse), which facilitates the introduction of natural effects into the perception of the prosthesis. The advantage of this set is also the natural color appearance due to the opal effect of five mamelon materials, two incisal materials and an incisal material. This set is also available in individual packages; if necessary, use in the arsenal of a dental technician there are special dentin masses, the main set of which consists of 14 colors, with their help, even under the most difficult conditions, a good aesthetic effect is achieved; Materials for the crown margin (“shoulder materials”) are supplied in a set of 14 basic colors. The advantage of this set of masses is the presence of: a special shade, which is used both in the office and in the dental laboratory for direct shade determination. Therefore, the availability of coloring for a dental technician makes it possible to carry out individual layer-by-layer application of masses, control the results of firing, carry out various types of layer-by-layer application of material, compare color shades; an insulating pencil with a modeling liquid, which provide an easy removal of the framework from the working model after modeling the crown margin; Paste Dentin Stain Set (IPS-Shades) - 15 shades supplied in paste form in syringes;

paints for ceramic materials (IPS-Stains-R) in the form of a paste for direct application to ceramic surfaces. In addition, they can be added to ceramic masses. Available in nine colors (from white to black).

Thus, the use of IPS-Classic ceramic masses provides:

simple economical application of pasty masses;

natural appearance of the cladding due to the opal effect and the light transmission of the various masses;

quick color correction with pasty dentine stains;

Creation optical effects using paste-like masses of the cutting edge;

minimal shrinkage of the masses during firing;

natural fluorescence;

the ability to use with most noble and non-precious metal alloys;

compatibility with Ivoclar ceramic masses;

Color matching with Chromascope.

Chromascope is a universal color shade for practical use. It consists of 20 colors, which are divided into 5 visual, removable color groups ("white", "yellow", "light brown", "gray", "dark brown"). After the determination of the main shade is completed, further color determination operations are carried out only within the corresponding group.

Consistently eliminating unnecessary effects in ChromaScope shade design (e.g. cervical, translucent areas, strong incisal and dentine discoloration, and surface staining) makes it much easier to determine the tooth shade.

The main advantage of the Chromascope color is its wide range of applications:

when prosthetics using ceramic materials IPS-Classic and IPS-Empress;

in prosthetics with removable dentures using plastic teeth SR-Antaris (anterior) SR-Postaris (lateral);

when prosthetics with fixed prostheses with polymer lining materials SR-Chromasite, SR-Spectrasite;

when filling teeth with Ivoclar-Vivadent materials such as Heliomolar, Helioprogress, Tetrik.

It should be noted that, like other firms specializing in the production of porcelain masses, artificial teeth and filling materials, Vita (Germany) has developed its own color scale - Vita-Lumin-Vacuum. This color is represented by four variants of the main types that make up a 16-color palette: A1, A2, A3, A3-5, A4, B1, B2, B3, B4, C1, C2, C3, C4, D2, D3, D4. The range of application of this color scale is as follows:

for ceramic materials from Vita Amega/Amega-800, VitaVMK68/95, Vita Timankeramik, Vita Hai-Keram, Vitadur Alpha;

when using artificial plastic and porcelain teeth Vitapan.

The set of shades represented by the shade does not necessarily reproduce the color of natural teeth. Very often there are individual characteristics that cannot be reproduced using only ground, dentin and enamel masses.

To meet all requirements, certain skills of the dental technician and special auxiliary materials are required, which are available in an additional set. A special set of mass for the edge of the crown (shoulder mass) strengthens the perimeter of the neck of the artificial crown and is used after firing the opaque (ground) layer.

Under different lighting, the color of natural tooth enamel can be of different shades - from bluish-white to yellow-orange. This play of color in the incisal area can be reproduced using incisal masses.

The Vita VMK 95 ceramic mass is based on the well-known VMK 68 porcelains. VMK 95 masses give reliable color reproduction. In the standard layering technique, good results are obtained with a three-layer scheme: opaque, dentinal and enamel layers.

A set of opaque dentin powder containing 16 porcelains and an additional set of 15 porcelains are also available.

Porcelain Vita Interno (12 colors) allows you to individualize the features of natural teeth, create an effect of depth. A high degree of fluorescence leads to an increase in brightness and intensifies color transmission. The chromatic effect of these porcelains can be enhanced by mixing with powders of dentin and translucent materials. Interna porcelains can also be used to create a depth effect when the depth of the dentine layer is insufficient due to lack of space.

Vita Accent is a set of fine-grained sets (20 colors) with a uniform distribution of coloring pigments, which allows the dental technician to accurately imitate the natural coloration of teeth at the last stage of denture technology.

Dyes allow you to reproduce a three-dimensional effect that gives a natural look to the prosthesis and the color harmony of artificial and natural teeth.

The kit includes a powder to improve the quality of the surface of the denture. Its addition to dyes Accent allows you to get the desired intensity of color, creates a greater transparency of dyes, and thus enhances the effect of three-dimensionality. The use of this powder contributes to the closure of micropores and minimizing trauma to the gingival margin.

Carat mass is the latest generation material from Dentsply (USA) and is able to easily reproduce the colors indicated on the Biodent and Vita color scale, and also has the property of opalescence.

Opalescence is the phenomenon of light scattering by a turbid medium, observed, for example, when illuminating most colloidal solutions.

The desired color of the veneer can be obtained with a transparent (with sufficient thickness of the veneer) or opaque (with insufficient thickness) dentin mass. Both dentine masses can be combined or even mixed with each other if desired. In addition to the main set, there is a set of incisal masses Karat Opaleffect Mass Karat Biopak is a ready-to-use opaque pasty porcelain mass that does not require mixing, modeling, condensation and special primer. With such a highly simplified technique, however, a thin, even layer can still be obtained.

Low-melting dental ceramics Duceram - LFC of the company "Ducera" (Germany) in its own way chemical composition, structure, machinability and performance is incomparable to any other dental ceramic. Its most outstanding property is low temperature processing, which served as the basis for its name - Low-Fusing Ceramic (LFC) Low-melting porcelain LFC is a crystalline structure with particles ranging in size from 5 to 15 microns. Duceram contains less leucite, resulting in a lower CTE and increased light transmission compared to conventional porcelain materials.

Since low melting ceramics are made from conventional Duceram material, the two materials are compatible. Thus, LFC and Duceram can be used in two-layer technology in both ceramic-metal and all-ceramic structures of fixed dentures.

For the manufacture of all-ceramic prostheses, Vitadur, Vitadur N, NBK 1000, ORS and its subsequent modification Optek, Hi-Keram based on aluminum oxide are used. Ivoclar (Liechtenstein) recommends using the IPS-Empress ceramic mass, which is based on leucite-strengthened glass containing latent particles that stimulate crystal growth.

The set of IPS-Empress materials is presented in sets:

raw ceramic masses in powder form (20 dentine colors on the Chromascope scale, 4 incisal masses; neutral and corrective masses) and modeling liquids;

nine light-curing core materials in syringes that provide great opportunities to mimic the color of natural teeth. Light polymerization of the stump material is carried out in the apparatus Spectramat-mini;

Phosphate molding compounds for investing wax-modeled crowns, veneers and inlays. Characteristics of the components of ceramic masses. The main natural components in the manufacturing process of ceramic masses for dentures are silicon oxide SiO2, feldspar and kaolin. Silicon oxide is included in the initial mixture in the form of silica, quartz sand and other raw materials. Feldspar is anhydrous aluminosilicates of potassium, sodium or calcium. At high temperatures, feldspar ensures the development of a vitreous phase, in which other components are dissolved. Its content in the ceramic mixture reaches 60–70%. Feldspar, more often potassium, is called microcline or orthoclase, depending on the structure. Orthoclase K 2 O x Al 2 O 3 x 6SiO 2 is the main material for obtaining dental ceramic mass. Sodium feldspar is called albite, calcium - anorthite.
Kaolin - white or light-colored clay - which is contained in the ceramic mass in the range from 3 to 6%. The main part of kaolin (99%) is aluminosilicate - kaolinite Al 2 O 3 x 2SiO 2 x 2H 2 O.
Dyes give the ceramic masses the colors characteristic of natural teeth. Usually dyes are metal oxides: oxides of titanium, cobalt, chromium, gold, silver, zinc, etc.

Any production of ceramics consists of the following technological stages: - preparation of raw materials (crushing);

Preparation of ceramic mass;

Product molding;

Decoration.

Ceramic technology imposes stringent requirements on the homogeneity of the ceramic mass, its moisture content, the fineness of grinding of raw materials, and the grain composition of materials.

Methods for preparing ceramic mass

The ceramic mass must be a technically homogeneous mixture that corresponds to this recipe. It must be well mixed, evenly moistened and ensure the formation of semi-finished products from it, of the appropriate shape.

There are four ways to prepare ceramic masses:

Dry - preparation of dry powders;

Plastic;

Slip;

Combined.

The choice of the ceramic mass preparation method is determined by the properties of the feedstock. The composition of the charge, the size and shape of the manufactured products and the requirements for the finished product.

The dry method is used when the clay has low plasticity, is difficult to process and has a high sensitivity to drying.

The plastic method, the oldest, is used for clay, which swells easily, has high plastic properties and mixes well with stony leaners and marshmallows. This mass can be obtained in two ways:

From previously obtained dry powders with subsequent moistening to 16 ... 25% moisture content;

Dehydration of the slip with a moisture content of about 40% to 16 ... 25% (combined method).

The slip method is used to obtain foundry slip.

Product molding methods

Methods for molding ceramic products are mainly determined by the properties of the ceramic mass, the type, shape and requirements of finished products, the purpose of any molding method is to impart density, size and the necessary strength to the semi-finished product. There are three fundamentally different molding methods:

Semi-dry pressing from dry press powders with a mass moisture content of 4-11%;

Plastic molding of products with a mass moisture content of 16-25%;

Casting products from foundry slips.

Semi-dry pressing is used when it is necessary to obtain products with exact dimensions and correct form. This ensures the production of products with high strength and low moisture content, which makes it possible to exclude the drying stage, combining it with firing. This method is used in the technology of bricks, refractory products, facing and floor tiles, and decorative products.

The plastic molding method is the oldest and most common. It is widely used in the production various kinds ceramics - porcelain, faience.

For plastic molding in industrial production, machine molding methods are used:

Squeezing the mass through the mouthpiece of the press;

Stamp pressing;

Rolling in the body of rotation;

Molding by rotating rollers.

To obtain decorative and artistic products, molding, stuffing, rolling and extrusion are used.

Casting products from foundry slips has three varieties:

Casting from water slips;

Hot casting using a thermoplastic binder (paraffin);

Casting of thin slip films on polymer binders.

The most common and widely applicable method is slip casting from aqueous suspensions. It is used in the formation of thin, decorative and artistic ceramics, including thin-walled products and products of complex shape.