SU675040A1 - Engobe - Google Patents

Description

i

The invention relates to the production of building materials, the predominance of ceramic, and can be used), for example, in the production of decorative ceramic brick, used in the outdoor areas of buildings, structures and the creation of interior interiors.

Aigob is known, including white-burning clay 80-90 wt.% And cullet 10-20 wt.% 1 Mineral dyes can be included in the preparation of a colored engobe.

The specified engobe is applied to the raw brick of molding moisture, then dried and calcined at 950-1000 ° C, after which a matte film of various colors is formed on the brick, depending on the dyestuffs injected.

However, as a result of the presence of a large amount of clay component, the frost resistance of the engobe is 10-25 cycles, which is not enough for facade cladding ceramics. In this case, incomplete sintering of the engobe causes a high water absorption (5–8%), as a result of which the engobe layer forms in the process of operation, which impairs the decorative qualities.

In addition, due to the shrinkage stresses of such an engobe during the heat treatment, the engobe layer can be applied with a thickness of no more than 300 microns, which is sufficient for obtaining a SIDE coating; an increase in the thickness of the layer leads to the formation of cracks on the decorative surface and the separation of the engobe.

However, this engobe can be applied only to the defect-free shard, since after drying of the atebral layer, all the cracks and gaps appear on the face edges.

The aim of the invention is to control frost resistance and improve decorative properties.

This is achieved by introducing white-burning burnt clay and, in addition, phosphoric acid, in an engobe, including white-burning clay and cullet, according to the ratio. components, wt.%:

Clay white-burnt with burnt 28-57 Cullet29-67

Ortofosyurna kispot Component1 1 is crushed in a ball mill mokryugo grinding to a residue on a sieve N (y) 5bO, 3- 0.4%. The composition has (physical properties that have physical properties,% 35-45 Density, 5-1.7 Flowability, c20-25 Engobe is applied by spraying onto the baked brick with a layer of 60-10 Å thick (10 µm, dried for 3-5 minutes at 200 -250 ° C and heat treated in gas tampered at a maximum temperature of 15002000 ° C for 0.25-1 minutes After the heat treatment, a vitrified, white-colored relief film is formed on the brick, which protects the brick from moisture and possesses good decorative qualities. To change the color of the film ceramic pigments can be introduced into the graft; using burnt white-burned clay as a clay component and the introduction of orthophos (}) acid eliminates the shrinkage that occurs during the drying and calcination process, resulting in a frost-resistant coating with enhanced moisture-proof and decorative properties , and to intensify the process of firing decorative bricks Example, To obtain engobe, white-burned clay is pre-ground to complete passage through a 10 mm sieve and fired for 3 hours in an electric muffle furnace at 900 ° C. Then three mixtures of ingredients are prepared, each containing, in weight,%: White-burned clay Burned 28 42.5 57 Cullet 67 48 29 Phosphoric acid 5.0 9.5 14 40% water is added to each composition, while the density of the slip is 1.68 g / cm with a yield strength of 25 s. The resulting mixture is ground in a porcelain ball mill to a residue on a sieve N 0.056 0.3-0.4% and sprayed onto the front faces of a brick with a film of thickness 600-1SUO microns. After drying for 5 minutes at 250 ° C, the front face of a brick with an engobe applied is subjected to heat treatment with a gas burner flame at 1,700 ° C for 1 minute followed by cooling for 7 min. Table 1 shows the compositions of the well-known and proposed south-engobe. Table 2 shows ({iikiko-mechanical properties of the known and proposed engobes. Table 1

Frost resistance, shasly

Water absorption engobe,%

Durability on otbyts, yoverkh1yustnOgo layer

Surface quality

38 42 35

0.42 0.18 0.12

1.22 1.27 1.25

Without de Without de Without defects of defects,

As can be seen from the table. 2, the frost resistance of the proposed coating significantly exceeds the frost resistance of the known engobe. In addition, it has the best moisture protection properties and decorative materials. The strength of the proposed engobe is 1.6-4 times greater than that of the known, the separation of the surface layer which occurs along the contact line, which indicates a weak adhesion of the coating to the shard and insufficient sintering, while the proposed engobe has the strength of adhesion of the surface a layer with a shard exceeds the strength of the shard itself.

The use of an engobe provides an opportunity to use an ordinary brick for decorative processing, having interruptions on the facets, since the proposed composition does not create shrinkage stresses in the drying process, and the melt formed during the heat treatment fills all the surface defects.

In addition, by reducing the number of defects resulting from the diversity of

coverage, the expected savings is 20 rubles. for every 100.0 pieces of bricks. At the same time, the use of engobe will allow to increase the operational and decorative qualities of bricks.

Claims (1)

Invention Formula Ango, including white-burning clay and cullet, characterized in that. in order to be frost-resistant and to improve the decorative properties, it contains white-burned clay and additionally with phosphoric acid in the following ratio of components, wt.%: White clay with burnt 28-57 Cullet 29 67 Phosphoric acid5-14 Sources of information taken into account in the examination 1, Rogova M, I. Technologists of artificial porous aggregates and ceramics, M., Gtroyizdat 1974, p.247.