The possibility of obtaining for steel white covering enamel with melting temperature 1000 -1100°C and firing temperature 750 -780°C and for aluminum white enamel with melting temperature 900 -950°C and firing temperature 530 -560°C is investigated. The physical and technological characteristics of the frits melted are measured and the temperature -time firing regimes with the enamel deposited in the form of slip are determined. It is established that introducing modifier oxides and glass-forming oxides makes it possible to lower the melting temperature by 15 -20% and the enamel firing temperature by 20 -30°C without introducing new components into the enamel composition.Coating enamels with melting temperature 1200 -1300°C and firing temperature interval 840 -869°C are currently used for enameling steel articles. Enamels with lower melting and firing temperatures can lower costs substantially.A literature search led to ways to lower the temperature characteristics of enamels. The following enamel compositions were chosen for investigation:alkali-earth oxides (Na 2 O : K 2 O : Li 2 O) were introduced in the ratio 3 : 2 : 1, which corresponds to a combined polyalkali effect, were introduced into enamels Nos. 1 and 4 to facilitate melting; aside from alkali-earth oxides, glass-forming oxides (SiO 2 : B 2 O 3 ) were introduced into enamels Nos. 2 and 5 in the ratio 2 : 1 to obtain a chemically more stable enamel; the ratio B 2 O 3 : P 2 O 3 in the enamels Nos. 2 and 6 is 3 : 1, which will make it possible to make the glass network even stronger and to improve the operating properties of the enamel without raising its melting temperature [1].In the present work we study the problem of obtaining white titanium enamel with melting temperature 1000 -1100°C and firing temperature 680 -700°C for steel and white enamel with melting temperature 900 -950°C and firing temperature 560 -600°C for aluminum.The enamel frits were melted in a periodic-operation Silit furnace at temperature (1000 -1100) ± 10°C. The total melting time was 3.5 -4 h. The meltings performed showed that borosilicate titanium enamels with compositions Nos. 4 and 6 were completely melted at 900 -1000°C. Gas release was moderate. The fusion process for these compositions was identical to the fusion of ordinary frit.The CLTE was investigated with a quartz dilatometer.The average values of the CLTE of enamels at temperatures 200 -500°C were (

Natural diatomite rocks are investigated. Their structure, mineralogical specifics, chemical composition, and phase transformation under thermal treatment are considered. It is demonstrated that diatomite rock is a promising material for enameling production.Diatomite rock is a loose, earthy or loosely cemented porous and lightweight rock of sedimentary origin, mainly formed by fragments of armor (skeletons) of diatom algae: diatomea and radiolaria. Diatomite is a microscopic singlecell diatom alga whose size ranges from 0.75 to 1500 mm; sometimes this rock is called infusorial earth, kieselghur, or mountain meal. The main components of the siliceous armor are silica hydrates of a different degree of water content (opals) SiO 2 × nH 2 O. Diatomite rock belongs to the group of silica-bearing materials. It analysis for the purpose of using it in the production of enamel frits is of interest in the context of the integrated application of local mineral materials and also in view of nsufficient knowledge of its technological properties.The Sverdlovsk Region has substantial resources of silica-bearing materials in the form of diatomite, tripolite, and opoka bedded at a small depth.We have investigated natural rock samples from the quarries of the Irbitskii and Kamyshlovskii Building Material Works. We have studied the structure, mineralogical specifics, and phase transformation in these rocks under thermal treatment ranging from room temperature to the melting point.Irbitskii diatomite is a yellowish-gray and Kamyshlovskii is a greenish-gray sedimentary rock whose main component is amorphous SiO 2 (70 -80%). The study of the physicomechanical properties of these rocks yielded the following data: their volume weight in lumps is within 500 -700 kg/m 3 , their porosity varies from 80 to 90%, the natural moisture is 7 -10%, their milling fineness (residue on a No. 008 sieve) is 9 -10%, and their specific surface area is 3800 cm 2 /g, which corresponds to a finely dispersed lightweight porous structure.A study of the granulometric composition of diatomite shows that the dustlike fraction (particle size 0.060 -0.005 mm) has up to 75% particles and the content of the sand fraction (particle size 1.00 -0.06 mm) is around 20%, and that of the argillaceous fraction (particle size below 0.005 mm) is around 5%. Based on these data, the diatomites considered can be attributed to the group of silty sandy loam, according to Okhotin's classification.To determine the mineral composition of Irbitskii diatomite rock, we performed x-ray phase analysis. A halo was identified in the range of small and medium angles, which points to a high degree of amorphousness of the main components of the rock. This conclusion is corroborated by the shape of the diffraction reflections; they have a blurred maximum and in some cases the half-width of a reflection is commensurate with its height. The main crystal phase is b-quartz, whose crystal lattice has the following typical diffraction reflections (d = 0.443, 0.034, and 0.181 nm).The average composit...

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The article considers high-temperature enamel coatings prepared from charges synthesizing enamel with a suffi ciently high fi ring temperature and providing the required protective properties and heat resistance. Brief scientifi c and experimental research is given for the coatings obtained based on compositions modifi ed with additions of refractory fi llers added in the form of nanosize oxide powders. Keywords: high-temperature protective coatings, heat resistance and thermal stability, thermal expansion coeffi cient, composite coatings, steel protection from gas corrosion.One method for protecting apparatus and equipment from gas corrosion is application to their surface of heat-resistant or high-temperature coatings.A number of specifi cations are laid down for high-temperature protective coatings. They should be continuous and impenetrable for a corrosive medium, exhibit good adhesive strength with metal, not worsen the production properties of the base material, etc.High-temperature coatings of two types are used: heat-resistant and thermally stable. Heat-resistant coatings are resistant to the action of corrosive media, being at a temperature not lower than 650°C (start of red incandescence). For a thermally stable coating, this temperature is above the operating limit.Formation of high-temperature multifunctional coatings is accomplished at comparatively high temperature of the order to 1200-1400°C, which in many cases leads to a reduction in strength and other properties of the metal protected by a coating. Therefore, a task arose of preparing coatings with improved or good heat resistance with a comparatively low formation temperature, characterized simultaneously by an increased value of the thermal expansion coeffi cient (TEC), playing an important role in creating heat-resistant coatings [1]. It is controlled by adding nanosize metal oxide powders and is selected in relation to the metal being protected.High-temperature heat-resistant coatings may be simple (single-component) or complex. The authors have carried out research aimed at preparing oxide coatings of the following types: crystalline (entirely or as a basis of composite or glassy-crystalline), and sitallized glass enamel.Composite high-temperature coatings are a combination of a glass matrix and refractory fi ller, distinguished by good operating and physicochemical properties as a result of combining the composition of multicomponent silicate enamels with refractory or chemically stable fi llers [2]. They are used in order to protect low-carbon, unalloyed, and alloy steels, nickel,