Some features of the structural instability of clay raw materials and its influence on the properties of ceramic products are considered. The influence of autoclave treatment on the dispersion processes of clays and kaolins has been studied. It is shown that the directed formation of the properties of materials at the stage of preliminary preparation will reduce the degree of non-equilibrium of the processes during firing and will lead to a better quality final product. Tab. 3, bibliography: 6 titles.
The properties of VK 94-1 alumina material press-powders (containing 95% Al 2 O 3 ) obtained by drying in a spray dryer and their effect on the properties of pressed samples have been investigated. ... The analysis of the technological process of pressing the capsule ammunition using clays previously dried in spray dryers has been carried out. Recommendations for further improvement of their work are given. Tab. 4, bibliography: 4 titles.
High-density ceramics with the composition LaYO 3 * YScO 3 with a total porosity of about 0.5% have been obtained by the method of co-chemical deposition, pressing and sintering. The electrical conductivity of this ceramics was measured and the activation energy of electrical conductivity was determined. The results obtained can be used for the manufacture of new types of thermistors, as well as for the synthesis of electrical insulating materials. Il. 2, bibliography: 6 titles.
The influence of the amount of paraffin and the method of its introduction into the molding mass (after dispersion and joint dispersion), prepared from technical alumina and 20% nitric acid, has been investigated. It was found that mechanochemical activation in the presence of paraffin makes it possible to achieve a greater effect in the regulation of structural, mechanical and rheological properties. The reasons influencing the properties of molding compounds are considered. Tab. 1, ill. 2, bibliography: 10 titles.
A block cellular alumina-vanadium catalyst for the selective reduction of nitrogen oxides with ammonia has been developed. With an average conversion of nitrogen oxides of more than 90%, the efficiency of the proposed catalyst is significantly higher than that of currently used industrial catalysts. Such a catalyst can be recommended for use in selective installations for the purification of exhaust gases from nitrogen oxides, which will significantly reduce the cost of manufacturing a catalytic unit. Tab. 1, bibliography: 5 titles.
The results of studies of mullite formation from compositions of hydromica clay - Al (OH) 3 are presented. It is shown that the formation of mullite (or solid solutions of mullite with corundum) is most intensively carried out at temperatures of 1150 - 1200 ° C from compositions in which the content of hydromica clay is 50 -60%. Tab. 1, ill. 4, bibliography: 7 titles.
The reasons for the appearance of certain types of defects during static pressing of ceramic products on automatic press are considered. Recommendations are given for their elimination in order to improve the quality of products in serial production. Tab. 1, bibliography: 4 titles.
To obtain highly dispersed, sintering-active forsterite powders, the sol-gel method was used. On the basis of these powders, a sufficiently strong and dense ceramic was obtained without additives at a firing temperature of 1350 ° C; however, complete sintering of forsterite is difficult due to intense recrystallization. Tab. 1, ill. 1, bibliography: 7 titles.
The results of experiments on hardening miniature bushings with an outer diameter of 1.2 - 3.5 mm made of forsterite ceramics by impregnation in salt solutions are presented. It is shown that an increase in the temperature of the first firing and a decrease in the duration of impregnation of semi-finished products leads to an increase in strength from 47% to 2.7 times, depending on the size of the products. The mathematical processing of the experimental results was carried out by the spline interpolation method. Tab. 2, ill. 2, bibliography: 3 titles.
The effect of a new viscosity reducer - 40% PAN (sodium polyacrylate) - on the rheological properties of majolica slip, as well as water hardness on the change in the moisture content of the suspension has been studied. The use of 40% PAN makes it possible to reduce its content in the slip by almost 2 times in comparison with water glass, improve the rheological properties of the slip, and also slightly reduce its moisture content. The optimal content of 40% PAN has been established for thinning slip from polymineral clay from the Gzhel deposit and majolica mass. Tab. 2, ill. 2, bibliography: 1 title.
