The influence of ceramic coating reinforcement on thermal engineering properties

Ceramic coatings, having a high melting point, can be obtained by melting materials in a plasma stream. For this purpose, plasma units like UPU, Kyiv-7 and others are used. But these coatings have a significant drawback − they resist poorly variable temperature loads, i.e. the thermal stability of these coatings is quite low. Now, not pure ceramics but mixtures of several oxides are sprayed to increase the thermal stability. In this article, the thermal stability of the spinel with mesh reinforcement and without reinforcement is studied. Methodology.. For the manufacture of such a composition sol-gel process was used. During the spraying of the indicated spinel, powder particles with a particle size of 50−100 μm were prepared and a UPU plasma unit was used. The thickness of sprayed coating was within 2…3 mm. Metal mesh was selected from stainless steel and NiCr with a lattice size of 3 mm. For fixing the mesh on the metal surface, point micro-welding was used. A device for measuring the thermal conductivity of IT-λ-400 was used to study the thermal conductivity coefficients for the spinel. The measurement of thermal conductivity was carried out in the monotonous heating mode using the dynamic calorimeter method. In the study of thermal conductivity, heat conductive paste up to 400 ºС was used. Results. The thermal conductivity of the spinel Аl2О3 Сr2О3 type slightly decreases with temperature increasing, approximately by 5…10 %, and amounts to 3.5…3.21 W/m∙K for the coating without reinforcement, and 5,46…4,46 W/m Кfor the reinforced The thermal conductivity of a coating is affected by its reinforcement with a mesh, which causes an increase in thermal conductivity in a wide range of temperatures from 25 to 400 °. Scientific novelty. The results of the study of thermal protective coatings reinforced with metal mesh for spinel are presented for the first time. Practical relevance. To obtain coatings for the spinel Аl2О3 Сr2О3 type with high thermal conductivity and strength, we can recommend the reinforcement with metal mesh.