The article presents a model for the formation of a thermodiffusion layer on steels. Thermodiffusion coatings on 45 steel and HVG steel were obtained by a chemical-thermal method in a powder mixture. Studies of layered X-ray diffraction phase and microrentgenospectral analysis of the studied coatings have been carried out. on steel. The obtained results of X-ray diffraction and microrentgenospectral analysis of diffusion coatings confirm the correctness of the model of formation of the diffusion layer and the theoretical prerequisites outlined. The results of the study can be used in the preparation of mixtures for thermal diffusion saturation.
Keywords: diffusion layer, diffusion chrome plating, diffusion coating
In this work, the effective thermal conductivity of porous materials is studied by a numerical method. A technique for designing an insulating material with specified geometric characteristics is proposed, which makes it possible to predict the thermal conductivity of porous insulation with sufficient accuracy. The design of foamed porous heat-insulating materials was based on the 3D Voronoi tessellation. The effective thermal conductivity of porous media was determined for twenty structures with different geometric characteristics. The thermophysical properties of the material corresponded to melamine. To verify the numerical solution, the effective thermal conductivity of the melamine sponge was determined experimentally. One regular structure and three irregular structures were compared with each other. The porosity of the insulating structures ranged from 0.722 to 0.987, the fiber diameter ranged from 0.0489 mm to 0.1259 mm. A theoretical solution is proposed for determining the effective thermal conductivity of regular structures. The technique proposed in the work can be used to design heat-insulating materials based on additive technologies, with specified heat-insulating and structural properties.
Keywords: effective thermal conductivity, porous structure, porous insulating material, 3D Voronoi tessellation