TEMPERATURE DISTRIBUTION DURING POWDER COATINGS APPLYING USING PLASMA STREAM WITHIN THEIR CONTACT WITH THE SUBSTRATE LAYER

This paper presents the results of mathematical modeling of temperature state of the “substrate – intermediate layer” system when applying ferromagnetic powder protective coatings on the steel samples. The authors consider the issues of temperature and temperature gradients distribution in the substrate and the underlayer, and in the area of their contact and describe in detail the process of coating applying using the plasma stream produced by the electrical discharge with the liquid cathode, as well as the plasma sprayer for ferromagnetic powder applying. The paper considers the method of ferromagnetic powder producing. To solve the issue, the authors use Fourier method and give the initial data for the computational scheme implementation. The results of numerical calculations are presented in the form of dependences of temperature behavior in time in the intermediate layer contact with the substrate and the time dependence of Q = q-φ value; where q – is the heat flux density incident to the underlayer free surface; and φ – is the heat flux density within the contact of the underlayer with the substrate. Data analysis shows that within the “substrate – intermediate layer” contact heat exchange systems with the similar values of thermal and physical characteristics of the constituent materials, the slow contact temperature growth in time is observed. Heat flux density within the contact area of underlayer and substrate layer in such systems slightly differs from the flux density causing the underlayer free surface heating and they tend to equalize with time. These t₁ (τ) and Q (τ) time dependences are stipulated by the condition when the substrate layer thickness exceeds considerably the underlayer thickness.