Basic Research On Numerical Simulation Of Planar Plasmasprayed TiO₂ Coating

Plasma spraying is a thermal spraying to prepare surface coating with functions of wear-resisting,anti-corrosion,high temperature resistance and anti-oidation.Its advantages include wide spraying material,low cost,good-quality preparation of the coating,high production effeiciency,etc.It has a broad research prospect and has become one of the hottest topic discussed heatedly among scholars at home and abroad.But during the process of spraying,deformation of work pieces or coating crack would be caused by thermal stress for uneven distribution of temperature.The effects on coating properties under dynamic temperature change could not be solved from the only perspective of craft experiments.Therefore,numerical simulation and validation of craft experiment was used to complete the study of impact on temperature to coating performance.It is indeed a feasible scheme that the result could be found in a more accurate,intuitive and simple way.Based on the temperature field distribution of plasma spraying process and the changing rule of stress and strain,numerical simulation and experimental verification of process parameters affecting the quality of coating is optimized.(1)This paper introduced the principle and characteristics of plasma spraying,summarized the forming principle and research status of plasma spraying simulation technology,analyzed the process parameters affecting the quality of plasma sprayed coating and the deformation principle of deformation(2)According to the characteristics of the forming process in actual spray,Determined the method of solving the non-linear heat conduction problem and the thermal coupling stress field in the spraying process;According to the actual coating forming process,used the APDL parametric language of ANSYS software with kill-element technology,established the spray simulation model realize the Gaussian light source model and the dynamic loading of the heat source.We analyzed the distribution of temperature field under different process parameters to spray thecomposite ceramic layer(80% TiO2 + 20% Al2O3)with single channel single layer.At the same time,analyzed the spraying of single-channel multi-layer ceramic layer,we could found the temperature field distribution of single-channel multi-layer.In the experiment,we selected a specific point of the coating temperature to get the experimental data acquisition and the simulation data comparison.It completed the optimization of the process parameters which was affecting the quality of the coating.(3)Based on the analysis results of temperature field,the indirect coupling method was used for thermal coating stress and strain analysis of in the same direction and back and forth spraying.and the coating thermal stress distribution and warping deformation were analyzed by indirect coupling method.The effects of the thermal stress distribution on the coating quality,the total displacement of the coating and the displacement of the point on the specific cross section of single-channel monolayer and multilayer sprayed ceramic layer were obtained.The results can be used as a reference for future research.