【摘要】 采用超音速等离子喷涂技术制备了Al2O3陶瓷涂层,利用XRD、SEM对涂层进行表征与分析。根据Box-Behnken二阶响应曲面法,基于涂层厚度h设计了三因素三水平的工艺优化试验,建立了喷涂电流I、等离子发生气体压力Pair、喷距d与响应输出值之间的数学模型。结果表明:涂层与基体结合界面良好,涂层致密且孔隙率极低;大颗粒在超音速等离子射流中熔化不充分而保留原始α-Al2O3相,工艺适用粉末要求粒径小且分布较窄,得到了沉积厚度的最终响应曲面法拟合方程。I或d增大,或Pair降低,h都呈增大趋势,最优工艺为Pair=3.5 MPa,I=340 A和d=230 mm。更多还原

【Abstract】 Al2O3ceramic coatings were prepared by supersonic plasma spraying technique. Microstructure and properties of the Al2O3 coatings were characterized by XRD and SEM. Based on Box-Behnken second-order response surface methodology,the optimization experiments with three factors and three levels were designed. The mathematical model was established between the spraying parameters of spraying current,pressure of plasma gas and spray distance,and the response value,thickness. The results indicate that the coating is dense,with low porosity and bonded well with the substrate. Large particles in the Al2O3 powders insufficiently melt in supersonic plasma jet and are preserved as the original α-Al2O3 phase,so the powders with small particle size and narrow distribution are required. The final fitting equation for coating thickness is obtained based on the experiment by response surface methodology. When I or d increasing or Pair decreasing,h tends to increase. The optimal process parameters of supersonic plasma spraying are Pair= 3. 5 MPa,I = 340 A and d = 230 mm.更多还原