基于正交实验设计方法的APS喷涂Al_2O_3涂层性能的研究

采用正交实验方法研究了大气等离子喷涂工艺参数主气流量、喷涂功率和送粉量对Al2O3陶瓷涂层结合强度和显微硬度的影响,通过X射线衍射仪和扫描电子显微镜研究了粉末和涂层的组织结构,采用WDW-50微机控制电子万能试验机、HV-1000维氏硬度计测量了涂层的结合强度、截面硬度,结合涂层组织结构并应用极差和方差分析方法对实验结果进行了分析,得到了优化后的工艺参数。结果表明,涂层由熔融和未熔融区域混合而成,截面形貌凹凸咬合,以机械结合为主。影响大气等离子喷涂Al2O3涂层性能工艺参数的主次顺序依次为:喷涂功率、主气流量、送粉量,随着功率和主气流量的升高,涂层的结合强度和硬度均出现先增加后降低的趋势。大气等离子喷涂Al_2O_3最优工艺参数为喷涂功率44KW,主气流量40L/min,送粉量40g/min,制备的涂层结合强度52MPa,显微硬度1219.4HV0.3,孔隙率值为4.00%。

Study on Properties of APS Sprayed Al2O3 Coatings Based on Orthogonal Design Method

The effects of main gas flow rate, spraying power and powder feeding rate on the bonding strength and microhardness of Al₂O₃ ceramic coating were studied by orthogonal experiment. The structure of powder and coating was studied by X-ray diffraction and scanning electron microscopy. The bonding strength and cross- section hardness of coating were measured by WDW-50 microcomputer controlled electronic universal testing machine and HV-1000 Vickers hardness tester. The experimental results were analyzed by range analysis and variance analysis combined with the coating structure, and the optimized process parameters were obtained. The results showed that the coating was composed of melted and unmelted regions, and the cross-section morphology was concave-convex occlusion, mainly mechanical bonding. The order of process parameters of sound atmospheric plasma spraying Al₂O₃ coating was spraying power, main gas flow rate and powder feeding rate. With the increase of power and main gas flow rate, the bonding strength and hardness of the coating increased first and then decreased. The optimum technological parameters of atmospheric plasma spraying Al₂O₃ were spraying power 44KW, main gas flow rate 40L/min, powder feeding rate 40g/min, bonding strength 52MPa, microhardness 1219.4HV0.3 and porosity 4.00%.