超音速等离子转移弧喷涂铝涂层的响应曲面法工艺优化

Process Optimization of Supersonic Plasma Transfer Arc Spraying Aluminum Coating by Response Surface Method

采用超音速等离子转移弧喷涂铝涂层,通过响应曲面法中的Box-Behnken中心组合试验设计了三因素三水平的工艺优化试验,建立了主气流量、工作电流和喷涂距离与涂层孔隙率之间的数学模型。对最优工艺参数条件下制备的铝涂层,利用SEM、XRD对涂层的微观形貌和组织成分进行表征;利用HMV-2000型维氏硬度计和MTS 809万能拉伸试验机对涂层的显微硬度和结合强度进行测试分析。结果表明:随着主气流量增大、工作电流减小或者主气流量减小、工作电流增大,孔隙率均呈减小趋势,得到的最优喷涂工艺为:主气流量:100 L/min,工作电流:200 A,喷涂距离:100 mm,丝与喷嘴的距离:10 mm,送丝速度:6 m/min。通过最优工艺制备的铝涂层,涂层致密,孔隙率为2.3%;涂层与基体的结合强度较高为24.4 MPa,显微硬度为44.5 HV0.1。

Aluminum coatings were sprayed by supersonic plasma transfer arc spraying.Three factors and three levels of process optimization experiments were designed through Box-Behnken central combination test in response surface methodology.Mathematical models between main gas flow rate,working current,spraying distance and coating porosity were established.The microstructure and composition of the coatings were characterized by SEM and XRD,and the microhardness and bonding strength of the coatings were tested and analyzed by HMV-2000 Vickers hardness tester and MTS 809 universal tensile tester.The results show that the porosity decreases with the increase of the main flow rate,the decrease of the working current or the decrease of the main flow rate and the increase of the working current.The optimal spraying process is as follows:the main flow rate:100 L/min,the working current:200 A,the spraying distance:100 mm,the distance between the wire and the nozzle:10 mm,and the feeding speed:6 m/min.The aluminum coating sprayed by the optimum process is compact with a porosity of 2.3%.The bonding strength between the coating and the substrate is 24.4 MPa and the microhardness is 44.5 HV0.1.