工艺参数对电弧喷涂NiAl涂层孔隙率和显微硬度的影响

Effects of Spraying Process Parameters on Porosity and Microhardness of Arc-sprayed Ni-Al Coating

使用PRAXAIR-9935设备通过电弧喷涂镍铝丝材得到镍铝涂层。采用正交试验设计方法探索电弧喷涂镍铝涂层孔隙率的变化规律,以获得最佳工艺参数;采用在线监测设备测量了不同实验条件下的焰流强度、粒子速度和温度。使用有能谱分析功能的扫描电子显微镜进行涂层成分和显微组织形貌分析,同时对涂层的硬度进行了测试。根据实验结果制定了最佳工艺参数值,喷涂电流130 A、喷涂电压33 V、雾化空气压力0.4 MPa和喷涂距离120 mm。结果表明,喷涂电压、电流、雾化空气压力和喷涂距离对孔隙率造成不同的影响。使用最佳工艺参数喷涂的镍铝涂层最小孔隙率可降低到5.5%,涂层的组织呈现出典型的层状结构特征。

The Ni-Al coating was sprayed by using an electric arc spray equipment with Ni-Al alloy wires.The porosity variations of Ni-Al coating were examined in a well-designed orthogonal test to attain an optimized spraying process.The intensity and velocity of the flame flow and particle temperature were detected by an online detection system.Morphologies and compositions of the Ni-Al coating were analyzed using a scanning electron microscope,and the microhardness was measured to optimize spraying parameters are as follows:electrical arc current of 130 A,voltage of 33 V and atomizing air pressure of 0.4 MPa,spraying distance of 120 mm.The results show that the spraying voltage,spraying current,atomizing air pressure and spray distance can induce different influence on the porosity of the Ni-Al coating.Under optimized spraying parameters,the minimum porosity of the Ni-Al coating can decrease to 5.5%and the coating shows the typical layer structure.