等离子喷涂NiCrAl涂层工艺优化研究

Optimization of process parameters for plasma spraying of NiCrAl

采用Metcod43NS(成分NiCrAl)粉末和PARXAIR-5710等离子喷涂系统制备NiCrAl涂层,为了使Ni-CrAl等离子喷涂涂层获得优良的涂层性能,选择涂层结合强度为判据,通过正交试验对NiCrAl等离子喷涂工艺进行了优化。利用扫描电镜,Axio Imager.A 1 m金相图像分析系统等手段对涂层界面形貌和孔隙率进行分析,同时对涂层的结合强度以及显微硬度进行测试。确定优化后的喷涂工艺参数为:喷涂电流为700 A,喷涂距离140 mm,主气流量56.6 L/min,辅气流量28.3 L/min。研究结果表明,喷涂电流、喷涂距离、主气流量、辅气流量对NiCrAl涂层结合强度具有不同的影响,在优化的喷涂工艺参数条件下,NiCrAl涂层结合强度为59.23 MPa,显微硬度为268HV,孔隙率为4.97%。

NiCrAl coatings were prepared by Metco443NS powder with plasma spraying system (Model PARXAIR-3710). In order to obtain the plasma-sprayed NiCrAl coatings with good properties, the plasma spraying process parameters were optimized with orthogonal experiment by taking the adhesive strength level as the criterion. The coatings appearance and porosity were studied hy scanning electron microscopy (SEM) and Axio Imager. A 1 m metallographic image analysis system. Meanwhile, the micro-hardness and adhesive strength of the coating were tested. The optimized processing parameters of the plasma spraying of NiCrAl coatings are:spraying current 700 A, spray distance 140 mm, primary gas flow rate 56.6 L/min and secondary gas flow rate 28.3 L/min. The studied result shows that spraying current, spraying distance, primary gas flow rate and secondary gas flow have different effect on the adhesive strength of NiCrAl coatings. The highest adhesive strength of Ni-CrAl coatings can be up to 59.23 MPa at the optimized parameters, micro-hardness is 268HV, and the porosity is 4.97%.