HVOF制备铝青铜涂层工艺优化及工艺参数对涂层性能的影响

Optimization of Preparation Process of Aluminum Bronze Coating byHVOF and Effect of Process Parameters on Coating Properties

目的利用超音速火焰喷涂技术,在铸铝表面沉积质量优良的铝青铜涂层。方法基于正交实验,研究煤油流量、氧气流量、送粉速率和喷涂距离对涂层厚度、孔隙率、显微硬度和结合强度的影响。通过XRD图谱,对喷涂粉末和涂层相结构组成进行分析。利用场发射扫描电子显微镜,观察涂层截面形貌,测量涂层厚度。使用ImageJ软件测量孔隙率。采用显微硬度计和电子万能试验机,测量涂层的显微硬度和结合强度。针对正交实验结果,采用极差分析法进行分析,确定最优的工艺参数。结果由极差法分析得到最优工艺参数:煤油流量为22 L/h,氧气流量为900 L/min,送粉速率为80 g/min,喷涂距离为200 mm。采用最优工艺参数制备涂层,测得涂层厚度为405.43μm,孔隙率为0.10%,结合强度为61.63 MPa,显微硬度为330.33HV0.3。结论与粉末相比,涂层的相组成未发生改变,均为α相和β′相。通过极差分析可知,不同工艺参数对涂层孔隙率、厚度、显微硬度和结合强度的影响程度不同。在本实验选取的主要工艺参数中,送粉速率对涂层孔隙率和厚度的影响程度最大,喷涂距离对涂层显微硬度的影响程度最大,煤油流量对结合强度的影响程度最大。

In order to obtain aluminum bronze coating with excellent coating quality on cast aluminum surface by High Velocity Oxygen Fuel spraying technology,the effects of kerosene flux,oxygen flux,powder feeding rate and spraying distance on coating thickness,porosity,microhardness and bonding strength are studied based on orthogonal experiment.The phase composition of the spray powder and coatings is analyzed by XRD.The cross-section morphology of the coating is observed by SEM,and the coating thickness is measured.The porosity is measured by ImageJ.The microhardness and bonding strength of the coating are measured by micro hardness tester and electronic universal testing machine.Range analysis method is used to analyze the results of orthogonal experiment to determine the optimal process parameters.It is obtained by range analysis that the optimal process parameters are kerosene flux 22 L/h,the oxygen flux 900 L/min,the powder feeding rate 80 g/min,and the spraying distance 200 mm.The coating thickness is 405.43μm,the porosity is 0.10%,the bonding strength is 61.63 MPa,and the microhardness is 330.3 HV0.3 when the optimal process is adopted.The results show that the phase composition of the spray powder and coating is the same,both of which areαphase andβ'phase.According to the range analysis table,different process parameters have different effects on the porosity,thickness,microhardness and bonding strength of the coating.The powder feeding rate has the greatest influence on the coating thickness and porosity,the spraying distance has the greatest influence on the micro hardness of the coating,and the kerosene flux has the greatest influence on the bonding strength.