大气等离子喷枪电极退化过程的监测与诊断

Monitoring and Diagnosis of the Degradation Process of Electrodes of Atmospheric Plasma Spraying Torch

等离子体喷涂过程中其电极表面不可避免地会出现烧蚀退化,导致射流能量分布变化,从而改变粒子的熔融加速过程,最终导致涂层质量的不均匀。本文针对美科F100喷枪电极烧蚀退化过程,设计了监测诊断实验,研究了喷枪运行30 h过程中电弧电压以及射流特征的演化情况。分析了电弧电压、喷枪功率等关键特征在喷枪长时间运行下随电极退化的变化规律,并将电压进行FFT变化后在50 kHz频域内找出具有相应衰减规律的特征峰。将拍摄所得的射流图片经图像处理后分析射流面积、长度、亮度等特征的变化规律。结果表明,喷枪电极的退化过程表现为三个阶段,不同阶段下喷枪的各项特征表现出不同的状态。研究结果可为实际生产中电极的及时更换提供指导。

The plasma spraying process inevitably results in degradation of the electrodes surface,leading to changes in the jet energy distribution,which alters the particle melt acceleration process and ultimately leads to non-uniform coating quality.In this paper,a monitoring and diagnostic experiment was designed to investigate the evolution of arc voltage and jet characteristics during 30 hours of gun operation for the degradation process of the Metco F100 gun electrodes.The key features such as arc voltage and gun power were analyzed for their variation with electrode degradation over a long period of gun operation,and the voltage was subjected to FFT variation to identify the characteristic peaks with corresponding decay patterns in the 50 kHz frequency domain.The captured jet images were processed to analyze the variation patterns of the jet area,length and brightness.The results show that the degradation process of the gun electrodes is manifested in three stages,and the characteristics of the gun show different states under different stages.The research results can provide guidance for the timely replacement of electrodes in actual production.