元素扩散对镍基合金涂层热疲劳性能的影响

Effect of elements diffusion behavior on thermal fatigue of nickel based alloy coating deposited with thermal spraying

利用热喷涂技术在铜合金表面制作了镍基合金涂层。通过金相显微镜、扫描电镜分析研究了涂层界面显微结构和元素扩散情况及对涂层的抗热疲劳性能的影响。结果表明,合金元素在涂层/基体界面附近连续分布,并在涂层/基体界面呈陡然变化。热处理时涂层/基体界面区出现互扩散层,温度和时间的增加可以改善Cu元素向涂层扩散的能力,整个热处理过程中温度是主要因素,时间是次要因素,元素扩散提高了镍基合金涂层的抗热疲劳能力,使得涂层在550℃试验条件下,经85次热循环后未出现裂纹扩展及剥落现象。

Thermal spraying technique was applied to produce nickel based alloy coating on Cu alloy. Optical microscope, SEM analysis were used to investigate the elemental diffusion and the microstructure in the interface between the nickel based alloy coating and the substrate. And the influence of the elements diffusion behavior on thermal fatigue resistance was studied. The results show that alloy elements distribute continuously from nickel based alloy coating to substrate, and have an abrupt change at the interface between the substrate and coating. During heat treatment, an inter-diffusion layer appears between the substrate and coating, and the ability of Cu element diffusion was improved with the increase of temperature and time. The main affecting factor was temperature, and the effect of time was followed during heat treatment. The thermal fatigue resistance of nickel based alloy coating was improved by elements diffusion. The thermal spraying coating endured 85 time thermal shock at 550 ℃ was perfect without defects such as crack and spalling.