涂层厚度对喷涂层疲劳磨损寿命影响的实验研究

采用等离子喷涂制备了不同厚度的铁基涂层，采用扫描电子显微镜（SEM）表征了涂层内部和结合界面处的微观结构，采用球盘式疲劳磨损试验机分别考察了不同厚度涂层的疲劳磨损行为，采用Weibull分布分析并对比了涂层的疲劳磨损寿命。结果表明：适当地增加喷涂层的厚度可以避免整层分层失效的发生，而从在整体上提升涂层的疲劳磨损寿命。采用有限元分析（FEM）研究了涂层内部的应力分布，发现厚涂层界面剪切应力值不足薄涂层界面剪切应力的二分之一，可见显著降低界面剪切应力是较厚涂层拥有更好疲劳性能的主因。

Experimental Investigation of Influence of Thickness on Contact Fatigue Lifetime of Sprayed Coatings

The aim of this paper was to address the influence of thickness on contact fatigue lifetime of sprayed coatings. Two Fe-based coatings with different thickness were deposited by plasma spraying. The microstructures of coating and interface between coating and substrate were characterized by scanning electron microscopy (SEM). The contact fatigue behaviors of the two kinds of coating were investigated by a ball on disk tester. The comparison of the RCF lifetime of the coatings was conducted by using a Weibull distribution. The results showed that the thick coating prevented the occurrence of catastrophic delamination, and prolonged the contact fatigue lifetime. Finite element method (FEM) was employed to analysis stress distribution within the coating. It is revealed that the magnitude of shear stress on the thicker coating interface was less than the half on thinner coating interface. Therefore the contact fatigue performance of thick coating was excellent owing to remarkable reduction of shear stress on the interface.