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研究了等离子喷涂层在不同应力水平下的接触疲劳失效模式与声发射幅值的对应关系,并分析了涂层的接触疲劳失效机理.结果表明:声发射幅值与接触应力的大小无明显的关系,根据疲劳失效时的声发射幅值可以判断涂层接触疲劳失效模式,幅值为87～93 dB时易发生剥落或分层失效,幅值为78～83 dB易发生点蚀失效.涂层表面微凸体与轴承球滚压接触产生黏着磨损以及涂层、磨粒、轴承球三者形成的三体磨料磨损是点蚀失效产生的主要原因.剥落失效主要与涂层表面微观缺陷处裂纹的萌生、扩展以及表面磨损行为有关.层内分层失效是由涂层内部最大剪切应力控制的,而界面分层失效主要是由涂层与基体的低结合强度、热失配以及界面剪切应力造成的.
The relationship between contact fatigue failure mode and acoustic emission amplitude of plasma sprayed coatings under different stress levels was studied and the mechanism of contact fatigue failure was analyzed.The results show that there is no significant difference between the amplitude of acoustic emission and the contact stress , The contact fatigue failure mode of the coating can be judged according to the AE amplitude when the fatigue failure occurs, and the peeling or delamination failure easily occurs when the amplitude is 87 ~ 93 dB, and the pitting corrosion failure is likely to occur when the amplitude is 78 ~ 83 dB Layer surface asperities and bearing balls rolling contact adhesion wear and abrasion, coating, abrasive particles, bearing ball three body abrasive wear is the main cause of pitting failure.Exfoliation failure and the coating surface microscopic defects Crack initiation, propagation and surface wear behavior.The layer failure is controlled by the maximum internal shear stress in the coating, while the interface failure is mainly caused by the low bond strength between the coating and the substrate, the thermal mismatch and the interface Shear stress caused by.