温度对铜表面喷涂层冷热疲劳性的影响及失效机理

文中用等离子喷涂在CuCo2Be表面制备了Cr3C2-NiCr涂层，并分别在500，550，600，650℃进行热震试验，研究温度对其疲劳寿命的影响；选用XRD，SEM，EDS等研究了涂层及化合物相的形成、不同温度热震后涂层内、外表面的微观形貌、氧化产物等.结果表明，涂层呈现层状，化合物为角状Cr3C2-NiCr，涂层与界面的结合以机械结合为主；XRD分析发现涂层中形成了一定非晶相，热震后涂层中存在铜、镍氧化物.分析其热震失效机制为:500℃时主要是热膨胀系数突变引起的应力与氧化共同作用；随热震温度升高，涂层与基体结合处应力增大，涂层失效机制逐步转变为应力主导失效.

Temperature effects on thermal fatigue performance of sprayed coatings on copper substrate and its failure mechanism

Cr3C2-NiCr coating was prepared by plasma spraying technique on CuCo2Be alloy substrate. High temperature thermal shock test were carried out at 500℃,550℃,600℃,650℃. The effect of temperature on the hot and cold fatigue life and failure mechanism of the coating was studied. The characteristic of the formedof phases, coating microstructure and the oxidation behavior after thermal shock failure both inside and outside were detailedly analyzed by XRD, SEM, EDS etc.The result showed that coatings present obvious layered structure while Cr3C2-NiCr compounds are angular. The EDS analysis of various phase and elements distribution, indicated that the combination of coating and interface is mainly mechanical bonding. Through XRD analysis it is found that coating has amorphous phase. The main part of the coating is made of copper, nickel oxide after thermal shock failure. The main failure mechanism of the high temperature thermal shock is the combination of thermal mismatched stress of and the oxidation o. Along with the thermal shock test temperature gradually increased from 550℃ to 650℃, the stress between coating and substrate was gradually increased,and the oxidation of copper alloy matrix was intensified.