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采用化学镀方法在TC4钛合金表面制备了Ni-P镀层,通过不同的退火温度处理试件,研究了影响镀层结合力的影响因素。用SEM分析了不同温度处理后镀层的结构从而建立不同热处理温度、保温时间与扩散层厚度的动力学方程;采用X射线衍射研究了扩散界面的产物及不同退火温度对镀层的热应力的影响。结果表明:400℃,2h、400℃,4h热处理之后无扩散层出现;在500℃,2 h、500℃,4 h、600℃,2 h、600℃,4 h、700℃,2 h、700℃,4 h热处理后均出现扩散层,并根据扩散层的厚度与热处理温度和时间的关系推导出其扩散的动力学方程:y=2.72 exp(-6353/T)t;不同温度热处理后Ni-P镀层的热应力显著增加;热处理后镀层的结合力有所增加,400℃,2h、400℃,4h、500℃,4h热处理后镀层与基体的结合力最好。
Ni-P coatings were prepared on the surface of TC4 titanium alloy by electroless plating method. The influence factors on the bonding strength of the coatings were studied by treating the specimens with different annealing temperature. The structure of the coating after different temperature treatments was analyzed by SEM to establish the kinetic equations of different heat treatment temperature, holding time and thickness of the diffusion layer. XRD was used to study the effect of the product and the annealing temperature on the thermal stress of the coating. The results showed that no diffusion layer appeared after heat treatment at 400 ℃, 2h, 400 ℃ and 4h, and no diffusion layer appeared after heat treatment at 500 ℃ for 2 h, 500 ℃, 4 h, 600 ℃, 2 h, 600 ℃, 4 h, 700 ℃, Diffusion layer appeared after heat treatment at 700 ℃ for 4 h, and its diffusion kinetic equation was deduced according to the relationship between diffusion layer thickness and heat treatment temperature and time: y = 2.72 exp (-6353 / T) t; after heat treatment at different temperatures The thermal stress of Ni-P coating increased significantly. The adhesion of the coating increased after heat treatment. The adhesion between the coating and the substrate was the best after 400 ℃, 2h, 400 ℃, 4h, 500 ℃, 4h heat treatment.