Ni-P-UFD复合镀层的晶化

Crystallization of Ni-P-ultrafine diamond(UFD) composite coating

采用超细金刚石 (UFD)粉末作为复合粒子 ,制备了Ni P UFD复合镀层 ,研究了复合镀层晶化过程的组织结构转变 ,并通过差热分析对比研究了Ni P镀层与Ni P UFD复合镀层的晶化温度及晶化激活能。结果表明 ,非晶态Ni P UFD复合镀层热处理时发生晶化 ,晶化后生成的稳定相为Ni3P和Ni,晶化过程中生成亚稳相Ni5P2 ,亚稳相最终会转变成稳定相。在相同的加热速率下 ,Ni P UFD复合镀层晶化的起始温度均低于Ni P镀层 ,但峰值温度与Ni P镀层相当 ;Ni P UFD复合镀层的晶化激活能高于Ni P镀层 ,说明UFD加入后非晶镀层的稳定性增加 。

Electroless Ni P composite coating was deposited using Ultrafine Diamond(UFD). The effects of UFD on crystallization temperature and the activation energy of crystallization of the coating were investigated.The results show that the amorphous Ni P UFD composite coating crystallizes during heat treatment, the stable phase resulted from crystallization are Ni 3P and Ni, and a metastable phase, Ni 5P 2, may appear during crystallization, while it transforms to stable phase by heat treatment. Under the same heating rate, the crystallization temperature of Ni P UFD composite coating is lower than that of Ni P coating, while the peak temperature of the two electroless coating are well matched. The crystallization activation energy of Ni P UFD is higher than that of Ni P coating, which means the composite coating is stabler than Ni P coating and the Ni P UFD coating is more difficult to crystallize than Ni P.