超细SiC对Ni-P化学合金镀层组织结构的影响

Electroless Ni-P-SiC Composite Coatings with Superfine Particles

在化学镀Ni-P合金溶液中添加不同粒径的超细SiC粒子进行化学镀,制备了三种Ni- P-SiC化学复合镀层；通过扫描电镜、X射线衍射仪、透射电镜和示差扫描量热分析仪对镀层的形貌和组织结构及其转变进行了表征。结果表明：化学复合镀层镀态下为非晶态结构,在一定温度热处理后晶化产生Ni_3P和镍晶体,晶化温度几乎不受SiC粒子影响；在较高温度下镍与SiC发生反应生成Ni-Si化合物,SiC粒径越小,与镍发生反应的起始温度越低；400℃热处理复合镀层的最终产物中除了镍和Ni_3P以外还有Ni_3Si和游离碳。

Superfine silicon carbide particles reinforced nickel-phosphorus （Ni-P） matrix composite coatings were prepared by eleetroless deposition. The morphology and structure as well as the phase transformation of the composite coatings were studied by SEM, XRD, TEM and DSC. It is shown that SiC particles eo-deposited homogeneously, and the structure of Ni-P-SiC composite coatings as deposited was amorphous. After certain heat treatment, the matrix of composite coatings crystallized into nickel crystal and nickel phosphide. At higher temperature, nickel reacted with SiC and generated nickel silieides accompanied by free carbon. Final products of Ni- P-SiC coating after completely heat treatment were consisted of Ni, Ni3P, Ni3Si and carbon. The finer the SiC particles in composite coating, the lower the temperature for the reaction to take place.