NdFeB磁性材料表面化学镀Ni-W-P合金形核过程研究

Nucleation process of electroless plating Ni-W-P alloy on NdFeB permanent magnet materials

为提高化学镀Ni-W-P合金镀层的耐腐蚀性,防止出现起泡、脱皮等现象,分析化学镀Ni-W-P合金的反应原理,观察其镀层沉积过程的表面形貌,研究其沉积机理。结果表明:在沉积初期,原子形核不均匀,且具有明显的择优倾向。同时发现原子首先还原在固-液界面处形成原子团,然后在基体表面的高能量区域优先沉积,而不是以单个原子的形式沉积于基体表面;随着反应继续进行,沉积晶粒并未明显长大,而是随着晶粒数目增加,晶粒逐渐连成片并向外扩展,直至覆盖整个基体表面,最后形成非晶态镀层。

In order to improve the corrosion resistance of electroless Ni-W-P coating, and prevent the occurrence of bubble, peeling and so on, the deposition mechanism of electroless Ni-W-P alloy coatings was studied by analyzing reaction principle and observing the surface morphology. The results suggest that the atomic nucleation is nonuniform and has obvious preferred orientation in the initial depositing stage. The atomic clusters are formed at the interface between solid-liquid at first, then preferably deposit on the high energy region of the matrix surface, rather than deposit on the substrate surface in the form of a single atom. As the reaction continues, the growth tendency for atomic crystal is not obvious, but with the increase of grain number, grains join together and grow into chain shape and gradually extend outward until covering the surface of substrate, finally amorphous coating is formed.