【摘要】 化学镀Ni-P镀层的显微组织对其服役性能有重要影响.通过SEM、TEM、XRD和DTA等分析手段,研究了压铸镁合金表面Ni-P镀层的晶化过程.结果表明,初始化学镀层不仅有非晶,还有亚稳态纳米晶;镀层的初始晶化温度大约为300℃,450℃晶化过程完成;升温过程中的原子扩散和纳米晶的长大导致有新的亚稳态相析出和转变;有序畴和析出物一起长大最终产生晶界.更多还原

【Abstract】 The microstructure of cladding material has greawt influence on the performance of electroless Ni-P deposit.Crystallization process in electroless nickel phosphorous(Ni-P) platings during continuous heating was investigated using XRD,SEM,TEM and DTA.Results show that in the as-deposited condition,platings are a mixture of amorphous and microcrystalline materials.It is also shown that the layers begin to crystallize at about 300 ℃,and finish crystallization process at 450 ℃.During the heat-treatment process,the metastable phases are precipitated and transformed as a result of atom diffusion and microcrystalline growing.Eventually,grain boundary is formed with order-scopes and precipitations growing up simultaneously.更多还原