摘要
利用 DSC 热扫描仪、X 射线衍射仪、透射电镜和显微硬度计等,研究了化学镀3.0%P、5.0%P、7.0%P 和10.0%P 合金的组织转变及硬化过程。低磷合金(P<7.05)系晶态过饱和固溶体,高磷合金为非晶态;在加热过程中,过饱和固溶体脱溶分解,析出第二相Ni_3P。非晶态镍磷合金发生晶化反应,然后生成 Ni_3P。镍磷合金镀层的显微硬度随热处理温度升高而增加,至400℃获得最大硬度值,而后又下降。低磷合金是典型的沉淀硬化机制,高磷合金表现为分散强化。
The process of microstructure transformation and hardening of Ni-P alloy with 3.0%P,5.0%P,7.0%P and 10%P were studied by means of DSC thermal analyzer,X-ray diffractometer,TEM and microhardness tester etc.The experimental results showed that the low phosphorus alloy is a crystallized supersaturated solid solution,and the high phosphorous alloy is amorphous.During heating,a second phase Ni_3P is precipitated from the supersaturated solid solution and the amorphous Ni-P alloy is crystallized forming Ni_3P.Microhardness of Ni-P alloy coating increases with the increase of heat treating temperature,and a maximum value is obtained at 400℃,and then the hardness is lowered when the temperature is over 400℃.The hardening mechanism of low phosphorous alloy is precipitation strengthening and that of high phosphorous alloy is dispersing strengthening.
关键词
化学镀层
镍磷合金
组织转变
硬化
electroless plating
Ni-P alloy
transformation
hardening
