(南京工程學(xué)院 材料工程學(xué)院，南京211167)
摘 要: 對(duì)傳統(tǒng)鎂合金化學(xué)鍍工藝進(jìn)行改進(jìn)，分析“零污水排放”化學(xué)鍍鎳新工藝的沉積機(jī)制。并以316L不銹鋼作為對(duì)比材料，研究該化學(xué)鍍鎳層的耐蝕性能。結(jié)果表明：新工藝獲得的Ni-P鍍層具有非晶結(jié)構(gòu)，且組織均勻致密；在20%H2SO4溶液中，鍍態(tài)和經(jīng)200 ℃熱處理的鍍層的耐蝕性均優(yōu)于316L不銹鋼的；Ni-P鍍層與316L不銹鋼在20%H2SO4溶液中的動(dòng)電位極化曲線對(duì)比表明，Ni-P鍍層具有更正的腐蝕電位，可對(duì)AZ91D鎂合金起到有效的保護(hù)作用。氟化鎂轉(zhuǎn)化膜在鍍液中是穩(wěn)定的，化學(xué)鍍后與鍍鎳層和鎂合金基體間的界面結(jié)合良好。
關(guān)鍵字: 鎂合金；化學(xué)轉(zhuǎn)化膜；沉積機(jī)制；耐蝕性；零污水排放工藝
（School of Material Engineering, Nanjing Institute of Technology, Nanjing 211167, China）
Abstract:Traditional process of electroless Ni-P plating on AZ91D magnesium alloy was improved, and the deposition mechanism of a new wastewater-free electroless nickel plating was investigated. Meantime, the corrosion resistance of the Ni-P coating was studied using stainless steel 316L as contrast material. The results show that the Ni-P coating prepared with the new process is amorphous, and its microstructure is compact and uniform. The corrosion resistance of both as-plated and heat-treated Ni-P coating at 200 ℃ is superior to that of stainless steel 316L in 20%H2SO4 solution. The potentiodynamic polarization curves in 20%H2SO4 solution indicate that the Ni-P coating has more positive corrosion potential than that of stainless steel 316L, and can provide good protection to magnesium alloy substrate. The MgF2 conversion film on the surface of magnesium alloy is stable in the bath. Good interface coherences, both in Ni-P coating-MgF2 film and in magnesium alloy matrix-MgF2 film, are formed.
Key words: magnesium alloy; chemical conversion film; deposition mechanism; corrosion resistance; wastewater-free process
