( 1. 湖南大學 化學化工學院, 長沙 410082；
2. 湖南高等建材專科學校 化學化工系, 衡陽 421008；
3. 沈陽工業(yè)大學 材料科學與工程學院， 沈陽 110023)
摘 要: 通過腐蝕實驗和陽極極化曲線研究了硫酸鎳主鹽配制的化學鍍鎳液成分和溫度對AZ91D鎂合金的腐蝕行為的影響， 比較了堿式碳酸鎳主鹽和硫酸鎳主鹽兩種鍍鎳液的腐蝕性以及施鍍后的鍍層質量。 結果表明： 硫酸鎳鍍液的腐蝕性比堿式碳酸鎳鍍液大， 在低溫下， 鎂合金在硫酸鎳鍍液中表面的氟化鎂膜不致密， 鍍液對基材的腐蝕性高； 而在高溫下， Mg2+與F-的反應性增強， 氟化反應完全， 形成的氟化鎂鈍化膜致密性高， 可保護鎂合金基體免遭鍍液的腐蝕。 在施鍍溫度下， 鍍液中F-的緩蝕作用， 可使SO2-4離子對鎂合金的腐蝕速率大大降低。
關鍵字: AZ91D鎂合金； 鍍液腐蝕； 化學鍍鎳； 硫酸鎳
LIU Zheng3, YE Li-yuan1
（ 1. School of Chemistry and Chemical Engineering,
Hunan University, Changsha 410082, China;
2. Department of Chemistry and Chemical Engineering,
Hunan College of Building Materials, Hengyang 421008, China;
3. School of Materials Science and Engineering,
Shenyang University of Technology, Shenyang 110023, China）
Abstract: Through the corrosion experiments and the anodic polarization curves, the effects of composition of plating bath and temperature on corrosion behavior of magnesium alloy AZ91D in electroless nickel plating bath composed of nickel sulfate were studied. The corrosion behavior of AZ91D in the baths with nickel sulfate or with basic nickel carbonate and the quality of the coating obtained in both baths, were compared. The results show that corrosion of magnesium alloy in the bath with nickel sulfate is suffered more seriously than that in the bath with basic nickel carbonate. At low temperature, MgF2 film on the surface of magnesium alloy in the bath with nickel sulfate is not compact and the coupons of magnesium alloy have a big corrosion rate, but at high temperature, the reactive of Mg2+ and F- increases, and MgF2 film on the surface of magnesium alloy becomes more compact. So MgF2 film can prevent magnesium alloy from further corrosion. At the plating temperature beyond 70 ℃, the corrosion rate of magnesium alloy caused by SO2-4 in the bath is reduced in presence of F-.
Key words: AZ91D magnesium alloy; bath corrosion; electroless nickel plating; nickel sulfate
