Al-Mn合金镀层的微观结构及耐蚀性  

Composition, structure and corrosion resistance of Al-Mn alloy coatings

作　　者：杨占红[1] 王小花[1] 李旺兴[2] 陈建华[2] 王升威[1] 

机构地区：[1]中南大学化学化工学院,长沙410083 [2]中国铝业公司郑州研究院,郑州450041

出　　处：《中国有色金属学报》2008年第4期666-670,共5页The Chinese Journal of Nonferrous Metals

基　　金：国家科技支撑计划资助项目(2006BAE03B03)

摘　　要：在AlCl3-NaCl-KCl低温共融盐中，添加无水MnCl2，接通直流电在铁片上获得Al—Mn合金镀层。用扫描电镜、能量色散谱、X射线衍射和极化曲线对分别对该合金镀层的形貌、组成、相结构及耐腐蚀性能进行测试。结果表明：纯铝镀层表面呈针状，锰质量分数9．20％的镀层表面呈花状，锰质量分数25．43％的镀层表面有无规则瘤节状凸起物且晶界模糊，而锰质量分数达到34．42％时，晶粒细化，晶界清晰；合金镀层中锰质量分数与熔盐中无水MnCl2的质量分数呈线性关系；锰质量分数为20．84％～29．74％的镀层为单一的非晶态结构，锰质量分数高于29．74％的镀层为Al8Mn5晶体与非晶态的双相结构；合金镀层的点蚀电压比纯铝镀层高180～360mV，单相非晶态合金镀层的耐蚀性优于双相镀层。Al-Mn alloy coatings were obtained on iron substrate from AICI3-NaCI-KCI low temperature molten salt with a controlled content of anhydrous MnCl2. SEM, EDS, XRD and polarization curves were used to investigate the composition, surface morphology, phase structure and corrosion resistance of the obtained deposits. The results show that the surface of the obtained pure aluminum coating is acicular, while the coating with 9.20%（mass fraction） Mn is flowery-like and irregular tumor-like outshoots and dark grain boundaries exist in the coating with 25.43% Mn. As Mn content achieves 34.42%, the obtained crystal is fined and the grain boundaries turn clear. The content of manganese increases linearly with increasing content of MnCl2. A single amorphous phase alloy coating is obtained when Mn content is between 20.84% and 29.74%, when the content of Mn beyond 29.74%, a mixture of amorphous and Al8Mn5 was obtained. The pitting potential of the obtained pure aluminum coating is enhanced by about 180-360 mV when added with Mn. The corrosion resistance of single amorphous phase alloys is better than that of the duel-phase structure deposits.

关 键 词：A1-Mn合金 低温熔融盐 电镀 微观结构 耐蚀性 

分 类 号：TQ153.2[化学工程—电化学工业]