AZ91D镁合金钒酸盐转化膜的最佳制备工艺  

Optimal Preparation Technology of Vanadate Conversion Coating on AZ91D Magnesium Alloy

作　　者：赵晴[1] 王帅星[1] 朱文辉[1] 简志超[1] 马刚[1] 

机构地区：[1]南昌航空大学轻合金加工科学与技术国防重点学科实验室,江西南昌330063

出　　处：《材料保护》2011年第2期30-32,7,共3页Materials Protection

摘　　要：过去,对镁合金钒酸盐无铬转化工艺的研究较少。通过正交试验和单因素试验优选了以NH4VO3为主盐的镁合金钒酸盐转化工艺。结果发现,在5 g/L NH4VO3,30 g/L H2PO2-,30 g/L NH4NO3,60℃条件下成膜15min可以在AZ91D镁合金表面形成均匀、完整的灰色转化膜;该膜层的微观形貌与铬酸盐转化膜类似,表面呈现出均匀分布的网状微裂纹,类似于"龟裂的土地",膜层主要成分为Mg,O,V,P,Al;经钒酸盐转化处理后,AZ91D镁合金的自腐蚀电位正移,自腐蚀电流密度显著降低,表明钒酸盐转化膜有效提高了AZ91D镁合金的耐蚀性。Vanadate conversion technology for AZ91D Mg alloy with NH4VO3 as the major salt was optimized based on orthogonal test and single-factor test.It was found that uniform and integral gray conversion coating was obtained on the surface of Mg alloy by immersing in the conversion solution composed of 5 g/L NH4VO3,30 g/L H2PO-2 and 30 g/L NH4NO3 at 60 ℃ for 15 min.Resultant vanadate conversion coating was similar to chromate conversion coating in microstructure.Namely,uniformly distributed net-like micro-cracks existed on the surface of the conversion coating,similar to 'the rimose land'.The conversion coating was mainly composed of Mg,O,V,P and Al,and was able to significantly increase the corrosion potential and decrease corrosion current density of Mg alloy,improving the corrosion resistance of Mg alloy.

关 键 词：钒酸盐转化膜 镁合金 微观形貌 耐蚀性 正交试验 单因素试验 

分 类 号：TG174.45[金属学及工艺—金属表面处理]