Corrosion action and passivation mechanism of magnesium alloy in fluoride solution

作     者：李建中 黄久贵 田彦文 刘常升 

作者机构：School of Metallurgy and Materials Northeastern University Steel Sheet Cold Rolling Plant Baosteel Branch Baosteel Co. Ltd. 

出 版 物：《中国有色金属学会会刊：英文版》 (Transactions of Nonferrous Metals Society of China)

年 卷 期：2009年第19卷第1期

页      面：50-54页

核心收录：

学科分类：0806[工学-冶金工程] 08[工学] 0818[工学-地质资源与地质工程] 0815[工学-水利工程] 0805[工学-材料科学与工程（可授工学、理学学位）] 080502[工学-材料学] 0703[理学-化学] 0813[工学-建筑学] 0814[工学-土木工程] 0702[理学-物理学] 

基　　金：Project supported by the Post-docotorate Fund of Northeastern University  China 

主　　题：镁合金 腐蚀 硫酸镍 金属腐蚀 

摘      要：Corrosion action and passive mechanism of magnesium alloy in the fluoride solution were studied by means of scanning electron microscopy(SEM), energy dispersive X-ray spectroscopy(EDS), and electrochemistry methods. The results show that an insoluble MgF2 film is generated on the surface of magnesium alloy activated in the hydrofluoric acid. And the mass of the deposited MgF2 film may reach a constant value, when the mass ratio of Mg/F on the magnesium alloy surface is fixed at 11.3-1. The activated magnesium alloy gains a ‘passivation state’ in a mixture of sulfuric acid and hydrofluoric acid at a volume ratio of less than 1.2. At the same time the mass of magnesium alloy is maintained as a function of the time. When the ratio is above 1.4, the mass of magnesium alloy rapidly decreases. The passive film formed through adsorption of HF2- (or H2F3-, H3F4-) ions by the deposited MgF2 film can protect the magnesium alloy from corrosion in fluoride solution, but not in non-fluoride solutions. The passive state is maintained for activated magnesium alloy in an acidic sulfuric nickel solution with added fluoride. If fluoride and carbonate are added to the acidic sulfuric nickel solution, a replacement reaction between magnesium alloy and solution takes place.