纯镁微弧氧化陶瓷层的耐蚀性和Ca-P沉积

摘要

To improve the corrosion resistance of magnesium in corrosive environments,a protective micro-arc oxidation (MAO )coating was prepared on magnesium substrate.The ceramic coating was then sealed in Na2 SiO 3 solution.The results of polarization curves show that the specimen with MAO coating sealed in Na2 SiO 3 solution has a better corrosion resistance in simulated body fluid (SBF).However,the coating cannot provide efficient protection for the magnesium substrate during the initial immersion in SBF.Until a precipitate layer resulting from corrosion of the magnesium substrate covers on the MAO coating,the degradation of the magnesium substrate was significantly delayed because of the sealing action of the precipitates.In addition,im-mersion tests also suggest that the specimen with MAO coating can efficiently induce Ca-P precipitation in SBF.%为提高镁在腐蚀环境中的耐蚀性,使用微弧氧化方法在纯镁表面制备1层保护性的陶瓷层,并在硅酸钠水溶液中对陶瓷层进行封孔。极化曲线测量结果表明,陶瓷层经封孔后在模拟体液(SBF)中具有更好的耐蚀性。但 SBF 浸泡实验揭示在浸泡初期,陶瓷层并不能有效保护基体镁,直至因镁腐蚀而产生的沉积物对陶瓷层中存在的孔洞进行二次封孔后,基体镁的腐蚀才被显著延缓。另外,SBF 浸泡实验也表明覆盖微弧氧化陶瓷层的样品能有效诱导 Ca-P 沉积。