High-purity magnesium coating on magnesium alloys by vapor deposition technique for improving corrosion resistance
High-purity magnesium coating on magnesium alloys by vapor deposition technique for improving corrosion resistance
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DOI：
10.2320/matertrans.44.504
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发表时间：
2003-04-01
影响因子：
1.2
通讯作者：
Inoue, H
中科院分区：
文献类型：
--
作者：
Tsubakino, H;Yamamoto, A;Inoue, H
研究了采用真空镀膜技术制备的高纯镁涂层的显微组织。此外，涂层和未涂层的镁合金和腐蚀行为之间的关系进行了解释，在盐浸泡试验过程中的原位激光显微镜观察。使用具有3 N级的镁和AZ 31镁合金作为蒸发源和用于沉积的衬底。改变基底的温度，导致炉中温度分布的变化，以优化沉积涂覆条件，从而在沉积层中获得均匀的微观结构和厚度。在300 K、587 ks、3%NaCl溶液中的盐浸试验中，涂层试样的耐蚀性上级3 N-Mg、AZ 31和AZ 91 E合金，与6 N-Mg合金相当。原位观察表明，显微组织的不均匀性，如第二相和晶界偏析，恶化镁合金的耐腐蚀性。因此，纯镁涂层在金相和电化学意义上没有不均匀性，可以提高镁合金的耐腐蚀性。
Microstructures, in coated magnesium alloy with high purity magnesium fabricated by applying a vacuum deposition technique were investigated. Moreover, relationships between microstructures in coated and un-coated magnesium alloys and corrosion behaviors were interpreted by in-situ laser microscopic observations during salt immersion tests. Magnesium with 3N-grade and AZ31 magnesium alloy were used for an evaporation source and a substrate for deposition. Temperature of the substrates was changed resulting in change in temperature profile in a furnace in order to optimize deposition coating conditions for obtaining homogeneous microstructures and thickness in deposited layer. The coated specimen revealed superior corrosion resistance to those on 3N-Mg, AZ31 and AZ91E alloys, and comparable to that on 6N-Mg in salt immersion tests using 3% NaCl solution at 300 K for 587 ks. In-situ observations showed that inhomogeneity in microstructures, such as second phases and grain boundary segregations, deteriorate corrosion resistance in magnesium alloys. Therefore, pure magnesium coated layer without inhomogeneity in metallographic and electrochemical meanings can improve the corrosion resistance on magnesium alloys.