Surface Modification on Magnesium Alloys by Magneisum Vapor Deposition.

通过镁气相沉积对镁合金进行表面改性。

• 批准号: 11225210
• 负责人: TSUBAKINO Harushige
• 金额: $ 18.69万
• 依托单位: University of Hyogo
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research on Priority Areas
• 财政年份: 1999
• 资助国家: 日本
• 起止时间: 1999 至 2002
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-11225210/
• 关键词: magnesium alloy; high purity; corrosion resistance; surface treatment; vapor deposition; retort method

Surface modification of magnesium alloys has been attempted in order to improve corrosion resistance in magnesium alloys by coating the surface with high purity magnesium applying vapor deposition technique. Principle of the technique is very simple ; pure magnesium with 3N grade or magnesium alloys are heated at about 973 K in vacuum with about 10^<-3> Pa, magnesium with high vapor pressure can be vaporized under the conditions, while heavy metal impurities such as Fe, Ni and Cu, which have deteriorative effects on corrosion resistance in magnesium alloys, can not be vaporized because of their low vapor pressure, purified magnesium vapor depositis on magnesium alloy substrate set at lower temperature region. Salt immersion tests have revealed that corrosion on the deposition coated specimen is decreased about one tenth of that on the un-coated specimen.In order to clarify the mechanism for improvement in corrosion resistance, in-situ laser microscopic observations were carried out. It … More has been shown that "filiform corrosion" occurred on AZ31 magnesium alloy and pure magnesium with 3N grade, while the filiform corrosion was never observed on high purity magnesium, 6N-Mg, and on the deposition coated specimen. Purification effect intrinsically included in vaporization-deposition process can improve the corrosion resistance in magnesium alloys.Specimens with small sizes, 10×10×6mm, were used in the preliminary experiments. large size specimens, 60×100×6mm, were attempted to be used for practical usage, and conditions for fabricating defect-less coating were optimized. Hot pressing and HIP treatment were also tried in order to improve adhesion strength. between the coated film and substrates. Corrosion resistance was also improved by hot pressing and HIP treatment.On the other hand, analyses of the corrosion products lead to another study for improving corrosion resistance. It has been shown that magnesium hydroxide formed by the corrosion reactions is easily changed into magnesium oxide by heating in air. That is, when the specimen is heated in air at about 673 K after immersion in salt solution with pH value of about 12, surface of the specimen was covered by magnesium oxide which is expected to show superior corrosion resistance. Indeed, time for occurring filiform corrosion on the specimen treated by the "artificial corrosion-oxidation method" is prolonged by a factor of twenty in comparison with that on the un-treated specimen.The deposition coated specimens were provided for the "Solid recycling group" in the same Scientific Research on Priority Areas, and superior property for recycle ability on the deposition coated specimen has been shown. Less

为了提高镁合金的耐蚀性，人们尝试用气相沉积技术在镁合金表面涂覆高纯镁。技术原理很简单；将3N级纯镁或镁合金在约973 K、约10^<-3> Pa的真空条件下加热，在此条件下，具有高蒸气压的镁可以汽化，而对镁合金耐腐蚀性有不良影响的重金属杂质如Fe、Ni、Cu等由于蒸气压低而不能汽化，纯化后的镁气相沉积在镁合金基体上，设置在较低温区。盐浸试验表明，沉积涂层试样的腐蚀程度比未涂层试样降低了约十分之一。为了阐明提高耐蚀性的机理，进行了原位激光显微观察。研究表明，AZ31镁合金和3N级纯镁均发生“丝状腐蚀”，而高纯镁、6N-Mg和沉积包覆试样均未发生丝状腐蚀。汽化沉积过程中固有的净化作用可以提高镁合金的耐蚀性。初步实验采用小尺寸试样10×10×6mm。尝试将大尺寸试样（60×100×6mm）用于实际应用，并优化了制备无缺陷涂层的条件。为了提高粘接强度，还尝试了热压和HIP处理。涂膜与基材之间。热压和HIP处理也提高了材料的耐蚀性。另一方面，对腐蚀产物的分析导致了另一项提高耐蚀性的研究。研究表明，腐蚀反应生成的氢氧化镁在空气中加热后很容易转化为氧化镁。即试样在pH值约为12的盐溶液中浸泡后，在673 K左右的空气中加热，试样表面被氧化镁覆盖，有望表现出优异的耐腐蚀性。的确，经过“人工腐蚀氧化法”处理的试样发生丝状腐蚀的时间比未经处理的试样延长了20倍。将沉积包覆试样提供给同一科学研究重点领域的“固体回收组”，表明沉积包覆试样具有优越的回收能力。少

项目成果

H.Tsubakino: "Coating on rugged surfaces of magnesium alloy with high-purity magnesium film."Materials Week 2001-Proc. Inter. Cong. on Advanced Materials and Processings, Munich, Germany, CD-RO M, Ed, Werkstoffwoch-Partnerschaft GbR. (2001)

H.Tsubakino：“在镁合金的粗糙表面上涂覆高纯度镁膜。”《材料周刊》2001 年出版。

A.Yamamoto, A.Watanabe, K.Sugahara, S.Fukumoto, H.Tsubakino: "In Situ Laser Microscopic Observations of Corrosion Behaviors in Magnesium and Deposition Coated Magnesium Alloys"Mater.Trans.. 42・7. 1243-1248 (2001)

A. Yamamoto、A. Watanabe、K. Sugahara、S. Fukumoto、H. Tsubakino：“镁和沉积涂层镁合金腐蚀行为的原位激光显微观察”Mater. 1243-1248。 2001）

H.Tsubakino, A.Yamamoto, A.Watanabe, K.Sugahara, S.Fukumoto: "Surface Modification of Mgnesium Alloys by Deposition Coating"Proc.4th Pacific Pim Inter.Conf.on Advanced Materials and Processing(PRICM4). 1263-1266 (2001)

H.Tsubakino、A.Yamamoto、A.Watanabe、K.Sugahara、S.Fukumoto：“通过沉积涂层对镁合金进行表面改性”Proc.4th Pacific Pim Inter.Conf.on Advanced Materials and Manufacturing (PRICM4)。

椿野晴繁: "純マグネシウム皮膜による表面処理材-真空蒸着法によるマグネシウムの防食-"金属. 71. 524-529 (2001)

Harushige Tsubakino：“具有纯镁膜的表面处理材料-通过真空蒸发法防止镁的腐蚀-”金属。 71. 524-529 (2001)

A.Yamamoto, H.Tsubakino: "In Situ Laser Microscopic Observations of Filiform Corrosion in Magnesium and AZ31 Magnesium Alloy"Proc.European Cong.on Advanced Materials and Processes. (in press). (2003)

A.Yamamoto、H.Tsubakino：“镁和 AZ31 镁合金中丝状腐蚀的原位激光显微观察”Proc.European Cong.on Advanced Materials and Process。