空间用超轻LA141镁锂合金表面腐蚀产物及腐蚀机理研究  

Research on Surface Corrosion Products and Corrosion Mechanism of Ultralight LA141 Magnesium-Lithium Alloy for Space Use

作　　者：孙理理[1] 王在铎 刘凤娟 宋轶军[1] 王萌 雷辉[1] 姜舟 李俊峰[1] 贺晨[1] 孟凡辉 曾一兵[1] SUN Li-li;WANG Zai-duo;LIU Feng-juan;SONG Yi-jun;WANG Meng;LEI Hui;JIANG Zhou;LI Jun-feng;HE Chen;MENG Fan-hui;ZENG Yi-bing(Aerospace Research Institute of Materials&Processing Technology,Beijing 100076,China;The First Military Representative Office of the Naval Equipment Department in Beijing Area,Beijing 100076,China)

机构地区：[1]航天材料及工艺研究所,北京100076 [2]海装驻北京地区第一军事代表室,北京100076

出　　处：《表面技术》2020年第12期44-49,共6页Surface Technology

基　　金：中央军委装备发展部预先研究项目(41423050307)。

摘　　要：目的明确空间用超轻LA141镁锂合金的腐蚀机理,为进一步设计防护涂层体系提供理论依据。方法将未腐蚀和已在空气中放置一段时间表面形成灰黑色腐蚀膜的超轻LA141镁锂合金的一部分放置于水溶液中,一部分暴露在空气中,研究其随时间延长的腐蚀产物生成规律,并用SEM、偏光显微镜对其腐蚀产物的微观形貌进行观察,用EDS能谱分析、XRD、红外光谱手段对其成分进行鉴定。结果超轻LA141镁锂合金放置于水溶液后,有细密的气泡(H2)逸出,并在表面迅速生成一层灰黑色腐蚀膜层。已生成腐蚀膜层的镁锂合金放入水中后,没有明显气泡逸出的现象,且腐蚀膜层厚度增加速度低于未生成腐蚀膜层的镁锂合金。通过在SEM、偏光显微镜下对腐蚀产物进行观察,并结合EDS、XRD和红外的分析结果,发现LA141镁锂合金放入水中后,锂金属优先腐蚀,生成大量氢气,同时也伴随着镁金属的腐蚀,生成氢氧化锂和氢氧化镁,氢氧化锂在空气中不稳定,接触空气后生成碳酸锂。结论腐蚀产物主要为氢氧化镁及碳酸锂。另外,腐蚀膜层能在一定程度上减缓底部镁锂合金的进一步腐蚀。该研究结果对设计选用抑制镁锂合金腐蚀的材料具有一定的参考价值。The purpose of this research is to clarify the corrosion mechanism of the ultralight LA141 magnesium-lithium alloy for space use,and to provide a theoretical basis for the further design of the protective coating system.Put one part of the ultralight LA141 magnesium-lithium alloy that had not been corroded and had been left in the air for a period of time with a gray-black corrosion film formed on the surface into the water,and the other part was exposed to the air,then studied its formation law of corrosion products over time,and used scanning electron microscope(SEM),polarizing microscope to observe the microscopic morphology of the corrosion products,and used energy dispersive spectroscopy(EDS),X-ray diffraction(XRD),infrared spectroscopy to identify its composition.After the ultralight LA141 magnesium-lithium alloys were placed in water,fine bubbles of H2 escaped,and a gray-black corrosion film quickly formed on the surface.After the magnesium-lithium alloy with a corrosion film layer was placed in water,there was no obvious bubbles escape phenomenon,and the thickness of the corrosion film layer increased at a slower rate than the magnesium-lithium alloy without a corrosion film layer.The corrosion products were observed under SEM and polarizing microscope,and combined with the analysis results of EDS,XRD and infrared.The corrosion products are mainly magnesium hydroxide and lithium carbonate.Therefore,come to the following conclusions,when the LA141 magnesium-lithium alloy is placed in water,lithium metal is corroded preferentially and a large amount of hydrogen is generated.At the same time,along with the corrosion of magnesium metal,lithium hydroxide and magnesium hydroxide are generated.Lithium hydroxide is unstable in the air and will generate lithium carbonate when exposed to air.The final detected surface corrosion products are mainly lithium carbonate and magnesium hydroxide.In addition,the corrosion film can slow down the further corrosion of the magnesium-lithium alloy at the bottom to a certain ext

关 键 词：空间用超轻镁锂合金 腐蚀规律 腐蚀产物 腐蚀机理 腐蚀抑制 

分 类 号：TG172[金属学及工艺—金属表面处理]