Al-Cr涂层低温扩散制备及其相组成的研究

来源期刊：金属学报2011年第2期

论文作者：李文川 蔡俊 凌国平

文章页码：231 - 235

关键词：Al-Cr涂层； 离子液体； 镀Al； 热处理

Key words：Al-Cr coating； ionic liquid； Al electrodeposition； heat treatment

摘    要：通过水溶液镀Cr后再用AlCl₃ EMIC(氯化1-甲基3-乙基咪唑)离子液体镀Al,制备Cr/Al复合镀层,其后通过低温扩散热处理制备Al-Cr涂层.用OM,SEM,BSE,EDS和XRD研究了短时间热处理时,热处理温度对Al-Cr涂层组成和结构的影响.结果表明,Cr/Al复合镀层在540℃时即可发生明显的互扩散,形成Al-Cr合金层.通过对复合镀层中Cr和Al镀层厚度的控制,可以得到不同组成的Al-Cr合金涂层.6.5μm Cr/15μm Al的复合镀层经640℃/960 min热处理,表面形成以Al₈Cr₅为主的合金涂层;1.6μm Cr/15μm Al的复合镀层经600℃/30 min热处理,可得到以Al₄Cr为主的Al-Cr涂层.

Abstract: The Al-Cr coating exhibits a good steam oxidation resistance and can act as tritium permeation barrier.It is necessary to prepare Al-Cr coating at low temperatures to avoid detrimental effect on the mechanical properties of the substrate.In the present study,a new process was proposed to prepare Al-Cr coating by electrodeposition of Cr/Al composite coatings firstly,and then heat treatment at low temperatures.The Cr/Al composite coatings were obtained by electrodepositing Cr from aqueous solution followed by electrodepositing Al from AlCl₃-EMIC ionic liquid.Effects of the temperature of heat treatment on the composition and phase of alloy layers were studied by using OM, SEM,BSE,EDS and XRD.The results showed that an Al-Cr alloy layer at the Cr/Al interface was formed even at low temperature of 540℃ by the interdiffuse between Al and Cr coating.The different Al-Cr alloy layers could be formed by controlling the thickness of Cr and Al in Cr/Al composite coatings.For 6.5μm Cr/15μm Al composite coating,the main phase was Al₈Cr₅ for 960 min heat treatment at 640℃,and for 1.6μm Cr/15μm Al composite coatings treated at 600℃ for 30 min,the main phase of alloy layer was Al₄Cr.