氧化铒阻氚涂层的金属有机分解法制备研究

Preparation of Erbium Oxide Tritium Barrier Coating through Metal Organic Decomposition

采用低沸点酯类和铒的羧酸盐制备前驱体溶液(MOD前驱体),用金属有机分解法在RAFM钢基体表面上制备氧化铒阻氚涂层,并对前驱体溶液的成膜过程进行了同步热分析(TG-DSC)。通过SEM、EDS、XRD对涂层显微结构进行分析。结果表明,MOD前驱体分解生成涂层过程,主要包括溶剂蒸发、大分子物质的挥发与反应及金属有机物的分解。并且蒸发与分解阶段,分别伴随有水解和结晶过程。铒盐质量分数对涂层的微观结构影响较大。当铒质量分数为2.3 wt.%时,可以完全覆盖在基体表面,形成完整致密的涂层,获得较高的阻氚因子。当热处理温度过高时,涂层易产生裂纹。热处理温度为600℃时最佳。制备的Er_(2)O_(3)涂层有较好的耐电化学腐蚀性能和致密性,以及良好的膜基结合力。采用超高阻微电流测试仪测量Er_(2)O_(3)涂层的常温电阻率为3.4×10^(9)Ω·cm,满足聚变堆初步设计的要求。

Er_(2)O_(3)tritium barrier coating was deposited on RAFM steel substrate by using metal-organic decomposition(MOD)method,where the precursor solution was prepared by using low boiling point esters and erbium carboxylates.TG-DSC synchronous thennal analysis was used to analyze the precursor solution,in order to identify film fbmiation temperature.Microstructure of the coating was analyzed by using SEM,EDS and XRD.The decomposition process of the MOD preexirsor includes solvent evaporation,volatilization and reaction of macromolecular substances and decomposition of metal organic matters.The evaporation and decomposition stage was accompanied by hydrolysis and crystallization process.Mass fraction of the erbium salt has a strong influence on microstructure of the coatings.When the mass fraction of erbium is 2.3 wt.%,the substrate can be entirely covered,forming dense coating with desired tritium resistance factor.When the heat treatment temperature is too high,the coating tends to crack.The optimal heat treatment temperature is 600℃.The Er_(2)O_(3)coating prepared in this work has promising electrochemical corrosion resistance,compactness and strong film-substrate adhesion.The Er_(2)O_(3)coating has room temperature resistivity of 3.4×10^(9)Ω·cm,which meets the requirements of the preliminary design of the fusion reactor.