室温熔盐镀铝—氧化法制备铝化物阻氘层技术研究

发布时间：2018-06-10 14:21

  本文选题：铝化物 + 室温熔盐电镀　； 参考：《中国工程物理研究院》2010年硕士论文

【摘要】： 氚对包容自身的金属结构材料仍具有高的渗透能力。氚的渗出可产生氚量的损失以及环境的放射性危害。在氚包容材料表面制备能够抑制氚渗出的涂层(阻氚层)是减少氚向环境逃逸的有效措施之一,也是解决ITER(国际热核聚变实验堆)涉氚系统中高温组件氚渗透问题的关键技术。FeAl/Al2O3铝化物阻氚层是公认具有优良阻氚性能与自修复功能的涂层。然而,目前的涂层制备方法还未能满足实用化要求。为此,提出一种新的制备方法：采用室温熔盐电镀铝方法先在不锈钢表面制备一定厚度的铝镀层,其后通过热处理得到富铝的Fe-Al涂层,最后经过氧化在Fe-Al层表面形成Al2O3膜,并在21-6-9、1Cr18Ni9Ti不锈钢表面开展了涂层的制备工艺、结构和性能研究,取得了较好的结果。 1.采用AlCl3-EMIC(氯化1-甲基3-乙基咪唑)室温熔盐体系在21-6-9钢上获得结合牢固的纯铝电镀层。镀层表面光滑、色泽均匀、结构致密,由数微米大小、均匀分布的等轴状晶粒生长而成。镀前处理、电流密度、电镀温度和电镀时间的影响程度依次降低：电化学清洗前处理能显著提高镀层结合强度；镀层颗粒尺寸随电流密度、沉积温度和电镀时间增加而增大,但电流密度的影响最为显著；镀层总厚度随电镀时间增加呈近似的线性增长关系。确定了较优的室温熔盐电镀铝工艺,并在1Cr18Ni9Ti不锈钢实物上取得满意的镀覆效果。 2.大气中、650-750℃下通过1-30h的热处理,在21-6-9不锈钢表面形成成分渐变、冶金结合的Fe-Al涂层。涂层厚度3-30μm,结构致密,双层或三层结构,成分由表面向基体中心逐渐从Al基化合物转变为Fe基化合物。涂层厚度除与热处理温度、热处理时间和预镀Al层厚度相关外,还受冷却速率的影响。大体上,Fe-Al涂层厚度(hFe-Al)与温度(T)、时间(t)和Al镀层厚度(hAl)间的关系为：hFe-Al=2.39×106t1/2h1/2Al exp[-116900/(RT)]。涂层形成过程受原子扩散控制,分为1)初始Fe-Al合金形成,2)Fe-Al涂层生长和3)Fe-Al涂层扩散退火三个阶段。 3.根据合金选择性氧化原理,采用700℃、低氧分压(Ar、10-2O2)氧化工艺,在21-6-9、1Cr18Ni9Ti不锈钢Fe-Al涂层表面制得结合牢固、致密的、100-300nm的Al203膜。最终所制涂层由微米级厚的FeAl/Fe3Al扩散层及纳米级的γ-Al2O3外层组成,层间及界面均无空洞。较优的氧化工艺为Fe-Al涂层700-750℃、10-2O2、Ar中氧化100-200h。 4.在1Cr18Ni8Ti不锈钢结构容器表面制备的FeAl/Al2O3铝化物阻氚层外表美观、结构致密、与基体结合良好；600-727℃涂层使容器的氘渗透率降低2-3个数量级,涂层抗750℃-室温冷热循环10余次。
[Abstract]:Tritium still has high permeability to metal structure materials containing its own. The leakage of tritium can lead to the loss of tritium and the radioactive hazard to the environment. It is one of the effective measures to reduce tritium escape to the environment by preparing a coating (tritium layer) on the surface of tritium containment material that can inhibit tritium exudation. It is also a key technology to solve the tritium permeation problem of high temperature modules in ITER (International Thermonuclear Experimental reactor). Feal / Al _ 2O _ 3 barrier tritium layer is recognized to have excellent tritium resistance performance and self-repair function. However, the current coating preparation methods have not been able to meet the practical requirements. In this paper, a new preparation method is proposed: aluminum coating with a certain thickness is prepared on stainless steel surface by room temperature molten salt electroplating method, then Fe-Al coating with rich aluminum is obtained by heat treatment, and Al _ 2O _ 3 film is formed on Fe-Al layer after oxidation. The preparation process, structure and properties of the coating on the surface of 21-6-9Si 1Cr18Ni9Ti stainless steel have been studied, and good results have been obtained. 1. AlCl3-EMIC (1-methyl-3-ethylimidazolium chloride) room temperature molten salt system was used to obtain solid bonded pure aluminum plating layer on 21-6-9 steel. The surface of the coating is smooth, the color is uniform and the structure is compact, which is formed by the growth of equiaxed grains of several micron size and uniform distribution. The effect of pretreatment, current density, electroplating temperature and electroplating time decreased in turn: the bonding strength of the coating was significantly increased by electrochemical cleaning treatment, and the particle size of the coating increased with the increase of current density, deposition temperature and electroplating time. However, the effect of current density is the most significant, and the total thickness of coating increases linearly with the increase of plating time. The optimum aluminum electroplating process with molten salt at room temperature was determined, and a satisfactory coating effect was obtained on 1Cr18Ni9Ti stainless steel. Fe-Al coating was formed on the surface of 21-6-9 stainless steel by heat treatment at 650-750 鈩，

本文编号：2003521