不同湿度下LiH的表面反应

Surface Reactions of LiH at Different Humidity

采用激光拉曼光谱、原子力显微镜(AFM)等技术在线研究LiH在空气和不同湿度氩气中的反应过程。实验观测到,LiH与H2O、CO2迅速反应生成LiOH、LiOH.H2O、Li2CO3等产物,并得到不同反应时间各产物深度分布和拉曼信号强度变化规律。用AFM测试了LiH反应中不同时间的表面生长速率。产物层在生长过程中有应力释放并产生裂纹,使H2O能够长期穿过产物层与LiH基体反应。LiH与水的反应受湿度影响很大,即使在纯度为99.995%的氩气中,仍可检测到LiOH产物。在相同条件下,LiH表面不同点位的反应速率不尽相同。

The reaction of LiH with vapor in atmosphere and Ar was in-situ investigated by laser Raman spectroscopy and atomic force microscope （AFM）, etc. Experiments show that a product layer composed of LiOH, LiOH ·H20 and Li2 CO3 forms as a result of the immediate reactions of LiH with H2O and CO2. The reaction velocity differs at distinct locations. In detail, the product distribution in depth and the variation rules of Raman intensity were discussed. Growth rates of surface products at different time were measured by AFM. Owing to stress release, microcracks appear in growing process, redounding to continuous penetration of H2O through the product layer into LiH bulk for further reactions. The reaction of LiH with H2O was considerably dependent on humidity that even in Ar with purity up to 99. 995 %, LiOH was still identified.