偏二甲肼在氟化镁涂层表面的吸附与反应

Absorption and Reactions of 1,1-dimethyl-hydrazine onthe Surface of Magnesium Fluoride Coating

研究了偏二甲肼在氟化镁涂层表面的吸附和化学反应情况.首先用液相或气相偏二甲肼沾染氟化镁涂层表面,再将涂层置于真空环境足够长时间,然后通过对比沾染前、后涂层表面的红外吸收光谱、X射线光电子能谱和漫反射率,了解涂层表面的吸附状况和性能变化.实验表明,覆盖于氟化镁涂层表面的偏二甲肼液膜分子,在真空环境下充分脱附的时间约为2h,充分脱附后的涂层表面只有单层化学吸附存在,其质量密度约为27ng/cm2,实验后氟化镁涂层表面的漫反射率下降了10%～15%;在-10℃的偏二甲肼饱和蒸气中沾染10min后,氟化镁涂层表面的原子组成和漫反射率变化很小,红外吸收光谱也没有偏二甲肼特征峰出现.

The absorption and chemical reactions of 1, 1-dimethyl-hydrazine (C2H8N2) on the surface of magnesium fluoride( MgF2 ) coating was studied. The coating surface is firstly contaminated by liquid or gaseous C2H8N2, and then it is placed into a vacuum environment for a long period. Contrasting the infrared absorption spectra, X-ray photoelectron energy spectra and diffusive reflectivity of MgF2 coating surfaces before and after experiment, it may be learned that the absorption and chemical reactions occur at the surface. The experimental results show that the molecules of a liquid film of C2H8N2 over MgF2 coating surface take about two hours to desorb adequately in a vacuum environment, after the adequate desorption, there only exists a single chemical absorption layer over the coating surface, with a mass density of about 27 ng/cm(2). The diffusive reflectivity of MgF2 coating surface decreases about 10% - 15% after the contamination of liquid C2H2N2. For MgF2 coating surfaces immersed in C2H8N2 vapor at the pressure of 3 kPa for ten minutes, there are neither changes in their atomic constitution and diffusive reflectivity, nor characteristic peaks of C2H8N2 appear in their infrared absorption spectrum.