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在轨运行的卫星容易受到分子污染影响,造成光学、热控等系统敏感表面性能退化,因此必须对分子污染进行控制。分子污染主要来源于材料放气,典型分子污染成分为邻苯二甲酸酯类和硅氧烷类,因此有必要研究其在敏感表面的吸附和脱附规律。本文建立了分子污染物吸附脱附试验系统,由污染物蒸发池、真空低温系统和石英晶体微量天平测量系统组成。建立了试验方法,利用阶梯升温的石英晶体微量天平测量得到平均粘附系数。利用上述试验系统得到了不同温度下典型污染成分邻苯二甲酸二辛酯的粘附系数。对3种工程经验模型进行了比较,找到了与实验数据符合最好的模型。对污染物在表面的脱附进行了测试及分析,提出多层吸附时可以采用蒸发速率公式计算脱附速率。最后对实验系统未来的改进进行了讨论。
Satellites orbiting satellites are susceptible to molecular contamination, causing degradation of sensitive surface properties of systems such as optics and thermal control. Therefore, molecular pollution must be controlled. Molecular contamination mainly comes from the deflation of materials. The typical molecular pollution components are phthalates and siloxanes. Therefore, it is necessary to study the adsorption and desorption laws on sensitive surfaces. This paper established a molecular pollutant adsorption and desorption test system, which consists of a pollutant evaporation cell, a vacuum cryogenic system and a quartz crystal microbalance measurement system. The test method was established, and the average adhesion coefficient was measured by using step-temperature quartz crystal microbalance. The adhesion coefficient of dioctyl phthalate, a typical pollutant at different temperatures, was obtained by the above experimental system. The three engineering experience models were compared to find the best model consistent with the experimental data. The desorption of pollutants on the surface was tested and analyzed. It is suggested that the evaporation rate formula can be used to calculate the desorption rate. Finally, the future improvement of experimental system is discussed.