Abstract

Degradation of temperature-control coatings (TCC) of “solar reflector” type caused by deposition of Au thin films was studied. “Mirror” OSO-S type coating and film PM-OA type coating were investigated. Au films with thickness of 1–24 nm were deposited on the samples by means of cathode sputtering of a pure Au target with the use of 300 eV Xe ions. A quartz microbalance was used for controlling the mass of the film deposited. The process was stopped when the frequency variation of the quartz resonator became equal to the given value. The film thickness was determined according to frequency variation of the quartz resonator. During the experiments, the thermo-optical properties (solar radiation absorptance A_S and emissivity ε) of TCC were measured at various film thicknesses. AFM investigations of the surface of samples were carried out too. As a result, the dependences of the values of A_S and ε on the film thickness d are ascertained. It is found that a significant variation of the A_S/ε ratio is established under film thickness less than 3.5 nm. Such films are characterized by granular structure and low conductivity. In this case, when ε variation is insufficient, changes in A_S value cause the main contribution to degradation of TCC properties. The permissible levels of contamination for OSO-S and PM-OA coatings are 1.2 × 10^–6 and 6.7 × 10^–6 g/cm² respectively. After deposition of a thick Au film, TCC properties are changed catastrophically: emissivity ε decreases to 0.2–0.3, absorptance increases by 2–3 times, and the A_S/ε ratio can increase by 5–10 times.

中文翻译：

---

金薄膜沉积过程中航天器温度控制涂层的降解

摘要

研究了由于金薄膜的沉积而导致的“太阳能反射器”型温控涂层的降解。研究了“镜面” OSO-S型涂料和薄膜PM-OA型涂料。通过使用300 eV Xe离子对纯Au靶进行阴极溅射，将厚度为1–24 nm的Au膜沉积在样品上。石英微量天平用于控制沉积膜的质量。当石英谐振器的频率变化等于给定值时，该过程停止。膜厚根据石英谐振器的频率变化来确定。在实验过程中，热光特性（太阳辐射吸收率A _S在各种膜厚度下测量TCC的发射率和ε）。还对样品表面进行了原子力显微镜研究。结果，确定了A _S和ε的值对膜厚度d的依赖性。发现在小于3.5nm的膜厚度下建立了A _S /ε比的显着变化。这种膜的特征在于颗粒结构和低电导率。在这种情况下，当ε变化不足时，A _S值的变化对TCC特性的降低起主要作用。OSO-S和PM-OA涂层的允许污染水平为1.2×10 ^–6和6.7×10 ^–6 g / cm^2个。沉积厚的Au膜后，TCC特性发生巨大变化：发射率ε降低至0.2-0.3，吸收率提高2-3倍，而A _S /ε比可以提高5-10倍。