Low energy proton irradiation tolerance of molybdenum disulfide lubricants

摘要: As the world’s space agencies look to long duration spaceflight beyond low earth orbit, engineering materials in deep space flight will endure galactic cosmic ray irradiation, of which 85% is protons. Characterization of proton irradiation damage near the threshold displacement energy is required to understand the mechanisms behind performance degradation and the fluence dependent effects of a thermalized spectrum on surface sensitive tribological characteristics. Here, tribological degradation of a space-grade molybdenum disulfide lubricant exposed to low energy (500 eV) protons is investigated as a function of fluence. A 21% increased coefficient of friction and 86% increase in wear rate is measured at 10 20 H/m 2, and 170% increased CoF and 465% increased wear rate at 3· 10 23 H/m 2. Associated softening and decreased stiffness is measured by nanoindentation. X-ray photoelectron spectroscopy and …