Magnesium Silicate Hydroxide–MoS2–Sb2O3 Coating Nanomaterials for High-Temperature Superlubricity

Expanding the low-friction temperature range of molybdenum disulfide-based coatings has been a topic of intense research interest. This paper introduces a coating concept, enabling achieving macroscale superlubricity, or near-zero friction, when exposed to open-air and high-temperature sliding conditions. This low-friction composite coating with a thickness of approximately 150–250 nm was accomplished by uniformly burnishing hydrothermally synthesized lamellate magnesium silicate hydroxide with an average diameter of 50 nm and an average thickness of 10 nm, molybdenum disulfide, and antimony trioxide powders onto a copper substrate. The tribological experiments performed in an open-air environment revealed that with the increase of testing temperature up to 200 °C or above (up to 300 or 400 °C), the coefficient of friction of the composite coating rapidly decreases and finally reaches the superlubricity state (the coefficient of friction is lower than 0.01). This intriguing superlubricity performance is attributed to the synergistic characteristics of lubricating antimony trioxide, molybdenum disulfide, and magnesium silicate hydroxide phases, enabling easy shearing of the film at high-temperature conditions. The results offer an approach for designing a solid lubricant solution for tribological applications.