Surface Engineering Design of Alumina/Molybdenum Fibrous Monolithic Ceramic to Achieve Continuous Lubrication from Room Temperature to 800 °C

Abstract

Al2O3/Mo fibrous monolithic ceramics are potential candidates for high-temperature applications because of their excellent high-temperature self-lubricated and fracture properties. This study aims at achieving the good self-lubricating ability at a wide temperature variation from room temperature (RT) to 800 °C and avoiding the abrasive wear of the material at the starting moment of the friction test. Three-dimensional composite-lubricating layers were formed by considering texture pattern as storage dimples and burnishing BaSO4 solid lubricant (SL) on the textured surface of Al2O3/Mo fibrous monolithic ceramics. The friction properties and wear mechanisms were studied from RT to 800 °C in a continuous heating process. The results show that the synergy effect of micro-texture, BaSO4 SL and oxidation products derived from Mo containing MoO3 improved the lubricating performances of the material at each temperature stage, thus realizing continuous lubrication in a wide temperature range. It is demonstrated that the friction coefficient of textured surface coated with BaSO4 SL was kept lower 0.57 when subjected to dry sliding against Al2O3 ceramic pin at the temperature from RT to 800 °C, and it even can be as low as 0.30 at 600 and 800 °C. This work is an extension of study that was previously published in Tribology Letters journal.