Reusable chromium oxide coating with lubricating behavior from 25 to 1000 °C due to a self-assembled mesh-like surface structure

The chromium oxide coatings are deposited on Ni-based high-temperature alloy substrates through an arc ion plating system and then annealed at 1000 degrees C in air for 2 h. During annealing process, Ti and Cr atoms in the substrate diffuse to coating surface and lead to the formation of a mesh-like heave structure comprised of Cr2O3 and Cr2Ti7O17 phases. The annealed coating exhibits the excellent self-lubricating behavior with friction coefficients below 03 from 25 to 1000 degrees C. Friction coefficients show no evident change even in five thermal cycles, showing a great potential as self-lubricating coating operated in a wide temperature range. While the mesh-like heave structure is damaged by friction, Ti and Cr atoms diffusion could continuously supplement the heave structure at the damaged locations at high temperature, enduing the mesh-like heave structure with the self-healing ability. (C) 2016 Elsevier B.V. All rights reserved.