Development of Si-modified CrAlSiN nanocomposite coating for anti-wear application in extreme environment

(Cr0.5Al0.5)(1 - x)SixN coatings with Si contents from 0 at.% to 11.5 at.% were deposited on Inconel 718 substrates by RF magnetron co-sputtering. In the ball-on-disc wear tests, the increased friction coefficient of (Cr0.5Al0.5)(1 - x)SixN coatings with increasing Si content at high temperature was revealed, owing to the occurrence of tribochemical reaction which is verified through XPS analysis. The hardness (H) and the reduced elastic modulus (E*) of (Cr0.5Al0.5)(1 - x)SixN coatings were acquired by a nanoindentation. The calculated yield pressure of (Cr0.5Al0.5)(1 - x)SixN coatings was proportional to the wear resistance of coatings at ultra-high temperature(500 degrees C, 850 degrees C and 950 degrees C). (Cr0.5Al0.5)(1 - x)SixN coating with maximum yield pressure as high as 8336 nm(2) by adding 9.0 at.% Si exhibited superior resistance to plastic deformation and wear. Moreover, the formation of protective third-layer on the surface resulted in the extremely low wear rate at 850 degrees C and 950 degrees C. On the basis of these improved tribological behaviors, the superior durability of (Cr0.5Al0.5)(1 - x)SixN coating is thus demonstrated. (C) 2015 Elsevier B.V. All rights reserved.