Title

Scratch response and tribological behaviour of CrAlNiN coatings deposited by closed field unbalanced magnetron sputtering system

Document Type

Journal Article

Publisher

Elsevier B.V.

School

School of Engineering

Comments

Originally published as: Sha, C., Zhou, Z., Xie, Z., & Munroe, P. (2019). Scratch response and tribological behaviour of CrAlNiN coatings deposited by closed field unbalanced magnetron sputtering system. Surface and Coatings Technology, 367, 30-40. Original article available here

Abstract

CrAlNiN coatings were deposited on M2 tool steels using closed-field unbalanced magnetron sputtering. The coating microstructure transformed from coarse columnar grains to fine equiaxed grains with increasing Ni content, which was accompanied by a general decrease in both hardness (H) and elastic modulus (E r ) values. The scratch tests showed both scratch toughness and adhesion strength were improved for coatings with higher ratios of H/E r and H 3 /E r 2 , whereby higher critical loads (L C1 and L C2 ) are required to initiate cohesive and adhesive failure. For the coatings with coarser columnar grains, the improved scratch toughness may be ascribed to tortuous crack deflection patterns. Improved wear resistance was found in the columnar grained coatings, which also exhibited the higher H/E r and H 3 /E r 2 values. The inferior wear resistance in the equiaxed grained coatings was suggested to arise from these coatings being more susceptible to grain pull-out processes during abrasive sliding. The wear debris composed of tribo-oxides serving as additional capacity for load bearing via re-distribution of the applied stress. This was believed to boost the wear resistance of the coatings. © 2019 Elsevier B.V.

DOI

10.1016/j.surfcoat.2019.03.053

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