Study of the structure, properties, scratch resistance and deformation behaviour of graded Cr-CrN-Cr(1-x)AlxN coatings

Abstract

An in-depth investigation of the structure, properties, scratch adhesion characteristics of graded Cr-CrN-Cr(1-x)AlxN coatings synthesized onto M42 steel substrates using closed – field unbalanced magnetron sputtering (CFUBMS) was carried out. Advanced microscopy (scanning and transmission electron microscopy), focused ion beam (FIB) imaging, X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD) and micro–scratch tests was used to investigate the microstructure, mechanical properties and scratch performance as a function of Al content. FIB and TEM investigations revealed that the coatings exhibited a distinct structure; i.e., an adhesive Cr layer, a CrN transition layer and a graded CrAlN top layer with a face centered cubic (FCC) B1 structure. A columnar morphology was exhibited by the coatings and the dimensions of the columnar grains decreased with increasing Al content. Residual stress measurements, obtained from the XRD – sin2ψ method, revealed increasing compressive stresses with increasing Al content. Furthermore, nanoindentation tests showed an increase in mechanical properties, fracture toughness index (H/E) and plastic deformation resistance (H3/E2) as the Al content increased, accompanied by a decrease in the critical load, LC, during scratch testing implying a decrease in scratch toughness.

Document Type

Journal Article

Date of Publication

2018

Publication Title

Ceramics International

Publisher

Ceramics International

School

School of Engineering

RAS ID

27275

Comments

Kabir, M. S., Munroe, P., Zhou, Z., & Xie, Z. (2018). Study of the structure, properties, scratch resistance and deformation behaviour of graded Cr-CrN-Cr (1-x) AlxN coatings. Ceramics International, 44(10), 11364-11373.

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Link to publisher version (DOI)

10.1016/j.ceramint.2018.03.187