Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
7886984 | Ceramics International | 2018 | 10 Pages |
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 - sin2Ï 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.
Related Topics
Physical Sciences and Engineering
Materials Science
Ceramics and Composites
Authors
Mohammad Sharear Kabir, Paul Munroe, Zhifeng Zhou, Zonghan Xie,