Microstructure and mechanical properties of the (Al1/6Cr1/6Nb1/6Ta1/6Ti1/3)O2 high-entropy ceramic coating prepared by laser cladding

Abstract

The (Al1/6Cr1/6Nb1/6Ta1/6Ti1/3)O2 high-entropy ceramic coating was fabricated by laser cladding in this study. For the continue and dense coating structure, there were pre-treatments including the squash presetting of feedstock powders and the deposition of Al2O3-TiO2 coating on steel substrate by atmospheric plasma spray. The XRD technology was conducted for investigating the phase transitions during the fabrication of (Al1/6Cr1/6Nb1/6Ta1/6Ti1/3)O2 coating. The SEM, EDS technologies and nano-indenter were operated for evaluating the microstructure, composition and mechanical properties of the (Al1/6Cr1/6Nb1/6Ta1/6Ti1/3)O2 coating. The results showed that the feedstocks with various structures were successfully transformed into the (Al1/6Cr1/6Nb1/6Ta1/6Ti1/3)O2 high-entropy ceramic with rutile structure as well as the formation of intermediate products in similar structures. The (Al1/6Cr1/6Nb1/6Ta1/6Ti1/3)O2 coating had a tight combination with the Al2O3-TiO2 coating and showed a thick and compact structure, which included various dendritic crystal structures composed of segregated Al2O3. The (Al1/6Cr1/6Nb1/6Ta1/6Ti1/3)O2 coating exhibited a high level of hardness (13.58 ± 2.05GPa) and elastic modulus (275.24 ± 32.26GPa).