Microstructural characteristics and mechanical properties of thermally sprayed conventional ceramic coatings reinforced with multiwalled carbon nanotubes

Abstract

This paper aims to develop a high-performance, cost-effective ceramic coating on AISI 1020 steel substrate. For this purpose, three kinds of conventional ceramic powders are taken in the composition Al2O3+3 wt%TiO2, WC+12 wt%Co and ZrO2+8 wt%Y2O3. The composites are coated on the steel surface using thermal spraying technology such as plasma flame for Al2O3+3 wt%TiO2 and ZrO2+8 wt%Y2O3 and high-velocity oxy-fuel for WC+12 wt%Co deposition. Recently, carbon nanotube–reinforced ceramic materials have gained more attention because of their excellent surface morphology properties. Adding nanocomposite to ceramic powders can considerably increase the microstructural characteristics and microhardness of thermal sprayed coatings. However, it is still challenging to obtain effective nanocomposite-doped conventional coating due to the elevated temperature of heat equipment. Thus, the conventional ceramic powders Al2O3+3 wt%TiO2, WC+12 wt%Co and ZrO2+8 wt%Y2O3 are combined with carbon nanotubes at a weight ratio of 1%, 3% and 5% for preparing reliable nanocomposite ceramic coating. The properties of nanocomposite mixed coatings are studied, and their performance is compared with conventional coatings. The coatings’ morphology, structure and phase composition are investigated through scanning electron microscopy and X-ray diffraction. In addition, Vickers microhardness and surface roughness are also determined.