Avaliação microestrutural dos efeitos de grafeno em revestimentos a base de metal duro para aplicações em ativos petrolíferos

Abstract

The addition of graphene in alloys has become an object of interest in the research and development of coatings. This material tends to improve properties such as wear and corrosion resistance of the coatings, resulting in an increase in the lifetime of assets in the oil and gas, automotive, and mining industries, among others. In this study, graphene oxide was synthesized and mixed with tungsten carbide – 12 wt% cobalt powder mixture with four different concentrations of 0, 0.5, 0.75, and 1 wt%. The prepared mixtures were thermally sprayed on 1020 steel plates using HVOF thermal spray technique. Powder mixtures and applied coatings were characterized by XRD, SEM-FEG, Raman, bending test, and Vickers microhardness. The results show that there was no phase change of graphene oxide after the thermal spray process. The coating with 0.5 wt% of graphene obtained higher hardness values than the other compositions, proving that graphene improves the mechanical properties of the coating. However, the compositions with higher graphene contents showed embrittlement and defects in their microstructure.