Estabilidade térmica de revestimentos de Inconel 625 reforçados com precipitados de alumineto de níquel

Abstract

Coatings are used to improve the chemical, mechanical, and even aesthetic properties of various types of materials. In metals, Nickel superalloys are highlighted for use in coatings due to their ability to work at high temperatures while maintaining mechanical properties and possessing excellent resistance to oxidation, but there are some difficulties in their processing. These difficulties can be overcome by using the process of additive manufacturing by Plasma Transferred Arc. This paper discusses how the addition of multiple layers of Ni-Al precipitates in a coating made with Inconel 625 significantly improves the hardness and oxidation resistance without compromising the weldability of the alloy, increasing its potential to operate at even higher temperatures. To this end, three test specimens were fabricated with different gradients of properties, allowing a comparison of which one achieved the best functionality. The results showed an increase in the hardness of the coatings, with the smooth gradient being 243.1% harder compared to the coating performed with Inconel 625 alone. There was also a significant improvement in oxidation resistance in the smooth gradient coating due to the presence of the intermetallic phases of nickel aluminides. With the improvement of the coating properties, demands in the aviation, power generation, petrochemical and steel industries can be better met.