Long-term Annealing of NiCrAlY LENS Coating on 316L Steel

Abstract

This article presents the results of a research on the behavior of NiCrAlY coating obtained by the LENS method on austenitic stainless steel type 316L under long-term annealing conditions at 1000°C for 25, 100 and 250 hours. The morphology of the NiCrAlY layer as a function of annealing time and temperature was characterized. The chemical composition and distribution of alloying elements were evaluated using scanning microscopy and micro-area chemical composition analysis. It was revealed that NiCrAlY coatings deposited by LENS method are characterized by good metallurgical quality. The long-term annealing of the NiCrAlY coating led to microstructural changes in the form of the disappearance of the original dendritic structure and the formation of a solid solution of nickel with chromium and a small amount of aluminum, as well as chromium α-Cr precipitates and Ni-Y-type phases. The effect of increasing iron concentration in the coating due to diffusion-to-core processes was also found