Structural transformations occurring in flame-sprayed Ni60Nb40 alloy coatings during heating in the presence of oxygen

Conclusions During the heating of flame-sprayed Ni₆₀Nb₄₀ alloy coatings in the presence of oxygen the process of crystallization of their amorphous matrix occurs at T > 750°K through the formation of the niobium oxide Nb₂U₅ and precipitation of nickel. Decomposition of the amorphous matrix is accompanied by a decrease in length of the coatings. The oxidation of niobium at 750–890°K prevents the formation of the equilibrium phases of the Ni-Nb system during the crystallization of the amorphous structure. During heating in the 890–1110°K range the metastable Ni₈Nb phase is present in the coatings.Translated from Poroshkovaya Metallurgiya, No. 12(300), pp. 21–26, December, 1987.