Mechanism and regularities of oxidation in Nb-Ti and Nb-Ti-Si systems

We study the processes of high temperature oxidation in Nb-Ti, Nb-Ti-Si, and Nb-Ti-Si-Mo systems and propose a mechanism of oxidation of VN-10 niobium alloy highly alloyed with titanium (up to 50%), a Ti-Nb-Ti composite multilayer material, and unalloyed niobium and VN-10 alloy subjected to diffusion saturation of their surface with silicon and molybdenum. It is shown that high alloying and (to a lesser extent) Ti-cladding of Nb allow one to suppress the process of catastrophic high temperature oxidation of it and increase significantly the heat resistance of the material. Additional formation of diffusion silicide and molybdenum-silicide layers on the surface of Nb alloys increases their heat resistance by more than a factor of ten.