材料期刊网

The oxidation of pure Ni and three Ni-Ti alloys containing 5, 10, and 15 wt.% Ti over the temperature range 650-850degreesC in air was studied to examine the effect of titanium on the oxidation resistance of pure nickel. Ni-5Ti is a single-phase solid solution, while the other two alloys consisted of nickel solid solution (alpha-Ni) and TiNi3. The oxidation of Ni-Ti alloys at 650degreesC follows an approximately parabolic rate law and produces a decrease in the oxidation rate of pure Ni by forming an almost pure TiO2 scale. At higher temperatures, Ni-Ti alloys also follow an approximately parabolic oxidation, and their oxidation rates are close to or faster than those of pure Ni. Duplex scales containing NiO, NiTiO3 and TiO2 formed. Some internal oxides of titanium formed, especially at 850degreesC. In addition, the two-phase structure of Ni-10Ti and Ni-15Ti was transformed into a single-phase structure beneath the scales.