The Kinetic Effects of Different Rare-earth Additives on the Oxidation Resistance of Ni₈₀Cr₂₀ Alloy

The kinetic effects of different rare-earth additives on the oxidation resistance of Ni₈₀Cr₂₀ electrical heating alloy at high temperature are studied through thermogravimetry under the condition that the residual content of rare-earth is fixed. The apparent activation energies and the rate constants of oxidation reaction are calculated in the range of 1 050-1 200℃. The mechanism of oxidation is discussed. The structure, composition, and the adhesion of the oxide films are investigated by X-ray, metallograph etc. The mechanism of the oxidation resistance of Ni₈₀Cr₂₀ alloys with different rare-earth additives is also discussed.