High-Temperature Oxidation of Nickel-Based Alloys and Estimation of the Adhesion Strength of Resulting Oxide Layers

摘要

The kinetics of isothermal oxidation (1100°C) of commercial nickel-based alloys with different content of sulfur (0.22-3.2 wt ppm) is studied. The adhesion strength in a metal/oxide system is estimated as a function of sulfur content and duration of high-temperature exposure. The scratch-test technique is proposed to quantitatively estimate the work of adhesion of resulting oxide films. It is found that the film microi-structure is composed of an inner α-Al_2O_3 layer and an outer NiAl_2O_ spinel layer, which are separated by discrete inclusions of TiO_2. Residual stresses in the oxide film are experimentally determined by X-ray dif-fraction.