Effect of Surface Preparation on the Isothermal Oxidation of Fe-33Ni-19Cr Alloy

Abstract

The effect of surface preparation on the isothermal oxidation behavior of Fe-33Ni-19Cr alloy was study in this paper. The surface preparation of the test samples was obtained by grinding process using different grit of silicon carbide abrasive paper, namely P600, P800 and P1000. The surface area and weight of the sample were measured before the oxidation test, by using Vernier caliper and analytical balance. The ground sample of Fe-33Ni-19Cr alloys were isothermally oxidized at 1000℃ for 150 hours in laboratory air. The weight of oxidized samples was recorded after the isothermal oxidation test at every 25 hours exposure duration in order to determine the oxidation kinetic of all samples. The oxide surface morphology of Fe-33Ni-19Cr alloy was characterized by scanning electron microscope. The oxidation kinetic of all samples displayed a weight gain pattern as the exposure duration increase, followed a parabolic rate law. While the result of surface morphology shows that the lowest grit of surface finish, P600, display less oxide exfoliation occurred.

Isothermal Oxidation Behaviour of 800H Nickel-Based Alloy

“…The heat treated samples were ground until P600 grit surface finishes. This process is to initiate a rut mark on the alloy surface that acts as a nucleation site for initial oxide formation [5][6]. The surface area of each sample was measured preceding the test.…”

“…When sufficient oxide thickness achieved, the oxidation rate starts to reduces due to the establishment of optimal oxide scale. The study on the oxidation rate can be seen through different experiment approach such as assorted alloy structure, surface modification and also a thermal treatment [5][6][7][8]. The refine grain structure has been notable to established excellent oxidation protection by lowering the oxidation rate and formation of uniform and adherence oxide layer [7][8].…”