High temperature oxidation of Ni-Fe-Cr-Al porous metal

This study investigated the high temperature oxidation of Ni-Fe-Cr-Al porous metal. Two types of open porous metals with pore sizes of 30 and 40 PPI were used. For 24-h, the isothermal oxidation TGA tests were conducted at three different temperatures of 900, 1000, and 1100 °C. The oxidation resistance of porous metal decreased with decreasing pore size. Porous metals mainly created oxides such as Al₂O₃, Cr₂O₃, NiAl₂O₄, and NiCr₂O₄. The porous metal represented increasingly faster dwindling of Al and Cr content and easy progress to internal oxidation, comparing to the oxidation of bulk metal. It is apparent that the oxidation resistance of porous metal decreases with decreasing pore size (increasing surface area). It should be also noted here that the weight gain in the porous metals (regardless of the pore size) are significantly large compared with that of the bulk metal (0.19 mg cm^-2 at 1100°C oxidation temperature for 24 h).