Surface characteristics and high temperature oxidation resistance performance of stainless steel foam modified by pack aluminizing and moderate oxidation

摘要

The composition, phase structures and morphology of surface coating of stainless steel foam modified by pack-aluminizing and moderate oxidation were characterized by EDX, XRD and SEM, the effects of pack aluminizing and moderate oxidation on the oxidation resistance performance of stainless steel foam at 800 °C were also investigated. The main inter-metallic phases present in aluminizing coating on the surface of aluminized stainless steel foam are NiAl and Ni_3Al, and the aluminizing coating is well-integrated with the foam substrate. The aluminized and oxidized foam displays excellent high temperature oxidation resistance performance, which may be due to the fact that the compact and uniform Al_2O_3 film formed on the outer layer of aluminizing coating obstructs the diffuse of oxidizing gas into matrix metal. Additionally, the surface layer reveals good property of thermal shock resistance, the treatment of pack aluminizing and moderate oxidation has little effect on the bending strength of foam.