Oxidation behavior of ferritic stainless steel interconnect coated by a simple diffusion bonded cobalt protective layer for solid oxide fuel cells

摘要

A protective cobalt coating is fabricated on AISI 441 ferritic stainless steel interconnect by diffusion bonding method for solid oxide fuel cells. Oxidation behavior of coated and bare steels are studied. Microstructure evolution of steels during oxidation is analyzed by XRD, SEM and TEM with EDS. After 800 degrees C/1000 h oxidation, three layers are observed on the coated steel surface: a Co3O4 top layer, a (Co,Fe)(3)O-4 middle layer and a Cr2O3 inner layer. The thickness of Cr2O3 of the coated steel is 2.7 mu m, while that of bare steel is 10.3 mu m. The out-migration of Cr is effectively suppressed.