High Temperature Oxidation Performance Of Metal Connectors For Solid Oxide Fuel Cells

Solid oxide fuel cell is a kind of efficient clean energy power generation device.with the country put forward the strategic goal of "carbon peak,carbon neutral" and vigorously promote the development of hydrogen energy industry.solid oxide fuel cell technology has been rapidly developed.The connector is a key component of solid oxide fuel cell reactor,which can series single cells,separate two reaction gases and construct flow channels.It has an important effect on the performance and lifetime of the SOFC stack.Metal materials have become the mainstream choice of connector materials because of their high mechanical strength,good electrical and thermal conductivity.low cost and easy processing.However,the harsh working environment of solid oxide fuel cells puts forward higher requirements for metal connector materials.In this paper,a series of high temperature oxidation experiments of ferritic stainless steel SUS430 and Crofer22H were carried out in the cathode atmosphere of solid oxide fuel cells at 700℃ and 800℃ for 200～1000h.In addition,the high temperature oxidation experiment of Mn-Co coating prepared on the surface of SUS430 material was carried out.By means of SEM,XRD and EDS,the microstructure of oxide layer on the surface and cross section of substrate and coating materials was observed,the phase composition and element distribution of oxide lay er were detected,and the oxidation mechanism of materials was analyzed.Through experimental research,detection and analysis,the high-temperature oxidation mechanism of substrate and coating materials was explored,and the application properties of materials were compared.which provided certain reference significance for the selection and improvement of materials.Among them,the main component of the oxide layer of SUS430 material at low temperature is Cr2O3,which has poor electrical conductivity;(Mn,Cr)3O4 spinel is formed on the surface of Crofer22H,and Laves phase is precipitated along the grain boundary in the same time.which improves the high temperature service performance of the material.The coating material has strong oxidation resistance and can inhibit the outward diffusion of Cr element.By comparison and selection,SUS430 and Crofer22H materials have different suitable operating temperature ranges,and the oxidation resistance of coating materials is better than that of base materials.