High Temperature Performance Of Steel With Ce-doped MnCu Alloy Layer

Solid oxide fuel cell(SOFC)is a type of fuel cell that is an all-solid-state structure.It can efficiently and cleanly convert the chemical energy in the fuel to electrical energy(up to 44%to 60%conversion efficiency).Among them,the connector is an important component of the solid oxide fuel cell,and it has the function of connecting the single cells in series and separating the fuel gas.Ferritic stainless steel is currently the most commonly used connector,it has the advantages of high temperature oxidation resistance and low cost,matching the thermal expansion coefficient of other components.However,ferritic stainless steel also has two major problems in working in SOFC:One is that ferritic stainless steel produces Cr at high temperatures,and Cr volatilizes the cathode Cr.Second,the ferrite stainless steel surface will produce a poor conductivity of the oxide film,resulting in degradation of battery performance.An effective way to solve this problem is to apply a protective layer on the surface of ferritic stainless steel.The(Mn,Cu)3O4 spinel has excellent electrical conductivity.The doped Ce element is expected to further improve its high temperature oxidation resistance and electrical conductivity,and become a new coating material for stainless steel connectors.In this work,Ce-doped Mn-Cu alloy coatings with different thicknesses were sputter deposited on SUS 430 stainless steel by DC magnetron sputtering.The oxidation behavior of the sputtered coating in the SOFC cathode environment(800?air)was studied.XRD and SEM were used to characterize the morphology and elemental distribution of samples in different oxidation stages,and the electrical properties of the surface oxide films were tested.The result is as follows:(1)The high-temperature oxidation kinetics of Ce-doped Mn-Cu coated stainless steel samples with different thickness were similar in the initial stage of oxidation.(2)High-temperature oxidation,The oxide film is composed of a double oxide with an outer layer of(Mn,Cu)3O4 spinel and an inner layer of Cr-rich oxide.(3)The thermal conversion layer of Ce doped Mn-Cu coating by sputtering has good electrical conductivity.