Ferrite Solid Oxide Fuel Cell Is Connected To The Performance Of The Material

As an efficient and clean power technology of the fourth generation, solid oxide fuel cell (SOFCs) received great attention at home and abroad. The connection board which is one of the four parts of solid fuel cell is mainly used for electron transmission and the separation of fuel gas and oxidizing gas between adjacent cells. With the operating temperature reduction of SOFCs, the heat-resistant alloys will replace the traditional ceramic material and become the new generation material for connection board. The application of metal connection board will greatly reduce production costs of SOFCs. Based on the advantage of abound resources, proper coefficient of heat expansion, high tractility, excellent deformability and low cost, Fe based alloy which is for solid oxide fuel cell with medium temperature and flat type has become the focus of connection material research. Crofer22 APU steel is the most promising SOFCs connection material, so it is necessary to study its various performances.This thesis adopted RX3-30-9 box type resistance furnace for high-temperature oxidation resistance test in still air of Crofer22 APU steel. Gleelbe-1500 thermal analog tester was also used to research the hot deformation behavior of Crofer22 APU steel compressed under high temperature. Then the fine texture of the experiments were studied by optical microscope(OM), silence emission microscope, transmission electronic microscope, etc.The whole experiment can be separated into two parts. First part is mainly study the performance of Crofer22 APU ferritic stainless steel which including the high temperature oxidation resistance, oxidation mechanism, electric conductivity and coefficient of heat expansion after oxidation, etc. This part came to the conclusion that the out layer of oxidation film consists of Fe3O4,Cr2O3,TiO2 and MnO. And the inner layer mainly consists of the oxide of Fe,Cr and Si.What's more,when the Crofer22 APU steel is oxidized 550 hours under 800℃,its average oxidation rate is 0.0136 g/m2·h.The second part is mainly study the hot deformation and structural change of Crofer22 APU ferritic stainless steel. First, Thermo-Calc thermodynamic software was used to draw up the phase diagram according to chemical composition of Crofer22 APU steel. According to the phase diagram, the hot deformation technology was deceided.lt can be concluded:the deformation rate of Crofer22 APU steel under 900℃～1150℃is 0.1～10 s-1, When in case of strain rate 0.1s-1 and strain temperature 900℃and 1000℃, the thermal deformation progress of Crofer22 APU steel is complete recrystallization, but uncomplete recrystallization at strain temperature 1100℃, the same as case of strain rate is 1.0 s-1. the recrystallization don't turn up,when strain rate is 10 s-1 at 900℃. When strain temperatures are 1000℃and 1100℃recrystallization grain growth is observable. its deformation activation energy and thermal deformationequation are as follow:...