Preparation On New Ni-cr-fe Alloy As Bipolar Plates For Pemfc

Bipolar plate is a very important component which can distribute the fuel and oxygen to the anode and cathode and also provide the electrical contact between adjacent cells in proton exchange membrane fuel cell (PEMFC). Cost and performance of PEMFC bipolar plates have a significant impact on the process of promoting the industrialization of fuel cells. In this paper, in order to solve the traditional high cost and not easy processing of graphite bipolar plate, and solve the presently high cost and low stability of coated metal, a new Ni-Cr-Fe alloy bipolar plate was used to replace the graphite or coated metal bipolar plate and a chemical surface treatment was applied to the surface modification of PEMFC Ni-Cr-Fe alloy bipolar plate. As a basis for the specific experiment, research on process of this method, micro-structure, corrosion resistance and contact resistance of Ni-Cr-Fe alloy bipolar plate after surface modification were carried out.In this paper, five formulas of Ni-Cr-Fe alloy were melting by vacuum induction furnace and were modified by several chemical solutions. The performance of Ni-Cr-Fe alloy bipolar plate was measured through corrosion resistance and surface conductivity in 0.5mol/L H2SO4+2ppm HF solution simulated the PEMFC condition. Single cell with Ni-Cr-Fe alloy bipolar plate was test comparing with graphite and coated metal ones.Ni-Cr-Fe alloy bipolar plate with a surface chemical treatment in X solution for 8min, whose mass ratio is 32%,30%,38%, was used as a candidate bipolar plate, and its performance on corrosion resistance and surface conductivity meets the needs of the standard of PEMFC. And the result of the single cell test was satisfactory.The valence state of the treated surface was analyzed by XPS, and the AES was carried out to determine the depth profiles of Fe, Ni, Cr, O and other elements in the surface layer. The morphology of the surface of the Fe-Ni-Cr alloy plates can be characterized by using FESEM and AFM. Many nanoscaled pyramids are found on the treated surface. Due to electrons are easily given out from the tips of a solid body, the nano-scaled pyramids may act as the contacts for the transportation of electrons. Despite the transportation along the surface of the bipolar plate is still difficult, the electrons can easily jump from the tips of the nano-contacts to the diffusion layer. The alloy plate thus exhibits the directional electron conductivity after the solution treatment.