Study On Surface Performance Modification Of Aluminum Bipolar Plate For Fuel Cell

Bipolar plate is one of the most important components in PEMFC, which occupies 80% and 45% in weight and cost respectively. Weight and cost of bipolar plate reduction have been the choke point for the industrialization.As a traditional structural material, aluminum is light, cheap and easily processed. But its acid-resistant performance is not well. So chromium electroplating and plasma nitriding are used to modify the performance of the aluminum plate's surfaces and electrochemistry performance tests are carried out to find out the application in the field of PEMFC.Intensive studies of chromium electroplating, chromium electroplating with cerium oxide and pretreatment technics are carried out in this paper. Then the well integrated and compact chromium layer is obtained by optimizing the technologic parameter, which is treated by plasma nitriding later. Plasma nitriding on the chromium layer of aluminum has at last come true for the first time. By employing X-ray Diffraction (XRD) and Scanning Electronic Microscopy (SEM), the surface microstructure and morphology have been analyzed. Finally the transformations of polarization curves and interfacial contact resistances have been compared by electrochemistry performance testing.The conclusions of this paper through examination mentioned above are:1. Chromium electroplating with cerium oxide can reduce the width of the cracks, make the chromium layer more compact, the crystal more exiguous and the quality better;2. The chromium layer on the aluminum can be transformed to nitride CrN and Cr₂N within 520℃～560℃. Excessive temperature and time can result in the fission and desquamation which may be related to the different thermal expansion coefficient;...