Effects of Metal Coating and Clamping Pressure on the Electrochemical Behavior of 316L Stainless Steel Bipolar Plate in Simulated Fuel Cell Environment

• Main Authors: Hsin-HuiLin, 林欣慧
• Other Authors: Wen-Ta Tsai
• Format: Others
• Language: zh-TW
• Published: 2010
• Online Access: http://ndltd.ncl.edu.tw/handle/98364469263624586855

碩士 === 國立成功大學 === 材料科學及工程學系碩博士班 === 98 === In this investigation, 316L stainless steel (SS) was used as the bi-polar plate substrate. Two types of coating were applied on the substrate using physical vapor deposition technique. The coatings were single layer of Zr52.4Cu32.2Al8.4Ni7 amorphous metal (NG) and nano-multilayered pure metals(NMZr), respectively. The polarization behaviors of the above coated specimens were investigated in 1M H2SO4 solution by conducting potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) tests. The experimental results showed that the nano-multilayered coating had a high polarization resistance than the Zr52.4Cu32.2Al8.4Ni7 amorphous coating. The difference in polarization resistance was determined by the chemical composition of the passive films formed on different coated electrodes. This study also investigate the effect of clamping pressure (0.1~1.0MPa) on electrochemical behavior of 316L SS. The electrochemical behavior of 316L SS proceeding in fuel cell-simulating testing cell was investigated in 1M H2SO4 solution by conducting potentiodynamic polarization and EIS tests. The experimental results showed that (1) the higher polarization resistance and smaller passive current density in fuel cell-simulating testing cell. The result comes from the lower electric conductivity in fuel cell-simulating testing cell, (2) the semi-circle for the Nyquist plot of different clamping pressure was depressed downward, because of the un-uniform electrochemical reaction on the surfaces under clamping pressure. The results of EIS reveal that the polarization resistance decreased obviously with the increase of clamping pressure.