模拟PEM燃料电池环境下垫片材料的机械性能研究

STUDY ON MECHANICAL PROPERTIES OF THE GASKET MATERIAL IN SIMULATED PEM FUEL CELL ENVIRONMENTS

通过实验的方法研究硅橡胶垫片材料在模拟的PEM燃料电池环境下的机械性能损伤情况。采用2种溶液模拟PEM燃料电池环境，一种溶液为接近实际PEM燃料电池环境的正规溶液（RS），另一种溶液为加速老化实验的加速持久性实验（ADT）溶液。采用电子天平测量试样暴露在模拟PEM燃料电池环境下一段时间后质量变化情况；通过光学显微镜观察垫片材料试样表面微观形貌变化；采用机械性能实验分别对未老化的试样和在模拟的PEM燃料电池环境下的老化试样进行研究。实验结果表职，试样在ADT环境下质量损失较大，在RS环境下试样质量变化不明显；光学显微镜结果表明试样表面由光滑变得粗糙，到产生裂纹，最后裂纹扩展；在模拟的PEM燃料电池环境下，随着老化时间的增加，试样抗拉强度和断裂伸长率随之降低；试样压缩永久变形随着老化时间的增加而增大，且随着酸性程度的增加而增大。

In this paper, the degradation of mechanical properties of silicone rubber gasket material was investigated experimentally in simulated PEM fuel cell environment. The two solutions were used to simulate the PEM fuel cell environment. One solution was called as the regular solution （RS）, which is close to the real PEM fuel cell environment, and another solution was an accelerated durability test （ADT） solution for the accelerated aging tests. Weight change was measured by electronic scales for the samples after exposure to the simulated PEM fuel cell environments over time. The optical microscopy was employed to study the surface microstructure changes of gasket material samples. The mechanical property tests were conducted for the samples before and after exposure to the simulated PEM fuel cell environments. The test results reveal that the weight obviously decreased for the sample after the exposure to the ADT solution, while the weight loss was not observed for the samples after the exposure to the RS environment over time. Optical microscopy results indicate that the surface conditions of the samples change from initially smooth to rough, crack appearance and finally crack propagation. The tensile test results show that the tensile strength and elongation at break were decreased with the aging time in simulated PEM fuel cell environments. It is found that the value of the compression set increased with the aging time and acidic concentration.