材料期刊网

用电弧离子镀方法在质子交换膜燃料电池(PEMFC)不锈钢双极板表面沉积一系列 Cr_1-xN_x(x=0.28-0.50)改性薄膜, 对薄膜的成分、相组成以及改性双极板的导电、耐蚀等性能进行了分析测试. 结果表明, 双极板的导电与耐蚀性能因沉积Cr_1-xN_x薄膜而显著提高, 并且与薄膜的成分和相组成密切相关: 当x值从0.28增加到0.50, 薄膜由Cr+Cr2N转变为Cr₂N, 再转变为Cr₂N+CrN, 最终变为CrN; 当薄膜由单相组成时, 双极板既导电又耐蚀、综合性能最好, 与原始不锈钢相比, 导电性能提高2个数量级以上, 而耐蚀性能提高近3个数量级.

In the proton exchange membrane fuel cell (PEMFC) with widely applicated future, the bipolar plate plays an important role in supporting the cell stack, collecting current, separating the oxidants from fuels and channeling the oxidants and fuels. The ideal bipolar plate should be of good electric conductivity, high corrosion resistance, high mechanical strength, low gas permeability, low cost and easy processing. Although the stainless steels can be used as bipolar plate materials, their corrosion resistance in fuel cell environment is not satisfied, and the cations induced by metal corrosion would poison the proton exchange membrane. A series of Cr_1-xN_x (x=0.28-0.50) films were deposited on the surface of stainless steel by arc ion plating (AIP), the composition and phases of Cr_1-xN_x films and the electric conductivity and corrosion resistance of the modified bipolar plates were tested. The results show that as the value of x varying from 0.28 to 0.50, the phases in the films change from Cr+Cr₂N to Cr₂N, then to Cr₂N+CrN and finally to CrN. The bipolar plates coated with the Cr_1-xN_x film with single phase structure show good electric conductivity and high corrosion resistance. Comparing with the original stainless steel, the electric conductivity and corrosion resistance of bipolar plates are enhanced by more two orders of magnitude and almost three orders of magnitude, respectively.