Corrosion behavior of Ni-Al alloy thin film deposited PEMFC metallic bipolar plates via pulse electroplating
| Autor: | Sen-yang Chan, 詹森仰 |
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| Rok vydání: | 2007 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 95 Stainless steels are considered to be good candidates for bipolar plate materials of PEM fuel cells due to their low cost, high strength and good manufacturability. However, corrosion of the metallic plates is a severe problem and affects the performance and lifetime of fuel cells. Ni-Al binary alloy diagram shows a few of intermetallic compounds that provide excellent properties of oxidation resistance, highly electrical and thermal conductivities and was selected as protective layer. NiAl films were deposited on AISI 304 stainless plates by pulse electroplating. Process parameters were determined from Pourbaix diagrams. Field emission scanning electron microscope, inductively coupled plasma atomic emission spectrometer grazing incident X-ray diffraction and potentiostat were used to analyze the film. Experimental results indicated that using the optimum concentration ratio Al+3/Ni+2 of 2.0 (i.e. [Al+3]= 1M ; [Ni+2]=0.5M) in the deposition solution, thin film with single-phase Ni3Al structure was obtained. Moreover, the analysis of the potential dynamics curves divulges that the sample annealed at 600oC under an annealing time of 60 minutes exhibits an excellent corrosion potential of 17 mV. Fe3+ and Cr2+ ions are undetectable in the corrosion-test solution, indicating that the AISI 304 substrate beneath the NiAl protective layer remains non-attacked. The surface resistance of the annealed thin film is 4.782 × 10-4 ohm/Sq, showing good electric conductivity. Keywords: Pulse electroplating, Pourbaix diagrams, Potential dynamics curves. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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