| Summary: | 碩士 === 中國文化大學 === 材料科學與奈米科技研究所 === 96 === The thesis studied the electrochemical property on the NiAlFe based
intermetallic alloys, including Ni47.5Al25Fe27.5, (Ni47.5Al25Fe27.5) 99Cr1,(Ni47.5Al25Fe27.5)99Nb1. For testing the corrosion rates of these three alloys,these alloys were statically immersed in 50 % of commercial nitric acid,hydrochloric acid and sulfuric acid, respectively. The results were alsocompared with the corrosion rates of commercial 304 stainless steel. In addition, the polarization curves of these three alloys in sodium chloride solutions with different concentrations were also tested for measuring their corrosion potentials and corrosion currents.
The results indicated that the corrosion resistances of these alloys
immersed in hydrochloric acid and sulfuric acid were better than that of commercial 304 stainless steel. However, the corrosion resistances of these alloys immersed in nitric acid were worse than that of commercial 304 stainless steel. Adding Cr or Nb into Ni47.5Al25Fe27.5 alloy could not improve their corrosion resistances of hydrochloric acid or sulfuric acid;but it could improve the corrosion resistance of nitric acid ofNi47.5Al25Fe27.5 alloy.
During the tests of polarization curves in sodium chloride solutions,
increasing the chloride ion would result in reducing the passivity
phenomenon for (Ni47.5Al25Fe27.5) 99Cr1, (Ni47.5Al25Fe27.5) 99Nb1 alloys.Also, the passive films of the alloys would be destroyed quickly when the concentration of sodium chloride solutions were increased. Therefore, the current densities of the anodic polarization curves thus decreased.
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