Studying the Corrosion Behavior of Pd–Cu Alloy Used in Hydrogen Purification Systems

Abstract

The use of hydrogen as an energy carrier is considered a global goal within the coming years. Therefore, using various alloys is unavoidable in purification processes; for example, hydrogen produced by any suitable upstream process is purified using a hydrogen-selective metallic membrane made of Pd or Pd-based alloys. During this work the corrosion behavior of Pd and Cu in acidic media (0.25 M HCl) at various operating conditions [temperatures (30 and 50 °C) and speeds of agitation (0, 300, 600, and 900 RPM)] was studied. Multiple regression analysis with respect to ANOVA was utilized to generate mathematical correlations. The derived correlations and three-dimensional mapping (i.e. surface response) revealed that increasing temperature and speed of agitation affected the corrosion rate of Pd and Cu. The corrosion rate of copper was much higher than palladium for the same conditions. This result indicates that alloying copper with palladium in the hydrogen purification systems is not acceptable due to the degradation that might occur in copper as a direct result of the galvanic corrosion phenomenon.