Preparation of Ni–Al alloys at reduced temperature for fuel cell applications

Abstract

Ni–Al alloys have been fabricated from the physical mixture of nickel and aluminum powders at temperatures below the melting point of aluminum using AlCl 3 vapor as an activator. Pure Ni 3Al intermetallic compound has been synthesized from the Ni–Al powder mixtures containing 15 wt% aluminum at 600 °C. From the powder mixture containing 5 wt% aluminum, a compound consisting of Ni–Al solid solution and Ni 3Al was produced at 600 °C, but this compound was converted entirely to a Ni–Al solid solution after annealing at 700 °C. The particle size and morphology of the Ni–Al solid solution were not greatly different from original nickel powders. It was observed that oxidation resistance was significantly enhanced by alloying of nickel with aluminum. The Ni–Al alloys synthesized in this study can be used as anode materials for high-temperature fuel cells which need improved resistance toward creep, sintering and redox cycling.