Production of bulk glassy alloy foams by high pressure hydrogen

A Pd–Cu–Ni–P bulk glassy alloy foam was fabricated by water quenching under pressurized hydrogen atmosphere and subsequent annealing above glass transition temperature under vacuum. At the water-quenching stage, a high density of fine bubbles is introduced. At the subsequent annealing stage, hydrogen atoms precipitate from the glassy phase to bubbles and then bubble expansion takes place above glass transition temperature. The fine and uniform structure of the foam seems to result from the formation of a high density of fine bubbles caused by high atmosphere hydrogen pressure.