Abstract
An attempt is made to deduce a solution to the problem of gas absorption in the aluminum bronze. The molten metal absorbs hydrogen in the alternative way. The cast surfaces have characteristic appearances both microscopically and electron-microscopically depending on the treatments for gas pick-up. The metals free from any impurities or contaminated with such an element as beryllium that has a stronger affinity to oxygen than aluminum and forms the protective oxide film absorb hydrogen during direct exposing to hydrogen. “Steam reaction” results in little gas pick-up in these metals. The protective films of γ-Al2O3 and BeO formed over the metal surfaces are identified. On the other hand, aluminum bronzes contaminated with such an impurity as calcium that has a stronger affinity to oxygen than aluminum and forms no protective film absorb hydrogen during the steam reaction. The contamination of calcium as little as 0.5% results in the formation of the particular crystalline substance pCaO·qAl2O3 or pCaO·qAl2O3·γHO restraining the formation of alumina.
