CORROSION RESEARCH ROUND‐UP

U.S.A. Aluminium at high temperatures. In continuing their study of the mechanism of corrosion, the authors included aluminium alloys that withstand a high temperature and are presumed to liberate hydrogen formed during corrosion into the solution. Samples of 1,100 aluminium and 1,100 aluminium − 0.9 nickel alloy (M388) were exposed to water at 290°C, and compared. The amount of hydrogen was comparable for the samples with the coatings intact. The M388 showed no hydrogen when the corrosion coating was removed; whereas the 1,100 aluminium showed an appreciable amount. Additional corrosion samples, each with larger quantities of metal removed, had progressively lower hydrogen contents. Since the solid solution of hydrogen in aluminium is small the idea of blisters or gas‐pockets seems valid. But an alternative hypothesis explained hydrogen as due to trapped or combined water in the retained oxide; but etching and wire brushing opened the blisters and no oxide was seen, yet the hydrogen content remained high when samples were analysed.