Determinatin of Hydrogen in Aluminium by the Argon-Carrier Hot Extraction Method

The argon carrier hot extraction method for the determination of hydrogen in metals previously reported was applied to the case of aluminium with satisfactory results. Sufficient sensitivity was attained by using an oil manometer as the detector. The sample was scraped with an ordinary lathe under a dry condition and heated to 600℃ in a stream of purified argon to extract hydrogen. The hydrogen extracted was filtered through a palladium tube at 550℃ and determined manometrically. Through this palladium tube, even 10～20μl of hydrogen could be filtered quantitatively. The extraction time was about 1hr and the shape of the extraction curve resembles that obtained by hot extraction in vacuo. Surface gas was determined by re-turning the degassed sample followed by extraction. It was found that the amount of surface gas was dependent not only upon the smoothness but also upon the freshness of the surface of sample. Coefficients of variation of the internal gas (the mean value of which was 0.36Nml/100g) and the surface gas (the mean value of which was 3.2×10^Nml/cm^2) of 99.9% aluminium were 7.8% and 11%, respectively