화학공학소재연구정보센터
Journal of Materials Science, Vol.44, No.13, 3402-3407, 2009
Hydrogen, porosity and oxide film defects in liquid Al
This article reports results from an experiment where a bubble of air was held at a constant temperature in a liquid Al melt, with the volume of the bubble monitored continuously using real-time X-ray equipment. When the H content of the surrounding melt was low, the volume of the trapped air bubble reduced with time, as the O and N in the bubble atmosphere reacted with the Al to form Al2O3 and AlN. When the H content of the melt was increased to about 0.3 ml 100 g(-1) Al, the H in solution passed into the air bubble causing its expansion. In an Al casting the same effect would cause an entrained double oxide film defect to act as a site for the growth of H-driven gas porosity. The way in which the oxide film defects might behave in forming H porosity has been discussed.