Influence of wall thickness and filling gas procedure on permeability of hollow glass microsphere

The influence of the wall thickness and filling gas procedure on the permeability of the hollow glass microspheres (HGM) were discussed. The primary experiments show that the deuterium permeation coefficient was 5.0×10-22 mol·m-1·s-1·Pa-1 with the wall thickness more than 2 mm at room temperature, while it was 1.56×10-20 mol·m-1·s-1·Pa-1 with the wall thickness less than 1 mm. The permeation coefficient of thin wall HGM increased 30 times more than that of thick one. The main reason for the effect of the wall thickness on the HGM permeability was microcrack on the HGM surface. The permeation coefficient increases about 50% if HGM experienced one cycle of filling and deflating gas, and doubles after two cycles owing to the voids and flaws on the HGM surface caused by high temperatur