... , in titaniumand zirconiumproduction, and ingas chromatography, because it is inert. Because of its inertness, thermally and calorically perfect nature, ... and weakened by air or nitrogen. A number of inert shelding gases are used in gas tungsten arc welding, but ... permeation rate) through glasses, ceramics, and synthetic materials, inert gases such as helium will not permeate most bulk metals. Flight ...