Reduction of Water Desorption from Stainless Steel by Silicon-carbon Coatings

Water desorption from stainless steel was reduced by silicon-carbon coatings deposited by chemical vapor deposition (CVD). Two types of film coatings were examined, both of which used organosilicon compounds as source materials. One was hexamethyldisiloxane (HMDSO), and the other was hexamethyldisilazane (HMDS). The surfaces of the film coatings exposed to atmospheric air were thought to be oxidized by oxygen and water in air. The amount of water desorbed from the stainless steel samples coated with either type of the films was less than 1/10 of that from the electropolished sample as measured through the thermal desorption spectroscopy. The amount from the coated samples was equivalent to the order of 1/100 of the water monolayer. The analysis by Auger electron spectroscopy showed that both films were composed of 50 at.% silicon and 40 at.% carbon. The remainder of the film deposited from the HMDSO was oxygen, and that of the film from the HMDS was nitrogen.