A methodology and system for applying coatings onto the interior surfaces of components, includes a vapor creation device, a vacuum chamber having a moderate gas pressure and an inert gas jet having controlled velocity and flow fields. The gas jet is created by a rarefied, inert gas supersonic expansion through a nozzle. By controlling the carrier gas flow into a region upstream of the nozzle an upstream pressure is achieved. The carrier gas flow and chamber pumping rate control the downstream pressure. The ratio of the upstream to downstream pressure along with the size and shape of the nozzle opening controls the speed of the gas entering the chamber. Vapor created from a source is transported into the interior regions of a component using binary collisions between the vapor and gas jet atoms. These collisions enable the vapor atoms to scatter onto the interior surfaces of the component and deposit.