METHOD OF COATING THE INTERIOR SURFACE OF HOLLOW OBJECTS

摘要

A method for forming a diffusion coating on the interior surface of a hollow object wherein a filament extending through a hollow object and adjacent to the interior surface of the object is provided with a coating material in a vacuum. An electrical current is the applied to the filament, to resistively heat the filament to a temperature sufficient to transfer the coating material from the filament to the interior surface of the object. Preferably, the filament is provided as a tungsten filament or molybdenum filament. Preferably, the coating materials are selected from the group consisting of Ag, Al, As, Au, Ba. Be, Bi, Ca, Cd, Co, Cr, Cu, Dy, Er, Eu, Fe, Ga, Ge, Hg, In, K, Li, Mg, Mn, Na, Ni, P, Pb, Pd, Pr, S, Sb, Sc, Se, Si, Sn, Sr, Te, TI, Y, Yb, Zn, and combinations thereof. The invention additionally allows for the formation of nitrides, hydrides, or carbides of all the possible coating materials where such compounds exist by providing a partial pressure of nitrogen, hydrogen, hydrocarbons, or combinations thereof within the vacuum.