Work piece with an internal channel, such as pipeline fitting, valve, pump or the like, a method and apparatus for vapor deposition of ueberzuegen in the inner channel

摘要

The bore surfaces are coated with a metal or metal cpd., esp., tantalum, by thermal decomposition or reaction of a compound (or compounds) in the gas phase. Specifically, the bore is of non-uniform cross-section and the gas flow direction is reversed at least once during the process. The workpiece is heated pref. by induction heating and susceptors may be used to block up all the bore openings except the two through which the gas is passed. Cpds. used include aluminium alkyl, cobalt-acetonyl acetate, cobalt nitrosyl carbonyl, 2-benzene chromium, chromium iodide, gold-3-(triphenyl phosphine), iodide, or mixtures of H2, hydrocarbons, or silanes with halides of Al, Co, Cr, Au, Mo, Nb, Ta, Ti, V, Zr, U, Th, Be, Ge or B, esp., H2 + Ta pentachloride.