Method of coating inner and outer surfaces of pipes for thermal solar and other applications

摘要

A method of coating at least one exterior surface of at least one workpiece is disclosed. The method may be used for coating inner and outer surfaces of pipes. A hollow workpiece is positioned within a chamber. A spacing between a multi-dimensional interior surface of the chamber and an exterior surface of the workpiece is fixed. Conditions are established to maintain a hollow cathode effect within the spacing and within the hollow workpiece. The conditions include biasing anodes at opposite ends of a hollow cathode effect region, and biasing the interior surface of the chamber and the workpiece as cathodes. The interior surface and the workpiece may be maintained at a common bias voltage or, in at least one embodiment, at differing voltages.