Patent attributes
An apparatus for coating surfaces of a workpiece is configured to establish a pressure gradient within internal passageways through the workpiece, so that the coating within the internal passageways exhibits intended characteristics, such as those relating to smoothness or hardness. The coating apparatus may include any or all of a number of cooperative systems, including a plasma generation system, a manipulable workpiece support system, an ionization excitation system configured to increase ionization within or around the workpiece, a biasing system for applying a selected voltage pattern to the workpiece, and a two-chamber system that enables the plasma generation to take place at a first selected pressure and the deposition to occur at a second selected pressure.