Method of and apparatus providing oxide reduction in a plasma environment

Abstract From the Canadian patent

In a plasma spraying system in which a main plasma gun electrically coupled to a workpiece or target and equipped with apparatus for introducing a spray powder therein provides a plasma stream to the target at high temperatures and supersonic speeds with an accompanying transfer arc between the main plasma gun and the target in a given polarity relative to the target, apparatus is present for simultaneously providing a second transfer arc at the target which has an opposite polarity relative to the target from the polarity of the transfer arc provided by the main plasma gun. The second transfer arc which is provided by a separate second or clean-up plasma gun electrically coupled to the …