Patent ID: 7750265

Claim:
A plasma spray coating system comprising a power source, one or more gas flow channels for supplying gas to a cathode, a material feeding module configured to introduce a powder into a stream of plasma generated by a plasma apparatus, and a control module, said control module controlling gas flow rates and electrical parameters within said plasma apparatus, said plasma apparatus including at least one cathode and anode module, one or more inter-electrode inserts located between said cathode module and said anode module, and a pilot insert under potential during ignition of said plasma spray coating system to provide pilot arcing with said cathode, said pilot insert disposed down-stream of said cathode and between said cathode and a first inter-electrode insert, said pilot including a first channel in communication with a second channel of said first inter-electrode insert, said first channel having an interior cross-sectional diameter opening Dp and said second channel having an interior cross-sectional diameter opening Dc, wherein Dp<Dc and 0.85>Dp/Dc>0.5; wherein Dc−Dp>1.5 mm; wherein said first and said second channels are axially aligned with said cathode; and wherein said pilot insert further includes at least one bypass opening configured to provide part of a flow of plasma gas through said pilot insert and into a space defined between said pilot insert and said first inter-electrode insert and to provide illuminating arcing between said pilot insert and said first inter-electrode insert.