encouraging heat transfer of the particles to the quench cylinder by constantly cooling it and by preventing adhesion of plasma sprayed splat quenched particles 72 to it it also provides for easy collection of the particles quench cylinder may be rotated by an air driven motor 74 means not shown may be provided for continuously emptying splat quenched particles the entire plasma spray process should be conducted in a non oxidizing atmosphere this may be accomplished by retaining the torch and quench wheel in a sealed atmosphere controlled chamber the quench cylinder of fig1 has vertical walls and an overhanging lip we have obtained our best results using a solid copper cylinder although other metals are also suitable fig2 shows another suitable quench cylinder 80 which has outwardly sloping walls flakes quenched in such a cylinder would tend to ride up the walls and fall over the sides fig3 shows a quench cylinder 84 with inwardly sloping walls 86 and an overhanging 88 flakes quenched in such a cylinder would tend to remain inside the cylinder and collect along the bottom edges during a run processing variables can be adjusted to obtain optimum results these include power level to the torch powder feed rate quench cylinder revolution rate cooling gas liquid flow rate plasma gas composition distance of the torch nozzle from the quench surface angle of the plasma flame with respect to the quench surface chamber atmosphere nozzle coolant flow rate etc one skilled in the art can easily adjust such parameters particularly in view of the following specific example a metco u2122 inc 10 mb plasma spray gun was installed in a vacuum chamber roughly as shown in fig1 the.