Co-spray abrasive coating

摘要

An abrasive grit is coated on a substrate by generating a high temperature plasma stream, injecting particles of matrix material into the stream, injecting downstream of the matrix material particles of abrasive grit and at such a distance from the substrate that the matrix particles and the grit particles come into simultaneous contact with the substrate surface and traversing the plasma spray gun across the substrate to be coated. The grit particles may be injected near to the substrate so that angularity of the grit particles is preserved by only limited contact with the plasma stream. A narrow substrate may be offset from the axis of the plasma spray stream to avoid the erosive zone at the axis of the spray. The coating of gas turbine blades is referred to.