| 摘要 |
<p>A coating of wear resistant tungsten carbide is applied to a photo-etched roto-gravure cylinder, the coating having a thickness in the range of from 15 to 35 microns. Tungsten carbide powder is supplied to a plasma flame spray gun by means of a powder feeder which supplies powder particles at a uniform density and at given sizes. The feeder comprises a hopper having air inlet and outlet passages and vertically spaced porous membranes which confine the powder and permit the passage of air. Air flow through the hopper suspends the powder particles of a desired diameter range adjacent a spray gun feed conduit. When copper cylinders are to be coated, the surface is allowed to oxidize to promote a chemical bonding of the coating to the surface.</p> |
