METHOD OF FORMING THIN WALL PROTECTING COATING FOR SLENDER SUBSTRATE

摘要

A process for producing thin walled coatings on elongated substrates by the electrostatic application of two superimposed layers of powder material is disclosed. The process comprises the steps of applying electrostatically a first layer of fusible powder material to an elongated substrate, at least partially fusing such first layer of powder material to provide a uniform coating on the elongated substrate, holding the at least partially fused coating at an elevated temperature below the full fusion temperature of the powder material to be applied as the second layer immediately prior to the application of such second layer, applying electrostatically a second layer of fusible powder material to the first layer, and fusing the total applied coating to achieve the desired coating thickness.