Treatment of chromium surfaces

Abstract

Abstract A process for forming on a substrate a surface having superior release properties and abrasion resistance comprises the steps of forming on said substrate a textured chromium surface having a plurality of substantially uniformly distributed depressions and peaks: applying to said textured surface a thin uniform deposit of fluorocarbon polymer; heating said textured surface to a temperature above the fusion temperature of said fluorocarbon polymer thereby forming a continuous film of fluorocarbon polymer on said textured surface; and removing said film from said peaks; thereby forming a release surface containing discrete islands of chromium substantially uniformly distributed throughout a continuous film of fluorocarbon polymer said chromium constituting 0.01 to 30% of the area of said surface. The substrate may be a metal roller. The substrate may be formed or provided with a textured surface and then chromiumplated or it may be chromium-plated and then treated e.g. by grit-blasting to produce the textured surface. The polymer may be applied as a fine powder or a liquid dispersion by spraying, which may be electrostatic, by hot platens under pressure or by the fluidised bed process: the surface may first be cleaned, degreased and de-gassed. After application of the polymer, the surface may be ground e.g. by means of an abrasive belt to expose the chromium peaks.

Inventors

No inventors recorded.

Bibliographic Details