PROCESS FOR MANUFACTURING ABRASION-RESISTANT COATINGS, IN PARTICULAR ON SPIRAL ROLLERS

摘要

A protective coating (10) of a tough metal is applied by galvanic deposition of grains of (H) of mechanically resistant material. This protective coating is then coated galvanically with a layer (11) of a harder metal having a thickness (D1) which corresponds approximately to the particle size of the grains of mechanically resistant material. A basic nickel bath containing silicon carbide grains (H) in suspension and an acid chromium bath are used. The spiral roller (1) rotates in the nickel bath at a surface speed such that a grid distance (R) between the cavities (V) in the surface of the roller is traversed in at least the time required for the ions in the nickel bath to travel a distance equal to the particle size.