CORROSION CONTROL

Press, Volume CII, Issue 30110, 19 April 1963, Page 7

CORROSION CONTROL

A N advanced method of applying corrosion-resis-tant coatings to small automotive parts has been placed in operation at American Motors' plant in Wisconson. The process, known technically as “mechanical plating.” is the first such system to be installed in a carj manufacturing plant. The system utilises the technique of impaction to apply dense zinc coatings to metal surfaces, providing superior rust protection at lower relative costs than other plating methods. Mechanical plating literally drives zinc metal particles into the part, resulting in coatings of greater density than the normal standard for such protective coatings. The process involves a series of degreasing and descaling baths and acid-etch-ing of surfaces to receive the plating. Parts are then placed in a rubber-lined tumbling barrel with glass beads as the impact agent. A measured amount of zinc powder is . added, together with a "promoter” chemical and ordinary tap water. The tumbling action of the glass beads “hammers” the metal particles into the part surfaces, building up the coating to the desired uniform thickness. The process eliminates the problem of embrittlement of highcarbon parts which frequently results from other plating methods.