Pretreatment for zinc and zinc alloy prior to chromating

摘要

PCT No. PCT/US91/07586 Sec. 371 Date Apr. 15, 1993 Sec. 102(e) Date Apr. 15, 1993 PCT Filed Oct. 9, 1991.Drying into place a covering of an aqueous solution of nickel and/or cobaltous sulfate and/or phosphate salts on a zinc or zinc alloy surface improves at least one of the blackening resistance and corrosion resistance after subsequent chromating treatment and the corrosion resistance and paint adherence after subsequent chromating treatment and painting.