ZN-NI-CO ALLOY PLATED STEEL SHEET HAVING SUPERIOR PLATING ADHESION AND CORROSION RESISTANCE AFTER PAINTING AND PRODUCTION THEREOF

摘要

PURPOSE:To obtain the titled alloy plated steel sheet having superior characteristics such as corrosion resistance in the naked state, corrosion resistance and waterproof secondary adhesion after painting, by forming an alloy layer consisting of a prescribed amt. in total of prescribed amts. of Ni and Co and the balance An and having a single =-phase on the surface of a steel sheet by plating. CONSTITUTION:An alloy layer consisting of 5wt.% in total of 1-4.2wt.% Ni and 0.7-3wt.% Co and the balance Zn and having a single eta-phase is formed on at least one side of a steel sheet by plating to obtain the titled Zn-Ni-Co alloy plated steel sheet. This plated steel sheet has satisfactory plating adhesion and cratering resistance after painting, superior corrosion resistance, external rust resistance and waterproof secondary adhesion after painting. The plated steel sheet having the above-mentioned characteristics can be easily obtd. by controlling a plating bath.