ZN-CO TYPE ALLOY COATED STEEL PLATE OF SUPERIOR CORROSION RESISTANCE

摘要

PURPOSE:To improve corrosion resistance, phosphating property and properties after painting by forming a single metal plating layer of Ni, Co, Sn, Cu or the like on the surface of a steel plate and further plating a Zn-Co alloy or a Zn-Co alloy contg. Fe, Sn, Mn, etc. thereon. CONSTITUTION:First, a plating layer by a single metal such as Ni, Co, Sn, Cu or the like is formed on the surface of a steel plate for automobiles at 0.03-1.50mu thicknesses. Next, a Zn-Co type alloy coating layer contg. 10-95% Co or a Zn-Co type multicomponent alloy coating layer contg. one or two or more kinds of Fe, Sn, and Mn, and of 10-95% the sum total thereof and Co is formed on this plating layer. The steel plate which is superior in corrosion resistance, and phosphating property as well as corrosion resistance and weldability after painting is obtained.