Manufacturing method of surface coated zinc nickel alloy electroplated steel plate excellent in corrosion resistance and coating ability

摘要

The present invention relates toSteel plateA step of forming a Zn Ni alloy electroplated steel plate having a Zn Ni alloy plated layer having a Ni -- Ni alloy plated layer having a Ni content of 5 to 20% by weight on the steel plate (S1) is performedPotassium hydroxide (KOH) or sodium hydroxide (NaOH) is used for distilled waterOr, both of these are provided with an alkaline electrolyte containing 4 to 250 g / L (S2) andIn the above alkaline electrolyteThe Zn Ni alloy plated steel plate is placed on the anode.After placing other metal plates on the cathodeApply an AC or DC power supply of 2 toThe step of obtaining an electroplated steel plate subjected to surface etching by electrolytic etching is performed so that the three-point average value of the average mean roughness (RA) of the surface of the Zn Ni alloy electroplated steel plate becomes 200 to 400 nm (S3)IncludingProblem to be solved: to provide a method of manufacturing a surface treated Zn Ni alloy electroplated steel plate.