Silver-cobalt-nickel electroplating solution and preparation method and electroplating method thereof

The invention discloses a silver-cobalt-nickel electroplating solution which comprises 1.5-2 g/L of silver chloride, 12-15 g/L of cobalt chloride, 60-70 g/L of nickel chloride, 7.2-10.3 g/L of brightener, 6.2-8.3 g/L of surfactant and the balance of eutectic solvent. The invention also discloses a preparation method of the silver-cobalt-nickel electroplating liquid and a method for preparing a silver-cobalt-nickel coating by using the electroplating liquid, taking a soluble silver plate, a cobalt plate and a nickel plate as anodes, taking a workpiece to be plated as a cathode, applying pulse current and electroplating at a certain temperature and current density. A silver-cobalt-nickel coating prepared by the electroplating solution is uniform and compact, and good in wear resistance and corrosion resistance; the silver-cobalt-nickel plating layer and a plating piece are good in binding property, high in hardness and improved in conductivity; and a silver plate, a cobalt plate and a nickel plate are used as a