Plating solution for electroless plating of Ni-W-Zn-P alloy coating and coating process thereof

The invention discloses a plating solution for electroless plating of a Ni-W-Zn-P alloy coating and a coating process thereof. The plating solution comprises 15-30 g/L of nickel sulfate, 30-60 g/L of sodium tungstate, 3-10 g/L of zinc sulfate, 80-120 g/L of sodium citrate, 15-25 g/L of sodium hypophosphite, 30-50 g/L of ammonium chloride, 10-20 mg/L of lead nitrate, 3-10 mL/L of lactic acid, and 0.15-0.3 g/L of cerium sulfate. In the experimental process, PH is regulated to be at 8.5-9.5 by ammonium hydroxide; the plating temperature is 70-90 DEG C; and plating time is 2 hours. A coating obtained through the coating process is 20-30 [mu] m in thickness and up to 600 HV0.1 in microhardness. The zinc sulfate is added to the plating solution, so that the obtained coating contains zinc, and corrosion resistance of the coating can be improved to a large extent. After heat treatment, a zinc-phosphorus alloy phase is separated out, so that texture is refined and a dispersion strengthening function is achieved. The cerium sulfate is added, so that not only is the plating speed increased, but also the coating is more even and compact.