The invention discloses a double-bottoming
electroplating method for a
nickel-plating
magnesium alloy hub. The method includes the following operation steps that firstly, preplating treatment is conducted; secondly, preplating
cyanide-free
copper bottoming treatment is conducted, wherein a plating solution of preplating
cyanide-free
copper includes 120-130 g / L of
copper sulfate, 160-180 g / L of
sodium ethylenediamine tetramethylene
phosphonate, 80-100 g / L of
potassium tartrate and 0.3-0.5 g / L of 2-
mercaptobenzothiazole, according to the technology of the plating solution of the preplating
cyanide-free copper, the pH of the plating solution is 8.5-9.5, the temperature of the plating solution is 45-55 DEG C, the
electroplating time is 15-25 min, the cathodic
current density is 1.2-1.4 A / dm<2>, the anodic
current density is 0.6-0.8 A / dm<2>, and gas stirring is adopted; thirdly,
pyrophosphate copper plating bottoming treatment is conducted, wherein a plating solution of
pyrophosphate copper plating treatment comprises 100-120 g / L of copper
pyrophosphate, 140-160 g / L of
potassium pyrophosphate, 6-8 mL / L of
ammonia water with the concentration of 25-30%, 8-12 g / L of
potassium citrate, 15-25 g / L of
potassium sodium tartrate, 0.2-0.3 mL / L of a brightening agent and the
balance water, according to the technology of the plating solution, the pH of the plating solution is 8.5-9.5, the temperature of the plating solution is 45-55 DEG C, the
electroplating time is 25-35 min, the cathodic
current density is 1.2-1.4 A / dm<2>, the anodic current density is 0.7-0.9 A / dm<2>, and gas stirring is adopted; and fourthly;
nickel electroplating is adopted.