Stainless steel anode passivation in the air, easily generate a 316 stainless steel plate density of passivation film, the passive film has good corrosion resistance. With the development of various industry, the application of stainless steel expanded rapidly, which leads to increasing demand of functional plating on stainless steel. The difficulties of the stainless steel plating on stainless steel on the bottom of the plating. If solved the bottom plating of stainless steel, can the conventional plating methods to realize composite plating. The bottom plating of the difficulty lies in the pretreatment of stainless steel. Before if mishandled, tend to cause coating layer, peeling, fall off wait for a phenomenon.
Process technological process is: the organic solvent chemical in addition to in addition to the oil - water - oil - water - acid - washing - activation and pre - pre plating nickel - plating bath and the copper plating - water - nickel plating and silver plating to washing, drying and packing.
Stainless steel plating pretreatment of the difficulty is how to x52 line pipe destroy the passivation layer on the surface of the stainless steel and stainless steel base material of activation. Preliminary determination by chemical method, thoroughly destroy passivation layer on the surface of the stainless steel. Then in the plating solution in advance, in the case of no electricity further metal substrate surface activation, quickly before the new passivation layer has not been generated by electrodeposition method on a layer of nickel plating, so as to realize the bottom plating of stainless steel.
Main process shows that organic solvent pretreatment soaking 316ti stainless steel degreasing part stainless steel parts can't electricity chemical degreasing degreasing methods. Because of some stainless steel parts after electrochemical degreasing, surface near black, which USES pickling also cannot make its become shining surface. In order not to damage on the surface of the stainless steel bright state, with oil on the surface of the industrial gas scrubbing of the first, reoccupy after washing detergent industry heating oil removal to 50 ~ 70 ℃.
Chemical oil removal using chemical degreasing remove oil on the surface of the parts again. Oil removal process specification for: NaOH60 ~ 80 g/L, Na2CO320 ~ 40 g/L, Na3PO450 ~ 70 g/L, Na2SiO310 ~ 15 g/L, 50 ~ 70 ℃, 3 ~ 5 min.
When the oil removal, must control the bath temperature and time. Degreasing time is too short, the oil on the surface of the stainless steel can not be completely clear; Degreasing time is too long, can make the stainless steel surface is rough, influence the surface roughness.
Acid in the process of stainless steel plating pretreatment, acid pickling is indispensable process. Because acid can remove the rust on the surface of the stainless steel, and can damage the surface oxidation film, make its surface of the substrate naked, pre - coating binding force can be greatly increased. The pickling process specification for: 30% HCl200 ~ 300 g/L, 15 ~ 25 ℃, 2 ~ 5 min.