Copper, nickel, chromium, one-step production process, in the production process, copper plating, nickel plating liquid is easy to bring in oxidants (hexavalent chromium) These oxidants can be reduced at the cathode, reducing the cathodic current efficiency of the plating process, even Can exclude the deposition of copper, nickel, so that parts of the deep recesses are not on the plating.
First, how does chromium get into the copper plating and nickel plating liquid?
1, copper, nickel, chromium, one-step production process, linked from the role of coal transmission, conventionally speaking, is linked to chrome after plating, cleaning is not clean, stick on the hanger chrome plating liquid into the copper, nickel cylinder.
2. Workers are not operating properly (eg, protective gloves from workers) to bring chromium into copper and nickel cylinders.
3. Chromium plating tank produces chrome mist, chrome mist sinks in the air, chromium falls into copper and nickel cylinders, etc.
Second, the harm of chromium
In the presence of Cr6+ in copper and nickel plating baths, the cathode current efficiency becomes lower, the workpiece coating becomes gray, the deposition speed is slow, the parts are deeply recessed and not coated, the coating is dark, orange peel-like, and no light brightness. Wait.
Third, the solution
1, the original solution is; the bath is strongly stirred, with air stirring, but also to increase the artificial mixing, under intense stirring, add 0.2 ~ 0.5g / L (Na2S2O4 · 2H2O) sodium dithionite, with Na2S2O4 · 2H2O will The hexavalent chromium in the plating solution is reduced to trivalent chromium, and then the pH is raised to remove trivalent chromium as chromium hydroxide.
The specific operation is as follows;
a. Adjust the plating PH=3 with sulfuric acid and heat the plating solution to 60~70 degrees
b. Add a certain amount of Na2S2O4·2H2O under intense agitation (the amount is best to be determined by a small test, generally 0.2~0.5g/L for 60 minutes.
c, increase the alkali solution (CaCO3 and NaOH) to increase PH = 6.2 or so, stir 60 minutes, then test, and adjust the PH = 6.2
At the same time, 2~3g/l of activated carbon can also be added.
d. Add 0.2 to 0.5 ml/l 30% hydrogen peroxide to oxidize excess Na2S2O4·2H2O to sulfate.
e, adjust the PH value, adjust the composition of the bath, add additional brightener, trial plating.
The above methods to solve these problems, the prerequisite is to stop production, of course, there are other methods, such as; ferrous sulfate method, potassium permanganate method, the above methods have to stop production to deal with the problem, but annoying.
2. The following describes a new processing method that is convenient, fast, and easy to operate;
ZS chromium removal agent; Yiwu has benefited from production, suitable for rapid removal of nickel, copper plating, hexavalent chromium impurities in the bath, (copper, nickel, chromium, one-step process required) can be added after stirring Resumption of production, per ml of chromium removal agent can handle hexavalent chromium (ycp +) 10mg.
Principle: After adding ZS chromium removing agent, the hexavalent chromium in the plating solution can be converted into trivalent chromium. According to the data of the root crucible, the trivalent chromium exists in the plating solution and has little harm, as shown by the actual test and application. The nickel plating solution can tolerate 30g/L trivalent chromium. The trivalent chromium converted by ZS chromium removing agent can be formed by nickel complexation to achieve the purpose of purifying the plating solution and removing chromium.
Excessive addition will not harm the bath. Dosage: 2-3ml/L.
Fourth, concluding remarks;
The best way to solve the problem is from the source. Good workshop management, chrome-plated racks for enhanced cleaning, chromium mist inhibitors in the chrome plating solution to avoid chrome mist escaping, etc. Of course, your regular addition of appropriate amount of chromium remover in the nickel cylinder is also beneficial and harmless.
First, how does chromium get into the copper plating and nickel plating liquid?
1, copper, nickel, chromium, one-step production process, linked from the role of coal transmission, conventionally speaking, is linked to chrome after plating, cleaning is not clean, stick on the hanger chrome plating liquid into the copper, nickel cylinder.
2. Workers are not operating properly (eg, protective gloves from workers) to bring chromium into copper and nickel cylinders.
3. Chromium plating tank produces chrome mist, chrome mist sinks in the air, chromium falls into copper and nickel cylinders, etc.
Second, the harm of chromium
In the presence of Cr6+ in copper and nickel plating baths, the cathode current efficiency becomes lower, the workpiece coating becomes gray, the deposition speed is slow, the parts are deeply recessed and not coated, the coating is dark, orange peel-like, and no light brightness. Wait.
Third, the solution
1, the original solution is; the bath is strongly stirred, with air stirring, but also to increase the artificial mixing, under intense stirring, add 0.2 ~ 0.5g / L (Na2S2O4 · 2H2O) sodium dithionite, with Na2S2O4 · 2H2O will The hexavalent chromium in the plating solution is reduced to trivalent chromium, and then the pH is raised to remove trivalent chromium as chromium hydroxide.
The specific operation is as follows;
a. Adjust the plating PH=3 with sulfuric acid and heat the plating solution to 60~70 degrees
b. Add a certain amount of Na2S2O4·2H2O under intense agitation (the amount is best to be determined by a small test, generally 0.2~0.5g/L for 60 minutes.
c, increase the alkali solution (CaCO3 and NaOH) to increase PH = 6.2 or so, stir 60 minutes, then test, and adjust the PH = 6.2
At the same time, 2~3g/l of activated carbon can also be added.
d. Add 0.2 to 0.5 ml/l 30% hydrogen peroxide to oxidize excess Na2S2O4·2H2O to sulfate.
e, adjust the PH value, adjust the composition of the bath, add additional brightener, trial plating.
The above methods to solve these problems, the prerequisite is to stop production, of course, there are other methods, such as; ferrous sulfate method, potassium permanganate method, the above methods have to stop production to deal with the problem, but annoying.
2. The following describes a new processing method that is convenient, fast, and easy to operate;
ZS chromium removal agent; Yiwu has benefited from production, suitable for rapid removal of nickel, copper plating, hexavalent chromium impurities in the bath, (copper, nickel, chromium, one-step process required) can be added after stirring Resumption of production, per ml of chromium removal agent can handle hexavalent chromium (ycp +) 10mg.
Principle: After adding ZS chromium removing agent, the hexavalent chromium in the plating solution can be converted into trivalent chromium. According to the data of the root crucible, the trivalent chromium exists in the plating solution and has little harm, as shown by the actual test and application. The nickel plating solution can tolerate 30g/L trivalent chromium. The trivalent chromium converted by ZS chromium removing agent can be formed by nickel complexation to achieve the purpose of purifying the plating solution and removing chromium.
Excessive addition will not harm the bath. Dosage: 2-3ml/L.
Fourth, concluding remarks;
The best way to solve the problem is from the source. Good workshop management, chrome-plated racks for enhanced cleaning, chromium mist inhibitors in the chrome plating solution to avoid chrome mist escaping, etc. Of course, your regular addition of appropriate amount of chromium remover in the nickel cylinder is also beneficial and harmless.