More Blisters
We are plating Type 303 stainless steel with copper using a cyanide copper plating bath. After the completion of the cyanide plating step, we observe blisters on the surface of the parts. We use 5-gal tanks. What are we doing wrong?
Q. We are plating Type 303 stainless steel with copper using a cyanide copper plating bath. After the completion of the cyanide plating step, we observe blisters on the surface of the parts. We use 5-gal tanks. What are we doing wrong? I.C.
A.Your e-mail does not mention the process you are currently using to plate the Type 303 stainless., nor do you mention how the surface is prepared prior to plating.
It is a given that it is very difficult, if not impossible, to plate copper directly onto a stainless steel surface. Normally a Woods nickel strike is applied before the copper plating. There are many formulations for a Woods nickel strike. One such formulation is as follows:
| Component | Concentration |
| Nickel (as nickel chloride) | 6 oz/gal |
| Hydrochloric acid | 10% by volume |
| Anodes | Nickel |
| Control Factors | Range |
| Temperature, °F | 75–85 |
| Current density, ASF | 45–50 |
| Time, sec | 30–60 |
After applying the Woods Nickel, rinse quickly and thoroughly and immediately place in the cyanide copper plating bath.
Something else to consider: Using small plating tanks makes it very difficult to get consistent results. I recommend larger tanks, 25–50 gal, for the process. Larger tanks allow you to maintain temperature and chemical component concentrations more accurately.
Related Content
-
Troubleshooting Alkaline Zinc
One of the most common problems that can arise when plating with alkaline zinc is an imbalance of brightener in the solution. In this helpful Ask the Expert article, Chad Murphy of Columbia Chemical discusses how different zinc metal concentrations and brightener concentrations can impact efficiency.
-
Trivalent Chrome Overview
As the finishing industry begins to move away from the use of hexavalent chromium to trivalent chromium, what factors should finishers consider as they make new investments? Mark Schario, chief technology officer for Columbia Chemical offers a helpful overview of this complicated topic.
-
How to Choose Between Sulfate and Chloride-Based Trivalent Chromium
There are several factors to consider when choosing between sulfate and chloride-based baths for trivalent chromium plating. Mark Schario of Columbia Chemical discusses the differences and what platers should keep in mind when evaluating options.
