What Is “Burning” from a Plating Bath?

We've all seen it. That crispy, flaky, nodular, usually dark deposit on the high current density extremes (edges, etc.). Usually, turning down the current is the reaction done immediately to try and remedy the problem. But exactly why does burning occur? An understanding of the mechanisms involved with the formation of a burn can better help a plater to avoid this nasty problem. Going back to high school chemistry (if you can remember that far back), you may have seen demonstrated the two electrodes from a battery, generator, or rectifier placed in a beaker of water. You will see gassing at … [Read more...]

Calculating Bath Drag Out

Let’s say you are performing a cost of operations study and need to know what your solution loss is due to drag out over the course of time. You could put something under a rack or barrel as it comes out of the process solution to catch what drains off and measure. However, this method is impractical, inaccurate, and unsafe. The best way to calculate drag out over time is to pick a component of the process that is not consumed in any other way except by drag out. A good example is sodium hydroxide in an alkaline zinc plating bath. Calculation Example: Let’s say that you check your … [Read more...]

Some Electrical Troubleshooting Notes

When trying to figure out what is causing a particularly stubborn plating problem, and checking out the chemistry seems fine, you know that you sometimes have to check out the electrical area of the process. These are a few things you can do with a VOM (volt-ohm meter). First of all, be sure you have a good VOM that has built in capacitance and not a cheap “battery tester." Checking for AC Ripple from Rectifier If the rectifier has recently dropped a diode or has degraded filter capacitors, it may not be filtering out the unwanted AC current properly. When this happens, the AC ripple is … [Read more...]

Use Potassium Permangante to Remove Contaminents in Bright Nickel Plating Solution

Unwanted organic contamination is a common problem when using bright nickel plating solutions. To remove contaminants both from outside sources and from brightner breakdown Oxidation treatments are routinely needed. Using potassium permanganate to oxidize and breakdown the organic contaminants so they can be more easily removed on a carbon pack-on filter is a common solution. Permanganate is a popular choice because it is a much stronger oxidizing agent than hydrogen peroxide and will will remove the more stubborn organic materials. Unfortunately overuse of the permanganate will cause … [Read more...]