Nickel plating helps protect and improve metal parts, but there are several problems that can affect quality. Here are five common issues and how to fix them.
Pinholes
Pinholes appear as small holes in the nickel coating, and they are usually caused by oil or other organic contamination in the plating bath. To solve this problem, clean the bath with activated carbon treatment to remove the oil and improve solution agitation to release trapped bubbles.
Rough Surfaces
Rough nickel coatings happen when the plating solution is dirty or the process is out of balance, and this creates an uneven, bumpy finish. Filter the bath thoroughly to remove particles, and control the pH levels to prevent hydroxide formation. Lowering the current density when it’s too high can also help, along with checking water and other additions for impurities.
Poor Adhesion
When nickel coating peels or flakes off, it’s usually because the base metal surface wasn’t activated to remove oxide layers or when plating current was interrupted during the process. A bath temperature that’s too low can also cause adhesion problems. These issues can be fixed by improving surface preparation steps and maintaining consistent temperature and current throughout the plating process. If you need electroless nickel plating, firms such as swmf.co.uk/surface-coatings/electroless-nickel-plating/ can offer this service.
Brittle Coatings
Brittle nickel coatings can crack or break when bent or under stress. This usually means that organic contaminants are trapped in the coating or heavy metals have polluted the bath. Treatment with activated carbon removes organic pollution, and electrolysis can remove metal contaminants without disrupting the entire bath.
Dark or Uneven Colour
When nickel plating looks dull or has colour variations, metal contamination is often the cause. Copper from previous plating is a common culprit. Improve rinsing between plating steps, and use electrolytic treatment with steel cathodes at low current to address this issue. Making sure that the pre-treatment of parts is done properly, checking for the right solution concentration and making sure that the electrical contacts are right will also help maintain consistent colour and brightness.