What Is Porosity And How Is It Caused?

29 Apr, 2021 Amy Stillwell

To perform its function properly, an electroplated surface of a product often needs to be flat and consistent. Any imperfections on the metal coating or exposed areas on an electroplated surface can lead to several issues; from poor performance to severe, irreversible damage to the product. In the telecommunications industry, for instance, an uneven or porous surface of a connector can lead to electrical resistance and unsatisfactory performance.

Sometimes a simple fix such as applying plating masking products can help fix an issue. Other times problems cannot be so easily rectified. Although modern metal plating techniques produce high-quality finished parts, imperfections can still occur and one of the most common imperfections affecting metal plated products is porosity.

What is porosity and how does it affect products?

Porosity refers to microscopic holes which can occur in an electroplated metal coating of a product. If these small holes reach the base metal, or underplate if one exists, the metal is exposed and can be damaged. The biggest impact porosity can have on a product is corrosion.

Corrosion creep happens when corrosive elements pass through the holes to the base material and contaminate the surface. Certain environments and the use of harsh chemicals such as chlorine and sulphur can increase the corrosion in porous metal plating. Corrosion can be an issue with larger holes too which can be protected by using metal masking products, such as metal masking tapes.

Porosity can also impact a product’s performance due to insufficient thickness of the coating which lessens the overall strength and ductility of the metal coating. For example, if you’re looking to apply a metal coating to achieve conductivity, porosity may lead to reduced conductivity and undesired results.

How do I prevent porosity in my products?

There are two ways you can prevent porosity from decreasing the durability and usability of your product and limit its negative effects:

  1. Ensure substrate surface is smooth before metal plating. By reducing the roughness and removing imperfections from the base metal which can lead to increased porosity, you can prevent the formation of pores. This can be achieved by polishing the surface thoroughly before electroplating.
  2. Applying an underplate. Although underplating cannot prevent porosity, it can help to prevent corrosion creep. If pores stop at the underplate rather than reaching the base metal, corrosion products cannot escape harming the metal plated surface.

There is also a range of plating masking products suitable for different electroplating processes which can also be used to protect the base metal surface from corrosion. Pull through plugs are designed to keep larger holes protected from harsh chemicals and contamination.

If you need advice on how to prevent porosity in your product or are experiencing any of the issues stated above, contact us. As a specialist in paint masking and plating masking products for electroplating, we can recommend the most suitable course of action for your product, and our sister company Dorsetware performs metal plating services in Dorset, Wiltshire, Hampshire, Devon and the M3 corridor. Get in touch with us today by calling 01202 661 300.