Cortec® Corporation demonstrates how specialised expertise and tailored corrosion protection strategies can effectively prevent serious damage in mixed-metal systems caused by galvanic corrosion.
The galvanic series, which ranks metals from most noble (least reactive) to least noble (most reactive), was a key factor in Cortec®’s solution to the corrosion problem. Metals such as platinum and gold are at the top of the series, offering high resistance to corrosion, while aluminium and zinc are more reactive and found at the bottom. Bronze, copper, and other ‘yellow’ metals fall in between. When metals from different points on this scale come into contact, especially in the presence of an electrolyte like water, corrosion can occur rapidly. The less noble metal sacrifices itself to protect the more noble one, often leading to unexpected degradation in the system.
Cortec® identified that components like steel fasteners, which are typically protected, were being compromised due to their proximity to more noble metals such as copper or brass. Standard protection methods overlooked the full range of materials, leaving more reactive metals vulnerable to faster corrosion. Recognising this gap, Cortec® implemented a comprehensive prevention strategy. This approach included the use of corrosion-inhibiting products designed to protect all metals within the system, rather than just one.
Cortec® used a combination of VpCI®-based coatings, packaging and liquid rust preventatives to significantly reduce the risk of galvanic corrosion throughout the system. This approach led to a notable enhancement in both the longevity and reliability of the installation, with no further signs of galvanic attack. This emphasises the crucial need for comprehensive protection across all materials and the risks involved in assuming that certain metals are immune to corrosion.