Galvanic corrosion, also known as dissimilar metal corrosion, can occur when two dissimilar conductive materials can come into contact in the presence of an electrolyte (such as water) and a pathway for electron transfer is created. In a composite context, this could mean contact between carbon composite and aluminium components or between a carbon reinforcement and aluminium honeycomb. Carbon fibre is a good electrical conductor and can produce a large galvanic potential with aluminium. The result of this is surface corrosion and extensive pitting; this can be very serious, particularly in instances where it occurs out of sight, as undetected, it may cause structural failure.
The issue of galvanic corrosion is not limited to aluminium and can occur with other metals and alloys, such as steel or stainless steel, in certain environmental conditions.
Dielectric non-wovens materials as an electrically isolating layer
The solution to stop galvanic corrosion occurring is to prevent moisture coming into contact with the carbon and the aluminium simultaneously. To achieve this, the materials must be separated. This can be achieved using one of TFP’s dielectric non-wovens which acts as an electrically isolating layer, providing a barrier to galvanic corrosion by preventing the electrochemical reaction.
Prevention of galvanic corrosion is just one application for TFP’s nonwovens which fulfil a number of purposes. These include improved surface finish for composites, resin flow media, improving interlaminar fracture toughness of a composite structure or imparting functionality such as abrasion resistance.
To find out more about TFP’s advanced nonwoven materials, typical applications and what else is
possible visit our website www.tfpglobal.com or talk to the team on the TFP stand F48 at SAMPE,
Baltimore from 19-20 May.