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Dielectric nonwovens provide barrier to galvanic corrosion

News International-French

17 Apr 2015

Dielectric nonwovens from Technical Fibre Products can be used to prevent galvanic corrosion, a common and destructive problem when aluminium or other metals come into contact with carbon fibre in a composite structure.

The nonwoven can prevent this by providing an extremely uniform, lightweight barrier between the two materials to isolate them, stopping an electrochemical reaction occurring.

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.

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 nonwovens 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.

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