For many applications, gaskets are treated with various other metals to achieve better surface properties, encourage or discourage adhesion, or resist chemical or microbial attack.
Adhesives are used where an immediate permanent bond is needed. They are usually a synthetic rubber, resin, or combination.
Fungicides resist mold growth and may be an integral part of the gasket material or applied as surface treatment. Common fungicides are betanaphthol, pentachlorophenhol, salicylanilide and various compounds of copper and mercury.
Graphite is applied as a dry flake, mixed with oil, or in a water emulsion to level surfaces and to inhibit adhesion.
Oil and hot paraffin dip coats prevent loss of moisture during storage.
Reflectors such as aluminum paint or lacquer offer some protection to gaskets located near heat sources.
Rubber coatings such as neoprene are applied as a dip coat to reduce oil penetrations, loss of moisture, and installation breakage. Polysulfide coatings help level the surfaces and promote sealing contact of relatively hard-fiber sheet materials.
Talc and mica dust are applied dry or in an adhesive vehicle to cut surface friction of gaskets. They are often used where mating parts must be rotated to close the joint.
