|The above photo illustratees metal hardware exhibiting corrosion due to improper elastomer selection.|
Corrosion is the result of chemical action of a fluid and/or the elastomer compound upon the metal surfaces of the seal gland cavity. O-ring material selection is primarily concerned with corrosive effects caused by the compound alone, although it should be noted that fluid corrosion of the gland metal will cause a change of surface finish that can seriously affect the seal, especially in a dynamic application. When rubber seals were first used, there were numerous instances in which the compound itself did act adversely upon metal causing actual pitting of the gland surface. Certain elastomer compounding ingredients, such as uncombined sulfur or certain types of carbon black were found to cause the problem. Currently, compounding expertise, modern chemicals and supplier testing has made reports of this type of corrosion rare. However, due to frequent introduction of new and improved compounding ingredients, continuous attention to potential corrosive effects is necessary.