Adhesion of a coating can be improved by the use of silane coupling agents. The preparation, application and properties of silane coupling agents is presented. The mechanism for the formation of Si-O-Substrate bonds will be discussed. Kinetic data, adhesion data and electron photomicrographs is discussed to support work on the rate of exchange of one alkoxy group for another on these silanes to give information about the bond-breaking/bond-formation process which is similar to that which occurs with silane coupling agents. The author prepared a series of epoxy coatings on mild steel which were subjected to salt-fog chamber exposure. These lasted in excess of 500 hours in the salt-fog chamber, whereas those without the silane coupling agent failed in less time.