At Clark Craft, we supply fasteners in corrosion-resistant metals. In the long run, when you consider the labor, maintenance, and replacement cost of a failed fastener, the cost would have been far less if the proper fastener had been used. Corrosion is the wearing away, or alteration of a metal by galvanic reaction, or by direct chemical atttack. An example is the rusting of iron, or steel. Direct Attack Corrosion.
Atmospheric corrosion is an example of direct chemical attack.
Present in the atmosphere are oxygen, carbon dioxide, water vapor, sulfur, and chlorine compounds. The severity of the attack is directly related to the amount of water vapor, sulfur and chlorine compounds present. All metals have specific relative electrical potential. When metals of different electrical potenial such as steel and copper are in contact in the presence of moisture, a low energy electric current flows from the metal having the higher position in the galvanic series. To help prevent direct attack corrosion.