Uniform chemical attack of metals is the simplest
form of corrosion, occurring in the atmosphere,
in solutions, and in soil, frequently under
normal service conditions. Excessive attack can
occur when the environment has changed from
that initially expected. Weathering steels, magnesium
alloys, zinc alloys, and copper alloys are
examples of materials that typically exhibit general
corrosion. Passive materials, such as stainless
steels, aluminum alloys, or nickel-chromium
alloys are generally subject to localized corrosion.
Under specific conditions, however, each
material may vary from its normal mode of corrosion.