Corrosion can be defined as “deterioration of a substance (usually a metal) because of a reaction with its environment”. Corrosion of metals is actually a chemical reaction caused primarily by attack of gaseous contaminants and is accelerated by heat and moisture. Rapid shifts in either temperature or humidity cause small portions of circuits to fall below the dew point temperature, thereby facilitating condensation of contaminants. There are three types of gases that can be considered as prime candidates in the corrosion of data center electronics: acidic gases such as hydrogen sulfide, sulfur and nitrogen oxides.

Restrictions on Hazardous Substances (RoHS), or lead-free, manufacturing regulations for electronic equipment that went into effect in 2006 only served to increase their concerns. Today companies selling consumer electronics, industrial process, and control systems products in the European Union. RoHS-compliant datacom and IT equipment, in particular, are at risk in locations with poor ambient air quality. Products with an immersion silver (ImmAg) surface finish will creep corrode in environments that electronic equipment manufacturers consider to be high sulfur (ISA Class G2 or higher). In high-pollution locations around the world, as a result, the number and types of corrosion failures have increased dramatically. The common component failures include hard disk drives (HDD), graphic cards, motherboards, DIMMs, capacitors, and transistors.