Passivation, in
physical chemistry and
engineering, refers to a material becoming "passive," that is, being less affected by environmental factors such as air and water. Passivation involves a shielding outer-layer of base material, which can be applied as a microcoating, or oxidation which occurs spontaneously in nature. As a technique, passivation is the use of a light coat of a protective material, such as
metal oxide, to create a shell against
corrosion. Passivation can occur only in certain conditions, and is used in
microelectronics to enhance silicon. The technique of passivation is used to strengthen and preserve the appearance of .