Corrosion protection

Corrosion protection using nickel

The term “corrosion” stems from the Latin “corrodere“, which means “to gnaw away at“. In the German Industry Standard DIN 50900, „Corrosion of Metals“, part 1, corrosion is described as “the reaction of a metallic material to its environment, which effects measurable change in the material and can lead to impairment of the function of a metal component or of an entire system.”

For example, if iron or steel are subject to certain environmental conditions, the well-known process of “rusting“ starts, i.e. the oxidation of iron to ferrous oxide.

There are several protective methods for avoiding this process, which generally come under the heading “corrosion protection“.

One of these methods is galvanic nickel plating, a passive protection method against corrosion which acts cathodically. The nickel layer forms a cover that prevents corrosively active substances, such as water or oxygen coming into contact with the iron. Nickel is not only corrosion-resistant, but is also resistant to heat and is ductile with decorative properties.

At ambient temperature, nickel is resistant to air, water, non-oxidizing acids (e.g. hydrochloric acid), lyes, and most organic substances. Yet the metal itself is not completely immune to corrosion: e.g., diluted nitric acid can dissolve nickel. Under certain circumstances, however, a nickel oxide passivation layer is formed, which further increases surface resistance.