In the watchmaking industry nickel is used together with stainless steel. The latter is a material watchmaking companies use to create water-resistant cases. However both nickel and watchmaking have a lot of other tangency points as well.
Nickel Throughout History
An alloy made of nickel, copper and zinc, named “nickel silver,” for more than 150 years has been used to crate plates and bridges in some of the most qualitative watches. The nickel silver, which includes about 15 – 20 percent Ni, was the one to replace the brass.
The composition was also the one to be used in the production of cases for inexpensive watches. Before that only silver was used. Over time the watch industry passed on to make watches of stainless steel.
Today pure nickel is used in electroplate watch parts, including bridges and plates that are made of brass. This is done to prevent oxidation of watch parts. Using a thin layer of nickel is all that is needed to protect the parts and maintain their shiny metallic appearance.
Throughout the history nickel was also used to create balance springs and pendulum rods. It is worth mentioning that Charles-Edouard Guillaume (1861-1938) in 1920 was awarded a Nobel Prize in Physics. The Swiss International Bureau of Weights and Measures worker was the one to discover anomalies in nickel-steel alloys.
His observation led to the discovery of Invar (ferronickel that comprises about 36% nickel. Invar has a very low coefficient of expansion) and Elinvar (variation of Invar).
The discoveries of the new alloys were of great use mainly in precision pendulum rods, watch balance springs, as well as thermostats, length standards.
What causes allergies to nickel?
If a sensitive skin of a person is in direct contact with a certain object containing nickel, there is a possibility that the allergic reaction occurs. If taking into consideration watches than it is necessary to mention the possible contact of skin with the case or bracelet of the watch.
Another reason for an allergic response of one’s skin refers to the fact that nickel is liberated quite easy from its alloy and onto the skin. It liberates in the form of positively or negatively charged particles. Positive ions can be transported by a fluid, which serves as an electrolyte. Very often the electrolyte is sweat, however the particles can be transported by water from the sea or from a swimming pool.
The stainless steel, which is used to make watch cases, is the one that liberates nickel ions in different amounts. The amount of liberated ions depends on the nature of the alloy as well as the proportions of the individual components. Note that stainless steel made for medical purposes practically does not liberate nickel ions.
People that are are allergic to nickel should avoid wearing costume jewelry made of nickel silver. The allergic reaction often shows up in the form of dermatitis.
A very important factor linked with liberation of nickel ions concerns the condition of metal surface that comes in contact with skin. Surfaces that are rough or porous hold back the electrolytic fluid thus turning into active zones where allergenic cations are produced. Afterwards the resulting metal corrosion produces even higher concentrations of the metal ions. When examining the case-back of a chrome-plated watch attacked by sweat, one may notice how much corrosion has taken place. In such a way the wearer of a watch can understand why the skin became sensitive.
Besides stainless steel watches and bracelets, it is also important to take into consideration the bi-color watches, meaning those that are made of gold and steel. These can also cause problems to a sensitive skin. Just like stainless steel, gold has different electric potentials, which is why sweat transports ions faster. Thus, an increase in corrosion represents a great risk of allergy. There is a close connection between the rate of corrosion and the rate of allergies.
Those who are allergic to nickel obviously should avoid wearing watches containing any nickel at all. An alternative for such watches might be some models from Swatch. The company produces watches made of synthetic materials. Another alternative can be luxury watches made of pink or yellow gold. It is worth mentioning that white gold quite often includes nickel the amount of which can cause allergic reaction of skin. Sensitive skin can also be affected by gold-plated watches. However, an allergic reaction may occur when such watches are worn for quite long periods of time. This is because the thin layer of gold wears off, thus exposing the skin to the metal that contains nickel.