High-end Materials for High-end Watches

» Hi-tech Watches [Nov 03, 2006]

Briefly about…

Since the very beginning of the watch history the watchmakers have observed, that if exposing watches to certain physical phenomena they begin deviating, thus showing the wrong time. Such physical phenomena could be magnetic fields, temperature oscillation or wearing out of some parts of the mechanism due to their friction.
With this began the search for such materials, which would be able to withstand all these phenomena; such materials, which would not be affected by any magnetic fields, which would not change their volume under heat and would not wear out.

First Steps

The technicians tried to use bimetallic parts to avoid such problems. Taking into consideration the properties of each metal, the watchmakers combined these metals to compensate negative effects of external nature. Thus, for example, building a steel-and-brass balance at those times became a real modality for avoiding such things. Since steel and brass are metals with different coefficient of thermal expansion (CTE) they act differently when exposed to different temperatures. This means that when the temperature sinks, one of the compounds contracts, while the other expands; when the temperature gets higher - the reverse happens. However, this type of compensating balance was a too costly procedure, which also took much time to produce.

The Industry's Breakthrough

The breakthrough came in the middle of the 19th century, when the experiments with anti-magnetic watches became very popular in the world of horology. However, first materials, which are used extensively today in the watch industry, have appeared in the end of the same century or at the beginning of the 20th century.

The most well-known materials, known for their good qualities of a low coefficient of thermal expansion and non-magnetism are Invar, Elinvar, Nivarox and Glucydur. These materials are all alloys consisting of different metals with different properties, thus building up the perfect building material for different parts of a watch's mechanism.

Invariable

Invar (which stands for "invariable") was developed by Charles Edouard Guillaume in 1896. It was also called FeNi, because it consisted mainly of iron (64%) and nickel (36%), though with additions of carbon and chromium. The alloy is now renowned worldwide in the world of horology for its exceptional property of controlled coefficient of thermal expansion and the ability to resist to magnetic fields. The French physicist received the Nobel Prize in Physics in 1920 for his contribution to this science.

Invar is extensively used today in assembling not only high-end watch mechanisms, but also in producing precise instruments. However at the same time it is a trademark of the French Company Imphy Alloys.

Elastically Invariable

Elinvar (which stands for the French "elasticité invariable" - elastically invariable) is another product of Guillaume's work. After Invar proved to be an excellent material for watch-making, in 1912 Guillaume developed another material, 29 % of which was nickel. This material was too soft, thus proved to be too difficult to work with. In 1920 Guillaume has found the solution for everything he sought for - Elinvar. It was a product of collaboration between Guillaume, Chenevard and Imphy laboratory. Elinvar became another good alternative to the bimetallic balances.

Never Oxidizing

Nivarox (which stands for "Nicht Variable Oxydfest" - in German this means "Not Variable, Resistant to Oxidation") is a another metallic alloy used as an alternative to the bimetallic 'technology' of watch-making. This alloy is composed of iron, nickel, chromium, titanium and beryllium. The material possesses properties, which were found very useful in building the balances of the timepieces. Nivarox makes the watches' hairsprings very durable thus excluding them to wear out; the material makes these parts almost immune to magnetic fields, oxidation and to oscillations of temperature.

Nivarox stabilizes the movement of the watch and makes it more resistant against external phenomena. This alloy made obsolete the expensive and sophisticated compensational balances. Nivarox is being used on different levels of production of watches by most watchmakers worldwide.

Beryllium Bronze Balances

Glucydur is another multi-metallic alloy, used in the watch industry for building different parts of the mechanism. It was developed at about the same time as the Nivarox.

This is an alloy of beryllium, copper and iron. With such properties as hardness, resistance to deformation and damage, immunity against magnetic fields and stability this alloy has become perfect for making balance wheels for watches' mechanisms. It is also resistant to corrosion and oxidation; it is rather inert chemically. It is extensively used by many watch brands in their mechanisms in order to produce high-end instruments for professionals.

It is still not clear whether "Glucydur" is just a name for this alloy or it is a brand name, but the experts of horology state that all beryllium bronze balances are "glucydur". This might mean that it is both a brand name and a simple name.

The materials described in this article are most commonly used in building watches immune to magnetic fields, which are also called anti-magnetic watches. Such watches are perfect instruments for such professionals as engineers, who deal with magnetic fields every day, thus the watch deviates. Medics, who deal with certain magnetic apparatus, could also find such watches quite useful, due to their magnetic resistance.

These materials show how the horology world is always evolving - it never remains static, because today if they don't evolve, they degenerate!

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