Glucydur is the trade name of a metal alloy

Alloy

An alloy is a mixture or metallic solid solution composed of two or more elements. Complete solid solution alloys give single solid phase microstructure, while partial solutions give two or more phases that may or may not be homogeneous in distribution, depending on thermal history...

 with a low coefficient of thermal expansion, used for making balance wheel

Balance wheel

The balance wheel is the timekeeping device used in mechanical watches and some clocks, analogous to the pendulum in a pendulum clock. It is a weighted wheel that rotates back and forth, being returned toward its center position by a spiral spring, the balance spring or hairspring...

s and other parts of mechanical watch

Mechanical watch

A mechanical watch is a watch that uses a mechanical mechanism to measure the passage of time, as opposed to modern quartz watches which function electronically. It is driven by a spring which must be wound periodically...

es.

Glucydur is a beryllium bronze

Bronze

Bronze is a metal alloy consisting primarily of copper, usually with tin as the main additive. It is hard and brittle, and it was particularly significant in antiquity, so much so that the Bronze Age was named after the metal...

; an alloy of beryllium

Beryllium

Beryllium is the chemical element with the symbol Be and atomic number 4. It is a divalent element which occurs naturally only in combination with other elements in minerals. Notable gemstones which contain beryllium include beryl and chrysoberyl...

, copper

Copper

Copper is a chemical element with the symbol Cu and atomic number 29. It is a ductile metal with very high thermal and electrical conductivity. Pure copper is soft and malleable; an exposed surface has a reddish-orange tarnish...

 and iron

Iron

Iron is a chemical element with the symbol Fe and atomic number 26. It is a metal in the first transition series. It is the most common element forming the planet Earth as a whole, forming much of Earth's outer and inner core. It is the fourth most common element in the Earth's crust...

. In addition to its low coefficient of thermal expansion, its hardness (400 Brinell

Brinell scale

The Brinell scale characterizes the indentation hardness of materials through the scale of penetration of an indenter, loaded on a material test-piece. It is one of several definitions of hardness in materials science....

), nonmagnetizability, and resistance to deformation and damage make it suited for making precision parts that must have high dimensional stability. Glucydur is also resistant to corrosion

Corrosion

Corrosion is the disintegration of an engineered material into its constituent atoms due to chemical reactions with its surroundings. In the most common use of the word, this means electrochemical oxidation of metals in reaction with an oxidant such as oxygen...

; it is rather inert chemically.

Glucydur was developed about the same time with another non-magnetic material, Nivarox

Nivarox

Nivarox is a Swiss company formed by a merger in 1984 between Nivarox SA and Fabriques d'Assortiments Réunis . It is currently owned by the Swatch Group. Nivarox is also the trade name of the metallic alloy from which its products are fabricated...

.