Elinvar
Encyclopedia
Elinvar is a nickel
steel
alloy
with a modulus of elasticity which does not change much with temperature
changes. The name is a contraction of the French elasticité invariable. It was invented in the late 1890s by Charles Édouard Guillaume
, a Swiss physicist who also invented Invar
, another alloy of nickel
and iron
, which has very low thermal expansion. Guillaume won the 1920 Nobel Prize
in Physics for these discoveries, which indicates how important these alloys were for scientific instruments.
Elinvar consists of 59% iron
, 36% nickel
, and 5% chromium
. It is almost nonmagnetic and corrosion resistant.
The largest use of Elinvar was in balance spring
s for mechanical watch
es and chronometer
s. A major cause of inaccuracy in watches and clocks was that ordinary steels used in springs lost elasticity slightly as the temperature increased, so the balance wheel
would oscillate more slowly back and forth, and the clock would lose time. Chronometers and precision watches required complex temperature-compensated balance wheels for accurate timekeeping. Springs made of Elinvar, and other low temperature coefficient alloys such as Nivarox
that followed, were not affected by temperature, so they made the temperature-compensated balance wheel obsolete.
Nickel
Nickel is a chemical element with the chemical symbol Ni and atomic number 28. It is a silvery-white lustrous metal with a slight golden tinge. Nickel belongs to the transition metals and is hard and ductile...
steel
Steel
Steel is an alloy that consists mostly of iron and has a carbon content between 0.2% and 2.1% by weight, depending on the grade. Carbon is the most common alloying material for iron, but various other alloying elements are used, such as manganese, chromium, vanadium, and tungsten...
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 modulus of elasticity which does not change much with temperature
Temperature
Temperature is a physical property of matter that quantitatively expresses the common notions of hot and cold. Objects of low temperature are cold, while various degrees of higher temperatures are referred to as warm or hot...
changes. The name is a contraction of the French elasticité invariable. It was invented in the late 1890s by Charles Édouard Guillaume
Charles Edouard Guillaume
Charles Édouard Guillaume was a Swiss physicist who received the Nobel Prize in Physics in 1920 in recognition of the service he had rendered to precision measurements in physics by his discovery of anomalies in nickel steel alloys.Guillaume is known for his discovery of nickel-steel alloys he...
, a Swiss physicist who also invented Invar
Invar
Invar, also known generically as FeNi36 , is a nickel steel alloy notable for its uniquely low coefficient of thermal expansion . The name, Invar, comes from the word invariable, referring to its lack of expansion or contraction with temperature changes.It was invented in 1896 by Swiss scientist...
, another alloy of nickel
Nickel
Nickel is a chemical element with the chemical symbol Ni and atomic number 28. It is a silvery-white lustrous metal with a slight golden tinge. Nickel belongs to the transition metals and is hard and ductile...
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...
, which has very low thermal expansion. Guillaume won the 1920 Nobel Prize
Nobel Prize
The Nobel Prizes are annual international awards bestowed by Scandinavian committees in recognition of cultural and scientific advances. The will of the Swedish chemist Alfred Nobel, the inventor of dynamite, established the prizes in 1895...
in Physics for these discoveries, which indicates how important these alloys were for scientific instruments.
Elinvar consists of 59% 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...
, 36% nickel
Nickel
Nickel is a chemical element with the chemical symbol Ni and atomic number 28. It is a silvery-white lustrous metal with a slight golden tinge. Nickel belongs to the transition metals and is hard and ductile...
, and 5% chromium
Chromium
Chromium is a chemical element which has the symbol Cr and atomic number 24. It is the first element in Group 6. It is a steely-gray, lustrous, hard metal that takes a high polish and has a high melting point. It is also odorless, tasteless, and malleable...
. It is almost nonmagnetic and corrosion resistant.
The largest use of Elinvar was in balance spring
Balance spring
A balance spring, or hairspring, is a part used in mechanical timepieces. The balance spring, attached to the balance wheel, controls the speed at which the wheels of the timepiece turn, and thus the rate of movement of the hands...
s for 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 and chronometer
Marine chronometer
A marine chronometer is a clock that is precise and accurate enough to be used as a portable time standard; it can therefore be used to determine longitude by means of celestial navigation...
s. A major cause of inaccuracy in watches and clocks was that ordinary steels used in springs lost elasticity slightly as the temperature increased, so the 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...
would oscillate more slowly back and forth, and the clock would lose time. Chronometers and precision watches required complex temperature-compensated balance wheels for accurate timekeeping. Springs made of Elinvar, and other low temperature coefficient alloys such as 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...
that followed, were not affected by temperature, so they made the temperature-compensated balance wheel obsolete.