Manganin
Encyclopedia
Manganin is a trademark
ed name for an alloy
of typically 86% copper
, 12% manganese
, and 2% nickel
. It was first developed by Edward Weston
in 1892, improving upon his Constantan
(1887).
Manganin foil
and wire
is used in the manufacture of resistor
s, particularly ammeter shunts, because of its virtually zero temperature coefficient of resistance value and long term stability. Several Manganin resistors served as the legal standard for the ohm in the United States from 1901 to 1990. Manganin wire is also used as an electrical conductor in cryogenic systems, minimizing heat transfer between points which need electrical connections.
Manganin is also used in gauges for studies of high-pressure
shock waves
(such as those generated from the detonation of explosives
) because it has low strain
sensitivity but high hydrostatic pressure sensitivity.
coefficient of resistance, inventing what he called his "Alloy No. 2."
It was produced in Germany where it was renamed "Constantan".
In 1892 Weston had finally completed his discovery of an alloy
of copper, nickel, and manganese prepared by a complicated series
of heat-treatments. In May, 1893, he received a basic patent on the
composition, manufacture, and use of the material for electrical
resistors. Production was carried out in Germany, and it
became known as "Manganin".
The availability of a practical conductive metal with an extremely
constant resistance over the range of ordinary temperatures
was a great advance in electrical technology and equipment design,
but Weston did not receive general recognition for this.
Trademark
A trademark, trade mark, or trade-mark is a distinctive sign or indicator used by an individual, business organization, or other legal entity to identify that the products or services to consumers with which the trademark appears originate from a unique source, and to distinguish its products or...
ed name for an 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...
of typically 86% 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...
, 12% manganese
Manganese
Manganese is a chemical element, designated by the symbol Mn. It has the atomic number 25. It is found as a free element in nature , and in many minerals...
, and 2% 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...
. It was first developed by Edward Weston
Edward Weston (chemist)
Edward Weston was an English-born American chemist noted for his achievements in electroplating and his development of the electrochemical cell, named the Weston cell, for the voltage standard...
in 1892, improving upon his Constantan
Constantan
Constantan is a copper-nickel alloy usually consisting of 55% copper and 45% nickel.Also known as Eureka.Its main feature is its resistivity which is constant over a wide range of temperatures...
(1887).
Manganin foil
Foil (chemistry)
A foil is a very thin sheet of metal, usually made by hammering or rolling a piece of metal. Foils are most easily made with malleable metals, such as aluminium, copper, tin, and gold. Foils usually bend under their own weight and can be torn easily. The more malleable a metal, the thinner foil can...
and wire
Wire
A wire is a single, usually cylindrical, flexible strand or rod of metal. Wires are used to bear mechanical loads and to carry electricity and telecommunications signals. Wire is commonly formed by drawing the metal through a hole in a die or draw plate. Standard sizes are determined by various...
is used in the manufacture of resistor
Resistor
A linear resistor is a linear, passive two-terminal electrical component that implements electrical resistance as a circuit element.The current through a resistor is in direct proportion to the voltage across the resistor's terminals. Thus, the ratio of the voltage applied across a resistor's...
s, particularly ammeter shunts, because of its virtually zero temperature coefficient of resistance value and long term stability. Several Manganin resistors served as the legal standard for the ohm in the United States from 1901 to 1990. Manganin wire is also used as an electrical conductor in cryogenic systems, minimizing heat transfer between points which need electrical connections.
Manganin is also used in gauges for studies of high-pressure
High pressure
High pressure in science and engineering is studying the effects of high pressure on materials and the design and construction of devices, such as a diamond anvil cell, which can create high pressure...
shock waves
Shock Waves
Shock Waves, , is a 1977 horror movie written and directed by Ken Wiederhorn...
(such as those generated from the detonation of explosives
Explosive material
An explosive material, also called an explosive, is a reactive substance that contains a great amount of potential energy that can produce an explosion if released suddenly, usually accompanied by the production of light, heat, sound, and pressure...
) because it has low strain
Strain (materials science)
In continuum mechanics, the infinitesimal strain theory, sometimes called small deformation theory, small displacement theory, or small displacement-gradient theory, deals with infinitesimal deformations of a continuum body...
sensitivity but high hydrostatic pressure sensitivity.
History
In 1887 Edward Weston discovered that metals can have a negative temperaturecoefficient of resistance, inventing what he called his "Alloy No. 2."
It was produced in Germany where it was renamed "Constantan".
In 1892 Weston had finally completed his discovery of an alloy
of copper, nickel, and manganese prepared by a complicated series
of heat-treatments. In May, 1893, he received a basic patent on the
composition, manufacture, and use of the material for electrical
resistors. Production was carried out in Germany, and it
became known as "Manganin".
The availability of a practical conductive metal with an extremely
constant resistance over the range of ordinary temperatures
was a great advance in electrical technology and equipment design,
but Weston did not receive general recognition for this.
Properties
Cu86/Mn12/Ni2
Electrical Properties
Temperature coefficient ( K-1 ) 0.00001
Electrical resistivity ( µOhmcm ) 43-48
Mechanical Properties
Elongation at break ( % ) <50
Izod impact strength ( J m-1 ) 107
Modulus of elasticity ( GPa ) 124-159
Tensile strength ( MPa ) 300-600
Physical Properties
Density ( g cm-3 ) 8.4
Melting point ( C ) 960
Thermal Properties
Coefficient of thermal expansion ( x10-6 K-1 ) 14-19 @ 20-100C
Maximum use temperature in air ( C ) 300
Thermal conductivity ( W m-1 K-1 ) 22 @ 23C
Cu84/Mn12/Ni4
Temperature coefficient of resistivity
TempDegC (Somerville 1910)
12 .000006
25 .000000
100 -.000042
250 -.000052
475 .000000
500 +.00011
Resistance of Wires - 20 deg C
Manganin Q = 44. x 10-6 ohm cm
Gage B&S / ohms per cm / ohms per ft
10 .000836 .0255
12 .00133 .0405
14 .00211 .0644
16 .00336 .102
18 .00535 .163
20 .00850 .259
22 .0135 .412
24 .0215 .655
26 .0342 1.04
27 .0431 1.31
28 .0543 1.66
30 .0864 2.63
32 .137 4.19
34 .218 6.66
36 .347 10.6
40 .878 26.8