Chromel is an

alloy An alloy is a mixture of chemical elements of which at least one is a metal. Unlike chemical compounds with metallic bases, an alloy will retain all the properties of a metal in the resulting material, such as electrical conductivity, ductility, ...

made of approximately 90%

nickel Nickel is a chemical element with symbol Ni and atomic number 28. It is a silvery-white lustrous metal with a slight golden tinge. Nickel is a hard and ductile transition metal. Pure nickel is chemically reactive but large pieces are slow to ...

and 10%

chromium Chromium is a chemical element with the symbol Cr and atomic number 24. It is the first element in group 6. It is a steely-grey, lustrous, hard, and brittle transition metal. Chromium metal is valued for its high corrosion resistance and hardne ...

by weight that is used to make the positive conductors of ANSI Type E (chromel-

constantan Constantan is a proprietary name A brand is a name, term, design, symbol or any other feature that distinguishes one seller's good or service from those of other sellers. Brands are used in business, marketing, and advertising for recogn ...

) and K (chromel-

alumel Alumel is an alloy consisting of approximately 95% nickel, 2% aluminium, 2% manganese, and 1% silicon. This magnetic alloy is used to make the negative conductors of ANSI Type K (chromel-alumel) thermocouple A thermocouple, also known as a "therm ...

)

thermocouple A thermocouple, also known as a "thermoelectrical thermometer", is an electrical device consisting of two dissimilar electrical conductors forming an electrical junction. A thermocouple produces a temperature-dependent voltage as a result of the ...

s. It can be used at temperatures up to in oxidizing atmospheres. Chromel is a registered trademark of Concept Alloys, Inc.

Chromel A

Chromel A is an alloy containing approximately 80% nickel and 20% chromium (by weight), with low-level quantities of Si (1%), Fe (0.5%), and Ni. It is used for its excellent resistance to high-temperature corrosion and oxidation. It is also commonly called

Nichrome Nichrome (also known as NiCr, nickel-chromium or chromium-nickel) is a family of alloys of nickel, chromium, and often iron (and possibly other elements) commonly used as resistance wire, heating elements in devices like toasters, electrical kettl ...

80-20, and is used for electric heating elements.

Chromel C

Chromel C is an alloy containing 60% nickel, 16% chromium and 24% iron. It is also commonly called

60 and is used for heating elements, resistance windings, and hot wire cutters.

Chromel-R

Chromel R has a composition of Cr 20%, Ni 80%. Chromel-R was also produced as a woven fabric of chromel wires. It was developed by

Litton Industries Litton Industries was a large defense contractor in the United States named after inventor Charles Litton Sr. During the 1960s, the company began acquiring many unrelated firms and became one of the largest conglomerates in the United States. ...

for use by

NASA The National Aeronautics and Space Administration (NASA ) is an independent agency of the US federal government responsible for the civil space program, aeronautics research, and space research. NASA was established in 1958, succeeding t ...

in the

Gemini Gemini may refer to: Space * Gemini (constellation), one of the constellations of the zodiac ** Gemini in Chinese astronomy * Project Gemini, the second U.S. crewed spaceflight program * Gemini Observatory, consisting of telescopes in the Northern ...

and Apollo programs. The Gemini G4C spacesuit did not use Chromel-R as standard. However the

Gemini 9 Gemini 9A (officially Gemini IX-A) With Gemini IV, NASA changed to Roman numerals for Gemini mission designations. was a 1966 crewed spaceflight in NASA's Gemini program. It was the seventh crewed Gemini flight, the 13th crewed American flight ...

mission was to test the use of the

Astronaut Maneuvering Unit An astronaut propulsion unit (or astronaut maneuvering unit) is used to move an astronaut relative to the spaceship during a spacewalk. The first astronaut propulsion unit was the Hand-Held Maneuvering Unit (HHMU) used on Gemini 4. Models Hand ...

, a free-flying 'rocket pack'. To protect against the hot exhaust of its

hydrogen peroxide Hydrogen peroxide is a chemical compound with the formula . In its pure form, it is a very pale blue liquid that is slightly more viscous than water. It is used as an oxidizer, bleaching agent, and antiseptic, usually as a dilute solution (3%� ...

engine,

Gene Cernan Eugene Andrew Cernan (; March 14, 1934 – January 16, 2017) was an American astronaut, naval aviator, electrical engineer, aeronautical engineer, and fighter pilot. During the Apollo 17 mission, Cernan became the eleventh human being to ...

's suit was given additional protection with an over-trouser layer of Chromel-R. The spacewalk during this flight gave a number of problems, with Cernan overheating and finding the suit difficult to move in it, with "all the flexibility of a rusty suit of armor". The Chromel-R layer was an integral part of the spacesuit,It may be seen being worn as the astronauts travel out to the launch pad, :File:S66-34075.jpg although the confined Gemini capsule did not require much movement until the spacewalk. Once pressurised, the suit became difficult to move in. Neil Armstrong's Apollo 11 Lunar EVA glove (27933065161)

Neil Armstrong's Apollo 11 Lunar EVA glove (27933065161)

Smaller patches of Chromel-R formed an outer layer of the Apollo spacesuit where abrasion resistance was needed. These patches can be seen as silver-grey areas over the white

Beta cloth Beta cloth is a type of fireproof silica fiber cloth used in the manufacture of Apollo/Skylab A7L space suits, the Apollo Thermal Micrometeoroid Garment, the McDivitt Purse, and in other specialized applications. Beta cloth consists of fine w ...

of the main suit. Using patches, rather than an entire garment, avoided the flexibility problems with Gemini. The upper areas of the overshoes, the gloves and patches beneath the

life support Life support comprises the treatments and techniques performed in an emergency in order to support life after the failure of one or more vital organs. Healthcare providers and emergency medical technicians are generally certified to perform basic ...

backpack were of Chromel-R. Gold-plated open-weave Chromel-R mesh has also been used as the reflecting surface for compact-folding parabolic antenna on spacecraft.

References and notes

External links

Materials properties of thermocouple wires sold by Omega Engineering, Inc.

Technical information on alloys at Electrovek-Steel Ltd.
Nickel–chromium alloys Nickel alloys Chromium alloys {{alloy-stub