A niobium alloy is one in which the most common element is

niobium Niobium is a chemical element; it has chemical symbol, symbol Nb (formerly columbium, Cb) and atomic number 41. It is a light grey, crystalline, and Ductility, ductile transition metal. Pure niobium has a Mohs scale of mineral hardness, Mohs h ...

Alloys used for the production of other alloys

The most common commercial niobium alloys are

ferroniobium Ferroniobium is an important iron-niobium alloy, with a niobium content of 60-70%. It is the main source for niobium alloying of HSLA steel and covers more than 80% of the worldwide niobium production. The niobium is mined from pyrochlore deposits ...

and nickel-niobium, produced by

thermite Thermite () is a pyrotechnic composition of powder metallurgy, metal powder and metal oxide. When ignited by heat or chemical reaction, thermite undergoes an exothermic redox, reduction-oxidation (redox) reaction. Most varieties are not explos ...

reduction of appropriate mixtures of the oxides; these are not usable as engineering materials, but are used as convenient sources of niobium for specialist steels and nickel-based

superalloy A superalloy, or high-performance alloy, is an alloy with the ability to operate at a high fraction of its melting point. Key characteristics of a superalloy include mechanical strength, thermal creep deformation resistance, surface stability, ...

s. Going via an iron-niobium or nickel-niobium alloy avoids problems associated with the high melting point of niobium.

Superconducting alloys

Niobium-tin and Niobium-titanium are essential alloys for the industrial use of

superconductors Superconductivity is a set of physical properties observed in superconductors: materials where electrical resistance vanishes and magnetic fields are expelled from the material. Unlike an ordinary metallic conductor, whose resistance decreases ...

, since they remain superconducting in high magnetic fields ( for Nb₃Sn, for NbTi); there are 1200 tons of NbTi in the magnets of the

Large Hadron Collider The Large Hadron Collider (LHC) is the world's largest and highest-energy particle accelerator. It was built by the CERN, European Organization for Nuclear Research (CERN) between 1998 and 2008, in collaboration with over 10,000 scientists, ...

, whilst Nb₃Sn is used in the windings of almost all hospital

MRI Magnetic resonance imaging (MRI) is a medical imaging technique used in radiology to generate pictures of the anatomy and the physiological processes inside the body. MRI scanners use strong magnetic fields, magnetic field gradients, and rad ...

machines.

Aerospace rivets

Niobium-titanium alloy, of the same composition as the superconducting one, is used for

rivets A rivet is a permanent mechanical fastener. Before being installed, a rivet consists of a smooth cylindrical shaft with a head on one end. The end opposite the head is called the ''tail''. On installation, the deformed end is called the ''sh ...

in the aerospace industry; it is easier to form than CP titanium, and stronger at elevated (> 300°C) temperatures.

Refractory alloys

Niobium-1% zirconium is used in rocketry and in the nuclear industry. It is regarded as a low-strength alloy. C-103, which is 89% Nb, 10% Hf and 1% Ti, is used for the rocket nozzle of the

Apollo service module The Apollo command and service module (CSM) was one of two principal components of the United States Apollo spacecraft, used for the Apollo program, which landed astronauts on the Moon between 1969 and 1972. The CSM functioned as a mother ship ...

and the

Merlin vacuum Merlin is a family of rocket engines developed by SpaceX. They are currently a part of the Falcon 9 and Falcon Heavy launch vehicles, and were formerly used on the Falcon 1. Merlin engines use RP-1 and liquid oxygen as rocket propellants in a Gas- ...

engines; it is regarded as a medium-strength alloy. It is typically produced using gas atomization or plasma atomization techniques. It is particularly used in additive manufacturing (3D printing) and powder metallurgy processes. Due to its corrosion resistance and high thermal efficiency, C103 helps reduce material waste and environmental pollution. High-strength alloys include C-129Y (10% tungsten, 10% hafnium, 0.1% yttrium, balance niobium), Cb-752 (10% tungsten, 2.5% zirconium), and the even higher strength C-3009 (61% niobium, 30% hafnium, 9% tungsten); these can be used at temperatures up to 1650°C with acceptable strength, though are expensive and hard to form. Nb-Hf-Ti is an alloy powder consisting of niobium (Nb), hafnium (Hf), and a small amount of titanium (Ti) provides high strength, ductility, high-temperature stability, and remarkable corrosion resistance. It is used in manufacturing biocompatible implants and devices such as

orthopedic implants Orthopedic surgery or orthopedics ( alternative spelling orthopaedics) is the branch of surgery concerned with conditions involving the musculoskeletal system. Orthopedic surgeons use both surgical and nonsurgical means to treat musculoskeletal ...

and dental prosthetics. Niobium alloys in general are inconvenient to weld: both sides of the weld must be protected with a stream of inert gas, because hot niobium will react with oxygen and nitrogen in the air. It is also necessary to take care (e.g. hard chrome-plating of all copper tooling) to avoid copper contamination.

References

{{reflist