Titanium nitride

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"TiN" redirects here. For the chemical element, see Tin.
Titanium nitride
Brown powdered titanium nitride
The structure of sodium chloride; titanium nitride's structure is similar.
Names
IUPAC name
Titanium nitride
Other names
Titanium(III) nitride
Identifiers
3D model (
JSmol
)
ECHA InfoCard
 100.042.819 Edit this at Wikidata
EC Number
  • 247-117-5
UNII
  • InChI=1S/N.Ti
  • N#[Ti]
Properties
TiN
Molar mass 61.874 g/mol
Appearance Brown as a pure solid, coating of golden color
Odor Odorless
Density 5.21 g/cm3[1]
Melting point 2,947 °C (5,337 °F; 3,220 K)[1]
insoluble
+38×10−6 emu/mol
Thermal conductivity
 29 W/(m·K) (323 K)[2]
Structure[3]
Face-centered cubic (FCC), cF8
Fm3m, No. 225
a = 0.4241 nm
4
Octahedral
Thermochemistry
24 J/(K·mol) (500 K)[2]
−95.7 J/(K·mol)[4]
Std enthalpy of
formation
(ΔfH⦵298)
 −336 kJ/mol[4]
Related compounds
Related coating
Titanium aluminum nitride
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
☒N verify (what is checkY☒N ?)

Titanium nitride (TiN; sometimes known as tinite) is an extremely hard

titanium alloys, steel, carbide, and aluminium
components to improve the substrate's surface properties.

Applied as a thin coating, TiN is used to harden and protect cutting and sliding surfaces, for decorative purposes (for its golden appearance), and as a non-toxic exterior for medical implants. In most applications a coating of less than 5 micrometres (0.00020 in) is applied.[5]

Characteristics

TiN has a

thermal expansion coefficient of 9.35×10−6 K−1, and a superconducting transition temperature of 5.6 K.[7][6]

TiN will oxidize at 800 °C in a normal atmosphere. TiN has a brown color, and appears gold when applied as a coating. It is chemically stable at 20 °C, according to laboratory tests, but can be slowly attacked by concentrated acid solutions with rising temperatures.[7] Depending on the substrate material and surface finish, TiN will have a

NaCl-type with a roughly 1:1 stoichiometry; TiNx compounds with x ranging from 0.6 to 1.2 are, however, thermodynamically stable.[8]

TiN becomes

superconductor-insulator transition.[10] A thin film of TiN was chilled to near absolute zero, converting it into the first known superinsulator, with resistance suddenly increasing by a factor of 100,000.[11]

Natural occurrence

Osbornite is a very rare natural form of titanium nitride, found almost exclusively in meteorites.[12][13]

Uses

TiN-coated drill bit
Dark gray TiCN coating on a Gerber pocketknife

A well-known use for TiN coating is for edge retention and corrosion resistance on machine tooling, such as drill bits and milling cutters, often improving their lifetime by a factor of three or more.[14]

Because of the metallic gold color of TiN, this material is used to coat

radio controlled cars. TiN is also used as a protective coating on the moving parts of many rifles and semi automatic firearms, as it is extremely durable. As well as being durable, it is also extremely smooth, making removing the carbon build up extremely easy. TiN is non-toxic, meets FDA guidelines, and has seen use in medical devices such as scalpel blades and orthopedic bone saw blades, where sharpness and edge retention are important.[15] TiN coatings have also been used in implanted prostheses (especially hip replacement
implants) and other medical implants.

Though less visible,

zirconium alloys for accident-tolerant nuclear fuels.[17][18] It is also used as a coating on some compression driver
diaphragms to improve performance.

Owing to their high biostability, TiN layers may also be used as electrodes in

BioMEMS).[21]

Fabrication

Titanium nitride (TiN) coated punches using cathodic arc deposition technique

The most common methods of TiN thin film creation are

GPa have been reported in the literature [24]) means that thick coatings tend to flake away, making them much less durable than thin ones. Titanium nitride coatings can also be deposited by thermal spraying whereas TiN powders are produced by nitridation of titanium with nitrogen or ammonia at 1200 °C.[7]

Bulk ceramic objects can be fabricated by packing powdered metallic titanium into the desired shape, compressing it to the proper density, then igniting it in an atmosphere of pure nitrogen. The heat released by the chemical reaction between the metal and gas is sufficient to sinter the nitride reaction product into a hard, finished item. See powder metallurgy.

Other commercial variants

A knife with a titanium oxynitride coating

There are several commercially used variants of TiN that have been developed since 2010, such as titanium carbon nitride (TiCN), titanium aluminium nitride (TiAlN or AlTiN), and titanium aluminum carbon nitride, which may be used individually or in alternating layers with TiN. These coatings offer similar or superior enhancements in corrosion resistance and hardness, and additional colors ranging from light gray to nearly black, to a dark, iridescent, bluish-purple, depending on the exact process of application. These coatings are becoming common on sporting goods, particularly knives and handguns, where they are used for both aesthetic and functional reasons.

As a constituent in steel

Titanium nitride is also produced intentionally, within some steels, by judicious addition of titanium to the

enthalpy of formation, and even nucleates directly from the melt in secondary steel-making. It forms discrete, micrometre-sized cubic particles at grain boundaries and triple points, and prevents grain growth by Ostwald ripening up to very high homologous temperatures. Titanium nitride has the lowest solubility product of any metal nitride or carbide in austenite, a useful attribute in microalloyed steel
formulas.

References

  1. ^
    ISBN 9781498754293
    .
  2. ^
    doi:10.1016/0925-8388(94)01315-9
    .
  3. doi:10.1016/0925-8388(92)90016-3
    .
  4. ^
    doi:10.1016/0925-8388(96)80039-9
    .
  5. ^ "TiN (Titanium Nitride) – Surface Coating". Retrieved 2024-02-17.
  6. ^
    doi:10.1116/1.577270
    .
  7. ^
    ISBN 978-0-8155-1392-6
    – via Google Books.
  8. ISBN 978-0-12-695950-5
    .
  9. doi:10.1103/PhysRevB.17.1095
    .
  10. S2CID 518088
    .
  11. ^ "Newly discovered 'superinsulators' promise to transform materials research, electronics design". PhysOrg.com. 2008-04-07.
  12. ^ "Osbornite". Mindat.org. Hudson Institute of Mineralogy. Retrieved Feb 29, 2016.
  13. ^ "Osbornite mineral data". Mineralogy Database. David Barthelmy. Sep 5, 2012. Retrieved Oct 6, 2015.
  14. ^ "Titanium Nitride (TiN) Coating". Surface Solutions. June 2014.
  15. ^ "Products". IonFusion Surgical. Retrieved 2009-06-25.
  16. S2CID 120728898
    .
  17. doi:10.1016/j.jnucmat.2018.10.013
    .
  18. doi:10.1016/j.jnucmat.2016.05.021
    .
  19. doi:10.1016/j.surfcoat.2009.09.075
    .
  20. PMID 11771699
    .
  21. doi:10.1002/adfm.201002062
    .
  22. ^ "Wear coatings for industrial products". Diffusion Alloys. Archived from the original on 2013-05-19. Retrieved 2013-06-14.
  23. ^ "Coatings". Coating Services Group. Retrieved 2009-06-25.
  24. doi:10.1016/j.surfcoat.2007.08.029
    .
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