Titanium carbide

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Titanium carbide
TiC-xtal-3D-vdW.png
Identifiers
CAS number 12070-08-5 YesY
Properties
Molecular formula TiC
Molar mass 59.89 g/mol
Appearance black powder
Density 4.93 g/cm3
Melting point 3,160 °C (5,720 °F; 3,430 K)
Boiling point 4,820 °C (8,710 °F; 5,090 K)
Solubility in water insoluble in water
Structure
Crystal structure Cubic, cF8
Space group Fm3m, No. 225
Coordination
geometry
Octahedral
Except where noted otherwise, data are given for materials in their standard state (at 25 °C (77 °F), 100 kPa)
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Infobox references

Titanium carbide, TiC, is an extremely hard (Mohs 9-9.5) refractory ceramic material, similar to tungsten carbide.

Titanium carbide is commercially used in tool bits. It has the appearance of black powder with NaCl-type face centered cubic crystal structure. It is mainly used in preparation of cermets, which are frequently used to machine steel materials at high cutting speed; however, it is also used as a surface coating on some watches made by companies such as Citizen and Tag Heuer.[citation needed]

The resistance to wear, corrosion, and oxidation of a tungsten carbide-cobalt material can be increased by adding 6-30% of titanium carbide to tungsten carbide. This forms a solid solution that is more brittle and susceptible to breakage.[citation needed]

Tool bits without tungsten content can be made of titanium carbide in nickel-cobalt matrix cermet, enhancing the cutting speed, precision, and smoothness of the workpiece. This material is sometimes called high-tech ceramic and is used as a heat shield for atmospheric reentry of spacecraft.[citation needed]

It can be etched with reactive-ion etching.

The mineralogical form is very rare and called khamrabaevite - (Ti,V,Fe)C.

Titanium-carbon clusters[edit]

A surprisingly stable cluster with formula Ti
8
C+
12
, was detected in 1992.[1][2] The 20 atoms were conjectured to be arranged as the vertices of a dodecahedron, with the titanium atoms at the corners of a cube [1] However, this claim was soon disputed by Linus Pauling[3] who proposed an alternative arrangement—with the Ti atoms still at the corners of a cube, but with the carbon atoms pushed inwards so as to be nearly coplanar with the faces of that cube.

Physical Properties[edit]

Titanium carbide has an elastic modulus of approximately 400GPa and a shear modulus of 188GPa.[4]

References[edit]

  1. ^ a b Guo, Bc; Kerns, Kp; Castleman, Aw, Jr (Mar 1992). "Ti8C12+-Metallo-Carbohedrenes: A New Class of Molecular Clusters?". Science 255 (5050): 1411–1413. doi:10.1126/science.255.5050.1411. ISSN 0036-8075. PMID 17801229. 
  2. ^ Guo, Bc; Wei, S; Purnell, J; Buzza, S; Castleman, Aw, Jr (Apr 1992). "Metallo-Carbohedrenes M8C12+ (M = V, Zr, Hf, and Ti): A Class of Stable Molecular Cluster Ions". Science 256 (5056): 515–516. doi:10.1126/science.256.5056.515. ISSN 0036-8075. PMID 17787948. 
  3. ^ L Pauling (1992). "Molecular structure of Ti8C12 and related complexes". Proc. Natl. Acad. Sci. USA 89 (17): 8175–6. doi:10.1073/pnas.89.17.8175. PMC 49879. PMID 11607323. 
  4. ^ Chang, R; Graham, L (1966). Applied Physics 37: 3778.