Editing Metal (section)

=== Metallic ceramics ===
[[File:Titanium nitride coating 90.jpg|thumb|TiN coated drill bit]]
There are many ceramic compounds which have metallic electrical conduction, but are not simple combinations of metallic elements. (They are not the same as [[cermet]]s which are composites of a non-conducting ceramic and a conducting metal.) One set, the transition metal nitrides has significant ionic character to the bonding, so can be classified as both ceramics and metals.<ref name="Stampfl-2001" /> They have partially filled states at the Fermi level<ref name="Stampfl-2001" /> so are good thermal and electrical conductors, and there is often significant charge transfer from the transition metal atoms to the nitrogen.<ref name="Stampfl-2001" /> However, unlike most elemental metals, ceramic metals are often not particularly ductile. Their uses are widespread, for instance [[titanium nitride]] finds use in orthopedic devices<ref>{{Cite journal |last1=van Hove |first1=Ruud P. |last2=Sierevelt |first2=Inger N. |last3=van Royen |first3=Barend J. |last4=Nolte |first4=Peter A. |date=2015 |title=Titanium-Nitride Coating of Orthopaedic Implants: A Review of the Literature |journal=BioMed Research International |language=en |volume=2015 |pages=1–9 |doi=10.1155/2015/485975 |doi-access=free |issn=2314-6133 |pmc=4637053 |pmid=26583113}}</ref> and as a wear resistant coating.<ref>{{Cite journal |last1=Santecchia |first1=Eleonora |last2=Hamouda |first2=A. M. S. |last3=Musharavati |first3=Farayi |last4=Zalnezhad |first4=Erfan |last5=Cabibbo |first5=Marcello |last6=Spigarelli |first6=Stefano |date=2015 |title=Wear resistance investigation of titanium nitride-based coatings |url=https://www.sciencedirect.com/science/article/pii/S0272884215009116 |journal=Ceramics International |volume=41 |issue=9, Part A |pages=10349–10379 |doi=10.1016/j.ceramint.2015.04.152 |issn=0272-8842}}</ref> In many cases their utility depends upon there being effective deposition methods so they can be used as thin film coatings.<ref>{{Cite journal |last=Matthews |first=A. |date=1985 |title=Titanium Nitride PVD Coating Technology |url=http://journals.sagepub.com/doi/10.1179/sur.1985.1.2.93 |journal=Surface Engineering |language=en |volume=1 |issue=2 |pages=93–104 |doi=10.1179/sur.1985.1.2.93 |issn=0267-0844}}</ref>