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{{Redirect|Borium|the synthetic chemical element|Bohrium}}
{{Short description|Hard, dense and stiff chemical compound}}
{{Use dmy dates|date=April 2020}}
{{Chembox
| Verifiedfields = changed
| Watchedfields = changed
| verifiedrevid = 452024347
| Name = Tungsten carbide
| ImageFile = Α-WC-polyhedral.png
| ImageName = α-Tungsten carbide in the unit cell
| ImageFile1 =
| ImageSize1 = 220px
| ImageName1 = Blocks of tungsten carbide
| IUPACName = Tungsten carbide
| OtherNames = Tungsten(IV) carbide 
Tungsten tetracarbide
|Section1={{Chembox Identifiers
| CASNo_Ref = {{cascite|correct|CAS}}
| CASNo = 12070-12-1
| PubChem = 2724274
| PubChem_Comment = (W+≡C−)
| EC_number = 235-123-0
| ChemSpiderID = 2006424
| RTECS = YO7250000
| UNNumber = 3178
| DTXSID = DTXSID4029305
| SMILES = [C-]#[W+]
| SMILES_Comment = (W+≡C−)
| StdInChI_Ref = {{stdinchicite|changed|chemspider}}
| StdInChI = 1S/C.W/q-1;+1
| StdInChI_Comment = (W+≡C−)
| StdInChIKey_Ref = {{stdinchicite|changed|chemspider}}
| StdInChIKey = UONOETXJSWQNOL-UHFFFAOYSA-N
}}
|Section2={{Chembox Properties
|C=1|W=1
| Formula = WC
| Appearance = Grey-black lustrous solid
| Density = 15.63 g/cm3<ref>http://gestis-en.itrust.de/nxt/gateway.dll/gestis_en/491085.xml</ref>
| Solubility = Insoluble
| SolubleOther = Soluble in {{chem|link=nitric acid|HNO|3}}, {{chem|link=hydrofluoric acid|HF}}<ref name=crc/>
| MeltingPtC = 2785–2830
| MeltingPt_ref = <ref name=crc>{{RubberBible92nd|page=4.96}}</ref><ref name=shthcc/>
| BoilingPtC = 6000
| BoilingPt_notes = at 760 mmHg<ref name=shthcc/>
| MagSus = 1·10−5 cm3/mol<ref name=crc/>
| ThermalConductivity =110 W/(m·K)<ref name=Blau2003/>
}}　
|Section3={{Chembox Structure
| CrystalStruct = [[Hexagonal crystal system|Hexagonal]], [[Pearson symbol|hP2]]<ref name=str/>
| SpaceGroup = P{{overline|6}}m2, No. 187<ref name=str>[[#Kurlov|Kurlov]], p. 22</ref>
| PointGroup = {{overline|6}}m2<ref name=str/>
| LattConst_a = 2.906 Å
| LattConst_b =
| LattConst_c = 2.837 Å<ref name=str/>
| LattConst_alpha =
| LattConst_beta =
| LattConst_gamma = 120
| MolShape = Trigonal prismatic (center at C)<ref name=Wells/>
}}
|Section4={{Chembox Thermochemistry
| HeatCapacity = 39.8 J/(mol·K)<ref name=Blau2003>{{cite book |author=Blau, Peter J. |title=Wear of Materials|url=https://books.google.com/books?id=2FO5T8u0oQUC&pg=PA1345|year=2003|publisher=Elsevier|isbn=978-0-08-044301-0|page=1345}}</ref>
| Entropy = 32.1 J/mol·K
}}
|Section8={{Chembox Related
| OtherAnions = [[Tungsten boride]] [[Tungsten nitride]]
| OtherCations = [[Molybdenum carbide]] [[Titanium carbide]] [[Silicon carbide]]
}}
}}

'''Tungsten carbide''' ([[chemical formula]]: '''WC''') is a [[chemical compound]] (specifically, a [[carbide]]) containing equal parts of [[tungsten]] and [[carbon]] atoms. In its most basic form, tungsten carbide is a fine gray powder, but it can be pressed and formed into shapes through [[sintering]] for use in [[industrial machinery]], [[cutting tool]]s, [[abrasive]]s, [[armor-piercing shell]]s and [[jewelry]].

Tungsten carbide is approximately twice as stiff as [[steel]], with a [[Young's modulus]] of approximately 530–700 GPa,<ref name=Blau2003/><ref name=Kurlov3/><ref name=Groover2010/><ref name=Cardarelli2008/> and is double the density of [[steel]]—nearly midway between that of [[lead]] and [[gold]]. It is comparable with [[corundum]] (α-{{chem|link=aluminium oxide|Al|2|O|3}}) in [[hardness]] and can be polished and finished only with abrasives of superior hardness such as [[cubic boron nitride]] and diamond powder, wheels and compounds.

==Naming==
Historically referred to as Wolfram, ''Wolf Rahm'', [[wolframite]] ore discovered by Peter Woulfe was then later carburized and cemented with a binder creating a composite now called "tungsten carbide".<ref>Helmenstine, Anne Marie. [http://chemistry.about.com/od/elementfacts/a/tungstenwolfram.htm Tungsten or Wolfram Facts]. chemistry.about.com</ref> Tungsten is Swedish for "heavy stone".

Colloquially among workers in various industries (such as [[machining]]), tungsten carbide is often simply called ''carbide.''

==Synthesis==
Tungsten carbide is prepared by reaction of tungsten metal and carbon at 1400–2000 °C.<ref name=Pierson>{{cite book |first=Hugh O.|last=Pierson|year=1992|title=Handbook of Chemical Vapor Deposition (CVD): Principles, Technology, and Applications|publisher=William Andrew Inc.|isbn=0-8155-1300-3}}</ref> Other methods include a lower temperature fluid bed process that reacts either tungsten metal or blue {{chem|link=tungsten(VI) oxide|WO|3}} with [[Carbon monoxide|CO]]/[[Carbon dioxide|{{CO2}}]] mixture and {{chem|H|2}} between 900 and 1200 °C.<ref>Lackner, A. and Filzwieser A. "Gas carburizing of tungsten carbide (WC) powder" {{US patent|6447742}} (2002)</ref>

WC can also be produced by heating WO3 with [[graphite]]: directly at 900 °C or in hydrogen at 670 °C following by carburization in [[argon]] at 1000 °C.<ref>{{cite journal |last1=Zhong|first1=Y. |journal=Journal of Materials Science|year=2011|volume=46|pages=6323–6331|doi= 10.1007/s10853-010-4937-y|title=A study on the synthesis of nanostructured WC–10 wt% Co particles from {{chem|WO|3}}, {{chem|Co|3|O|4}}, and graphite|issue=19|last2=Shaw |first2=L. |bibcode=2011JMatS..46.6323Z|s2cid=137383773 }}</ref> [[Chemical vapor deposition]] methods that have been investigated include:<ref name=Pierson/>
*reacting [[tungsten hexachloride]] with hydrogen (as a [[reducing agent]]) and [[methane]] (as the source of carbon) at {{convert|670|°C|K}}
:{{chem|WCl|6}} + {{chem|H|2}} + {{chem|CH|4}} → WC + 6{{hsp}}HCl
*reacting [[tungsten hexafluoride]] with hydrogen (as reducing agent) and [[methanol]] (as source of carbon) at {{convert|350|°C|K}}
:{{chem|WF|6}} + 2{{hsp}}{{chem|H|2}} + {{chem|CH|3|OH}} → WC + 6{{hsp}}HF + {{chem|H|2|O}}

==Chemical properties==
There are two well-characterized compounds of tungsten and carbon, WC and '''tungsten semicarbide''', {{chem|W|2|C}}. Both compounds may be present in coatings and the proportions can depend on the coating method.<ref>{{cite journal
|title=Comparative study of WC-cermet coatings sprayed via the HVOF and the HVAF Process
|last=Jacobs|first=L.|author2=M. M. Hyland |author3=M. De Bonte
|journal=[[Journal of Thermal Spray Technology]]|volume=7|issue=2
|year= 1998|pages=213–8|doi=10.1361/105996398770350954
|bibcode=1998JTST....7..213J|s2cid=135552046}}</ref>

Another meta-stable compound of tungsten and carbon can be created by heating the WC phase to high temperatures using plasma, then quenching in inert gas (plasma spheroidization).<ref>{{cite journal|last1=Károly|first1=Z.|last2=Szépvölgyi|first2=János|date=2005-02-01|pages=221–224|title=Plasma Spheroidization of Ceramic Particles|volume=44|doi = 10.1016/j.cep.2004.02.015|journal=Chemical Engineering and Processing |issue=2}}</ref> This process causes macrocrystalline WC particles to spheroidize and results in the non-stoichiometric high temperature phase {{chem|W|C|1-x|}} existing in a meta-stable form at room temperature. The fine microstructure of this phase provides high hardness (2800-3500 HV) combined with good toughness when compared with other tungsten carbide compounds. The meta-stable nature of this compound results in reduced high temperature stability.

At high temperatures WC decomposes to tungsten and carbon and this can occur during high-temperature [[thermal spraying|thermal spray]], e.g., in high velocity oxygen fuel (HVOF) and high energy plasma (HEP) methods.<ref>{{cite journal
|title=Microstructural evaluation of tungsten carbide-cobalt coatings
|last=Nerz|first=J.|author2=B. Kushner |author3=A. Rotolico
|journal=Journal of Thermal Spray Technology|year=1992|volume=1|issue=2|pages=147–152|doi=10.1007/BF02659015
|bibcode=1992JTST....1..147N|s2cid=135907562}}</ref>

[[Oxidation]] of WC starts at {{convert|500–600|°C|K}}.<ref name=Pierson/> It is resistant to [[acid]]s and is only attacked by [[hydrofluoric acid]]/[[nitric acid]] (HF/{{chem|HNO|3}}) mixtures above room temperature.<ref name=Pierson/> It reacts with [[fluorine]] gas at room temperature and [[chlorine]] above {{convert|400|°C|K}} and is unreactive to dry {{chem|H|2}} up to its melting point.<ref name=Pierson/> Finely powdered WC oxidizes readily in [[hydrogen peroxide]] aqueous solutions.<ref>{{cite journal |doi= 10.1021/cm980544o |title= Reaction of Metal, Carbide, and Nitride of Tungsten with Hydrogen Peroxide Characterized by 183W Nuclear Magnetic Resonance and Raman Spectroscopy |journal= Chemistry of Materials |volume= 11 |issue= 3 |pages= 691–697 |year= 1999 |last1= Nakajima |first1= H. |last2= Kudo |first2= T. |last3= Mizuno |first3= N.}}</ref> At high temperatures and pressures it reacts with aqueous [[sodium carbonate]] forming [[sodium tungstate]], a procedure used for recovery of scrap cemented carbide due to its selectivity.

==Physical properties==
Tungsten carbide has a high melting point at {{convert|2870|°C|K}}, a boiling point of {{convert|6000|°C|K}} when under a pressure equivalent to {{convert|1|atm|kPa|3|abbr=off}},<ref name=shthcc>{{cite book |url=https://books.google.com/books?id=RYt0Wzb60b4C&pg=PA2670|title=Sittig's Handbook of Toxic and Hazardous Chemicals and Carcinogens |edition=6th |page=2670 |first=Richard P. |last=Pohanish |year=2012 |publisher=[[Elsevier|Elsevier, Inc.]] |isbn=978-1-4377-7869-4}}</ref> a thermal conductivity of 110 W·m−1·K−1,<ref name=Blau2003/> and a [[coefficient of thermal expansion]] of 5.5 µm·m−1·K−1.<ref name=Kurlov3>[[#Kurlov|Kurlov]], p. 3</ref>

Tungsten carbide is extremely hard, ranking about 9 to 9.5 on the [[Mohs scale of mineral hardness|Mohs scale]], and with a [[Vickers hardness test|Vickers]] number of around 2600.<ref name=Groover2010>{{cite book |author=Groover, Mikell P. |title=Fundamentals of Modern Manufacturing: Materials, Processes, and Systems|url=https://books.google.com/books?id=QU-Qvud3OvoC&pg=PA135|date=2010|publisher=John Wiley & Sons|isbn=978-0-470-46700-8|page=135}}</ref> It has a [[Young's modulus]] of approximately 530–700 GPa,<ref name=Blau2003/><ref name=Kurlov3/><ref name=Groover2010/><ref name=Cardarelli2008/> a [[bulk modulus]] of 630–655 GPa, and a [[shear modulus]] of 274 GPa.<ref name=Kurlov135>[[#Kurlov|Kurlov]], pp. 30, 135</ref> It has an ultimate tensile strength of 344 MPa,<ref name=Cardarelli2008>{{cite book |author=Cardarelli, François |title=Materials Handbook: A Concise Desktop Reference|url=https://books.google.com/books?id=PvU-qbQJq7IC&pg=PA640|date=2008|publisher=Springer Science & Business Media|isbn=978-1-84628-669-8|page=640}}</ref> an ultimate compression strength of about 2.7 GPa and a Poisson's ratio of 0.31.<ref name=Kurlov135/>

The speed of a longitudinal wave (the [[speed of sound]]) through a thin rod of tungsten carbide is 6220 m/s.<ref>{{cite news |url=http://www.rfcafe.com/references/general/velocity-sound-media.htm|title=Velocity of Sound in Various Media|publisher=RF Cafe |access-date=4 April 2013 |last1=Cafe|first1=Kirt Blattenberger RF}}</ref>

Tungsten carbide's low [[electrical resistivity]] of about 0.2 ''µ''Ω·m is comparable with that of some metals (e.g. [[vanadium]] 0.2 ''µ''Ω·m).<ref name=Pierson/><ref name=Kittel>{{cite book |first=Charles|last=Kittel|title=[[Introduction to Solid State Physics]]|edition=7th|year=1995|publisher=Wiley-India|isbn=81-265-1045-5}}</ref>

WC is readily [[wetting|wetted]] by both molten [[nickel]] and [[cobalt]].<ref name=Ettmayer>{{cite book |first=Peter|last=Ettmayer|author2=Walter Lengauer |title=Carbides: transition metal solid state chemistry encyclopedia of inorganic chemistry|year=1994|publisher=John Wiley & Sons|isbn=0-471-93620-0}}</ref> Investigation of the phase diagram of the W-C-Co system shows that WC and Co form a pseudo binary [[Eutectic point|eutectic]]. The [[phase diagram]] also shows that there are so-called η-carbides with composition {{chem|(W,Co)|6|C}} that can be formed and the brittleness of these phases makes control of the carbon content in WC-Co cemented carbides important.<ref name=Ettmayer/> In the presence of a molten phase such as cobalt, [[abnormal grain growth]] is known to occur in the sintering of tungsten carbide, with this having significant effects on the performance of the product material.

==Structure==
[[File:Alpha tungsten carbide crystal structure.png|thumb|α-WC structure, carbon atoms are gray.<ref name=str/>]]
There are two forms of WC, a [[hexagonal crystal system|hexagonal]] form, α-WC ([[Pearson symbol|hP2]], [[space group]] P{{overline|6}}m2, No. 187),<ref name=str/><ref name=Wells>{{cite book |last=Wells|first=A. F.|year=1984|title=Structural Inorganic Chemistry|edition=5th|publisher= Oxford Science Publications|isbn=0-19-855370-6}}</ref> and a [[Cubic crystal system|cubic]] high-temperature form, β-WC, which has the [[cubic crystal system#Rock-salt structure|rock salt structure]].<ref>{{cite journal |title=Phase Equilibria in the System Tungsten—Carbon|last=Sara|first=R. V.|journal=Journal of the American Ceramic Society|volume=48|year=1965|issue=5|pages=251–7 |doi=10.1111/j.1151-2916.1965.tb14731.x}}</ref> The hexagonal form can be visualized as made up of a simple hexagonal lattice of metal atoms of layers lying directly over one another (i.e. not close packed), with carbon atoms filling half the interstices giving both tungsten and carbon a regular trigonal prismatic, 6 [[coordination number|coordination]].<ref name=Wells/> From the unit cell dimensions<ref>{{cite journal |title=Untersuchungen im System Tantal-Wolfram-Kohlenstoff|last=Rudy|first=E.|author2=F. Benesovsky |journal=Monatshefte für Chemie|year=1962|volume=93|issue=3|pages=1176–95|doi=10.1007/BF01189609}}</ref> the following bond lengths can be determined: the distance between the tungsten atoms in a hexagonally packed layer is 291 pm, the shortest distance between tungsten atoms in adjoining layers is 284 pm, and the tungsten carbon bond length is 220 pm. The tungsten-carbon bond length is therefore comparable to the single bond in {{chem|W({{chem|CH|3}})|6}} (218 pm) in which there is strongly distorted trigonal prismatic coordination of tungsten.<ref>{{cite journal |last=Kleinhenz|first=Sven|author2=Valérie Pfennig |author3=Konrad Seppelt |journal=Chemistry: A European Journal|year=1998|issue=9|volume=4|pages=1687–91|title=Preparation and Structures of [W(CH3)6], [Re(CH3)6], [Nb(CH3)6]−, and [Ta(CH3)6]− |doi=10.1002/(SICI)1521-3765(19980904)4:9<1687::AID-CHEM1687>3.0.CO;2-R}}</ref>

Molecular WC has been investigated and this gas phase species has a bond length of 171 pm for {{chem|184|W}}{{chem|12|C}}.<ref>{{cite journal |title=Optical spectroscopy of tungsten carbide (WC)|last=Sickafoose|first=S.M.|author2=A.W. Smith |author3=M. D. Morse |journal=[[J. Chem. Phys.]]|volume=116|issue=3|year=2002 |doi=10.1063/1.1427068|page=993|bibcode=2002JChPh.116..993S}}</ref>

==Applications==

===Cutting tools for machining===
{{See also|Cemented carbide}}
[[File:Tungsten carbide.jpg|220px|thumbnail|left|Cemented carbide drill and end mills]]
[[Sintering|Sintered]] tungsten carbide–cobalt [[cutting tool (machining)|cutting tools]] are very abrasion resistant and can also withstand higher temperatures than standard [[high-speed steel]] (HSS) tools. Carbide cutting surfaces are often used for [[machining]] through materials such as [[carbon steel]] or [[stainless steel]], and in applications where steel tools would wear quickly, such as high-quantity and high-precision production. Because carbide tools maintain a sharp cutting edge better than steel tools, they generally produce a better finish on parts, and their temperature resistance allows faster machining. The material is usually called [[cemented carbide]], solid carbide, hardmetal or tungsten-carbide cobalt. It is a [[metal matrix composite]], where tungsten carbide particles are the aggregate, and metallic [[cobalt]] serves as the matrix.<ref name=Rao>{{cite book |author=Rao|title=Manufacturing Technology Vol.II 2E|url=https://books.google.com/books?id=3sS5a4jqzS8C&pg=PA30|publisher=Tata McGraw-Hill Education|isbn=978-0-07-008769-9|page=30|year=2009}}</ref><ref>{{cite book |author=Davis, Joseph R., ASM International Handbook Committee|title=Tool materials|url=https://books.google.com/books?id=Kws7x68r_aUC&pg=PA289|year=1995|publisher=ASM International|isbn=978-0-87170-545-7|page=289}}</ref>

===Ammunition===
Tungsten carbide, in its monolithic sintered form, or much more often in cemented tungsten carbide cobalt composite (see above), is often used in [[armour-piercing bullet|armor-piercing ammunition]], especially where [[depleted uranium]] is not available or is politically unacceptable. {{chem|W|2|C}} projectiles were first used by German [[Luftwaffe]] [[anti-tank warfare|tank-hunter]] squadrons in [[World War II]]. However, owing to the limited German reserves of tungsten, {{chem|W|2|C}} material was reserved for making machine tools and small numbers of [[armour-piercing, core rigid|projectiles]]. It is an effective penetrator due to its combination of great hardness and very high density.<ref name=Ford2000>{{cite book |author=Ford, Roger |title=Germany's Secret Weapons in World War II|url=https://books.google.com/books?id=lU8xBhe9ntsC&pg=PA125|year=2000|publisher=Zenith Imprint|isbn=978-0-7603-0847-9|page=125}}</ref><ref name=Zaloga2005>{{cite book |author=Zaloga, Steven J. |title=US Tank and Tank Destroyer Battalions in the ETO 1944–45|url=https://books.google.com/books?id=sCdlGIbmHjoC&pg=PA37|year=2005|publisher=Osprey Publishing|isbn=978-1-84176-798-7|page=37}}</ref>

Tungsten carbide ammunition is now generally of the [[Sabot (firearms)|sabot]] type. SLAP, or [[Saboted light armor penetrator|saboted light armour penetrator]], where a plastic sabot discards at the barrel muzzle, is one of the primary types of saboted small arms ammunition. Non-discarding jackets, regardless of the jacket material, are not perceived as sabots but as bullets. Both of the designs are, however, common in designated light armor-piercing small arms ammunition. Discarding sabots such as are used with M1A1 Abrams main gun are more commonplace in precision high-velocity gun ammunition.<ref>{{cite book |author1=Green, Michael |author2=Stewart, Greg |name-list-style=amp |title=M1 Abrams at War|url=https://books.google.com/books?id=M1P6jT8_yrgC&pg=PA66|year=2005|publisher=Zenith Imprint|isbn=978-0-7603-2153-9|page=66}}</ref><ref name=Tucker2004>{{cite book |author=Tucker, Spencer |title=Tanks: an illustrated history of their impact|url=https://books.google.com/books?id=N481TmqiSiUC&pg=PA348|year= 2004|publisher=ABC-CLIO|isbn=978-1-57607-995-9|page=348}}</ref>

===Mining and foundation drilling===
[[File:Drill bit 2-italy.JPG|thumb|A tricone roller cone assembly from a raiseboring reamer, showing the protruding tungsten carbide buttons inset into the rollers]]
Tungsten carbide is used extensively in mining in top hammer rock drill bits, [[down-the-hole drill|downhole hammers]], [[roller cone bit|roller-cutters]], [[longwall mining|long wall plough]] chisels, [[longwall mining|long wall shearer]] picks, [[raise borer|raiseboring]] reamers, and [[tunnel boring machines]]. It is generally utilised as a button insert, mounted in a surrounding matrix of steel that forms the substance of the bit. As the tungsten carbide button is worn away the softer steel matrix containing it is also worn away, exposing yet more button insert.

===Nuclear===
Tungsten carbide is also an effective [[neutron reflector]] and as such was used during early investigations into nuclear chain reactions, particularly for weapons. A [[criticality accident]] occurred at [[Los Alamos National Laboratory]] on 21 August 1945 when [[Harry Daghlian]] accidentally dropped a tungsten carbide brick onto a [[plutonium]] sphere, known as the [[demon core]], causing the [[critical mass|subcritical mass]] to go supercritical with the reflected [[neutron]]s.

===Sports usage===
[[File:Nokian Gazza Extreme 294 29er.jpg|thumb|A [[Nokian Tyres|Nokian]] bicycle tire with tungsten carbide spikes. The spikes are surrounded by aluminum.]]
[[Trekking pole]]s, used by many [[hiking|hikers]] for balance and to reduce pressure on leg joints, generally use carbide tips in order to gain traction when placed on hard surfaces (like rock); carbide tips last much longer than other types of tip.<ref name=Connally2004>{{cite book |author=Connally, Craig |title=The mountaineering handbook: modern tools and techniques that will take you to the top|url=https://books.google.com/books?id=c0MUESWJo2oC&pg=PA14|year=2004|publisher=McGraw-Hill Professional|isbn=978-0-07-143010-4|page=14}}</ref>

While [[ski pole]] tips are generally not made of carbide, since they do not need to be especially hard even to break through layers of ice, rollerski tips usually are. [[Roller skiing]] emulates [[cross country skiing]] and is used by many skiers to train during warm weather months.

Sharpened carbide tipped spikes (known as studs) can be inserted into the drive tracks of [[snowmobile]]s. These studs enhance traction on icy surfaces. Longer v-shaped segments fit into grooved rods called wear rods under each snowmobile ski. The relatively sharp carbide edges enhance steering on harder icy surfaces. The carbide tips and segments reduce wear encountered when the snowmobile must cross roads and other abrasive surfaces.<ref name=Hermance2006>{{cite book |author=Hermance, Richard |title=Snowmobile and ATV accident investigation and reconstruction|url=https://books.google.com/books?id=-msCn1jK8z8C&pg=PA13|year= 2006|publisher=Lawyers & Judges Publishing Company|isbn=978-0-913875-02-5|page=13}}</ref>

Car, motorcycle and bicycle [[tire]]s with tungsten carbide studs provide better traction on ice. They are generally preferred to steel studs because of their superior resistance to wear.<ref name=HampGorr2011>{{cite book |author1=Hamp, Ron |author2=Gorr, Eric |author3=Cameron, Kevin |name-list-style=amp |title=Four-Stroke Motocross and Off-Road Performance Handbook|url=https://books.google.com/books?id=24kHuJV2LcAC&pg=PA69|year=2011|publisher=MotorBooks International|isbn=978-0-7603-4000-4|page=69}}</ref>

Tungsten carbide may be used in [[farrier]]y, the shoeing of [[horse]]s, to improve traction on slippery surfaces such as roads or ice. Carbide-tipped hoof nails may be used to attach the [[horseshoe|shoe]]s;<ref name=mustad>{{cite web |title=Road nail |url=http://www.mustadhoofnails.com/subcat/40/product/1369/page/0/road_nail/ |publisher=Mustad Hoof Nails |url-status=unfit |archive-url=https://web.archive.org/web/20120326173505/http://www.mustadhoofnails.com/subcat/40/product/1369/page/0/road_nail/ |archive-date=26 March 2012}}</ref> in the United States, borium – chips of tungsten carbide in a matrix of softer metal such as [[bronze]] or mild steel – may be welded to small areas of the underside of the shoe before fitting.<ref name=syd>[Post-Graduate Foundation in Veterinary Science] (1997). [https://books.google.it/books?hl=en&id=CGZWAAAAYAAJ ''Farriery: a convention for farriers and veterinarians, in conjunction with AustralAsian Farrier News'']. Sydney South, NSW: University of Sydney. Accessed March 2019.</ref>{{Rp|73}}

===Surgical instruments===
Tungsten carbide is also used for making surgical instruments meant for open surgery (scissors, forceps, hemostats, blade-handles, etc.) and [[laparoscopic surgery]] (graspers, scissors/cutter, needle holder, cautery, etc.). They are much costlier than their stainless-steel counterparts and require delicate handling, but give better performance.<ref name=ReichertYoung1997>{{cite book |author1=Reichert, Marimargaret |author2=Young, Jack H. |title= Sterilization technology for the health care facility|url= https://books.google.com/books?id=HDzcboqJR9kC&pg=PA30|year= 1997|publisher= Jones & Bartlett Learning|isbn= 978-0-8342-0838-4|page= 30}}</ref>

===Jewelry===
[[File:Tungsten Carbide.jpg |thumb|Tungsten carbide ring]]
Tungsten carbide, typically in the form of a [[cemented carbide]] (carbide particles [[brazing|brazed]] together by metal), has become a popular material in the bridal jewelry industry due to its extreme hardness and high resistance to scratching.<ref name=forever/><ref>[http://trademarks.justia.com/774/86/seranite-77486248.html ''SERANITE – Trademark Details''] Justia Trademark, 2013</ref> Even with high-impact resistance, this extreme hardness also means that it can occasionally be shattered under certain circumstances.<ref>{{cite web |url= http://cherylkremkow.com/designer-jewelry/breaking-tungsten-carbide/|title= Breaking Tungsten Carbide|date= 29 October 2009|access-date= 2009-10-29|publisher= Cheryl Kremkow}}</ref> Some consider this useful, since an impact would shatter a tungsten ring, quickly removing it, where precious metals would bend flat and require cutting. Tungsten carbide is roughly 10 times harder than 18k gold. In addition to its design and high polish, part of its attraction to consumers is its technical nature.<ref name=forever>{{cite web |url= https://www.forevermetals.com/jewelry-tungsten-carbide-ring/|title= Tungsten Carbide Manufacturing|website= forevermetals.com|access-date= 2005-06-18|publisher= Forever Metals |archive-url=https://web.archive.org/web/20070304235856/http://www.forevermetals.com/jewelry-tungsten-carbide-ring/ |archive-date=2007-03-04}}</ref> Special tools, such as locking pliers, may be required if such a ring must be removed quickly (e.g. due to medical emergency following a hand injury accompanied by swelling).<ref>{{cite journal |title= Removal of a Tungsten Carbide Ring from the Finger of a Pregnant Patient: A Case Report Involving 2 Emergency Departments and the Internet| pmc=4799811 | pmid=27042363 | doi=10.1155/2016/8164524 | volume=2016 | year=2016 | journal=Case Rep Emerg Med | page=8164524 | last1 = Moser | first1 = A | last2 = Exadaktylos | first2 = A | last3 = Radke | first3 = A| doi-access=free }}</ref>

===Other===
[[File:Spherical Tungster Carbide under Scanning Electron Microscope.png|thumb|Spherical tungsten carbide under [[scanning electron microscope]], magnification x950, Material Laboratory]]
Tungsten carbide is widely used to make the rotating ball in the tips of [[ballpoint pen]]s that disperse ink during writing.<ref>{{cite web |title=How does a ballpoint pen work?|work= Engineering|publisher= HowStuffWorks|date= 1998–2007|url= http://science.howstuffworks.com/question683.htm|access-date= 2007-11-16}}</ref>

Tungsten carbide is a common material used in the manufacture of [[gauge block]]s, used as a system for producing precision lengths in [[dimensional metrology]].{{citation needed|date=April 2013}}

English guitarist [[Martin Simpson]] is known to use a custom-made tungsten carbide [[slide guitar|guitar slide]].<ref>{{cite web |title= Wolfram Martin Simpson Signature Slide|url= http://www.wolframslides.com/mssig.php|work= Wolfram Slides|access-date= 6 August 2013}}</ref> The hardness, weight, and density of the slide give it superior [[sustain]] and volume compared to standard glass, steel, ceramic, or brass slides.

Tungsten carbide has been investigated for its potential use as a [[catalyst]] and it has been found to resemble [[platinum]] in its catalysis of the production of water from hydrogen and oxygen at room temperature, the [[redox|reduction]] of [[tungsten trioxide]] by hydrogen in the presence of water, and the [[isomerisation]] of 2,2-dimethylpropane to 2-methylbutane.<ref>{{cite journal |title= Platinum-Like Behavior of Tungsten Carbide in Surface Catalysis|first= R. B.|last= Levy|author2=M. Boudart |journal= Science|year= 1973|volume= 181|issue= 4099|pages= 547–9|doi= 10.1126/science.181.4099.547|pmid= 17777803|bibcode= 1973Sci...181..547L|s2cid= 39638807}}</ref> It has been proposed as a replacement for the [[iridium]] catalyst in [[hydrazine]]-powered [[spacecraft propulsion|satellite thrusters]].<ref>{{cite journal |title= Nitride and carbide of molybdenum and tungsten as substitutes of iridium for the catalysts used for space communication|last1= Rodrigues|first1= J.A.J.|first2= G. M. |last2=Cruz|journal= Catalysis Letters|volume= 45|pages= 1–2|year= 1997|doi= 10.1023/A:1019059410876|last3= Bugli|first3= G.|last4= Boudart|first4= M.|last5= Djéga-Mariadassou|first5= G.|s2cid= 92178880}}</ref>

A tungsten carbide coating has been utilized on brake discs in high performance automotive applications to improve performance, increase service intervals and reduce brake dust.<ref>{{cite web |title=Hard like Diamond|date= 2017-12-14|url= https://newsroom.porsche.com/en/christophorus/porsche-cayenne-turbo-surface-coated-brake-pscb-matthias-leber-weissach-14589.html|access-date= 2018-05-12}}</ref>

==Toxicity==
The primary health risks associated with tungsten carbide relate to inhalation of dust, leading to [[silicosis]]-like pulmonary [[fibrosis]].<ref>{{cite journal |last1= Sprince|first1= NL.|last2= Chamberlin|first2= RI.|last3= Hales|first3= CA.|last4= Weber|first4= AL.|last5= Kazemi|first5= H.|title= Respiratory disease in tungsten carbide production workers|journal= Chest|volume= 86|issue= 4|pages= 549–557|date= 1984|doi= 10.1378/chest.86.4.549|pmid= 6434250}}</ref> Cobalt-cemented tungsten carbide is also anticipated to be a human [[carcinogen]] by the American [[National Toxicology Program]].<ref name="12th Report on Carcinogens">{{cite web|url= http://ntp.niehs.nih.gov/go/roc12|title= 12th Report on Carcinogens|publisher= National Toxicology Program|access-date= 2011-06-24|url-status= dead|archive-url= https://web.archive.org/web/20110625114247/http://ntp.niehs.nih.gov/go/roc12|archive-date= 25 June 2011}}</ref>

==References==
{{Reflist|30em}}

==Cited sources==
*{{cite book |ref=Kurlov|author1=Kurlov, Alexey S. |author2=Gusev, Aleksandr I. |title=Tungsten Carbides: Structure, Properties and Application in Hardmetals|url=https://books.google.com/books?id=vcLBAAAAQBAJ&pg=PA3|date=2013|publisher=Springer Science & Business Media|isbn=978-3-319-00524-9|doi= 10.1007/978-3-319-00524-9|s2cid=136700223 |lccn= 2013942113}}

==External links==
{{Commons category|Tungsten carbide}}
*[http://www.inchem.org/documents/icsc/icsc/eics1320.htm International Chemical Safety Card 1320]
*[https://www.cdc.gov/niosh/npg/npgd0647.html NIOSH Pocket Guide to Chemical Hazards]

{{Tungsten compounds}}
{{Carbides}}

{{DEFAULTSORT:Tungsten Carbide}}
[[Category:Carbides]]
[[Category:Superhard materials]]
[[Category:Tungsten compounds]]
[[Category:Rock salt crystal structure]]

Tungsten carbide - Revision history

>Forbes72: added Category:Rock salt crystal structure using HotCat