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	{{chembox		{{chembox
		⚫	| verifiedrevid = 402711744
	| Watchedfields = changed
⚫	| verifiedrevid = 261549740
	| ImageFile = Magnesium-diboride-3D-balls.png		| ImageFile = Magnesium-diboride-3D-balls.png
	| ImageSize =		| ImageSize =
	| IUPACName =		| IUPACName =
	| OtherNames =		| OtherNames =
	| Section1 = {{Chembox Identifiers		|Section1={{Chembox Identifiers
	| CASNo = 12045-63-5		| CASNo = 12045-63-5
	| CASNo_Ref = {{cascite}}		| CASNo_Ref = {{cascite|correct|CAS}}
			| ChemSpiderID = 21171261
⚫	| PubChem =
	| SMILES =		| EINECS = 234-961-4
		⚫	| PubChem = 11412340
			| StdInChI=1S/B2.Ti/c1-2;
			| StdInChIKey = TXVDUUNOLJOZCR-UHFFFAOYSA-N
			| SMILES = ..
	}}		}}
	| Section2 = {{Chembox Properties		|Section2={{Chembox Properties
	| Formula = TiB<sub>2</sub>		| Formula = TiB<sub>2</sub>
	| MolarMass = 69.489 g/mol		| MolarMass = 69.489 g/mol
	| Appearance = non lustrous metallic grey		| Appearance = non lustrous metallic grey
	| Density = 4.52 g/cm<sup>3</sup>		| Density = 4.52 g/cm<sup>3</sup>
	| MeltingPtC = 3230		| MeltingPtC = 3230
	| BoilingPt =		| BoilingPt =
	| Solubility =		| Solubility =
	}}		}}
	| Section3 = {{Chembox Structure		|Section3={{Chembox Structure
	| CrystalStruct = Hexagonal, Space group P6/mmm. Lattice parameters at room temperature: ''a''=302.36 ], ''C''=322.04 pm		| CrystalStruct = Hexagonal, ]
			| SpaceGroup = P6/mmm
	| Coordination =		| Coordination =
			| LattConst_a = 302.36 ]
			| LattConst_c = 322.04 pm
	| MolShape = }}		| MolShape = }}
	| Section7 = {{Chembox Hazards		|Section7={{Chembox Hazards
	| MainHazards =		| MainHazards =
	| FlashPt =		| FlashPt =
	| Autoignition =		| AutoignitionPt =
	}}		}}
	}}		}}
	'''Titanium diboride''' (chemical formula TiB<sub>2</sub>) is an extremely hard ] compound composed of ] and ] which has excellent ]. TiB<sub>2</sub> is also a reasonable electrical conductor,<ref name="tib1">J. Schmidt et al. "Preparation of titanium diboride TiB2 by spark plasma sintering at slow heating rate" Sci. Technol. Adv. Mater. 8 (2007) 376 </ref> an unusual property for a ceramic, so it can be used as a cathode material in ] and can be shaped by ].		'''Titanium diboride''' (TiB<sub>2</sub>) is an extremely hard ceramic which has excellent heat conductivity, oxidation stability and ]. TiB<sub>2</sub> is also a reasonable electrical conductor,<ref name="tib1">J. Schmidt et al. "Preparation of titanium diboride TiB2 by spark plasma sintering at slow heating rate" Sci. Technol. Adv. Mater. 8 (2007) 376 </ref> so it can be used as a cathode material in ] and can be shaped by ].
	==Physical properties==		==Physical properties==
	TiB<sub>2</sub> is very similar to ], an important base material for ]s, and many of its properties (e.g. ], ], ] and ] resistance) are superior to those of TiC:<ref name="basu">B. Basu et al. "Processing and properties of monolithic TiB2 based materials" </ref>		TiB<sub>2</sub> shares some properties with ] and ], but many of its properties are superior to those of B<sub>4</sub>C & TiC:<ref name="basu">{{Cite journal|last1=Basu|first1=B.|last2=Raju|first2=G. B.|last3=Suri|first3=A. K.|date=2006-12-01|title=Processing and properties of monolithic TiB<sub>2</sub> based materials|journal=International Materials Reviews|volume=51|issue=6|pages=352–374|doi=10.1179/174328006X102529|bibcode=2006IMRv...51..352B |s2cid=137562554|issn=0950-6608}}</ref>
	*Exceptional hardness (~25–35 GPa at room temperature, more than three times harder than fully hardened ]), which is retained up to high temperature.
			===Exceptional hardness at extreme temperature===
	*High ] (3225&nbsp;°C),
			*2nd hardest material at 3000°C (])
			*3rd hardest material at 2800°C (])
			*4th hardest material at 2100°C (])
			*5th hardest material at 1000°C (])
			===Advantages over other borides===
			*Highest boride ]
			*Highest boride ]
			*Highest boride ]
			*3rd highest boride ] (3230 °C) (])
			===Other advantages===
	*High ] (60-120 W/(m K)),		*High ] (60-120 W/(m K)),
	*High ] (~10<sup>5</sup> S/cm)		*High ] (~10<sup>5</sup> S/cm)
			===Drawbacks===
			* Difficult to ] due to high melting temperature
			* Difficult to sinter due to the high ]
			* Limited to pressing to small Monolithic pieces using of ]
	==Chemical properties==		==Chemical properties==
	With respect to chemical stability, TiB<sub>2</sub> is more stable in contact with pure iron than ] or ].<ref name="basu"/>		With respect to chemical stability, TiB<sub>2</sub> is more stable in contact with pure iron than ] or ].<ref name="basu"/>
	TiB<sub>2</sub> is resistant to oxidation in air at temperatures up to 1100&nbsp;°C,<ref name="basu"/> and to ] and ] acids, but reacts with ]s, ] and ].		TiB<sub>2</sub> is resistant to oxidation in air at temperatures up to 1100&nbsp;°C,<ref name="basu"/> and to ] and ] acids, but reacts with ]s, ] and ].
	==Production==		==Production==
	TiB<sub>2</sub> does not occur naturally in the earth. Titanium diboride powder can be prepared by a variety of high-temperature methods, such as the direct reactions of ] or its oxides/hydrides, with elemental ] over 1000&nbsp;°C, ] by ] of ] and ], or hydrogen reduction of boron halides in the presence of the metal or its halides. Among various synthesis routes, electrochemical		TiB<sub>2</sub> does not occur naturally in the earth. Titanium diboride powder can be prepared by a variety of high-temperature methods, such as the direct reactions of ] or its oxides/hydrides, with elemental ] over 1000&nbsp;°C, ] by ] of ] and ], or hydrogen reduction of boron halides in the presence of the metal or its halides. Among various synthesis routes, electrochemical synthesis and solid state reactions have been developed to prepare finer titanium diboride in large quantity. An example of solid state reaction is the borothermic reduction, which can be illustrated by the following reactions:
	synthesis and solid state reactions have been developed to prepare finer titanium diboride in large quantity. An example of solid state reaction is the borothermic reduction, which can be illustrated by the following reaction
	:2 TiO<sub>2</sub> + B<sub>4</sub>C → 2 TiB<sub>2</sub> + 4 CO		(1) 2 TiO<sub>2</sub> + B<sub>4</sub>C + 3C → 2 TiB<sub>2</sub> + 4 CO
			(2) TiO<sub>2</sub> + 3NaBH<sub>4</sub> → TiB<sub>2</sub> + 2Na<sub>(g,l)</sub> + NaBO<sub>2</sub> + 6H<sub>2(g)</sub><ref>{{cite journal|last1=Zoli|first1=Luca|last2=Galizia|first2=Pietro|last3=Silvestroni|first3=Laura|last4=Sciti|first4=Diletta|title=Synthesis of group IV and V metal diboride nanocrystals via borothermal reduction with sodium borohydride|journal=Journal of the American Ceramic Society|volume=101|issue=6|pages=2627–2637|date=23 January 2018|doi=10.1111/jace.15401|url=https://zenodo.org/record/1292491|doi-access=free}}</ref>
⚫	These synthesis routes, however, cannot produce nanosized powders. Nanocrystalline (5–100 nm) TiB<sub>2</sub> was synthesized using the following techniques:
	* Solution phase reaction of NaBH<sub>4</sub> and TiCl<sub>4</sub>, followed by annealing the amorphous precursor obtained at 900–1100&nbsp;°C.<ref>S. E. Bates et al. "Synthesis of titanium boride (TiB)2 nanocrystallites by solution-phase processing" </ref>
		⚫	The first synthesis route (1), however, cannot produce nanosized powders. Nanocrystalline (5–100&nbsp;nm) TiB<sub>2</sub> was synthesized using the reaction (2) or the following techniques:
	*Mechanical alloying of a mixture of elemental Ti and B powders.<ref>A. Y. Hwang and J. K. Lee "Preparation of TiB2 powders by mechanical alloying " </ref>
	*Self-propagating high temperature synthesis process involving addition of varying amounts of NaCl.<ref>A. K. Khanra et al. "Effect of NaCl on the synthesis of TiB2 powder by a self-propagating high-temperature synthesis technique" </ref>		* Solution phase reaction of NaBH<sub>4</sub> and TiCl<sub>4</sub>, followed by annealing the amorphous precursor obtained at 900–1100&nbsp;°C.<ref>S. E. Bates et al. "Synthesis of titanium boride (TiB)2 nanocrystallites by solution-phase processing" </ref>
	*Solvothermal reaction in benzene of metallic sodium with amorphous boron powder and TiCl<sub>4</sub> at 400&nbsp;°C:<ref>Y. Gu et al. "A mild solvothermal route to nanocrystalline titanium diboride" </ref>		*Mechanical alloying of a mixture of elemental Ti and B powders.<ref>A. Y. Hwang and J. K. Lee "Preparation of TiB2 powders by mechanical alloying " </ref>
			*] process involving addition of varying amounts of NaCl.<ref>A. K. Khanra et al. "Effect of NaCl on the synthesis of TiB2 powder by a self-propagating high-temperature synthesis technique" </ref>
			*Milling assisted self-propagating high-temperature synthesis (MA-SHS).<ref>{{Cite journal|last=Amin Nozari|date=2012|title=Synthesis and characterization of nano-structured TiB2 processed by milling assisted SHS route|journal=Materials Characterization|volume=73|pages=96–103|doi=10.1016/j.matchar.2012.08.003|display-authors=etal}}</ref>
			*Solvothermal reaction in benzene of metallic sodium with amorphous boron powder and TiCl<sub>4</sub> at 400&nbsp;°C:<ref>Y. Gu et al. "A mild solvothermal route to nanocrystalline titanium diboride" </ref>
	::TiCl<sub>4</sub> + 2 B + 4 Na → TiB<sub>2</sub> + 4 NaCl		::TiCl<sub>4</sub> + 2 B + 4 Na → TiB<sub>2</sub> + 4 NaCl
	Many TiB<sub>2</sub> applications are inhibited by economic factors, particularly the costs of densifying a high melting point material - the melting point is about 2970&nbsp;°C, and, thanks to a layer of titanium dioxide that forms on the surface of the particles of a powder, it is very resistant to ]. Admixture of about 10% ] facilitates the sintering,<ref></ref> though sintering without silicon nitride has been demonstrated as well.<ref name="tib1"/>		Many TiB<sub>2</sub> applications are inhibited by economic factors, particularly the costs of densifying a high melting point material - the melting point is about 2970&nbsp;°C, and, thanks to a layer of titanium dioxide that forms on the surface of the particles of a powder, it is very resistant to ]. Admixture of about 10% ] facilitates the sintering,<ref>{{Cite web |url=http://www.patentgenius.com/patent/6420294.html |title=Titanium diboride sintered body with silicon nitride as a sintering aid and a method for manufacture thereof |access-date=2008-07-02 |archive-date=2016-03-03 |archive-url=https://web.archive.org/web/20160303183326/http://www.patentgenius.com/patent/6420294.html |url-status=dead }}</ref> though sintering without silicon nitride has been demonstrated as well.<ref name="tib1"/>
	Thin films of TiB<sub>2</sub> can be produced by several techniques. The ] of TiB<sub>2</sub> layers possess two main advantages compared with ] or ]: the growing rate of the layer is 200 times higher (up to 5&nbsp;μm/s) and the inconveniences of covering complex shaped products are dramatically reduced.		Thin films of TiB<sub>2</sub> can be produced by several techniques. The ] of TiB<sub>2</sub> layers possess two main advantages compared with ] or ]: the growing rate of the layer is 200 times higher (up to 5&nbsp;μm/s) and the inconveniences of covering complex shaped products are dramatically reduced.
	==Potential applications==		==Potential applications==
			Current use of TiB<sub>2</sub> appears to be limited to specialized applications in such areas as impact resistant ], ]s, ]s, neutron absorbers and wear resistant coatings.<ref>{{cite web |url=https://www.preciseceramic.com/blog/top-10-ceramic-materials-with-the-highest-thermal-conductivity.html |title=Top 10 Ceramic Materials with the Highest Thermal Conductivity |date=Sep 24, 2024 |last=Ross |first=Lisa |website=Advanced Ceramic Materials |access-date=Nov 8, 2024}}</ref>
		⚫	TiB<sub>2</sub> is extensively used for evaporation boats for vapour coating of ].<ref>{{cite journal |last1=McKinon |first1=Ruth |last2=Grasso |first2=Salvatore |year=2017 |title=Flash spark plasma sintering of cold-Pressed TiB2-hBN |journal=Journal of the European Ceramic Society |volume=37 |issue=8 |pages=2787-2794 |doi=10.1016/j.jeurceramsoc.2017.01.029}}</ref> It is an attractive material for the aluminium industry as an ] to refine the ] when ] ]s, because of its wettability by and low solubility in molten aluminium and good electrical conductivity.
	Current use of TiB<sub>2</sub> appears to be limited to specialized applications in such areas as impact resistant ], ]s, ]s and wear resistant coatings.
			]s of TiB<sub>2</sub> can be used to provide wear and ] resistance to a cheap and/or tough substrate.<ref>{{cite journal |last1=Wu |first1=Zhengtao |last2=Ye |first2=Rongli |year=2022 |title=Reprint of: Improving oxidation and wear resistance of TiB2 films by nano-multilayering with Cr |journal=Surface and Coatings Technology |volume=442 |page=128602 |doi=10.1016/j.surfcoat.2022.128602}}</ref>
⚫	TiB<sub>2</sub> is extensively used as evaporation boats for vapour coating of ]. It is an attractive material for the aluminium industry as an ] to refine the ] when ] ]s, because of its wettability by and low solubility in molten aluminium and good electrical conductivity.
	]s of TiB<sub>2</sub> can be used for wear and ] resistance that TiB<sub>2</sub> can provide to a cheap and/or tough substrate.
	==References==		==References==
	{{reflist}}		{{Reflist|2}}
			==Compare==
			*]
	==See also==		==See also==
			{{div col|colwidth=22em}}
	{{colbegin|3}}
	*]		*]
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	*]		*]
	*]		*]
	*]		*]
	*]		*]
	{{colend}}		{{div col end}}
	{{Titanium compounds}}		{{Titanium compounds}}
			{{Borides}}
	]		]
	]		]
	]		]