Editing Boron nitride (section)

==Other forms of boron nitride==
=== Atomically thin boron nitride ===
{{Main|Boron nitride nanosheet}}
Hexagonal boron nitride can be exfoliated to mono or few atomic layer sheets. Due to its analogous structure to that of graphene, atomically thin boron nitride is sometimes called ''white graphene''.<ref name="LiChen2016">{{cite journal|last1=Li|first1=Lu Hua|last2=Chen|first2=Ying|title=Atomically Thin Boron Nitride: Unique Properties and Applications|journal=Advanced Functional Materials|volume=26|issue=16|year=2016|pages=2594–2608|doi=10.1002/adfm.201504606|arxiv=1605.01136|bibcode=2016arXiv160501136L|s2cid=102038593}}</ref>

====Mechanical properties====
Atomically thin boron nitride is one of the strongest electrically insulating materials. Monolayer boron nitride has an average Young's modulus of 0.865TPa and fracture strength of 70.5GPa, and in contrast to graphene, whose strength decreases dramatically with increased thickness, few-layer boron nitride sheets have a strength similar to that of monolayer boron nitride.<ref>{{Cite journal|last1=Falin|first1=Aleksey|last2=Cai|first2=Qiran|last3=Santos|first3=Elton J.G.|last4=Scullion|first4=Declan|last5=Qian|first5=Dong|last6=Zhang|first6=Rui|last7=Yang|first7=Zhi|last8=Huang|first8=Shaoming|last9=Watanabe|first9=Kenji|date=2017-06-22|title=Mechanical properties of atomically thin boron nitride and the role of interlayer interactions|journal=Nature Communications|volume=8|pages=15815|doi=10.1038/ncomms15815|pmid=28639613|pmc=5489686|arxiv=2008.01657|bibcode=2017NatCo...815815F}}</ref>

====Thermal conductivity====
Atomically thin boron nitride has one of the highest thermal conductivity coefficients (751 W/mK at room temperature) among semiconductors and electrical insulators, and its thermal conductivity increases with reduced thickness due to less intra-layer coupling.<ref>{{Cite journal|last1=Cai|first1=Qiran|last2=Scullion|first2=Declan|last3=Gan|first3=Wei|last4=Falin|first4=Alexey|last5=Zhang|first5=Shunying|last6=Watanabe|first6=Kenji|last7=Taniguchi|first7=Takashi|last8=Chen|first8=Ying|last9=Santos|first9=Elton J. G.|date=2019|title=High thermal conductivity of high-quality monolayer boron nitride and its thermal expansion|journal=Science Advances|language=en|volume=5|issue=6|pages=eaav0129|doi=10.1126/sciadv.aav0129|issn=2375-2548|pmc=6555632|pmid=31187056|arxiv=1903.08862|bibcode=2019SciA....5..129C}}</ref>

====Thermal stability====
The air stability of graphene shows a clear thickness dependence: monolayer graphene is reactive to oxygen at 250&nbsp;°C, strongly doped at 300&nbsp;°C, and etched at 450&nbsp;°C; in contrast, bulk graphite is not oxidized until 800&nbsp;°C.<ref name="LiSantos2014"/> Atomically thin boron nitride has much better oxidation resistance than graphene. Monolayer boron nitride is not oxidized till 700&nbsp;°C and can sustain up to 850&nbsp;°C in air; bilayer and trilayer boron nitride nanosheets have slightly higher oxidation starting temperatures.<ref name="LiCervenka2014">{{cite journal|last1=Li|first1=Lu Hua|last2=Cervenka|first2=Jiri|last3=Watanabe|first3=Kenji|last4=Taniguchi|first4=Takashi|last5=Chen|first5=Ying|title=Strong Oxidation Resistance of Atomically Thin Boron Nitride Nanosheets|journal=ACS Nano|volume=8|issue=2|year=2014|pages=1457–1462|doi=10.1021/nn500059s|pmid=24400990|arxiv=1403.1002|bibcode=2014arXiv1403.1002L|s2cid=5372545}}</ref> The excellent thermal stability, high impermeability to gas and liquid, and electrical insulation make atomically thin boron nitride potential coating materials for preventing surface oxidation and corrosion of metals<ref name="LiXing2014">{{cite journal|last1=Li|first1=Lu Hua|last2=Xing|first2=Tan|last3=Chen|first3=Ying|last4=Jones|first4=Rob|title=Nanosheets: Boron Nitride Nanosheets for Metal Protection (Adv. Mater. Interfaces 8/2014)|journal=Advanced Materials Interfaces|volume=1|issue=8|year=2014|pages=n/a|doi=10.1002/admi.201470047|doi-access=free}}</ref><ref>{{Cite journal|last1=Liu|first1=Zheng|last2=Gong|first2=Yongji|last3=Zhou|first3=Wu|last4=Ma|first4=Lulu|last5=Yu|first5=Jingjiang|last6=Idrobo|first6=Juan Carlos|last7=Jung|first7=Jeil|last8=MacDonald|first8=Allan H.|last9=Vajtai|first9=Robert|date=2013-10-04|title=Ultrathin high-temperature oxidation-resistant coatings of hexagonal boron nitride|journal=Nature Communications|volume=4|issue=1|pages=2541|doi=10.1038/ncomms3541|pmid=24092019|bibcode=2013NatCo...4.2541L|doi-access=free}}</ref> and other two-dimensional (2D) materials, such as [[black phosphorus]].<ref>{{Cite journal|last1=Chen|first1=Xiaolong|last2=Wu|first2=Yingying|last3=Wu|first3=Zefei|last4=Han|first4=Yu|last5=Xu|first5=Shuigang|last6=Wang|first6=Lin|last7=Ye|first7=Weiguang|last8=Han|first8=Tianyi|last9=He|first9=Yuheng|date=2015-06-23|title=High-quality sandwiched black phosphorus heterostructure and its quantum oscillations|journal=Nature Communications|volume=6|issue=1|pages=7315|doi=10.1038/ncomms8315|pmid=26099721|pmc=4557360|arxiv=1412.1357|bibcode=2015NatCo...6.7315C}}</ref>

====Better surface adsorption====
Atomically thin boron nitride has been found to have better surface adsorption capabilities than bulk hexagonal boron nitride.<ref>{{Cite journal|last1=Cai|first1=Qiran|last2=Du|first2=Aijun|last3=Gao|first3=Guoping|last4=Mateti|first4=Srikanth|last5=Cowie|first5=Bruce C. C.|last6=Qian|first6=Dong|last7=Zhang|first7=Shuang|last8=Lu|first8=Yuerui|last9=Fu|first9=Lan|author9-link=Lan Fu (engineer)|date=2016-08-29|title=Molecule-Induced Conformational Change in Boron Nitride Nanosheets with Enhanced Surface Adsorption|journal=Advanced Functional Materials|volume=26|issue=45|pages=8202–8210|doi=10.1002/adfm.201603160|arxiv=1612.02883|bibcode=2016arXiv161202883C|s2cid=13800939}}</ref> According to theoretical and experimental studies, atomically thin boron nitride as an adsorbent experiences conformational changes upon surface adsorption of molecules, increasing adsorption energy and efficiency. The synergic effect of the atomic thickness, high flexibility, stronger surface adsorption capability, electrical insulation, impermeability, high thermal and chemical stability of BN nanosheets can increase the [[Raman spectroscopy|Raman sensitivity]] by up to two orders, and in the meantime attain long-term stability and reusability not readily achievable by other materials.<ref>{{Cite journal|last1=Cai|first1=Qiran|last2=Mateti|first2=Srikanth|last3=Yang|first3=Wenrong|last4=Jones|first4=Rob|last5=Watanabe|first5=Kenji|last6=Taniguchi|first6=Takashi|last7=Huang|first7=Shaoming|last8=Chen|first8=Ying|last9=Li|first9=Lu Hua|date=2016-05-20|title=Inside Back Cover: Boron Nitride Nanosheets Improve Sensitivity and Reusability of Surface-Enhanced Raman Spectroscopy (Angew. Chem. Int. Ed. 29/2016)|journal=Angewandte Chemie International Edition|volume=55|issue=29|pages=8457|doi=10.1002/anie.201604295|doi-access=free|hdl=10536/DRO/DU:30086239|hdl-access=free}}</ref><ref>{{Cite journal|last1=Cai|first1=Qiran|last2=Mateti|first2=Srikanth|last3=Watanabe|first3=Kenji|last4=Taniguchi|first4=Takashi|last5=Huang|first5=Shaoming|last6=Chen|first6=Ying|last7=Li|first7=Lu Hua|date=2016-06-14|title=Boron Nitride Nanosheet-Veiled Gold Nanoparticles for Surface-Enhanced Raman Scattering|journal=ACS Applied Materials & Interfaces|volume=8|issue=24|pages=15630–15636|doi=10.1021/acsami.6b04320|pmid=27254250|arxiv=1606.07183|bibcode=2016arXiv160607183C|s2cid=206424168}}</ref>

====Dielectric properties====
Atomically thin hexagonal boron nitride is an excellent dielectric substrate for graphene, molybdenum disulfide ({{chem2|MoS2}}), and many other 2D material-based electronic and photonic devices. As shown by electric force microscopy (EFM) studies, the electric field screening in atomically thin boron nitride shows a weak dependence on thickness, which is in line with the smooth decay of electric field inside few-layer boron nitride revealed by the first-principles calculations.<ref name="LiSantos2014">{{Cite journal|last1=Li|first1=Lu Hua|last2=Santos|first2=Elton J. G.|last3=Xing|first3=Tan|last4=Cappelluti|first4=Emmanuele|last5=Roldán|first5=Rafael|last6=Chen|first6=Ying|last7=Watanabe|first7=Kenji|last8=Taniguchi|first8=Takashi|year=2015|title=Dielectric Screening in Atomically Thin Boron Nitride Nanosheets|journal=Nano Letters|volume=15|issue=1|pages=218–223|doi=10.1021/nl503411a|pmid=25457561|arxiv=1503.00380|bibcode=2015NanoL..15..218L|s2cid=207677623}}</ref>

====Raman characteristics====
Raman spectroscopy has been a useful tool to study a variety of 2D materials, and the Raman signature of high-quality atomically thin boron nitride was first reported by Gorbachev et al. in 2011.<ref>{{Cite journal|last1=Gorbachev|first1=Roman V.|last2=Riaz|first2=Ibtsam|last3=Nair|first3=Rahul R.|last4=Jalil|first4=Rashid|last5=Britnell|first5=Liam|last6=Belle|first6=Branson D.|last7=Hill|first7=Ernie W.|last8=Novoselov|first8=Kostya S.|last9=Watanabe|first9=Kenji|date=2011-01-07|title=Hunting for Monolayer Boron Nitride: Optical and Raman Signatures|journal=Small|volume=7|issue=4|pages=465–468|doi=10.1002/smll.201001628|pmid=21360804|arxiv=1008.2868|s2cid=17344540}}</ref> and Li et al.<ref name="LiCervenka2014"/> However, the two reported Raman results of monolayer boron nitride did not agree with each other. Cai et al., therefore, conducted systematic experimental and theoretical studies to reveal the intrinsic Raman spectrum of atomically thin boron nitride.<ref>{{Cite journal|last1=Cai|first1=Qiran|last2=Scullion|first2=Declan|last3=Falin|first3=Aleksey|last4=Watanabe|first4=Kenji|last5=Taniguchi|first5=Takashi|last6=Chen|first6=Ying|last7=Santos|first7=Elton J. G.|last8=Li|first8=Lu Hua|date=2017|title=Raman signature and phonon dispersion of atomically thin boron nitride|journal=Nanoscale|volume=9|issue=9|pages=3059–3067|doi=10.1039/c6nr09312d|pmid=28191567|url=https://pure.qub.ac.uk/portal/en/publications/raman-signature-and-phonon-dispersion-of-atomically-thin-boron-nitride(5f58d958-22ab-450f-97fb-cd7c0f25f5b4).html|arxiv=2008.01656|s2cid=206046676}}</ref> It reveals that atomically thin boron nitride without interaction with a substrate has a G band frequency similar to that of bulk hexagonal boron nitride, but strain induced by the substrate can cause Raman shifts. Nevertheless, the Raman intensity of G band of atomically thin boron nitride can be used to estimate layer thickness and sample quality.[[Image:STMnm-2.JPG|thumb|left|150px|BN nanomesh observed with a [[scanning tunneling microscope]]. The center of each ring corresponds to the center of the pores]]
[[File:Oil absorption by BN aerogel.jpg|thumb|upright=1.5|Top: absorption of [[cyclohexane]] by BN aerogel. Cyclohexane is stained with [[Sudan II]] red dye and is floating on water. Bottom: reuse of the aerogel after burning in air.<ref name=nat>{{cite journal|doi=10.1038/srep10337|pmid=25976019|title=Ultralight boron nitride aerogels via template-assisted chemical vapor deposition|journal=Scientific Reports|volume=5|pages=10337|year=2015|last1=Song|first1=Yangxi|last2=Li|first2=Bin|last3=Yang|first3=Siwei|last4=Ding|first4=Guqiao|last5=Zhang|first5=Changrui|last6=Xie|first6=Xiaoming|pmc=4432566|bibcode=2015NatSR...510337S}}</ref>]]

===Boron nitride nanomesh===
{{Main|Nanomesh}}
[[nanomesh|Boron nitride nanomesh]] is a nanostructured two-dimensional material. It consists of a single BN layer, which forms by [[self-assembly]] a highly regular mesh after high-temperature exposure of a clean [[rhodium]]<ref name="corso04">{{cite journal | author = Corso, M. | title = Boron Nitride Nanomesh | journal = Science | volume = 303 | pages = 217–220 | doi = 10.1126/science.1091979 | year = 2004 | pmid = 14716010 | issue = 5655 |bibcode = 2004Sci...303..217C | s2cid = 11964344 |display-authors=etal}}</ref> or [[ruthenium]]<ref name="goriachko07">{{cite journal | author = Goriachko, A. | title = Self-Assembly of a Hexagonal Boron Nitride Nanomesh on Ru(0001) | journal = Langmuir | volume = 23 | issue = 6 | pages = 2928–2931 | doi = 10.1021/la062990t | pmid = 17286422 | year = 2007 |display-authors=etal}}</ref> surface to [[borazine]] under [[ultra-high vacuum]]. The nanomesh looks like an assembly of hexagonal pores. The distance between two pore centers is 3.2&nbsp;nm and the pore diameter is ~2&nbsp;nm. Other terms for this material are boronitrene or white graphene.<ref>[http://jacobs.physik.uni-saarland.de/forschung/Graphene.htm Graphene and Boronitrene (White Graphene)] {{Webarchive|url=https://web.archive.org/web/20180528042221/http://jacobs.physik.uni-saarland.de/forschung/Graphene.htm |date=2018-05-28}}. physik.uni-saarland.de</ref>

The boron nitride nanomesh is air-stable<ref name="bunk07">{{cite journal | author = Bunk, O. | title = Surface X-Ray Diffraction Study of Boron-Nitride Nanomesh in Air | journal = Surface Science | volume = 601 | pages = L7–L10 | doi = 10.1016/j.susc.2006.11.018 | year = 2007 | issue = 2 |bibcode = 2007SurSc.601L...7B | url = https://www.dora.lib4ri.ch/psi/islandora/object/psi%3A18158 |display-authors=etal}}</ref> and compatible with some liquids.<ref name="berner07">{{cite journal | author = Berner, S. | title = Boron Nitride Nanomesh: Functionality from a Corrugated Monolayer | journal = Angewandte Chemie International Edition | volume = 46 | issue = 27 | pages = 5115–5119 | doi = 10.1002/anie.200700234 | pmid = 17538919 | year = 2007 |display-authors=etal}}</ref><ref name="widmer07">{{cite journal | author = Widmer, R. | title = Electrolytic ''in situ'' STM Investigation of h-BN-Nanomesh |url=http://webmail.physik.unizh.ch/groups/osterwalder/zz_publications_old/EC_Widmer.pdf |archive-url=https://ghostarchive.org/archive/20221009/http://webmail.physik.unizh.ch/groups/osterwalder/zz_publications_old/EC_Widmer.pdf |archive-date=2022-10-09 |url-status=live| journal = Electrochemical Communications | volume = 9 | pages = 2484–2488 | doi = 10.1016/j.elecom.2007.07.019 | year = 2007 | issue = 10 |display-authors=etal}}</ref> up to temperatures of 800&nbsp;°C.<ref name="corso04"/>

[[File:Flame test of buckypapers.jpg|thumb|upright=1.5|BN nanotubes are flame resistant, as shown in this comparative test of airplanes made of cellulose, carbon [[buckypaper]] and BN nanotube buckypaper.<ref name="BNpaper">{{cite journal|doi=10.1039/C5RA02988K |title=Polymer nanocomposites from free-standing, macroscopic boron nitride nanotube assemblies |journal=RSC Adv |volume=5 |issue=51 |pages=41186 |year=2015 |last1=Kim |first1=Keun Su |last2=Jakubinek |first2=Michael B. |last3=Martinez-Rubi |first3=Yadienka |last4=Ashrafi |first4=Behnam |last5=Guan |first5=Jingwen |last6=O'Neill |first6=K. |last7=Plunkett |first7=Mark |last8=Hrdina |first8=Amy |last9=Lin |first9=Shuqiong |last10=Dénommée |first10=Stéphane |last11=Kingston |first11=Christopher |last12=Simard |first12=Benoit |bibcode=2015RSCAd...541186K}}</ref>]]

===Boron nitride nanotubes===
{{Main|Boron nitride nanotube}} Boron nitride tubules were first made in 1989 by Shore and Dolan This work was patented in 1989 and published in 1989 thesis (Dolan) and then 1993 Science. The 1989 work was also the first preparation of amorphous BN by B-trichloroborazine and cesium metal.

Boron nitride nanotubes were predicted in 1994<ref>{{cite journal | doi = 10.1103/PhysRevB.49.5081 | pmid = 10011453 | title = Theory of Graphitic Boron Nitride Nanotubes | year = 1994 | author = Rubio, A. | journal = Physical Review B | volume = 49 | issue = 7 | pages = 5081–5084 |bibcode = 1994PhRvB..49.5081R | url = https://zenodo.org/record/1233727 |display-authors=etal}}</ref> and experimentally discovered in 1995.<ref name="N.G. Chopra, R.J. Luyken 1995">{{cite journal | doi = 10.1126/science.269.5226.966 | title = Boron Nitride Nanotubes | year = 1995 | author = Chopra, N. G. | journal = Science | volume = 269 | pages = 966–7 | pmid = 17807732 | issue = 5226 |bibcode = 1995Sci...269..966C | s2cid = 28988094 |display-authors=etal}}</ref> They can be imagined as a rolled up sheet of h-boron nitride. Structurally, it is a close analog of the [[carbon nanotube]], namely a long cylinder with diameter of several to hundred nanometers and length of many micrometers, except carbon atoms are alternately substituted by nitrogen and boron atoms. However, the properties of BN nanotubes are very different: whereas carbon nanotubes can be metallic or semiconducting depending on the rolling direction and radius, a BN nanotube is an electrical insulator with a bandgap of ~5.5 eV, basically independent of tube chirality and morphology.<ref>{{cite journal | doi = 10.1209/0295-5075/28/5/007 | title = Stability and Band Gap Constancy of Boron Nitride Nanotubes | year = 1994 | author = Blase, X. | s2cid = 120010610 | journal = Europhysics Letters | volume = 28 | page = 335 | issue = 5 |bibcode = 1994EL.....28..335B |display-authors=etal}}</ref> In addition, a layered BN structure is much more thermally and chemically stable than a graphitic carbon structure.<ref>{{cite journal | url = http://www.glue.umd.edu/~cumings/PDF%20Publications/15.APL81han.pdf | doi = 10.1063/1.1498494 | title = Transformation of B<sub>x</sub>C<sub>y</sub>N<sub>z</sub> Nanotubes to Pure BN Nanotubes | year = 2002 | author = Han, Wei-Qiang | journal = Applied Physics Letters | volume = 81 | page = 1110 | issue = 6 |bibcode = 2002ApPhL..81.1110H |display-authors=etal}}</ref><ref name="golberg">{{cite journal | title = Boron Nitride Nanotubes | doi = 10.1002/adma.200700179 | journal = Advanced Materials | volume = 19 | year = 2007 | page = 2413 | issue = 18 | last1 = Golberg | first1 = D. | last2 = Bando | first2 = Y. | last3 = Tang | first3 = C. C. | last4 = Zhi | first4 = C. Y. | bibcode = 2007AdM....19.2413G | s2cid = 221149452}}</ref>

===Boron nitride aerogel===
{{Main|Boron nitride aerogel}}
Boron nitride aerogel is an [[aerogel]] made of highly porous BN. It typically consists of a mixture of deformed BN nanotubes and [[Boron nitride nanosheet|nanosheets]]. It can have a density as low as 0.6&nbsp;mg/cm<sup>3</sup> and a specific surface area as high as 1050&nbsp;m<sup>2</sup>/g, and therefore has potential applications as an [[Absorption (chemistry)|absorbent]], catalyst support and gas storage medium. BN aerogels are highly [[hydrophobic]] and can absorb up to 160 times their weight in oil. They are resistant to oxidation in air at temperatures up to 1200&nbsp;°C, and hence can be reused after the absorbed oil is burned out by flame. BN aerogels can be prepared by template-assisted [[chemical vapor deposition]] using [[borazine]] as the feed gas.<ref name=nat/>

===Composites containing BN===
Addition of boron nitride to [[silicon nitride]] ceramics improves the [[thermal shock]] resistance of the resulting material. For the same purpose, BN is added also to silicon nitride-[[alumina]] and [[titanium nitride]]-alumina ceramics. Other materials being reinforced with BN include alumina and [[zirconia]], [[borosilicate glass]]es, [[glass ceramic]]s, [[vitreous enamel|enamels]], and composite ceramics with [[titanium boride]]-boron nitride, titanium boride-[[aluminium nitride]]-boron nitride, and [[silicon carbide]]-boron nitride composition.<ref>{{cite book | title = Handbook of Composite Reinforcements | author = Lee, S. M. | publisher = John Wiley and Sons | year = 1992 | isbn = 978-0471188612}}</ref>

Zirconia Stabilized Boron Nitride (ZSBN) is produced by adding [[zirconia]] to BN, enhancing its thermal shock resistance and mechanical strength through a [[sintering]] process.<ref>{{cite web |url=https://www.preciseceramic.com/blog/boron-nitride-variants-pbn-hbn-cbn-zsbn.html |title=Diverse Classification Factors of Boron Nitride and Their Correlation with PBN, HBN, CBN, and ZSBN Variants
 |last=Lisa |first=Ross |website=Precise Ceramics |access-date=June 8, 2024}}</ref> It offers better performance characteristics including Superior [[corrosion]] and [[erosion]] resistance over a wide temperature range.<ref>{{cite book |author=<!-- Not Stated --> |title=New Steel: Mini & Integrated Mill Management and Technologies |date=1996 |publisher=Chilton Publishing |pages=51–56}}</ref> Its unique combination of thermal conductivity, [[lubricity]], mechanical strength, and stability makes it suitable for various applications including cutting tools and wear-resistant coatings, thermal and electrical insulation, aerospace and defense, and high-temperature components.<ref>{{cite journal |last1=Hayat |first1=Asif |last2=Sohail |first2=Muhammad |last3=Hamdy |first3=Mohamed |date=2022 |title=Fabrication, characteristics, and applications of boron nitride and their composite nanomaterials |url=https://www.sciencedirect.com/science/article/abs/pii/S2468023022000062 |journal=Surfaces and Interfaces |volume=29 |doi=10.1016/j.surfin.2022.101725 |access-date=June 8, 2024}}</ref><ref>{{cite journal |last1=Eichler |first1=Jens |last2=Lesniak |first2=Cristoph |date=2008 |title=Boron nitride (BN) and BN composites for high-temperature applications |url=https://www.sciencedirect.com/science/article/abs/pii/S0955221907004700 |journal=Journal of the European Ceramic Society |volume=28 |issue=5 |pages=1105–1109 |doi=10.1016/j.jeurceramsoc.2007.09.005}}</ref>

===Pyrolytic boron nitride (PBN)===

Pyrolytic boron nitride (PBN), also known as [[Chemical vapor deposition|Chemical vapour-deposited]] Boron Nitride(CVD-BN),<ref>{{cite web |url=https://www.preciseceramic.com/blog/introduction-of-pyrolytic-boron-nitride-pbn.html |title=About Pyrolytic Boron Nitride |last=Rose |first=Lisa |website=Precise Ceramic |access-date=May 31, 2024}}</ref> is a high-purity [[ceramic]] material characterized by exceptional chemical resistance and mechanical strength at high temperatures.<ref>{{cite web |title=Pyrolytic Boron Nitride (PBN) |url=https://www.shinetsu.co.jp/en/products/electronics-materials/pyrolytic-boron-nitride-pbn/ |website=Shin-Etsu Chemical Co., Ltd. |access-date=May 31, 2024}}</ref>
Pyrolytic boron nitride is typically prepared through the thermal decomposition of [[boron trichloride]] and [[ammonia]] vapors on [[graphite]] substrates at 1900&nbsp;°C.<ref>{{cite journal |last1=Moore |first1=A. |title=Compression Annealing of Pyrolytic Boron Nitride |journal=Nature |volume=221 |pages=1133–1135 |date=1969-03-22 |issue=5186 |doi=10.1038/2211133a0 |bibcode=1969Natur.221.1133M |url=https://www.nature.com/articles/2211133a0 |access-date=May 31, 2024}}</ref>

Pyrolytic boron nitride (PBN) generally has a hexagonal structure similar to hexagonal boron nitride (hBN), though it can exhibit stacking faults or deviations from the ideal lattice.<ref>{{cite web |title=An Overview of Pyrolytic Boron Nitride (PBN) |url=https://www.sputtertargets.net/an-overview-of-pyrolytic-boron-nitride-pbn.html |website=Sputter Targets |date=3 December 2018 |access-date=May 31, 2024}}</ref> Pyrolytic boron nitride (PBN) shows some remarkable attributes, including exceptional chemical inertness, high [[dielectric]] strength, excellent thermal shock resistance, non-wettability, non-toxicity, oxidation resistance, and minimal [[outgassing]].
<ref>{{cite journal |last1=Lipp |first1=A. |last2=Schwetz |first2=K.A. |last3=Hunold |first3=K. |title=Hexagonal boron nitride: Fabrication, properties and applications |journal=Journal of the European Ceramic Society |volume=5 |issue=1 |pages=3–9 |date=1989 |doi=10.1016/0955-2219(89)90003-4 }}</ref><ref>{{cite journal |last1=Moore |first1=A.W. |title=Characterization of pyrolytic boron nitride for semiconductor materials processing |journal=Journal of Crystal Growth |volume=106 |issue=1 |pages=6–15 |date=1990 |doi=10.1016/0022-0248(90)90281-O |bibcode=1990JCrGr.106....6M }}</ref>

Due to a highly ordered planar texture similar to pyrolytic graphite (PG), it exhibits anisotropic properties such as lower [[dielectric]] constant vertical to the [[crystal]] plane and higher bending strength along the [[crystal]] plane.<ref>{{cite journal |last1=Rebillat |first1=F. |last2=Guette |first2=A. |title=Highly ordered pyrolytic BN obtained by LPCVD |journal=Journal of the European Ceramic Society |volume=17 |issue=12 |pages=1403–1414 |date=1997 |doi=10.1016/S0955-2219(96)00244-0}}</ref> PBN material has been widely manufactured as [[crucibles]] of compound [[semiconductor]] crystals, output windows and [[dielectric]] rods of traveling-wave tubes, high-temperature [[Jig (tool)|jigs]] and [[Insulator (electricity)|insulator]].<ref>{{cite journal |last1=Gao |first1=Shitao |last2=Li |first2=Bin |title=Micromorphology and structure of pyrolytic boron nitride synthesized by chemical vapor deposition from borazine |journal=Ceramics International |volume=44 |issue=10 |pages=11424–11430 |date=2018 |doi=10.1016/j.ceramint.2018.03.201}}</ref>