Editing Dielectric strength (section)

== Break down field strength ==

The field strength at which break down occurs depends on the respective geometries of the dielectric (insulator) and the electrodes with which the [[electric field]] is applied, as well as the rate of increase of the applied electric field. Because dielectric materials usually contain minute defects, the practical dielectric strength will be a significantly less than the intrinsic dielectric strength of an ideal, defect-free, material. Dielectric films tend to exhibit greater dielectric strength than thicker samples of the same material. For instance, the dielectric strength of silicon dioxide films of thickness around 1 [[micron|μm]] is about 0.5{{nbsp}}GV/m.<ref>
{{cite journal
 | title=Electrical insulation properties of sputter-deposited SiO<sub>2</sub>, Si<sub>3</sub>N<sub>4</sub> and Al<sub>2</sub>O<sub>3</sub> films at room temperature and 400 °C
 | date=2009-01-21
 | doi=10.1002/pssa.200880481
 | volume=206
 | issue=3
 | journal=Physica Status Solidi A
 | pages=514–519
 | bibcode=2009PSSAR.206..514B
|last1 = Bartzsch|first1 = Hagen| last2=Glöß
 | first2=Daniel
 | last3=Frach
 | first3=Peter
 | last4=Gittner
 | first4=Matthias
 | last5=Schultheiß
 | first5=Eberhard
 | last6=Brode
 | first6=Wolfgang
 | last7=Hartung
 | first7=Johannes
 | s2cid=93228294
 }}</ref> However very thin layers (below, say, {{nowrap|100 nm}}) become partially conductive because of [[electron tunneling]].{{clarify|reason=does this not seem to contradict the above 'films tend to exhibit greater dielectric strength than thicker samples of the same material.' since samples 'a few hundred nm to a few μm thick is approximately 0.5 GV/m' and samples less than '100nm are partially conductive...'|date=November 2018}} Multiple layers of thin dielectric films are used where maximum practical dielectric strength is required, such as high voltage [[capacitor]]s and pulse [[transformer]]s. Since the dielectric strength of gases varies depending on the shape and configuration of the electrodes,<ref>
{{cite journal
 | last1=Lyon | first1=David
 |display-authors=et al.
 | title=Gap size dependence of the dielectric strength in nano vacuum gaps
 | journal=IEEE
 | volume=20
 | issue=4
 | pages=1467–1471
 | date=2013
 | doi=10.1109/TDEI.2013.6571470
| s2cid=709782
 }}</ref> it is usually measured as a fraction of the dielectric strength of [[nitrogen gas]].

Dielectric strength (in MV/m, or 10{{sup|6}}&sdot;volt/meter) of various common materials:

{| class="wikitable sortable"
|-
! Substance
! data-sort-type=number | Dielectric strength<br>(MV/m) or (Volt/micron)
|-
| [[Helium]] (relative to nitrogen)<ref name="CRC">''[[CRC Handbook of Chemistry and Physics]]''</ref><br>{{clarify|date=January 2019}}
| {{nts|0.15}}
|-
| [[Air]]<ref>{{cite web
| url=https://hypertextbook.com/facts/2000/AliceHong.shtml
| title=Dielectric Strength of Air
| first=Alice
| last=Hong
| year=2000
| website=The Physics Factbook
| editor-last=Elert
| editor-first=Glenn
| access-date=2020-06-18
}}</ref>

<ref>{{cite web
| url=https://pact.in/blog/2024/04/dielectric-strength-of-air
| title=Unveiling the Magic of Air
| access-date=2024-04-27
}}</ref>

| {{nts|3}}
|-
| [[Sulfur hexafluoride]]<ref name="CRC"/>
| {{ntsh|9.15}}8.5–9.8
|-
| [[Alumina]]<ref name="CRC"/>
| {{nts|13.4}}
|-
| Window [[glass]]<ref name="CRC"/>
| {{ntsh|11.8}} 9.8–13.8
|-
| [[Borosilicate glass]]<ref name="CRC"/>
| {{ntsh|30}} 20–40
|-
| [[Silicone oil]], [[mineral oil]]<ref name="CRC"/><ref>{{cite web| last =Föll |first =H. |url=http://www.tf.uni-kiel.de/matwis/amat/elmat_en/kap_3/backbone/r3_5_1.html |title=3.5.1 Electrical Breakdown and Failure |publisher=Tf.uni-kiel.de |access-date=2020-06-18}}</ref>
| {{ntsh|12.5}} 10–15
|-
| [[Benzene]]<ref name="CRC"/>
| {{nts|163}}
|-
| [[Polystyrene]]<ref name="CRC"/>
| {{nts|19.7}}
|-
| [[Polyethylene]]<ref>{{cite web
| url=https://hypertextbook.com/facts/2009/CherryXu.shtml
| title=Dielectric strength of polyethylene
| first=Cherry
| last=Xu
| year=2009
| website=The Physics Factbook
| editor-last=Elert
| editor-first=Glenn
| access-date=2020-06-18
}}</ref>
| {{ntsh|20.3}} 19–160
|-
| [[Neoprene]] rubber<ref name="CRC"/>
| {{ntsh|21.65}} 15.7–26.7
|-
| Distilled [[water]]<ref name="CRC"/>
| {{ntsh|67.5}} 65–70
|-
|-
| [[Beryllium oxide]]<ref>"[https://www.azom.com/properties.aspx?ArticleID=263 Azom Materials - Beryllium Oxide Properties]". azom.com. Retrieved 2023-12-05.</ref>
| {{ntsh|29}} 27–31
|-
| High [[vacuum]] (200 [[Pascal (unit)|μPa]])<br>(field emission limited)<ref>{{Cite conference |conference =20th International Symposium on Discharges and Electrical Insulation in Vacuum |url=http://www.htee.tu-bs.de/forschung/veroeffentlichungen/giere2002.pdf |title=HV dielectric strength of shielding electrodes in vacuum circuit-breakers |last1=Giere |first1=Stefan |last2=Kurrat |first2=Michael  |last3= Schümann |first3=Ulf  | access-date=2020-06-18 |archive-url=https://web.archive.org/web/20120301112907/http://www.htee.tu-bs.de/forschung/veroeffentlichungen/giere2002.pdf |archive-date=2012-03-01 |url-status=dead }}</ref>
| {{ntsh|30}} 20–40<br>(depends on electrode shape)
|-
| [[Fused silica]]<ref name="CRC"/>
| {{ntsh|570}} 470–670
|-
| Waxed paper<ref>{{cite web
| url=https://hypertextbook.com/facts/2007/DashaMulyukova.shtml
| title=Dielectric strength of waxed paper
| first=Dasha
| last=Mulyakhova
| year=2007
| website=The Physics Factbook
| editor-last=Elert
| editor-first=Glenn
| access-date=2020-06-18
}}</ref>
| {{ntsh|50}} 40–60
|-
| [[PTFE]] (Teflon, [[Extrusion|extruded]] )<ref name="CRC"/>
| {{nts|19.7}}
|-
| [[PTFE]] (Teflon, insulating film)<ref name="CRC"/><ref>{{cite web|author=Glenn Elert |url=https://physics.info/dielectrics/ |title=Dielectrics - The Physics Hypertextbook |publisher=Physics.info |access-date=2020-06-18}}</ref>
| {{ntsh|116.5}} 60–173
|-
| [[PEEK]] (Polyether ether ketone)
| {{nts|23}}
|-
| [[Mica]]<ref name="CRC"/>
| {{nts|118}}
|-
| [[Diamond]]<ref>{{cite web|url=https://www.researchgate.net/publication/267937297|title=Electronic properties of diamond|publisher=el.angstrom.uu.se|access-date=2013-08-10}}</ref>
| {{nts|2000}}
|-
| [[PZT]]
| {{ntsh|17}} 10–25<ref>
{{cite journal
 | title = Electrical Characteristics of Ferroelectric PZT Thin Films for DRAM Applications
 | last = Moazzami | first = Reza |author2=Chenming Hu |author3=William H. Shepherd
 | journal = IEEE Transactions on Electron Devices
 | date=September 1992 
 | volume = 39 | issue = 9 | page = 2044
 | url = http://www.eecs.berkeley.edu/~hu/PUBLICATIONS/Hu_papers/Hu_JNL/HuC_JNL_114.pdf
 | bibcode = 1992ITED...39.2044M | doi = 10.1109/16.155876
}}</ref><ref>
{{cite journal 
 | url = https://www.researchgate.net/publication/237514139
 | title = Performance of Piezoelectric Ceramic Multilayer Components Based on Hard and Soft PZT
 | author = B. Andersen
 | author2 = E. Ringgaard
 | author3 = T. Bove
 | author4 = A. Albareda
 | author5 = R. Pérez
 | name-list-style = amp
 | journal = Proceedings of Actuator 2000
 | year = 2000
 | pages = 419–422
}}</ref>
|-
| [[Perfect vacuum]]
| {{ntsh|1e12}} [[Schwinger limit|10<sup>12</sup>]]<ref>{{cite journal |last1=Buchanan |first1=Mark |title=Past the Schwinger limit |journal=Nature Physics |date=November 2006 |volume=2 |issue=11 |pages=721 |doi=10.1038/nphys448}}</ref><ref>{{cite Q |1=Q27447776 |title=On the Schwinger limit attainability with extreme power lasers |journal=Phys. Rev. Lett. |edition=105 |year=2010 |volume=105 |issue=22 |page=220407 |doi=10.1103/PhysRevLett.105.220407 |pmid=21231373 |arxiv=1007.4306 |s2cid=36857911}}</ref>
|}