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[[datoteka:Otpor.jpg|mini|desno|250px|Specifična [[vodljivost]] je [[električna vodljivost]] žice presjeka 1 [[Četvorni metar|mm<sup>2</sup>]] dužine 1[[metar|m]].]] | |||
[[datoteka:Permeability by Zureks.svg|mini|desno|250px|Pojednostavljeni usporedni pregled magnetske permeabilnosti: [[Feromagnetizam|feromagnetika]] (μ<sub>f</sub>), [[Paramagnetizam|paramagnetika]](μ<sub>p</sub>), [[vakuum]]a (μ<sub>0</sub>) i [[Dijamagnetizam|dijamagnetika]] (μ<sub>d</sub>).]] | [[datoteka:Permeability by Zureks.svg|mini|desno|250px|Pojednostavljeni usporedni pregled magnetske permeabilnosti: [[Feromagnetizam|feromagnetika]] (μ<sub>f</sub>), [[Paramagnetizam|paramagnetika]](μ<sub>p</sub>), [[vakuum]]a (μ<sub>0</sub>) i [[Dijamagnetizam|dijamagnetika]] (μ<sub>d</sub>).]] | ||
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| 1.26 · 10<sup>0</sup> | | 1.26 · 10<sup>0</sup> | ||
| 1 000 000 <ref>{{ | | 1 000 000 <ref>{{Citiranje weba|url=http://www.metglas.com/products/page5_1_2_6.htm |title="Metglas Magnetic Alloy 2714A", ''Metglas'' |publisher=Metglas.com |date= |accessdate=2011-11-08}}</ref> | ||
| kod 0.5 [[Tesla|T]] | | kod 0.5 [[Tesla|T]] | ||
| 100 kHz | | 100 kHz | ||
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| 2.5 · 10<sup>-1</sup> | | 2.5 · 10<sup>-1</sup> | ||
| 200 000 <ref name="Iron">{{ | | 200 000 <ref name="Iron">{{Citiranje weba|url=http://hyperphysics.phy-astr.gsu.edu/hbase/tables/magprop.html#c2 |title="Magnetic Properties of Ferromagnetic Materials", ''Iron'' |publisher=C.R Nave Georgia State University |date= |accessdate=2013-12-01}}</ref> | ||
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| 1.0 · 10<sup>-1</sup> | | 1.0 · 10<sup>-1</sup> | ||
| 80 000 <ref name="Nanoperm">{{ | | 80 000 <ref name="Nanoperm">{{Citiranje weba|url=http://www.magnetec.de/eng/pdf/werkstoffkennlinien_nano_e.pdf |title="Typical material properties of NANOPERM", ''Magnetec'' |format=PDF |date= |accessdate=2011-11-08}}</ref> | ||
| kod 0.5 T | | kod 0.5 T | ||
| 10 kHz | | 10 kHz | ||
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| 2.5 · 10<sup>-2</sup> | | 2.5 · 10<sup>-2</sup> | ||
| 20 000 <ref name="hyper">{{ | | 20 000 <ref name="hyper">{{Citiranje weba|url=http://hyperphysics.phy-astr.gsu.edu/hbase/solids/ferro.html |title="Relative Permeability", ''Hyperphysics'' |publisher=Hyperphysics.phy-astr.gsu.edu |date= |accessdate=2011-11-08}}</ref> | ||
| kod 0.002 T | | kod 0.002 T | ||
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| 6.3 · 10<sup>-2</sup> | | 6.3 · 10<sup>-2</sup> | ||
| 50 000 <ref name="nickal">{{ | | 50 000 <ref name="nickal">{{Citiranje weba|url=http://www.nickel-alloys.net/nickelalloys.html |title=Nickel Alloys-Stainless Steels, Nickel Copper Alloys, Nickel Chromium Alloys, Low Expansion Alloys |publisher=Nickel-alloys.net |date= |accessdate=2011-11-08}}</ref> | ||
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| 2.3 · 10<sup>-2</sup> | | 2.3 · 10<sup>-2</sup> | ||
| 18 000 <ref name="vacuumschmeltze">{{ | | 18 000 <ref name="vacuumschmeltze">{{Citiranje weba|url=http://www.vacuumschmelze.com/fileadmin/Medienbiliothek_2010/Downloads/HT/2013-03-27_Soft_Magnetic_Cobalt-_Iron_Alloys_final_version.pdf |title="Soft Magnetic Cobalt-Iron Alloys", ''Vacuumschmeltze'' |publisher=www.vacuumschmeltze.com |date= |accessdate=2013-08-03}}</ref> | ||
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| 1.26 · 10<sup>-3</sup> - 2.26 · 10<sup>-3</sup> | | 1.26 · 10<sup>-3</sup> - 2.26 · 10<sup>-3</sup> | ||
| 1 000 – 1 800<ref name="Carpenter">{{ | | 1 000 – 1 800<ref name="Carpenter">{{Citiranje weba|url=http://www.cartech.com/techarticles.aspx?id=1476|title=Magnetic Properties of Stainless Steels|author=Carpenter Technology Corporation|publisher=Carpenter Technology Corporation|year=2013}}</ref> | ||
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| 1.26 · 10<sup>-6</sup> - 8.8 · 10<sup>-6</sup> | | 1.26 · 10<sup>-6</sup> - 8.8 · 10<sup>-6</sup> | ||
| 1.003–7 <ref name="SSAS">{{ | | 1.003–7 <ref name="SSAS">{{Citiranje weba|url=http://www.bssa.org.uk/cms/File/SSAS2.81-Magnetic%20Properties.pdf|title=Magnetic Properties of Stainless Steel|author=British Stainless Steel Association|publisher=Stainless Steel Advisory Service|year=2000}}</ref> | ||
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|[[Aluminij]] | |[[Aluminij]] | ||
| 2.22 · 10<sup>-5</sup> <ref name="clarke">{{ | | 2.22 · 10<sup>-5</sup> <ref name="clarke">{{Citiranje weba|author=Richard A. Clarke |url=http://www.ee.surrey.ac.uk/Workshop/advice/coils/mu/ |title=Clarke, R. ''Magnetic properties of materials'', surrey.ac.uk |publisher=Ee.surrey.ac.uk |date= |accessdate=2011-11-08}}</ref> | ||
| 1.256665 · 10<sup>-6</sup> | | 1.256665 · 10<sup>-6</sup> | ||
| 1.000022 | | 1.000022 | ||
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| 1 <ref>{{ | | 1 <ref>{{Citiranje weba|author=NDT.net |url=http://www.ndt.net/article/ndtce03/papers/v078/v078.htm |title=Determination of dielectric properties of insitu concrete at radar frequencies |publisher=Ndt.net |date= |accessdate=2011-11-08}}</ref> | ||
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Posljednja izmjena od 29. svibanj 2025. u 10:40
Magnetska vodljivost (oznaka Λ) šipke ili žice, ploštine poprječnoga presjeka S i duljine l, dana je izrazom:
gdje je: μ - magnetska permeabilnost; recipročna je vrijednost reluktancije (magnetskoga otpora) magnetskoga kruga; mjerna je jedinica henri (H). [1]
Magnetska permeabilnost
Podrobniji članak o temi: Magnetska permeabilnostMagnetska permeabilnost je elektromagnetna osobina materijala koja pokazuje intenzitet magnetizacije tijela kada su ona izložena vanjskim magnetnom polju. Magnetska permeabilnost se označava grčkim slovom mi (μ). Pojam magnetska permeabilnost osmislio je Oliver Heaviside 1885. U jedinicama SI sustava, permeabilnost se izražava u Henrijima po metru (H/m), ili u Newtonima po Amperu na kvadrat (N/A2) ili Volt · sekunda na Amper · metar {Vs/Am}.
Magnetska permeabilnost vakuuma ili univerzalna magnetska konstanta (znak ) je prirodna konstanta magnetske permeabilnosti za vakuum, koja iznosi: = 4π · 10–7 H/m [2] ili = 12.566370614 · 10–7 N/A². Jednaka je recipročnoj vrijednosti umnoška dielektrične permitivnosti vakuuma ε0 i kvadrata brzine svjetlosti c u vakuumu: μ0 = 1/(ε0c2). [3]
Vrijednosti za neke materijale
| Materijal | Susceptibilnost χm (volumetrijski SI) |
Permeabilnost μ [H/m] | Relativna permeabilnost μ/μ0 | Magnetsko polje | Frekvencija (max.) |
|---|---|---|---|---|---|
| Metglas | 1.26 · 100 | 1 000 000 [4] | kod 0.5 T | 100 kHz | |
| Željezo (99.95% čisto Fe normalizirano u H) | 2.5 · 10-1 | 200 000 [5] | |||
| Nanoperm | 1.0 · 10-1 | 80 000 [6] | kod 0.5 T | 10 kHz | |
| Mu-metal | 2.5 · 10-2 | 20 000 [7] | kod 0.002 T | ||
| Mu-metal | 6.3 · 10-2 | 50 000 [8] | |||
| Kobalt-željezo (trake visoke permeabilnosti) | 2.3 · 10-2 | 18 000 [9] | |||
| Permalloy | 8 000 | 1.0 · 10-2 | 8 000 | kod 0.002 T | |
| Željezo (99.8% čisto) | 6.3 · 10-3 | 5 000 | |||
| Električarski čelik | 5.0 · 10-3 | 4 000 | kod 0.002 T | ||
| Feritični nehrđajući čelik (normaliziran) | 1.26 · 10-3 - 2.26 · 10-3 | 1 000 – 1 800[10] | |||
| Martenzitni nehrđajući čelik (normaliziran) | 9.42 · 10-4 - 1.19 · 10-3 | 750 – 950 | |||
| Ferit (manganski cink) | > 8.0 · 10-4 | 640 (ili više) | 100 kHz ~ 1 MHz | ||
| Ferit (niklov cink) | 2.0 · 10-5 - 8.0 · 10-4 | 16 – 640 | 100 kHz ~ 1 MHz | ||
| Ugljični čelik | 1.26 · 10-4 | 100 | kod 0.002 T | ||
| Nikal | 1.26 · 10-4 - 7.54 · 10-4 | 100 – 600 | kod 0.002 T | ||
| Martenzitni nehrđajući čelik (kaljen) | 5.0 · 10-5 - 1.2 · 10-4 | 40 – 95 | |||
| Austenitni nehrđajući čelik | 1.26 · 10-6 - 8.8 · 10-6 | 1.003–7 [11] | |||
| Neodimijev magnet | 1.32 · 10-6 | 1.05 [12] | |||
| Platina | 1.25697 · 10-6 | 1.000265 | |||
| Aluminij | 2.22 · 10-5 [13] | 1.256665 · 10-6 | 1.000022 | ||
| Drvo | 1.25663760 · 10-6 | 1.00000043 | |||
| Zrak | 1.25663753 · 10-6 | 1.00000037 [14] | |||
| Beton (suhi) | 1 [15] | ||||
| Vakuum | 0 | 4π × 10−7 (μ0) | 1 (točno, po definiciji) | ||
| Vodik | -2.2 · 10-9 [13] | 1.2566371 · 10-6 | 1.0000000 | ||
| Teflon | 1.2567 · 10-6 [7] | 1.0000 | |||
| Safir | -2.1 · 10-7 | 1.2566368 · 10-6 | 0.99999976 | ||
| Bakar | -6.4 · 10-6 ili -9.2 · 10-6 [13] | 1.256629 · 10-6 | 0.999994 | ||
| Voda | -8.0 · 10-6 | 1.256627 · 10-6 | 0.999992 | ||
| Bizmut | -1.66 · 10-4 | 1.25643 · 10-6 | 0.999834 | ||
| Supravodič | −1 | 0 | 0 |
Izvori
- ↑ vodljivost, [1] "Hrvatska enciklopedija", Leksikografski zavod Miroslav Krleža, www.enciklopedija.hr, 2014.
- ↑ The NIST reference on fundamental physical constants
- ↑ magnetska permeabilnost vakuuma, [2] "Hrvatska enciklopedija", Leksikografski zavod Miroslav Krleža, www.enciklopedija.hr, 2014.
- ↑ ""Metglas Magnetic Alloy 2714A", ''Metglas''". Metglas.com. http://www.metglas.com/products/page5_1_2_6.htm Pristupljeno 8. studeni 2011.
- ↑ ""Magnetic Properties of Ferromagnetic Materials", ''Iron''". C.R Nave Georgia State University. http://hyperphysics.phy-astr.gsu.edu/hbase/tables/magprop.html#c2 Pristupljeno 1. prosinac 2013.
- ↑ ""Typical material properties of NANOPERM", ''Magnetec''" (PDF). http://www.magnetec.de/eng/pdf/werkstoffkennlinien_nano_e.pdf Pristupljeno 8. studeni 2011.
- ↑ 7,0 7,1 ""Relative Permeability", ''Hyperphysics''". Hyperphysics.phy-astr.gsu.edu. http://hyperphysics.phy-astr.gsu.edu/hbase/solids/ferro.html Pristupljeno 8. studeni 2011.
- ↑ "Nickel Alloys-Stainless Steels, Nickel Copper Alloys, Nickel Chromium Alloys, Low Expansion Alloys". Nickel-alloys.net. http://www.nickel-alloys.net/nickelalloys.html Pristupljeno 8. studeni 2011.
- ↑ ""Soft Magnetic Cobalt-Iron Alloys", ''Vacuumschmeltze''". www.vacuumschmeltze.com. http://www.vacuumschmelze.com/fileadmin/Medienbiliothek_2010/Downloads/HT/2013-03-27_Soft_Magnetic_Cobalt-_Iron_Alloys_final_version.pdf Pristupljeno 3. kolovoz 2013.
- ↑ Carpenter Technology Corporation (2013). "Magnetic Properties of Stainless Steels". Carpenter Technology Corporation. http://www.cartech.com/techarticles.aspx?id=1476
- ↑ British Stainless Steel Association (2000). "Magnetic Properties of Stainless Steel". Stainless Steel Advisory Service. http://www.bssa.org.uk/cms/File/SSAS2.81-Magnetic%20Properties.pdf
- ↑ Lua error in Modul:Citation/CS1 at line 4096: data for mw.loadData contains unsupported data type 'function'.
- ↑ 13,0 13,1 13,2 Richard A. Clarke. "Clarke, R. ''Magnetic properties of materials'', surrey.ac.uk". Ee.surrey.ac.uk. http://www.ee.surrey.ac.uk/Workshop/advice/coils/mu/ Pristupljeno 8. studeni 2011.
- ↑ B. D. Cullity and C. D. Graham (2008), Introduction to Magnetic Materials, 2nd edition, 568 pp., p.16
- ↑ NDT.net. "Determination of dielectric properties of insitu concrete at radar frequencies". Ndt.net. http://www.ndt.net/article/ndtce03/papers/v078/v078.htm Pristupljeno 8. studeni 2011.