Razlika između inačica stranice »Magnetska permeabilnost«
Izvor: Hrvatska internetska enciklopedija
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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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Trenutačna izmjena od 08:19, 1. prosinca 2021.
Pojednostavljeni usporedni pregled permeabilnosti: feromagnetika (μf), paramagnetika(μp), vakuuma (μ0) i dijamagnetika (μd).
Magnetska 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 [math]\displaystyle{ \mu_0 }[/math]) je prirodna konstanta magnetske permeabilnosti za vakuum, koja iznosi: [math]\displaystyle{ \mu_0 }[/math]= 4π · 10–7 H/m [1] ili [math]\displaystyle{ \mu_0 }[/math] = 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). [2]
Dielektrična permitivnost vakuuma, permitivnost vakuuma, dielektričnost vakuuma ili dielektrična konstanta vakuuma (znak ε0) je prirodna konstanta koja je jednaka recipročnoj vrijednosti umnoška magnetske permeabilnosti vakuuma μ0 i kvadrata brzine svjetlosti c u vakuumu: ε0 = 1/(μ0c2) = 8.854187817 · 10–12 F/m. [3]
Relativna magnetna permeabilnost
Relativna magnetska permeabilnost (znak μr) je fizikalna veličina koja opisuje magnetsku propusnost tvari u odnosu na magnetsku permeabilnost vakuuma; to je količnik magnetske permeabilnosti μ i magnetske permeabilnosti vakuuma μ0 ([math]\displaystyle{ \mu_0 = 4 \pi \times 10^{-7} }[/math]). Mjerna je jedinica relativne magnetske permeabilnosti broj jedan (1):
- [math]\displaystyle{ \mu_{r} = \frac{\mu}{\mu_{0}} }[/math]
Magnetna susceptibilnost se može iskazati pomoću relativne magnetne permeabilnosti:
- [math]\displaystyle{ \chi_m = \mu_r - 1 \, }[/math]
Relativna magnetska permeabilnost dijamagnetičnih tvari nešto je manja od 1, na primjer relativana je magnetska permeabilnost vode 0.999991, srebra 0.9999975, bakra 0.999994. Relativna magnetska permeabilnost paramagnetičnih tvari nešto je veća od 1, na primjer platine 1.000265, aluminija 1.0000082, zraka 1.00000037, a relativna magnetska permeabilnost feromagnetičnih tvari značajno je veća od 1, na primjer relativna je magnetska permeabilnost čistog željeza 5 000, a mi-metala (slitina od 77% nikla, 16% željeza, 5% bakra, 2% kroma ili molibdena) 50 000 do 80 000. [4]
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 [5] | kod 0.5 T | 100 kHz | |
| Željezo (99.95% čisto Fe normalizirano u H) | 2.5 · 10-1 | 200 000 [6] | |||
| Nanoperm | 1.0 · 10-1 | 80 000 [7] | kod 0.5 T | 10 kHz | |
| Mu-metal | 2.5 · 10-2 | 20 000 [8] | kod 0.002 T | ||
| Mu-metal | 6.3 · 10-2 | 50 000 [9] | |||
| Kobalt-željezo (trake visoke permeabilnosti) | 2.3 · 10-2 | 18 000 [10] | |||
| 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[11] | |||
| 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 [12] | |||
| Neodimijev magnet | 1.32 · 10-6 | 1.05 [13] | |||
| Platina | 1.25697 · 10-6 | 1.000265 | |||
| Aluminij | 2.22 · 10-5 [14] | 1.256665 · 10-6 | 1.000022 | ||
| Drvo | 1.25663760 · 10-6 | 1.00000043 | |||
| Zrak | 1.25663753 · 10-6 | 1.00000037 [15] | |||
| Beton (suhi) | 1 [16] | ||||
| Vakuum | 0 | 4π × 10−7 (μ0) | 1 (točno, po definiciji) | ||
| Vodik | -2.2 · 10-9 [14] | 1.2566371 · 10-6 | 1.0000000 | ||
| Teflon | 1.2567 · 10-6 [8] | 1.0000 | |||
| Safir | -2.1 · 10-7 | 1.2566368 · 10-6 | 0.99999976 | ||
| Bakar | -6.4 · 10-6 ili -9.2 · 10-6 [14] | 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
- ↑ The NIST reference on fundamental physical constants
- ↑ magnetska permeabilnost vakuuma, [1] "Hrvatska enciklopedija", Leksikografski zavod Miroslav Krleža, www.enciklopedija.hr, 2014.
- ↑ dielektrična permitivnost vakuuma, [2] "Hrvatska enciklopedija", Leksikografski zavod Miroslav Krleža, www.enciklopedija.hr, 2014.
- ↑ relativna magnetska permeabilnost, [3] "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. studenoga 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. prosinca 2013.
- ↑ ""Typical material properties of NANOPERM", ''Magnetec''" (PDF). http://www.magnetec.de/eng/pdf/werkstoffkennlinien_nano_e.pdf Pristupljeno 8. studenoga 2011.
- ↑ 8,0 8,1 ""Relative Permeability", ''Hyperphysics''". Hyperphysics.phy-astr.gsu.edu. http://hyperphysics.phy-astr.gsu.edu/hbase/solids/ferro.html Pristupljeno 8. studenoga 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. studenoga 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. kolovoza 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
- ↑ Juha Pyrhönen, Tapani Jokinen, Valéria Hrabovcová (2009). Design of Rotating Electrical Machines. John Wiley and Sons. str. 232. ISBN 0-470-69516-1. http://books.google.com/?id=_y3LSh1XTJYC&pg=PT232
- ↑ 14,0 14,1 14,2 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. studenoga 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. studenoga 2011.