Permanent Rare Earth Magnets from CMS Magnetics Garland TX

Permanent Magnets from CMS Magnetics Garland TX
Our manufacturer has been involved in research, development and manufacturing of rare earth permanent magnets since the middle of 1980. Now, we supply various rare earth permanent magnetic products to our customers in various fields, such as NMR (Nuclear Magnetic Resonance), loud speakers and mechanical devices, in large production quantities at VERY competitive pricing. We supply rare earth permanent magnetic materials in powder form or in sintered as well as polymer-bonded magnet form. We also supply other permanent magnet materials including Alnico, Ceramic (Ferrite) and Flexible magnet materials. We specialize in manufacturing permanent magnets according to customers’ requirements in terms of composition, magnetic characteristics, shape, and size. If you have any needs for permanent magnetic products, please contact us. You will be very happy to have us as your vendor, supplying you with high quality products at unbeatable prices.
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Permanent Magnet Materials
Permanent magnets are used in the following major groups: acoustic transducers, motors and generators, magneto mechanical devices, and magnetic field and imaging systems with neodymium magnets. You will find permanent magnets in many products, such as televisions, telephones, computers, audio systems and

10ZHAO-23

automobiles.

The permanent magnet family consists, in general terms, of non-rare earth permanent magnets and rare earth magnets. The non-rare earth magnets include Alnico (Aluminum-Nickel-Cobalt) magnets and Ceramic (Strontium and Barium Ferrite) magnets. Rare earth magnets include Sm-Co (Samarium-Cobalt) magnets and Nd-Fe-B (Neodymium-Iron-Boron) magnets.

Although non-rare earth magnets are used in the majority of these applications due to their economic cost, rare earth permanent magnets have many distinguishing characteristics, such as a large Maximum Energy Product, (one performance index for permanent magnets). Dozens of magnetic materials which contain rare earth have been developed recently. Two major families of rare earth permanent magnets, Sm-Co magnets and Nd-Fe-B magnets, have been widely used in a variety of applications. Each family has its own advantages and disadvantages.
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Nd-Fe-B Magnets
Nd-Fe-B magnets have a higher Maximum Energy Product, (BH)max, than Sm-Co magnets. (BH) max of Nd-Fe-B can easily reach 30 MGOe and even goes up to 48 MGOe. Nd-Fe-B magnets can replace Sm-Co magnets in most cases, especially where operating temperature is less than 80 degrees Centigrade. The temperature stabilityof Nd-Fe-B is not as good as Sm-Co magnets. Magnetic performance of Nd-Fe-B magnets will deteriorate rapidly above about 180 degrees Centigrade. Compared to Sm-Co magnets, the corrosion and oxidation resistance of Nd-Fe-B is relatively low. Sintered Nd-Fe-B permanent magnets are made with several steps. At first, a Nd-Fe-B alloy is formulated based on the properties of final permanent magnets supposed to reach. The alloy is produced in a vacuum furnace. Then the alloy is crushed into a powder form. Sintered Nd-Fe-B permanent magnets are formed by powder metallurgical process. These magnets can be die pressed or isostatically pressed. During the pressing process, magnetic fields are applied with assistance of specially designed fixture to align magnetic “domains” and optimize the magnetic performance of these magnets. Then pressed magnets are placed into a furnace under protective atmosphere for sintering. After sintering the magnet shape is rough, and need to be machined and ground to achieve desired shape and size. A surface coating is usually applied on Nd-Fe-B magnets. Zinc or nickel coating is common used as a protective layer. Other materials such as cadmium chromate, aluminum chromate, tin or polymer (epoxy) are also used for this purpose. Both Nd-Fe-B and Sm-Co magnets can be made either in sintered or polymer-bonded magnets. The polymer (such as epoxy)-bonded magnets can be produced with close tolerances off tool, with little or no finishing required. Stamford Magnets supplies polymer-bonded Nd-Fe-B permanent magnets made by both compression moulding and injection moulding. The sintered magnets usually require some finishing operations in order to hold close mechanical tolerances. The sintered magnets, however, provide better magnetic properties than bonded magnets.

A: Sintered Nd-Fe-B Magnet Properties

   1. Use of sintered Nd-Fe-B permanent magnets, as the piece part magnet or as it’s assembly, made by non-licensee is prohibited by the Patent Law of the United States of America. All of sintered neodymium-iron-boron (Nd-Fe-B) permanent magnets, which Stanford Magnets Company supplies, are licensed.

2. The grades listed are only a portion of the products we carry; please contact us for the grade you need

3. The data listed are the typical properties, and the data in parentheses are the minimum values

4. Some general properties: Density: 7.4 -7.6; Hardness: 600 {Hv}

Grade Br
(KGs)
Hc
(KOe)
Hci
(KOe)
(BH)max
(MGOe)
Curie Temp .
(°C)
Max. Op. Temp
(°C)
N28UH 10.2-10.8 >9.6 >25 26-29 350 180
N28EH 10.4-10.9 >9.8 >30 26-29 350 200
N30UH 10.8-11.3 >10.2 >25 28-31 350 180
N30EH 10.8-11.3 >10.2 >30 28-31 350 200
N33 11.3-11.7 >10.5 >12 31-33 310 80
N33H 11.3-11.7 >10.5 >17 31-34 320 120
N33SH 11.3-11.7 >10.6 >20 31-34 340 150
N33UH 11.3-11.7 >10.7 >25 31-34 350 180
N35 11.7-12.1 >10.9 >12 33-36 310 80
N35H 11.7-12.1 >10.9 >17 33-36 320 120
N35SH 11.7-12.1 >11.0 >20 33-36 340 150
N38 12.1-12.5 >11.3 >12 36-39 310 80
N38H 12.1-12.5 >11.3 >17 36-39 320 120
N38SH 12.1-12.5 >11.4 >20 36-39 340 150
N40 12.5-12.8 >11.6 >12 38-41 310 80
N40H 12.4-12.8 >11.6 >17 38-41 320 120
N40SH 12.4-12.8 >11.8 >20 38-41 340 150
N42 12.8-13.2 >11.6 >12 40-43 310 80
N42H 12.8-13.2 >12.0 >17 40-43 320 120
N45 13.2-13.8 >11.0 >12 43-46 310 80
N48 13.8-14.2 >10.5 >11 46-49 310 80

 

B: Properties of Polymer Bonded Nd-Fe-B Magnets by Compression Moulding

Note:
1. The grades listed are only a portion of the products we carry; please contact us for the grade you need
2. The data listed are the typical properties, and the data in parentheses are the minimum values

 

Grade Br
(KGs)
Hc
(KOe)
Hci
(KOe)
(BH)max
(MGOe)
Density
(g/cm³)
Recoil
Perm.
Temp. Coeff.
of Br (%/°C).
Max. Op. Temp
(°C)
BNP-6 5.2-6.0 3.8-4.5 8.0-10 5-7 5.3-5.8 1.15 -0.13 140
BNP-8 6.0-6.5 4.5-5.5 8.0-12 7-9 5.6-6.0 1.15 -0.13 140
BNP-10 6.5-7.0 4.5-5.8 8.0-12 9-10 5.8-6.1 1.22 -0.07 ~ -0.105 120
BNP-12 7.0-7.6 5.3-6.0 8.0-11 10-12 6.0-6.2 1.22 -0.13 130
BNP-8H 5.5-6.2 5.0-6.0 12-16 6-9 5.6-6.0 1.15 -0.07 ~ -0.105 120

 

C: Properties of Polymer Bonded Nd-Fe-B Magnets by Injection Moulding

Note:
1. The grades listed are only a portion of the products we carry; please contact us for the grade you need
2. The data listed are the typical properties, and the data in parentheses are the minimum values

 

Grade Br
(KGs)
Hc
(KOe)
Hci
(KOe)
(BH)max
(MGOe)
Density
(g/cm³)
Recoil
Perm.
Temp. Coeff.
of Br (%/°C).
BNI-2 2.0-4.0 1.5-3.0 7.0-9.0 0.8-3.0 3.5-4.0 1.25 -0.13
BNI-4 4.0-4.9 3.1-3.9 7.2-9.2 3.5-4.5 4.0-5.0 1.20 -0.10
BNI-6 4.9-5.7 3.9-4.8 8.0-10.0 5.2-7.0 5.0-5.5 1.20 -0.10
BNI-8 5.7-6.3 4.8-5.4 8.5-10.5 7.4-8.4 5.0-5.5 1.20 -0.10
BNI-8H 4.8-5.6 4.2-5.0 13-17 5.0-6.5 5.0-5.5 1.13 -0.15

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Sm-Co magnets
Two common compositions of Sm-Co magnets are Sm1Co5 and Sm2Co17. Generally, the cost of Sm-Co magnets is higher than Neodymium magnets. As a big advantage, Sm-Co magnets can operate at higher temperatures up to 300 degrees Centigrade. Sm-Co magnets are widely used in applications in which higher operating temperature and higher corrosion and oxidation resistance are crucial.

A: Sintered Sm-Co Magnet Properties

Note:
1. The grades listed are only a portion of the products we carry; please contact us for the grade you need
2. The data listed are the typical properties, and the data in parentheses are the minimum values

Sm1Co5

Grade Br 
(KGs)
Hc 
(KOe)
Hci 
(KOe)
(BH)max
(MGOe)
Curie Temp .
(°C)
Max. Op. Temp
(°C)
Sm1Co5-18 >8.5 >7.8 >17 17-19 750 250
Sm1Co5-20 >9.0 >8.0 >17 19-22 750 250
Sm1Co5-24 >10.0 >8.5 >15 22-24 750 250
Sm1Co5-26 >10.2 >9.5 >15 24-26 750 250

Sm2Co17

Grade Br 
(KGs)
Hc 
(KOe)
Hci 
(KOe)
(BH)max
(MGOe)
Curie Temp .
(°C)
Max. Op. Temp
(°C)
Sm2Co17-24 >9.5 >8.0 >17 20-24 800 250
Sm2Co17-26 >10.5 >8.5 >17 24-26 800 250
Sm2Co17-28 >10.5 >9.5 >15 26-28 800 250
Sm2Co17-30 >10.8 >9.8 >12 28-30 800 250

B: Bonded Sm-Co Magnet Properties

Sm1Co5

Grade Br 
(KGs)
Hc 
(KOe)
Hci 
(KOe)
(BH)max
(MGOe)
Curie Temp .
(°C)
Max. Op. Temp
(°C)
SCB6 4.5 (4.0) 4.0 (3.5) 11(10) 6 (4) 720 120
SCB8 5.5 (5.0) 4.5 (4.0) 11(10) 8 (6) 720 120

Sm2Co17

Grade Br 
(KGs)
Hc 
(KOe)
Hci 
(KOe)
(BH)max
(MGOe)
Curie Temp .
(°C)
Max. Op. Temp
(°C)
SCB10 6.5 (6.0) 5.2 (4.5) 11.0 (10.0) 10 (8) 720 120
SCB12L 8.0 (7.0) 4.5 (4.0) 6.0 (5.0) 12 (10) 720 120
SCB12 8.0 (7.0) 5.5 (5.0) 11.0 (10.0) 12 (10) 720 120

 

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Alnico:
Alnico magnetic material is an alloy of aluminum-nickel-cobalt which possesses an excellent temperature stabilityand high residual induction . However, its low coercive forcelimits its applications in many cases. Casting and sintering are two major processes used to manufacture the Alnico magnets. Alnico magnets with complex shapes may be manufactured by casting. However, once the Alnico magnets are formed, it is difficult to machine or drill them due to the hard and brittle mechanical properties of Alnico.

A: Casted Al-Ni-Co Magnet Properties

Note:
The grades listed are only a portion of the products we carry; please contact us for the grade you need

 

Grade Material Br
(KGs)
Hc
(KOe)
Hci
(KOe)
(BH)max
(MGOe)
Curie Temp .
(°C)
Max. Op. Temp
(°C)
ANCI 1 Isotropic Cast Alnico1 7.2 0.47 0.48 1.4 860 540
ANCI 2 Isotropic Cast Alnico 2 7.5 0.56 0.58 1.7 860 540
ANCI 3 Isotropic Cast Alnico 5 7.0 0.48 0.50 1.35 860 540
ANCA 5 Anisotropic Cast Alnico 5 12.5 0.64 0.64 5.5 860 540
ANCA 5-7 Anisotropic Cast Alnico 5-7 13.5 0.74 0.74 7.5 860 540
ANCA 6 Anisotropic Cast Alnico 6 10.5 0.78 0.80 3.9 860 540
ANCA 8 Anisotropic Cast Alnico 8 8.2 1.65 1.65 5.3 860 540

 

B: Sintered Al-Ni-Co Magnet Properties

Note:
The grades listed are only a portion of the products we carry; please contact us for the grade you need

 

Grade Material Br
(KGs)
Hc
(KOe)
Hci
(KOe)
(BH)max
(MGOe)
Curie Temp .
(°C)
Max. Op. Temp
(°C)
ANSI 2 Isotropic Sintered Alnico 2 7.1 0.55 0.55 1.4 860 540
ANSA 5 Anisotropic Sintered Alnico 5 10.8 0.60 0.60 3.8 860 540
ANSA 6 Anisotropic Sintered Alnico 6 9.4 0.79 0.80 2.9 860 540
ANSA 8 Anisotropic Sintered Alnico 8 7.2 1.50 1.69 4.0 860 540

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  1. Ceramic (Hard Ferrite) 
    Ceramic magnets are composed of iron oxide, barium and strontium elements. This class of magnets has a higher magnetic flux density, higher coercive force, and higher resistance to demagnetization and oxidation compared to other non-rare earth permanent magnets. The biggest advantage of such magnets is their low cost, which makes the hard ferrite magnets very popular in many permanent magnet applications. Due to their ceramic nature, ferrite magnets are very hard and brittle. Special machining techniques must to be utilized for these magnets.

Ceramic (Hard Ferrite) Permanent Magnets

Note:
The grades listed are only a portion of the products we carry; please contact us for the grade you need

 

Grade Br
(KGs)
Hc
(KOe)
Hci
(KOe)
(BH)max
(MGOe)
Curie Temp .
(°C)
Max. Op. Temp
(°C)
Ceramic 1 2.2 1.86 3.25 1.10 450 300
Ceramic 5 3.8 2.4 2.5 1.1 450 300
Ceramic 7 3.4 3.25 4.0 2.75 450 300
Ceramic 8 3.85 2.95 3.20 3.5 450 300
Ceramic 10 4.2 2.95 3.05 4.2 450 300

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  1. Flexible and Plastic Magnets 
    Flexible magnets can be either isotropic and anisotropic. The anisotropic flexible magnets are made by extrusion or injection. Properties such as high elasticity, flexibility and machinability make these magnets a favorite candidate for many permanent magnet applications in industry and in home appliances.

Flexible Permanent Magnets

Note:
1. The grades listed are only a portion of the products we carry; please contact us for the grade you need
2. The data listed are the typical properties, and the data in parentheses are the minimum values
3. Some general properties: Density: 3.6 g/cm3; Operating Temp.: -40 ~ 100 °C; Hardness (Shore) 45 – 50; Tensile Strength: 50 Kg.f/cm2

 

Grade Br 
(KGs)
Hc 
(KOe)
Hci 
(KOe)
(BH)max
(MGOe)
Max. Op. Temp
(°C)
Standard 1.7 1.2 2.4 0.6 100
HF1 2.0 1.8 2.6 1.0 100
HF2 2.3 2.0 2.6 1.2 100
HF3 2.45 2.12 3.1 1.5 100
HF4 2.65 2.4 3.3 1.7 100

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  1. How to Choose Permanent Magnet Materials 
    Each permanent magnet material discussed above has its own pros and cons. How to choose the right one for your particular application is a challenge to any user. A balance between cost and performance must be considered in selecting of permanent magnet material. In Reference Information section of this page, several reference books are listed. These books may be helpful to you in designing and selecting permanent magnet materials. Following is a Comparison Table to help you select a right permanent magnet material for your applications.

Permanent Magnet Material Comparison Table

Note: The data listed in the table are for reference only

    Material         Cost Index        Maximum Energy Products
(BH)max    (MGOe)    
  Coercivity
Hci   (KOe)  
  Maximum Working
Temperature   (°C)  
    Machinability    
Nd-Fe-B (sintered) 65% Up to 45 Up to 30 180 Fair
Nd-Fe-B (bonded) 50% Up to 10 Up to 11 150 Good
Sm-Co (sintered) 100% Up to 30 Up to 25 350 Difficult
Sm-Co (bonded) 85% Up to 12 Up to 10 150 Fair
Alnico 30% Up to 10 Up to 2 550 Difficult
Hard Ferrite 5% Up to 4 Up to 3 300 Fair
Flexible 2% Up to 2 Up to 3 100 Excellent

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  1. How to Choose the Correct Grade of Permanent Magnet Materials 
    Selecting a grade is the next step, once you have decided which permanent magnet material is best for your application. Generally, a grade indicates the Maximum Energy Product of a magnet. For instance, Grade 32 implies the (BH)max is about 32 MGOe. A higher grade of permanent magnet has a better performance. However, higher grade is usually associated with a higher cost. Taking sintered Nd-Fe-B magnets as an example, the price of Grade 45 is twice and even more of that of Grade 33. Other property parameters, such as Br and Hci, also need to be considered in selecting a grade. One way to select the suitable grade for your application is “trial and error”. You can purchase the several magnets with different grades (some suppliers have these magnets available on their shelves) and try each grade until you find one right for your application. [Back to the beginning of this page]
  2. How to Prepare Your Inquiry
    Our manufacturer specializes in manufacturing permanent magnets according to customers’ specifications. In order for us to supply you the right product at a good price, we need you to provide us with as much information as possible about your magnet (See our Quotation Request Form). We need to know:
    1. The permanent magnet material,
    2. Whether rare earth permanent magnets should be sintered or bonded,
    3. The (BH)max,
    4. Requirements for Br, Hci and other properties,
    5. Size, shape, and tolerances (send drawings if possible),
    6. Magnetization direction,
    7. Coatingson surface (if needed),
    8. Quantity.
    Once we have such information, we will send you a price quotation with lead time. Please shop around to be sure you get the best price for the high quality permanent magnets you need.

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  1. Glossary

Anisotropic Magnet: A magnet having a preferred direction of magnetic orientation, so that the magnetic characteristics are optimum in that direction.

Coercive force, Hc: The demagnetizing force, measured in Oersted, necessary to reduce observed induction, B to zero after the magnet has previously been brought to saturation.

Curie temperature: The temperature at which the parallel alignment of elementary magnetic moments completely disappears, and the materials is no longer able to hold magnetization.

Flux: The condition existing in a medium subjected to a magnetizing force. This quantity is characterized by the fact that an electromotive force is induced in a conductor surrounding the flux at any time the flux changes in magnitude. The unit of flux in the GCS system is Maxwell. One Maxwell equals one volt x seconds.

Gauss, Gs: A unit of magnetic flux density in the GCS system; the lines of magnetic flux per square inch. 1 Gauss equals 0.0001 Tesla in the SI system.

Hysteresis Loop: A closed curve obtained for a material by plotting corresponding values off magnetic induction, B (on the abscissa), against magnetizing force, H (on the ordinate).

Induction, B: The magnetic flux per unit area of a section normal to the direction of flux. The unit of induction is Gauss in the GCS system

Intrinsic Coercive Force, Hci: An intrinsic ability of a material to resist demagnetization. Its value is measured in Oersted and corresponds to zero intrinsic induction in the material after saturation. Permanent magnets with high intrinsic coercive force are referred as “Hard” permanent magnets, which usually associated with high temperature stability.

Irreversible Loss: Defined as the partial demagnetization of a magnet caused by external fields or other factors. These losses are only recoverable by remagnetization. Magnets can be stabilized to prevent the variation of performance caused by irreversible losses.

Isotropic Magnets: A magnet material whose magnetic properties are the same in any direction, and which can therefore be magnetized in any direction without loss of magnetic characteristics.

Magnetic Flex: The total magnetic induction over a given area.

Magnetizing Force: the magnetomotive force per unit length at any point in a magnetic circuit. The unit of the magnetizing force is Oersted in the GCS system

Maximum Energy Product, (BH)max.: There is a point at the Hysteresis Loop at which the product of magnetizing force H and induction B reaches a maximum. The maximum value is called the Maximum Energy Product. At this point, the volume of magnet material required to project a given energy into its surrounding is a minimum. This parameter is generally used to describe how “strong” this permanent magnet material is. Its unit is Gauss Oersted. One MGOe means 1,000,000 Gauss Oersted.

Oersted, Oe: A unit of magnetizing force in GCS system. 1 Oersted equals 79.58 A/m in SI system.

Permeability, Recoil: The Average slope of the minor hysteresis loop.

Polymer-Bonding: Magnet powders are mixed with a polymer carrier matrix, such as epoxy. The magnets are formed in a certain shape, when the carrier is solidified.

Rare Earths: A family of elements with an atomic number from 57 to 71 plus 21 and 39. They are lanthanum, cerium, praseodymium, neodymium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, lutetium, scandium, and yttrium.

Remenance, Bd: The magnetic induction which remains in a magnetic circuit after the removal of an applied magnetizing force. If there is an air gap in the circuit, the remenance will be less than the residual induction, Br.

Reversible Temperature Coefficient: A measure of the reversible changes in flux caused by temperature variations.

Residual Induction, Br: A value of induction at the point at Hysteresis Loop, at which Hysteresis loop crosses the B axis at zero magnetizing force. The Br represents the maximum magnetic flux density output of this material without an external magnetic field.

Saturation: A condition under which induction of a ferromagnetic material has reach its maximum value with the increase of applied magnetizing force. All elementary magnetic moments have become oriented in one direction at the saturation status.

Sintering: The bonding of powder compacts by the application of heat to enable one or more of several mechanisms of atom movement into the particle contact interfaces to occur; the mechanisms are: viscous flow, liquid phase solution-precipitation, surface diffusion, bulk diffusion, and evaporation-condensation. Densification is a usual result of sintering.

Surface Coatings: Unlike Samarium Cobalt, Alnico and ceramic materials, which are corrosion resistant, Neodymium Iron Boron magnets are susceptible to corrosion. Base upon of magnets’ applications, following coatings can be chosen to apply on surfaces of Neodymium Iron Boron magnets.

Surface Coatings

  Coating Performance     Coating Thickness    Corrosion-Resistant
in Salt Fog (Hr)  
  Color     PCT (Hr)
at 120 °C, 2 atm, 100% RH  
Zn > 8 µm > 24 Silver
Color Zn > 10 µm > 72 multicolor 12
Ni-Cu-Ni > 12 µm > 72 Silver, Lustrous 24
Epoxy 15 – 30 µm > 72 Black

Stability: An ability to resist to demagnetizing influences expected to be encountered in operation. These demagnetizing influences can be caused by high or low temperatures or by external magnetic fields.

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  1. Reference Information

REFERENCE BOOKS

Following books may be helpful for you in designing and selecting permanent magnet materials.

  1. Permanent Magnet Design and Application Handbook, by Lester R. Moskowitz; published by Krieger Publishing Company, Malabar, Florida; ISBN 0-89464-768-7
  2. Permanent Magnet Materials and Their Application, by Dr. Peter Campbell
  3. Standard Specifications for Permanent Magnet Materials, Published by Magnetic Materials Producers Association; (312) 201-0101, (312) 201-0214 (fax)
  4. Permanent Magnet Guidelines, Published by Magnetic Materials Producers Association; (312) 201-0101, (312) 201-0214 (fax)

MEASUREMENT SYSTEMS

Unit Symbol cgs System SI System English System
Length L centimeter (cm) meter (m) inch (in)
Flux ø maxwell weber (Wb) maxwell
Flux Density B gauss (G) Tesla (T) lines/in2
Magnetizing force H Oersted (Oe) ampere turns/m (At/m) ampere turns/in (At/in)
Magnetomotive Force F gilbert (Gb) ampere turn (At) ampere turn (At)
Permeability in air µ0 1 4 pi x 10-7 3.192

 

CONVERSION TABLE

from cgs to SI from SI to cgs
1 Oe = 7.962 x 10 A/m 1 A/m = 1.256 x 10-2Oe
1 G = 1 x 10-4 T 1 T = 1 x 10 4G
1 Gb = 0.796 At 1 At = 1 .265 Gb
1 maxwell = 1 x 10 -8 Wb 1 Wb = 1 x 10 8 maxwell
1 G Oe = 7.962 x 10 -3 J/m3 1 J/m3 = 1.256 x 10 2 G Oe