Grades of Neodymium

Grades are defined as N35, N38, N42, N38SH, N50, N52. Neodymium magnets are all graded by the material they are made of. The higher the grade (the number following the 'N'), the stronger the magnet. The highest grade of neodymium magnet available from Quantum Energy is N52. If there is any letter following the grade, this letter refers to the temperature rating of the magnet. If there are no letters following the grade, then the magnet is standard temperature neodymium. The temperature ratings are standard (no designation) - M - H - SH - UH - EH. You find the temperature rating of each grade of magnet on the product specification page for each magnet.

Demagnetization

Permanent rare earth magnets have a high resistance to demagnetization, unlike most other types of magnets. Permanent rare earth magnets will not lose their magnetization around other magnets or if dropped. They will however, begin to lose strength if they are heated above their maximum operating temperature, which is 176°F (80°C) for standard N grades. Permanent rare earth magnets will completely lose their magnetization if heated above their Curie temperature, which is 590°F (310°C) for standard N grades. Some of Quantum Energy magnets are of high temperature material, which can withstand higher temperatures without losing strength. Please review the product specification page for each magnet before purchasing.

Strength

Permanent rare earth neodymium magnets are over ten times stronger than the strongest ceramic magnet. If currently using ceramic magnets in your products, in most cases a smaller neodymium magnet can be utilized as a replacement while having a greater holding force. Please review the product specification page for each magnet before purchasing.

Air Gap

The "external" distance from one pole of the magnet to the other though a non-magnetic material (usually air).

Anisotropic Magnet

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

C.G.S. / CGS

Abbreviation for the "Centimeter, Grams, Second" system of measurement.

Coercive Force, Hc

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

Curie Temperature, Tc

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

Flux, ø

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 CGS unit of flux is the MAXWELL.

Gauss

Lines of magnetic flux per square centimeter, CGS unit of flux density, equivalent to lines per square inch in the English system, and webers per square meter or Tesla in the SI system.

Hysteresis Loop

A closed curve obtained for a material by plotting corresponding values of magnetic induction, B, (on the abscissa) against magnetizing force, H, (on X axis, Y axis).

Induction, B

The magnetic flux per unit area of a section nor- mal to the direction of flux. Measured in Gauss, in the CGS system of units.

Intrinsic Coercive Force, Hci

Measured in Oersteds in the CGS system, this is a measure of the material’s inherent ability to resist demagnetization. It is the demagnetization force corresponding to zero intrinsic induction in the magnetic material after saturation. Practical consequences of high Hci values are seen in greater temperature stability for a given class of mate- rial, and greater stability in dynamic operating conditions.

Irreversible Loss

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

Isotropic Magnet

A magnet material whose magnetic proper- ties are the same in any direction, and which can therefore be magnetized in any direction without loss of magnetic characteristics.

Leakage Flux

A magnetic flux that doesn't follow its intended path in a magnetic circuit.

Magnetizing Force, H

The magnetomotive force per unit length at any point in a magnetic circuit. Measured in Oersteds in the CGS system.

Maximum Energy Product, BHmax

The point on the Demagnetization Curve where the product of B and H is a maximum and the required volume of magnet material required to project a given energy into its surroundings is a minimum. Measured in Mega Gauss Oersteds, MGOe.

North Pole

That pole of a magnet which, when freely suspended, would point to the north magnetic pole of the earth. The definition of polarity can be a confusing issue, and it is often best to clarify by using “north seeking pole” instead of “north pole” in specifications.

Oersted, Oe

A CGS unit of measure used to describe magnetizing force. The English system equivalent is Ampere Turns per Inch, and the SI system’s is Ampere Turns per Meter.

Orientation Direction

The direction in which an anisotropic magnet should be magnetized in order to achieve optimum magnetic properties. Also known as the “axis”, “easy axis”, or “angle of inclination”.

Residual Induction, Br

This is the point at which the hysteresis loop crosses the B axis at zero magnetizing force, and represents the maximum flux output from the given magnet material. By definition, this point occurs at zero air gap, and therefore cannot be seen in practical use of magnet materials.

Saturation

The condition under which all elementary magnetic moments have become oriented in one direction. A ferromagnetic material is saturated when an increase in the applied magnetizing force produces no increase in induction. Saturation flux densities for steels are in the range of 16,000 to 20,000 Gauss.

Stabilization

Exposure of a magnet to demagnetizing influences expected to be encountered in use in order to prevent irreversible losses during actual operation. Demagnetizing influences can be caused by high or low temperatures, or by external magnetic fields.

Permeance Coefficient, Pc

Ratio of the magnetic induction, Bd, to its self demagnetizing force, Hd. Pc = Bd/Hd. This is also known as the “load line” or operating point of the magnet and is useful in estimating the flux output of the magnet in various con- ditions. As a first order approximation, Bd.Hd = Lm/Lg, where Lm is the length of the magnet and Lg is the length of an air gap that the magnet is subjected to. Pc is therefore a function of the geometry of the magnetic circuit.

Pole Pieces

Ferromagnetic materials placed on magnetic poles used to shape and alter the effect of the lines of flux.