Sm-Fe-N magnet powders are produced in a similar way to Nd-Fe-B, except that nitrogen is introduced by heat treatment of rapidly quenched Sm-Fe flakes in a nitrogen atmosphere. These flakes are then mixed with a polymer binder and pressed or injected to make isotropic bonded magnets, NITROQUENCH-P.

Magnetic performance of (BH)max=112 kJ/m3 is at the highest level in the world and has excellent corrosion and heat resistance, which opens the door to various new applications.

Features of NITROQUENCH-P

・Material Powder

Provided by Daido Steel’s original manufacturing technique

・Highest magnetic properties among all isotropic bonded magnets

(BH)max exceeding NdFeB bonded magnets, 98 ～ 112 kJ/m3

・Excellent corrosion resistance

Possible to use without coating in certain application environment

・Excellent heat resistance

Thermal coefficient of remanence -0.05 %/deg C ～ -0.07 %/deg C (-20 ～ +120 deg.C.)

・Long-term stability

Better than NdFeB bonded magnets

・Magnetizing field requirement

Magnetizing field required for near saturation is 2400 kA/m (30 kOe), which is higher than for NEOQUENCH-P.
Technical support for magnetizing, such as multiple pole magnetization is available on request.

Applications of NITROQUENCH-P

Taking advantage of higher magnetic properties and better corrosion / heat resistance than Nd-Fe-B bonded magnets, NITROQUENCH-P can be used for a variety of applications, such as immersible pumps, cell phones and sensors.

Manufacturing process of NITROQUENCH-P

NITROQUENCH-P is produced by either compression molding or injection molding.

Injection molding

Injection molded magnets are made by injecting the special compound, a mixture of SmFeN magnet powder and high performance polymer, into the mold. These magnets cover a wide range of characteristics as isotropic bonded magents, including heat resistance and higher performance. Injection molding offers very flexible shape design as well as overmolding and insert molding with other parts for easy and reliable assemblies.

Injection mold magnet

Simultaneous molded assembled parts with other part or high end resin part.

Feature of injection mold magnet

  1. Injection molded magnet has high level of charcteristic as isotropic bonded magnet.
  2. Since this is isotropic manget, magnetization direction is free to choose, and advantageous for the multipole magnetization.
  3. Injection molding shows better dimensional accuracy and excellent serial productivity.
  4. Thin wall thickness minimum 0.3 mm, complicated shape can be produced. *1
  5. The metal part such as backyoke, hub, shaft or other resin part can be produced with this simultaneous injection mold method.
  6. Since the resin wraps the manget powder, it is rust proof and can be used by no coating. *2

※1 There is some case that manufacturing the thickness 0.3 mm could be difficult because of design, please consult with sales staff.
※2 When the coating is necessary by use condition, appropriate coating for the injection mold is prepared. Please consult with sales staff.

2 Shots technology

2 Shots technology is the method of simultaneous injection molding magnetic powder & resin material together.

Feature of 2 shots injection molding

  • Skipping bonding and assembling process
  • Improving concentricity
  • Decreasing manufacturing cost

Compression magnet

Compression product is made from mixing magnetic powder with resin binder and reaches higher level of performance than injection mold product’s.

Compression product

Bond to the shaft or yoke, assembled part set magnet.

Feature of compression product

  1. As isotropic bonded manget, the highest level of magnetic performance
  2. Since this is isotropic manget, magnetization direction is free to choose, and advantageous for the multipole magnetization.
  3. Wall thickness (Minimum 0.3 mm) is available to produce. *1
  4. An excellent anti-rust performance is realized by the Daido original coating technology.

※1 Up to the shape 0.3 mm thickness might be difficult. Please consult with sales staff.

Properties and detailed data of NITROQUENCH-P

Material properties of isotropic bonded SmFeN magnets (NITROQUENCH-P)

Magnetic properties

Compression molded magnets

SP-14 SP-14L
Remanence
Br		 mT 750 ～ 820 750 ～ 830
(kG) (7.5 ～ 8.2) (7.5 ～ 8.3)
Coercivity
HCB		 kA/m 450 ～ 520 430 ～ 510
(kOe) (5.7 ～ 6.5) (5.5 ～ 6.4)
Intrinsic Coercivity
HCJ		 kA/m 670 ～ 800 550 ～ 670
(kOe) (8.5 ～ 10.0) (7.0 ～ 8.5)
Maximum Energy Product
(BH)max		 kJ/m3 98 ～ 112 98 ～ 112
(MGOe) (12.4 ～ 14.0) (12.4 ～ 14.0)
Temperature Coefficient of B % / ℃ -0.05 ～ -0.07
Method of forming Compression moulding
  • The data in these tables are obtained from Daido’s standard test pieces and are not guaranteed values.
  • These values may vary depending on the magnet shape, dimensions, test conditions and equipment. It is recommended that the figures be verified in actual products.
  • Guaranteed values may be set up by consultation for specific shape and sizes.
  • NITROQUENCH-P is a series of SmFeN bonded magnets using certain polymers as a binder. When exposed to heat, physical, mechanical, or dimensional changes may occur. Please test the products in the specific environment before actual use.
  • The contents of data are subject to change without prior notice.

Typical physical & mechanical properties

SP-14, SP-14L
Density g/cm3 5.8 ～ 6.4
Thermal Expansion Coefficient 10-6/℃
(20℃ ～ 100℃)		 12.6
Bending strength (JIS K7171) MPa
(kgf/mm2)		 52
5.3
Bending Modulus (JIS K7171) MPa
(kgf/mm2)		 10800
1100
Ring Crushing Strength (JIS Z2507) MPa
(kgf/mm2)		 54
5.5

 

Corrosion Resistance

Coatings Dimension Lasting time
96Hr 192Hr 300Hr 500Hr 1000Hr
No coating OD 21 × ID 9 × 7.0 mm L A A A A A
Electrodeposition coating OD 21 × ID 9 × 7.0 mm L A A A A A

Degree of rust

  • No rust: A
  • Spotted rust: B
  • All surface rust: C

Appearance after humidity test

Test conditions

80 ℃ × 95 % RH × 300 hours

Specimen dimensions

OD 21 × ID 9 × 7.0 mm L

Magnetic properties of Isotropic bonded SmFeN magnets (NITROQUENCH-P)

Demagnetization curves

Magnetization behavior of Isotropic bonded SmFeN magnets (NITROQUENCH-P)

Coatings for isotropic bonded SmFeN magnets (NITROQUENCH-P)

Compression molded NITROQUENCH-P shows better corrosion resistance than NdFeB counterparts. While these magnets kept in dry air will be rust free for a long time, in a humid environment, the moisture in the air will cause rust on the surface.

Therefore surface coating is necessary for most applications. Daido provides 5 types of coatings for your specific shape and use environment.

Due to higher polymer binder content, injection molded magnets have higher corrosion resistance and in most cases can be used without coatings.

Coating method Coating thickness
(µm)		 Corrosion resistance
Time to rust formation in humidity test (hours)		 Application shape
60℃×95%R.H. 80℃×95%R.H.
Resin coating Electrodeposition coating (epoxy) 20 ～ 35 500 300 Various shapes
Spray coating (epoxy) 15 ～ 30 400 200 Various shapes
Dip coating (epoxy) 1 ～ 5 100 50 Small parts
Barrel spray coating
(epoxy)		 3 ～ 18 200 100 Small parts
Metal plating Ni plating 10 ～ 30 500 300 Various shapes

※Please consult with our sales staff for details.

Note for using NITROQUENCH-P

  1. Magnet is generally easy to crack. Please protect your eyes from splinter not to get injure.Since this magnet has strong power to pull each other, please notice not to place the hand.
  2. Magnet is fragile, once it got crack or chipping, it might lead lower characteristic or strength deterioration. In case of high rpm motor, even its magnet got broken, please design for the rotor not to scutter splinter.
  3. Please notice that even unmagnetized magnet sometimes absorbs tiny magnetic substance. When you mount a magnet, please use asembled parts after washing it.
  4. Approaching strong magnet might destroy records of magnetic media. Please do not bring magnet close to magnetic card, magnetic tape, prepaid card, and so on.
  5. Getting magnet close to electronic devices, scale meter board, control board might get out of order and broken or accident. Please keep magets away from it.
  6. It is very dangerous to bring magnet close to the person who wear an electronic medical device such as a pacemaker. Please keep magnets away from the person, or medical device might get affected and doesn’t work properly.
  7. Please don’t use or keep in the environments such as high humidity and high temperature. The magnets might get rust or deterioration of performance and mechnical strength. Rust proof depends upon the surface coating, please consult with us beforehand.
    1. Corrosive gas atmosphere (Cl, NH3, SOx, NOx…)
    2. High electro-conductivity (Electrolyte water …)
    3. Hydrogen gas atmosphere (H2, …)
    4. Acid, Alkali, Organic solvent
    5. Water, Oil, …
  8. Ni-plating would be needed to protect surface on the magnet from rust up to the working environment. Nd-Fe-B magnet needs to be coated or special treatment in many cases. Please select appropriate surface treatment to cope with the working environment.
  9. The rare earth alloy magnetic powder is classified as dangerous materials (flammable solid) in the Japanese Fire Services Act. Please do not use when there is possibilities of generating magnetic powder dust, because the finer dust is easy to catch fire.
  10. Dust caused by friction while magnet using or machinning, is easy to get fire. So please not to use the magnet where it generate magnetic dust in the air.
  11. Please don’t swallow magnet by mistake.If you swallow it by any chance, please consult with the doctor immediately.
  12. Please keep the magnet away from the place children can reach.
  13. Please keep the magnet away from especially the person who has metalic alergy, since touching magnet might cause skin trouble or swells in red. If you get symptom like this, please don’t touth magnets.