Rare Earth Magnet DIANET®

Creating Time - Optimizing Time - Enriching Time
Seiko Instruments Inc. (SII), founded in 1937 as a member of the Seiko Group specializing in the
manufacture of watches, has leveraged its core competency in high precision watches
to create a wide range of new products and technologies.
Over the years SII has developed high-precision processed parts and machine toolsthat pride themselves on their sub-micron processing capability,
quartz crystals that came about as a result of our quartz watch R&D,
and electronic components such as micro batteries.
Optimizing our extensive experience and expertise, we have since diversified
into such new fields as compact, lightweight, exceedingly quiet thermal printers,
and inkjet printheads, a key component in wide format inkjet printers for corporate use.
SII, in the years to come, will maintain an uncompromised dedication
to its time-honored technologies and innovations of craftsmanship, miniaturization, and efficiency
that meet the needs of our changing society and enrich the lives of those around us.

Genealogy of Seiko Group
1947 Wako Co., Ltd.
2001 Seiko Watch Corporation
1881 K. Hattori

Hattori Seiko Co., Ltd.

Seiko Corporation

2006 Seiko NPC Corporation1975 Nippon Precision
Circuits Inc.

1998 Seiko Time Systems Inc.
1892 Seikosha

2022 Seiko Group Corporation

Seiko Holdings Corporation

Seikosha Co., Ltd.

2021 Seiko Time Creation Inc.

1996 Seiko Clock Inc.
1996 Seiko Precision Inc.
2013 Seiko Solutions Inc.

1937 Daini Seikosha Co., Ltd.

Seiko Instruments &Electronics Ltd.

2004

Seiko Instruments Inc.

CONTENTSDIANET® Samarium Cobalt Magnet.................................. 3

Surface Processing and Measurement.............................. 8

IATF16949 Certification...................................................... 4

Check Sheet for Quotation ............................................... 9

Basic Characteristics.......................................................... 5

Environmental Policy / Cautions....................................... 10

Temperature Characteristics.............................................. 6

Product Introduction......................................................... 11

Heat-demagnetizing Factor
and Processing-related Deterioration............................. 7

DIANET® Samarium Cobalt Magnet“DIANET”, Which has its origin inrotor magnets of quartz watches,
has superior heat resistanceand strong magnetic force eventhough its outside diameter isonly 1 mm or less.
“DIANET” is used for a wide
range of automotive products,
and its advanced quality
and performance are highly
recognized.
Leveraging SII’s strength inInternal quartz watch movement
technologies for small-sized
products, DIANET® is used in other applications in addition to quartz watches, including
actuators for smartphone cameras and medical devices.

■ Manufacturing process
Resolution

Pulverization

Quartz watch movement

Powderprocessing
Horizontal magnetic
field molding■ Features of DIANET

Vertical magnetic
field molding

Sintering• Superior heat resistance and reflow mountable.
• Superior corrosion resistance. No corrosionrelated deterioration of magnetic properties.
• No processing-related deterioration of magnetic
properties, thus contributing to equipment
downsizing and reducing energy consumption.

Inspection

Processing
Surfaceprocessing• Superior precision processing that meets
dimensional tolerance requirements in microns.
• Minimum dispersion of magnetic characteristics
achieved with SII's unique processing technology.

Magnetization• Our near net shape processing technology
makes it possible to provide magnets at low
cost.

Thermal aging
treatment

Inspection

Packagingand shipment

3

IATF16949 Certification

SII acquired IATF16949 certification for its magnet products.
IATF16949 is an international standard specifying the requirementsof a quality management system for automotive production.

■ DM-R32
Residual magnet flux density
System

2-17 based(Sm2Co17)

Br

Material

DM-R32

Maximum energy product

Coercive force
bHc

iHc

BHmax

(T)

(G)

(kA/m)(Oe)(kA/m)(Oe)(kJ/m3)(MGOe)

1.08 to 1.14

10,800 to 11,400

748 to 859

9,400 to 10,800

1,592 ≤

20,000 ≤214 to 247

27.0 to 31.0

Comparison of Heat-demagnetizing Factor (FLUX value)
DM-R32
NdFeB

Heat-demagnetizing Factor (%)

95.0%
85.0%
75.0%
65.0%
55.0%
45.0%
35.0%
0

50

100

150

200

250

300

350

400

Temperature (ºC)
The heat-demagnetizing factor varies depending on the usage environment and conditions. This does not guarantee
the heat-resistant temperature.

4

Basic Characteristics■ Basic Characteristics
Residual magnet flux density
System

1-5 based(SmCo5)2-17 based(Sm2Co17)

Material

Coercive force

Br

Maximum energy product

bHc

iHc

BHmax

(T)

(G)

(kA/m)(Oe)(kA/m)(Oe)(kJ/m )

(MGOe)

DM-20

0.79 to 0.87

7,900 to 8,700

613 <

7,700 <

1,114 to 1,910

14,000 to 24,000

123 <

15.5 <

DM-R220.90 to 1.06

9,000 to 10,600

588 to 796

7,400 to 10,000

580 to 2,109

7,300 to 26,500

155 to 215

19.5 to 27.0

DM-26

1.03 to 1.08

10,300 to 10,800

302 to 637

3,800 to 8,000

302 to 668

3,800 to 8,400

155 to 215

19.5 to 27.0

DM-30S

1.09 to 1.15

10,900 to 11,500

405 to 756

5,100 to 9,500

374 to 1,115

4,700 to 14,000

200 to 239

25.0 to 30.0

DM-30L1.08 to 1.13

10,800 to 11,300

684 <

8,600 <

1,074 to 2,348

13,500 to 29,500

200 to 243

25.0 to 30.5

DM-R321.08 to 1.14

10,800 to 11,400

748 to 859

9,400 to 10,800

1,592 ≤

20,000 ≤214 to 247

27.0 to 31.0

3

■ Range of Magnetic Characteristics
(kG)
12.0

(T)
1.20

11.5

1.15

Residual magnet flux density

DM-30S
11.0

1.10

10.5

1.05

10.0

1.00

DM-30L

DM-R32

DM-26

DM-R22
9.5

0.95

9.0

0.90

8.5

0.85

DM-20
8.0

0.80

7.5

0.75

0

500

5

1,000

10

1,500

15

20

2,000

25

2,500 (kA/m)

30

(kOe)

Coercive force
Note: Magnetic characteristics will vary depending upon the customer’s specified dimensions and shape. Please contact us for details.

5Temperature Characteristics■ DM-R22 B-H
1.5

2

3 4 56
B(kG)
12

1
20°C
50°C
100°C
150°C
200°C

11
10
9
8

0.75

Permeance coefficient

Permeance coefficient■ DM-20 B-H

2

3 4 56
B(kG)
12

1
20°C
50°C
100°C
150°C
200°C

11
10
9
8

0.75

7

0.5

1.5

7

0.5

6

6

5

5

4

0.3

3

0.2

4

0.3

3

0.2

2

2

1
10

8

6

4

2

0

Permeance coefficient■ DM-26 B-H

1-H(kOe) 12

10

8

6

4

2

0

1.5

2

3 4 56
B(kG)
12

1
20°C
50°C
100°C
150°C
200°C

11
10
9
8

0.75

1.5

2

3 4 56
B(kG)
12

1
20°C
50°C
100°C
150°C
200°C

11
10
9
8

0.75

7

0.5

7

0.5

6

6

5

5

4

0.3

4

0.3

3

0.2

3

0.2

2

2

1
10

8

6

4

2

0

0

Permeance coefficient■ DM-30L B-H

1-H(kOe) 12

10

8

6

4

2

0

1.5

2

3 4 56
B(kG)
12

1
20°C
50°C
100°C
150°C
200°C

11
10
9
8

0.75

7

0.5

6

1.5

2

3 4 56
B(kG)
12

1
20°C
50°C
100°C
150°C
200°C

11
10
9
8

0.75

7

0.5

6

5
4

0.3

3

0.2

2

5
4

0.3

3

0.2

2

1
-H(kOe) 12

60■ DM-R32 B-H
Permeance coefficient-H(kOe) 120■ DM-30S B-H
Permeance coefficient-H(kOe) 12

0

10

8

6

4

2

0

0

1
-H(kOe) 12

10

8

6

4

2

0

0

Heat-demagnetizing Factor and Processing-related Deterioration■ Heat-demagnetizing Factor
Samarium cobalt magnets (SmCo magnets) have a Curie temperature* of over 800°C,
which is higher than that of Neodymium magnets (NdFeB magnets). This superior heat resistance enables reflow soldering for the mounting process.
* Curie temperature (Tc): the temperature at which a ferromagnetic substance becomes paramagnetic on heating.

Comparison of Heat-demagnetizing Factor (FLUX value)
DM-30L
DM-30S
NdFeB

Heat-demagnetizing Factor (%)

95.0%
85.0%
75.0%
65.0%
55.0%
45.0%
35.0%
0

50

100

150

200

250

300

350

400

Temperature (ºC)
The heat-demagnetizing factor varies depending on the usage environment and conditions. This does not guarantee
the heat-resistant temperature.

■ Processing-related Deterioration
Compared to Neodymium magnets (NdFeB magnets), samarium cobalt magnets (SmComagnets) do not easily deteriorate during processing. Accordingly, the magnetic property ofsamarium cobalt does not deteriorate when processed into micro magnets.

7

Surface Processing and Measurement■ Surface Processing
Depending on usage, we recommend nickel electroplating to be conducted.
• Protects the surface of the magnet, and prevents chipping.
• Prevents generating magnetic powder due to breakage or chipping, and eases handling.

■ Measurement of Demagnetization Curves
Vibrating sample magnetometer
Vibrating sample magnetometers measure residual flux density, coercive force, and maximum energy product.

AmplifierElectromagnet

Coil

Sample1. Measurement of the Total Magnetic Flux.

Flux
Unit: Weber (Wb)
Maxwell (Mx)Nonmagnetic stick
Sample magnet

Coil

Fluxmeter-- Electromagnetec induction --Measures the amount of entire magnetic flux of the sample magnet.

2. Measurement of the Magnetic Flux density on the magnet surface (Bd)

Bd
Unit: Tesla (T)Hall Element Part

Gauss (G)N

S

Gauss Meter
Sample magnet-- Hall effect --Measures the amount of magnetic flux per unit area on the surface of the sample magnet.

8Check Sheet for Quotation
Please fill out the following form to receive a quotation.
1. Specifications
1-1. Dimensions and tolerance
Dimensions

Tolerance

D or L1d or L2t

1-2. Characteristics· Simplified schematic

D

t

Br:
iHc:
bHc:

d

BHmax:
t

1-3. Magnetic or nonmagnetic
1-4. Magnetization direction (D·L1·L2·t)
L2

1-5. With/without markings
1-6. With/without surface treatment
1-7. Usage temperature: Min.

L1

/ Max.

1-8. High temperature conditions: Time:/ No. of times:/ Frequency:

1-9. Mounting method (bonding, insertion, caulking, etc.)
1-10. With/without reflow soldering

2. Number of samples
3. Mass production quantity
4. Mass production timing
5. Usage
6. Desired price (yen/piece)

9

Environmental Policy / Cautions

Environmental Policy
The Seiko Group recognizes that the preservation of the global environment is one of the most important issues in the world today. We will
constantly strive to help realize a sustainable society that will benefit everyone.
1. We are committed to a wide range of environmentally responsible activities, and we will continue to make unceasing efforts toimprove our environmental performance, thereby providing increased value for all our stakeholders.
2. We not only comply with all relevant laws and regulations, but also go far beyond legal compliance in our efforts to reduce
environmental risks and prevent pollution.
3. Being acutely aware of the part we have to play in mitigating climate change, we are working hard to reduce greenhouse gas
emissions.
4. Because we recognize the limits of our precious natural resources, we are increasing our efforts to reuse and recycle every resource
possible.
5. We are also working to preserve biodiversity, recognizing that our business activities inevitably affect surrounding ecosystems, andthat we also benefit from the health and diversity of those systems.
6. We rigorously ensure proper management of all chemical substances used in production as well as any that are contained in ourfinished products.
7. We consider the environment throughout the entire life cycle of our products. We are proud that our products and services actively
contribute to environmental conservation.
8. Environmental responsibility starts as a management imperative, but to effectively carry out that mission requires the understanding
and cooperation of every employee throughout our Group. With that in mind, we are working to raise everyone’s environmental
awareness so that all of us can work together to protect and nurture our natural environment.
9. Transparency is another part of our social responsibility. We are therefore promoting active disclosure of material information about
our environmental activities and promoting increased communication with local, regional, and global stakeholders.
10. In order to derive maximum benefits from these policies, we establish clear environmental targets and strategies to attain them.
Then we steadily improve our efforts by constantly re-examining both our targets and our progress towards achieving them.

Cautions When Using Magnets
WARNING• It is extremely dangerous to place magnets near persons who have electronic
medical devices such as pacemakers installed. There is a risk of damage tonormal operation status of the medical device. Please use with highest caution.
• Be careful not to swallow magnets. If a magnet has been swallowed, consult
a physician immediately. Keep magnets out of the reach of children.
CAUTION• Depending on the size and shape used, a magnet may not achieve the magnetic
characteristics values noted in the catalogue. Confirm in advance by using asample, etc.
• When magnetization is performed by the customer, allocate sufficient magnetic
field for the material and coercive force. When the strength of the magnetic
field is insufficient, magnetic characteristics of the original design specifications
may not be obtained. Consult with the manufacture for the size of the magnetic
field needed for magnetization.
• Avoid using and storing magnets in the following environments. Weather resistance differs according to the material of each magnet, so consult in advanceabout corrosion prevention, etc.
1. Corrosive gas atmosphere (Cl, NH3, SOx, NOx)
2. Highly conductive environment (in water containing electrolytes, etc.)
3. Hydrogen atmosphere
4. Acidic, alkaline, or organic solvents, etc.
5. In water or oil• When using an adhesive to bond the yoke and hole piece, etc., of two magnets,
confirm reliability by inspecting the type, volume, conditions, and strength, etc.,of the adhesive.
• When performing processes such as press fitting or shrink fitting, there is arisk of degradation of the magnetic characteristics or cracking of the magnet
or its counterpart materials. Be sure to confirm in advance by using a sample.
• A magnetized magnet absorbs debris such as iron powder, so remove it fromits packing case in a dust free environment.
• Magnets are susceptible to shock, and cracking and chipping occur easily, so
handle with care. When cracking or chipping occur during handling, there is arisk of degradation of characteristics or strength.
• Magnets are generally made from materials that chip easily, so handle withcare. Store in a place where shock will not occur. In addition, be sure to store
in a location where the magnet will not come into contact with rain-water, etc.
• Magnetized magnets should be covered with a non-magnetic material such asa wooden box after clearly marking the fact that the magnet is magnetized.
• When a magnet is placed close to a magnetic tape, floppy disk, prepaid card,
ticket, or electronic watch, there is a risk that the magnetic recording will bedamaged and that the item will become magnetized and no longer be usable.
There is also a risk of cards and tickets becoming unusable due to the effectof an electronic key, so do not place electronic keys in your pocket together
with cards, tickets, etc.

10

• Persons who are sensitive to or have allergic reactions to metal may develop
rashes or redness of the skin if they come into contact with a magnet. If suchreactions are known to occur, do not touch magnets.
• Typically, components of a magnet may begin to dissolve in water, so do notdrink water that has been in contact with a magnet.
• Magnets typically crack easily. A magnet fragment may enter the eye or cause
injury, so use caution in handling.
• The absorption force of magnets is strong, so be careful not to let your hand
get pinched.
• The alloy powder of rare earth magnets is specified by fire safety law asclass II (flammable solid) and class I hazardous materials. There is a dangerof ignition or inflammation of fine powder generated due to friction during
use of a magnet, so do not use in such a way that risks generating magnetic
powder.
• There is a danger of auto-ignition with fine particles of rare earth magnets,
so when processed by the customer, do not leave chips or filings in theatmosphere, and be sure to store these in a container filled with water. As a
preparation in case a fire starts, have sand available for use. If a fire begins,cover the fire with the sand, and remove flammable objects.
• Avoid storing in locations with high temperature and high humidity.

IMPORTANT
1. The information herein is subject to change without notice.
2. Neither reproduction, duplication nor unauthorized use of this catalog inwhole or part is allowed without the prior written approval of Seiko Instruments Inc.
3. The colors of the products reproduced herein (“Products”) may be different
from the actual colors. Check colors on actual products before using the
Products.
4. Circuits and respective application methods described herein are for reference only. Seiko Instruments Inc. shall not be liable for any damages orlosses resulting from any claim by third parties that any Products or application methods described herein infringe any right intellectual property right. All
intellectual property rights with respect to the Products belong exclusively
to Seiko Instruments Inc.
Seiko Instruments Inc. does not grant users of the Products any right or
license to the Products hereunder.
5. When Products include Strategic Products (or Services) stipulated in theForeign Exchange and Trade Control Law, they shall not be exported without
permission of governmental authorities.
6. The Products are designed for consumer equipment and cannot be usedas part of any device or equipment which influences the human body or
requires a significantly high reliability, such as physical exercise equipment,
medical equipment, disaster prevention equipment, gas related equipment,
vehicles, aircraft and equipment mounted on vehicles.

Product Introduction

B

M

11

Micro-Energy Division who manufactures the products described inthis catalog holds the ISO 9001 quality management system
certificate, and the ISO 14001 environmental management systems
certificate.

www.sii-me.com

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Telephone:+81-43-211-1735 Facsimile:+81-43-211-8034

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Shenzhen Branch

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518008, China
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Torrance, CA 90501, U.S.A.
Telephone: +1-310-517-7802
Facsimile: +1-310-517-7792
Email:info@seikoinstruments.com
http://www.sii-me.com

Contact us(Specifications are subject to change without notice.)

Released in February 2023
Copyright©2023 Seiko Instruments Inc. All Right Reserved.

No.MGC3020EJ-04P2311