REC(SAMARIUM COBALT) MAGNETS

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Kelley Stewart Lester
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1 REC(SAMARIUM COBALT) MAGNETS Introduction... 1 Material Characteristics... 2 / Characteristic Distribution... 3 Temperature Characteristics Reversible Temperature Coefficient... 4 Irreversible Demagnetization... 4 Reversible Temperature Change... 4 Design Data Comparison with Other Magnets... Magnetization Field... Demagnetization Curves of Various Magnets... 6 Production Processes... 6 Demagnetization Curves/Magnetic Characteristics REC32AH... 7 REC32A... 8 REC REC26A... REC REC REC REC Conformity to RoHS Directive: This means that, in conformity with EU Directive 22/9/EC, lead, cadmium, mercury, hexavalent chromium, and specific bromine-based flame retardants, PBB and PBDE, have not been used, except for exempted applications.

(1/14) Samarium Cobalt Magnets REC Series INTRODUCTION The demand for rare earth cobalt magnets has been rising in recent years not only in electronic equipment but also in industrial and other

2 (1/14) Samarium Cobalt Magnets REC Series INTRODUCTION The demand for rare earth cobalt magnets has been rising in recent years not only in electronic equipment but also in industrial and other equipment in response to the growing requirements placed on small physical sizes and high performance levels. TDK s leading material among its rare earth cobalt magnets is its Series Its temperature characteristics are on a par with those of alnico magnets, and in addition it displays the dual advantages of an ultra-small size and ease of use. Centered on its REC32A which has the world s highest maximum energy product, such as the REC3, REC26A, REC26, REC24 and REC22 magnets contribute to conservation of resources and work wonders in all kinds of equipment because of their ultra-high performance. Conformity to RoHS Directive: This means that, in conformity with EU Directive 22/9/EC, lead, cadmium, mercury, hexavalent chromium, and specific bromine-based flame retardants, PBB and PBDE, have not been used, except for exempted applications.

3 (2/14) MATERIAL CHARACTERISTICS High Magnetization Characteristics Material, REC32AH Series These new materials have a higher coersive force than the currently available REC32A and their use in a high temperature environment or in an intense demagnetization field is possible. FEATURES Have a coercive force higer than 2kOe. APPLICATIONS AC servo-motors, motors, actuators, bias magnets, sensors for automobile Material Residual flux density Intrinsic coercive force Maximum energy product REC32AH 1,1±3 11.1±.3 [ka/m] 796±48 (koe).±.6 [ka/m] >91 (koe) >2 [kj/m 3 ] 27±16 26±2 Composition Series 2-17(Sm2[Co, Cu, Fe, Zr]17) Series 1-(SmCo) Material REC32A REC3 REC26A REC26 REC24 REC22 REC18 [Magnetic characteristics] Residual flux density 1 to to to.8.2 to to to to 8.7 (koe) 6. to to to. 6. to to to 8. (koe) 8.min. 6.2 to 7. 8.min..min. 6.2 to 7..min. 12. to 2. Maximum energy product 28 to to to 27 to to 24 2 to to 19 [Physical characteristics] Curie temperature C 8 to 8 8 to 8 8 to 8 8 to 8 8 to 8 8 to 8 7 to 7 (K) (73 to 1123) (73 to 1123) (73 to 1123) (73 to 1123) (73 to 1123) (73 to 1123) (973 to 23) Thermal expansion coefficient C// C 1 C (1/K) (8 6 ) (8 6 ) (8 6 ) (8 6 ) (8 6 ) (8 6 ) (6 6 ) 1 C (1/K) (11 6 ) (11 6 ) (11 6 ) (11 6 ) (11 6 ) (11 6 ) (13 6 ) Thermal kcal/mhr C 11 conductivity (W/mK) (12) (12) (12) (12) (12) (12) (13) Specific heat cal/g C (J/kgK) (33) (33) (33) (33) (33) (33) (377) Specific resistivity Ω cm Density g/cm to to to to to to to 8.3 (kg/m 3 ) (8.3 to 8. 3 ) (8.3 to 8. 3 ) (8.3 to 8. 3 ) (8.3 to 8. 3 ) (8.3 to 8. 3 ) (8.3 to 8. 3 ) (8.1 to ) [Mechanical characteristics] Deflection strength kg/mm 2 18 (N/m 2 ) (1. 8 ) (1. 8 ) (1. 8 ) (1. 8 ) (1. 8 ) (1. 8 ) (1.8 8 ) Compressive kg/mm strength (N/m 2 ) (8 8 ) (8 8 ) (8 8 ) (8 8 ) (8 8 ) (8 8 ) ( 8 ) Tensile strength kg/mm (N/m 2 ) (3. 7 ) (3. 7 ) (3. 7 ) (3. 7 ) (3. 7 ) (3. 7 ) (4 7 ) Young s modulus kg/mm (N/m 2 ) ( ) ( ) ( ) ( ) ( ) ( ) ( ) Vickers hardness Hv to 6 to 6 to 6 to 6 to 6 to 6 4 to C// is the value measured in the easy magnetization direction. C is the value measured in the vertical direction to the easy magnetization direction. Figures in parentheses are given in SI units. 1(G)= 4 (T) 1(Oe)= 3 /4π(A/m)

4 (3/14) / CHARACTERISTIC DISTRIBUTION REC32A [T] REC3 REC26A REC26 REC24 REC22 Residual flux density.9 9 REC (koe) 6 7 8[kA/m]

5 (4/14) TEMPERATURE CHARACTERISTICS REVERSIBLE TEMPERATURE COEFFICIENT Reversible temperature coefficient at to +2 C Temperature C to 2 C 2 C to C C to 2 C REC32A, 3, 26A, 26, 24, 22.3%/ C.3%/ C.3%/ C REC IRREVERSIBLE DEMAGNETIZATION Relationship between irreversible demagnetization and operating point after 12 C and 2 C aging. REC32A, 26A REC3, 24 REC26, 22 REC18 A.T. A.T. A.T. A.T. 12 C 16 C 2 C 12 C 2 C 12 C 2 C B/H B/H B/H B/H 12 C 2 C. 9% 14% 19% % 2%. 4% 7%. 4% 7% REVERSIBLE TEMPERATURE CHANGE REC18 REC22, 24 26, 26A 3, 32A Reversible change ratio B/B(%) 2 Temperature( C) REC22, 24 26, 26A 3, 32A 8 REC18

6 (/14) DESIGN DATA COMPARISON WITH OTHER MAGNETS COMPARISON BETWEEN REC24, FB4A(FERRITE) AND ALNICO MAGNETS FOR SPEAKER Item FB4A(Ferrite) REC24 Alnico 4,G,G 13,G 2,2Oe 6,2Oe 6Oe Magnetic 2,22Oe 6,Oe Oe characteristics Bd 2,7G,9G,G Bd Hd 3.MGOe 24MGOe.MGOe BaCO3=% Fe2O3=8% Sm=% Co=1% Fe=% Cu=8% Co=24% Ni=14% Al=8% Cu=3.2% Raw materials Zr=1% Fe=.8% Both BaCO3 and Fe2O3 are low-priced, and the raw material sources are stable. Co and Ni are high-priced, so it is difficult to obtain stable supplies of raw materials. Magnet density.g/cm 3 8.g/cm 3 7.3g/cm 3 Required length of magnet (Lm) Required cross sectional area of magnet(am) Required volume of magnet(vm) Required weight of magnet(wm) Magnetic circuit For the sake of comparison, length of FB4A is made "1". For the sake of comparison, area of FB4A is made "1". 1 1=1 1 = Operating point Bd is lower than that of Alnico and Hd is higher. Therefore, magnet shape is flat and the optimum magnetic circuit is such that, as in the figure below, the magnet is externally positioned. S N S 1,3 =.32 times 4, 2,7 =.46 times, =. times 8% less than FB4A. 8.=1.28 About 7% more than FB4A Operating point Bd is between that of FB4A and Alnico, and Hd is the highest. Therefore, the magnet may be positioned either internally or externally. The optimum magnetic circuit is compact and flat as in the figure below. S N S 1,3 =2.6 times 2,7 =.27 times, = 3% less than FB4A 7.3=.11 2% more than FB4A Operating point Bd is higher than that of FB4A and Hd is lower. Therefore, magnet is made rod-shaped and the optimum magnetic circuit is such that, as in the figure below, the magnet is internally positioned. S N S Figures in parentheses are given in SI units. 1(G)= 4 (T) 1(Oe)= 3 /4π(A/m) MAGNETIZATION FIELD Careful consideration must be given to the applied magnetic field with magnetization. Magnetization fields are characterized by special features. In order to obtain the prescribed magnetic characteristics, magnetization must be performed in a magnetic field of more than 2 koe. Please consult us about magnetization. REC18 7 Magnetization factor(%) REC24 REC3 REC22 REC26 REC26A REC32A 2 (koe) Magnetization field 199[kA/m] Caution on usage Magnetized products have a strong attractive power and if allowed to come into close contact with other products, may cause breakage or cracks.

7 (6/14) S OF VARIOUS MAGNETS PRODUCTION PROCESSES OF TDK s REC3 AND REC18 B/H REC18 SmCo REC3 Sm2(Co, Cu, Fe, Zr) 17 REC32A REC3 12 Sm-36 Co-64(wt%) Raw materials Fusion Sm-, Co-1. Fe- Cu-8, Zr-1(wt%) REC26 Rough crushing 8 Fine milling B/H. Ba-Ferrite Alnico Pt-Co 6 4 B 1, C 1hr Argon gas atmosphere 9 C 1hr Molding in magnetic field Sintering Multi-stage aging 1,2 C 1hr Vacuum 8 4 C Step-tempering.2 2 Maching (koe) Magnetization Figures in parentheses are given in SI units. 1(G)= 4 (T) 1(Oe)= 3 /4π(A/m)

8 (7/14) S/ REC32AH B/H C 2 C 6 C C 14 C 18 C..3 BxH 3 2 [koe] 2 (ka/m) Residual flux density 1,1±3 (G) 11,±3 [ka/m] 796±48 (Oe),±6 Intrinsic coercive force [ka/m] >91 (Oe) >2, Maximum energy product [kj/m 3 ] 27±16 26±2

9 (8/14) REC32A B/H C 2 C C 2 C. BxH (koe) [ka/m] 7 Residual flux density 1,13±3 (G) 11,3±3 [ka/m] 637±8 (Oe) 8,±1, Intrinsic coercive force [ka/m] >637 (Oe) >8, Maximum energy product [kj/m 3 ] 239±16 3±2 Reversible permeability to 1. µrev to 1. Reversible temperature [%/K].3 coefficient (%/ C).3 Curie temperature [K] 1,73 to 1,123 Tc ( C) 8 to 8

10 (9/14) REC3 B/H C 2 C C 2 C. BxH (koe) [ka/m] 7 Residual flux density 1,±2 (G) 11,±2 [ka/m] 9±32 (Oe) 6,4±4 Intrinsic coercive force [ka/m] ±32 (Oe) 6,6±4 Maximum energy product [kj/m 3 ] 239±8 3±1 Reversible permeability to µrev to Reversible temperature [%/K].3 coefficient (%/ C).3 Curie temperature [K] 1,73 to 1,123 Tc ( C) 8 to 8

11 (/14) REC26A B/H C 2 C C 2 C. BxH (koe) [ka/m] 7 Residual flux density 1,4±4 (G),4±4 [ka/m] 637±8 (Oe) 8,±1, Intrinsic coercive force [ka/m] >637 (Oe) >8, Maximum energy product [kj/m 3 ] 199±16 ±2 Reversible permeability to 1. µrev to 1. Reversible temperature [%/K].3 coefficient (%/ C).3 Curie temperature [K] 1,73 to 1,123 Tc ( C) 8 to 8

12 (11/14) REC26 B/H C 2 C C 2 C. BxH (koe) [ka/m] 7 Residual flux density 1,±3 (G),±3 [ka/m] 732±64 (Oe) 9,2±8 Intrinsic coercive force [ka/m] >796 (Oe) >, Maximum energy product [kj/m 3 ] 27±16 26±2 Reversible permeability to 1. µrev to 1. Reversible temperature [%/K].3 coefficient (%/ C).3 Curie temperature [K] 1,73 to 1,123 Tc ( C) 8 to 8

13 (12/14) REC24 B/H C 2 C C 2 C. BxH (koe) [ka/m] 7 Residual flux density 1,±2 (G),±2 [ka/m] 9±32 (Oe) 6,4±4 Intrinsic coercive force [ka/m] ±32 (Oe) 6,6±4 Maximum energy product [kj/m 3 ] 183±8 23±1 Reversible permeability to µrev to Reversible temperature [%/K].3 coefficient (%/ C).3 Curie temperature [K] 1,73 to 1,123 Tc ( C) 8 to 8

14 (13/14) REC22 B/H C 2 C C 2 C. BxH (koe) [ka/m] 7 Residual flux density 9±3 (G) 9,±3 [ka/m] 684±64 (Oe) 8,6±8 Intrinsic coercive force [ka/m] >796 (Oe) >, Maximum energy product [kj/m 3 ] 17±16 22±2 Reversible permeability to 1. µrev to 1. Reversible temperature [%/K].3 coefficient (%/ C).3 Curie temperature [K] 1,73 to 1,123 Tc ( C) 8 to 8

15 (14/14) REC18 B/H C 2 C C 2 C. BxH (koe) [ka/m] 7 Residual flux density 8±2 (G) 8,±2 [ka/m] 637±4 (Oe) 8,± Intrinsic coercive force [ka/m] 1,273±318 (Oe) 16,±4, Maximum energy product [kj/m 3 ] 143±8 18±1 Reversible permeability to 1. µrev to 1. Reversible temperature [%/K].4 coefficient (%/ C).4 Curie temperature [K] 973 to 1,23 Tc ( C) 7 to 7

NEOREC(NEODYMIUM-IRON-BORON) MAGNETS

NEOREC(NEODYMIUM-IRON-BORON) MAGNETS Introduction... 1 Features/Applications... 2 / Characteristics Distribution... 3 Irreversible Demagnetization Characteristics... Magnet Structures/Magnetic Characteristics/