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HOEGANAES INSULATED POWDER COMPOSITES CHARACTERISTICS AND ELECTROMAGNETIC APPLICATION GUIDELINES
HOEGANAESINSULATED POWDER COMPOSITESCHARACTERISTICS AND ELECTROMAGNETIC APPLICATION GUIDELINES
HOEGANAESINSULATED POWDER COMPOSITES
BENEFITS OF INSULATEDPOWDER MATERIALS• Isotropic magnetic structure permits
3-dimensional magnetic flux path capability
• Easily shaped into complex configurations using conventional powder metallurgy compaction process
• Similar magnetic saturation induction values to wrought steel laminations
• Low inherent eddy current losses associated with the dielectric polymer coating
• Flexibility to engineer performance characteristics to satisfy application requirements
• Preferred alternative to laminations for new electric motor designs
INTRODUCTIONThe molecular field theory was developed nearly100 years ago. At that time, it was explained thatgroups of iron atoms are magnetized in one direction with equal groups of atoms magnetizedin the opposite direction, thus fully compensatingeach other with zero net magnetic moment. These groups of atoms are referred to as magnetic domains. In a given iron powder particle, there are a substantial number ofdomains all arranged in a way to give a zero magnetic moment. Extremely fine particles canpotentially represent single domain structures.Lodestone happens to be a natural, single domainiron ore (magnetite), which exhibits intrinsic permanent magnet characteristics. Its discoveryhad a significant impact on the history of theworld. The development of Insulated PowderComposites represents the next step toward further advancement in soft magnetic material systems!
BENEFITS OF THE POWDERMETALLURGY PROCESS• Net Shape Capability
• Complex Shapes
• Engineered Materials
• High Production Rates
• Tolerance Control
• Good Surface Finish
APPLICATIONS CHARTFor switching actuators and ignition coils, fuel injectors,motor applications
Resistivity Strength Induction B Permeability micro- (MPa) 10 kA/m (T) Max
ohm-meter
Ancorlam >50 90 1.47 470Ancorlam HR >1300 60 1.52 400Ancorlam 2HR* >475 90 1.64 610
For higher frequency applications, power electronics
Resistivity Strength Induction B Permeability micro- (MPa) 10 kA/m (T) Max
ohm-meter
Ancorlam 2FHR >1300 60 1.51 360Ancorlam HR >1300 60 1.51 400
For motor applications requiring high induction and permeability, actuators, frequencies up to 400 Hz
Resistivity Strength Induction B Permeability micro- (MPa) 10 kA/m (T) Max
ohm-meter
Ancorlam 2 50 50 1.60 550Ancorlam 2HR* 475 90 1.64 610
*Density of 7.6 g/cm3
Grade modification is possible to meet application specific properties
POWDER METALLURGYPROCESSES FORELECTROMAGNETIC GRADES
Composite Production:Admix Metal Powder, Additives,Coating Materials
Press Ready Insulated Powder CompositeMaterial
Optional Secondary Curing or StressRelieving
Optional Finishing Processes:MachiningPolymer ImpregnationPlating
Finished ElectromagneticComponent
L = Inductance (mH)µ = PermeabilityA = Cross-sectional area (cm2)I = Path length (cm)N = Number of turns
Microstructure illustrating insulative coating
100µm
CONVERSIONS / CALCULATIONS1 Tesla = Gauss X 10-4
1 Tesla = 1 Weber per meter2
1 Gauss = 1 Maxwell per cm2
Amp-Turns per meter = Oersteds x 79.5 (1 Amp-Turn per meter = 0.0125 Oe)
Tesla/Meter =
Gauss x 1.26 10-6
Amp-Turns Oersted
Frequency =rpm x Number of Poles (rotating electrical devices)
120
Inductance = L = 4πµAN2 I
Cold or Warm Compaction
Iron powders exposed to a magnetic field gradually begin to realign the individualdomains by slowly orienting themselves towardthe direction of the applied magnetic field.
When the magnetic field is switched off, the domains remain partially oriented in the originalmagnetic direction. Zero magnetism is realizedwhen the reverse field equals the coerciveforce. With further increases in the reverse field,the domains revert to the new direction.
The field required to reverse the domaindepends upon the crystalline symmetry andanisotropic properties. This energy is very smallin the case of a soft magnetic material, and considerably greater for a hard magnetic material, i.e., types that maintain high remanence, typically referred to as permanentmagnets.
The most commonly used soft magnetic material involves electrical steel laminations forlow frequency (60 – 200 Hz) applications. Low-end performance materials include cold-rolled, motor lamination steels, whereasintermediate to high-end characteristics areachieved with silicon-iron, or oriented steels.Laminations are prevalent because of existingdesign familiarity, relatively low costs and adequate magnetic performance. Nevertheless,the limited two-dimensional flux path capabilityand relatively low energy efficiency at higher operating frequency make them undesirable fornew electric motor designs.
HOEGANAESINSULATED POWDER COMPOSITES
INSULATED POWDER COMPOSITES
The introduction of uniformly coated iron particles providing a three-dimensional distributed air gap with an isotropic flux path,allows designers to reconsider conventionaltopology restrictions typical of steel laminations. Along with the benefits of PM netshape manufacturing capability, insulated composite materials exhibit inherently low eddy current losses even when subjected to operating frequencies exceeding 400 Hz. Composite manufacturing flexibility providesthe ability to engineer soft magnetic characteristics to suit specific applicationrequirements. Incorporating different iron powder size distributions, and coating types toincrease resistivity, various attributes can bemanipulated to enhance the material’s permeability, structural density or core-losscharacteristics.Coupling new electrical device design topologies with insulated powder compositesand high-energy permanent magnets providesthe necessary performance enhancementsalong with concurrent improvements in component efficiency, packaging and simplified manufacturing processes. The additional magnetizing force (mmf) of the permanentmagnet compensates for the lower permeabilityof the soft magnetic composite grades. The complementary materials and new designs provide greater performance and enhanced efficiency, with the ability to reduce manufacturing costs and component package size.Applications for these magnetic materialsinclude high-efficiency electric motors, high-frequency transformers, and unique electrical components. The electrical designengineer has three-dimensional shape-makingflexibility plus the high material utilization inherent with the PM process. Design flexibilityis enhanced further by the ability to bondtogether small segments to form larger, morecomplex shapes.
INSULATED POWDER COMPOSITE PERFORMANCE
Insulated Powder Composite manufacturing flexibility provides the ability to engineer soft magnetic characteristics to suit specific application requirements. Incorporating different iron powder size distributions and coating types to increase bulk resistivity various attributes can bemanipulated to enhance the material’s structural density, induction, permeability or core-loss characteristics.Grade modification is possible to meet application specific properties.
Anc
orLa
m
Anc
orLa
m H
R
Anc
orLa
m 2
F H
R
Anc
orLa
m 2
All properties improve with higher compaction pressures(density), especially induction, permeability and core-loss.
Compacting pressure (MPa) 830 830 830 830 830
Powder temp. (oC) RT RT RT RT RT
Tool temp. (oC) 80 80 80 80 80
Curing temp. (oC) >300 >300 >300 >300 >300
Cured density 7.47 7.45 7.6 7.43 7.5
Induction B @ 10 kA/m (T) 1.47 1.52 1.64 1.5 1.6
Permeability at 60 Hz 470 370 610 360 550
Resistivity, micro-ohm-meter >50 >1300 >500 >1300 >50
Coercive field strength (A/m) 300 270 246 280 245
Strength (MPa) 90 60 90 60 40
Core-loss @ 1T (watts/kg)
60 Hz 9 7.6 6.6 7.3 9
100 Hz 15 13 11.2 13.5 15
200 Hz 31 27 24 27 31
400 Hz 67 53 52 54 67
1000 Hz - 147 172 146 245
Anc
orLa
m 2
HR
AncorLam®
AncorLam® is a high performance insulated powder material suitable for a variety of soft magnetic applications. Specific applications include switching actuators and ignition coils, fuel injectors, and motor applications.
AncorLam® consists of high purity iron powder with a specialized coating/lubricant system that minimizes hysteresis and eddy current losses over a range of frequencies. This material is provided as a press-ready premix for warm or cold die compaction.
AncorLam is a lower cost option giving good balance between Core Loss and Induction.
Performance of AncorLam® at 7.45 g/cm3
Induction at 40 kA/m (T) 1.90Induction at 10 kA/m (T) 1.47Maximum permeability 470Coercive field strength (A/m) 300Core-loss at 400 Hz, 1T, W/kg 67Core-loss 1 kHz, 1T, W/kg —Green density (g/cm3) 7.47Cured strength (MPa) 90Resistivity micro-ohm-meter >50Apparent density (g/cm3) 2.85-3.10Hall flow (s/50 g) 32 max
HYSTERESIS LOOPAncorLam
-2.5
-2
-1.5
-1
-0.5
0
0.5
1
1.5
2
2.5
-5000 -4000 -3000 -2000 -1000 0 1000 2000 3000 4000 5000
Indu
ctio
n in
Tes
la
Applied Field in A/m
AncorLam® (continued)
CORE-LOSS VS. INDUCTION60 Hz, 100 Hz, 200 Hz, 400 Hz, 1k Hz, 5k Hz, 10 kHz
PERMEABILITY VS. INDUCTION, FREQUENCY60 Hz, 100 Hz, 200 Hz, 400 Hz, 1000 Hz, 5000 Hz
0
50
100
150
200
250
300
350
400
450
500
0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2
Cor
e-lo
ss in
Wat
ts/k
g
Induction in Tesla
0.001
0.01
0.1
1
10
100
1000
10000
0.001 0.01 0.1 1 10
60 Hz
10 kHz
Cor
e-lo
ss in
Wat
ts/k
g
Induction in Tesla
5000 Hz
60 Hz
10 kHz5 kHz1 kHz400 Hz200 Hz100 Hz60 Hz
AncorLam® HRAncorLam® HR has a constant permeability over a wide frequency range providing a lower cost option for high frequency applications.
AncorLam® HR consists of high purity iron powder with a specialized coating/lubricant system that minimizes hysteresis and eddy current losses over a range of frequencies. This material is provided as a press ready premix for warm or cold die compaction.
Performance of AncorLam® HR at 7.45 g/cm3
Induction at 40 kA/m (T) 1.90Induction at 10 kA/m (T) 1.52Maximum permeability 370Coercive field strength (A/m) 270Core-loss at 400 Hz, 1T, W/kg 53Core-loss 1 kHz, 1T, W/kg 147Green density (g/cm3) 7.45Cured strength (MPa) 60Resistivity micro-ohm-meter >1300Apparent density (g/cm3) 2.85-3.10Hall flow (s/50 g) 32 max
HYSTERESIS LOOPAncorLam HR
Indu
ctio
n in
Tes
la
-2.5
-2
-1.5
-1
-0.5
0
0.5
1
1.5
2
2.5
-5000 -4000 -3000 -2000 -1000 0 1000 2000 3000 4000 5000
Applied Field in A/m
AncorLam® HR (continued)
CORE-LOSS AT VARIOUS FREQUENCIES AND INDUCTION60 Hz, 100 Hz, 200 Hz, 400 Hz, 1000 Hz, 5000 Hz, 10000 Hz
PERMEABILITY AT VARIOUS FREQUENCIES60 Hz, 100 Hz, 200 Hz, 400 Hz, 1000 Hz, 5000 Hz, 10000 Hz
0
50
100
150
200
250
300
350
400
0 0.4 0.8 1.2 1.6 2
Perm
eabi
lity
Induction in Tesla
10000 Hz
60 Hz
0.0001
0.001
0.01
0.1
1
10
100
1000
10000
0.001 0.01 0.1 1 10
Cor
e-lo
ss in
Wat
ts/k
g
Induction in Tesla
10 kHz5 kHz1 kHz400 Hz200 Hz100 Hz60 Hz
AncorLam® 2HRAncorLam® 2 HR is bested suited for motor and actuator applications. Providing good induction and permeability for applications up to 1000 HZ.
AncorLam® 2 HR consists of high purity iron powder with a specialized coating/lubricant system that increase permeability while limiting losses. This material is provided as a press ready premix for warm or cold die compaction.
Performance of AncorLam® 2HR
Induction at 40 kA/m (T) 2.02*Induction at 10 kA/m (T) 1.64*Maximum permeability 610*Coercive field strength (A/m) 246*Core-loss at 400 Hz, 1T, W/kg 52*Core-loss 1 kHz, 1T, W/kg 172*Green density (g/cm3) 7.60*Cured strength (MPa) 90*Resistivity micro-ohm-meter >475*Apparent density (g/cm3) 2.85-3.10*Hall flow (s/50 g) 32 max** Density is 7.6 g.cm3
HYSTERESIS LOOPAncorLam 2HR*(7.6 DENSITY)
-2.5
-2
-1.5
-1
-0.5
0
0.5
1
1.5
2
2.5
-10000 -8000 -6000 -4000 -2000 0 2000 4000 6000 8000 10000
Indu
ctio
n in
Tes
la
Applied Field in A/m
AncorLam® 2HR (continued)
CORE-LOSS VS INDUCTION (7.6 DENSITY)60 Hz, 100 Hz, 200 Hz, 400 Hz, 1000 Hz, 5000 Hz, 10000 Hz
PERMEABILITY VS INDUCTION (7.6 DENSITY)60 Hz, 100 Hz, 400 Hz, 1000 Hz, 5000 Hz, 10000 Hz
0
100
200
300
400
500
600
700
0 0.5 1 1.5 2 2.5
60 Hz
10 kHz
Perm
eabi
lity
Induction in Tesla
0.0001
0.001
0.01
0.1
1
10
100
1000
10000
0.01 0.1 1 10
10 kHz5 kHz1 kHz400 Hz200 Hz100 Hz60 Hz
Cor
e-lo
ss in
Wat
ts/k
g
Induction in Tesla
AncorLam® 2FHRAncorLam® 2FHR is targeted and engineered for higher frequency applications up to 31 Khz.
AncorLam® 2FHR consists of high purity iron powder with a specialized coating/lubricant system that minimizes hysteresis and eddy current losses over a range of frequencies. This material is provided as a press ready premix for warm or cold die compaction.
Performance of Ancorlam® 2FHR at 7.45 g/cm3
Induction at 40 kA/m (T) 1.90Induction at 10 kA/m (T) 1.50Maximum permeability 360Coercive field strength (A/m) 300Core-loss at 400Hz, 1T, W/kg 54Core-loss 1kHz, 1T, W/kg 146Green density (g/cm3) 7.43Cured strength (MPa) 60Resistivity micro-ohm-meter >1300Apparent density (g/cm3) 2.85-3.10Hall flow (s/50 g) 32 max
HYSTERESIS LOOPAncorLam 2FHR
Indu
ctio
n in
Tes
la
Applied Field in A/m
-2.5
-2
-1.5
-1
-0.5
0
0.5
1
1.5
2
2.5
-5000 -4000 -3000 -2000 -1000 0 1000 2000 3000 4000 5000
AncorLam® 2FHR (continued)
CORE-LOSS AT VARIOUS FREQUENCIES60 Hz, 100 Hz, 200 Hz, 400 Hz, 1000 Hz, 5000 Hz, 10000 Hz
PERMEABILITY AT VARIOUS FREQUENCIES AND INDUCTION60 Hz, 100 Hz, 200 Hz, 400 Hz, 1000 Hz, 5000 Hz, 10000 Hz
Perm
eabi
lity
Induction in Tesla
0
50
100
150
200
250
300
350
400
0 0.4 0.8 1.2 1.6 2
10000 Hz
60 Hz
Cor
e-lo
ss in
Wat
ts/k
g
Induction in Tesla
0.001
0.01
0.1
1
10
100
1000
10000
0.001 0.01 0.1 1 10
10 kHz5 kHz1 kHz400 Hz200 Hz100 Hz60 Hz
AncorLam® 2AncorLam® 2 is a high performance insulated powder material suitable for a variety of soft magnetic applications that require high permeability. Used for applications up to 400 HZ.
Performance of AncorLam® 2 at 7.45 g/cm3
Induction at 40 kA/m (T) 1.95Induction at 10 kA/m (T) 1.60Maximum permeability 550Coercive field strength (A/m) 245Core-loss at 400 Hz, 1T, W/kg 67Core-loss 1 kHz, 1T, W/kg 245Green density (g/cm3) 7.49Cured strength (MPa) 40Resistivity micro-ohm-meter >50Apparent density (g/cm3) 2.85-3.10Hall flow (s/50 g) 32 max
DC HYSTERESIS LOOPAncorLam 2
Indu
ctio
n in
Tes
la
Applied Field in A/m
-2.5
-2
-1.5
-1
-0.5
0
0.5
1
1.5
2
2.5
-5000 -4000 -3000 -2000 -1000 0 1000 2000 3000 4000 5000
Applied Field in A/m
AncorLam® 2 (continued)
CORE-LOSS AT VARIOUS FREQUENCIES60 Hz, 100 Hz, 200 Hz, 400 Hz, 1000 Hz, 5000 Hz, 10000 Hz
AC PERMEABILITY60 Hz, 100 Hz, 200 Hz, 400 Hz, 1000 Hz, 5000 Hz, 10000 Hz
Perm
eabi
lity
Induction in Tesla
0
100
200
300
400
500
600
0 0.5 1 1.5 2 2.5
10000 Hz
60 Hz
Cor
e-lo
ss in
Wat
ts/k
g
Induction in Tesla
0.001
0.01
0.1
1
10
100
1000
10000
0.001 0.01 0.1 1 10
10 kHz5 kHz1 kHz400 Hz200 Hz100 Hz60 Hz
RELEVANCE OF MATERIAL CHARACTERISTICS ON END-USEPERFORMANCE FOR ELECTROMAGNETIC DEVICES
Permeability Influences the output power ofthe electrical device. Wrought lamination stacks represent two-dimensional values typically ranging between 1500 and 5000, whereas theisotropic IP grades approach ~500 permeability. Some conversions may necessitate higher inputcurrent to achieve similar flux density. However,3-dimensional flux paths provide greater designand performance flexibility. In addition, use ofhigh-energy permanent magnet materials cancompensate for the lower permeability of thesoft magnetic composite grades.
Induction Influences the ultimate torque capability of rotating machines. Lower valuescan be offset by increasing the backing section(material mass), while maintaining optimal component packaging associated with optimized end-winding and slot fill.
Strength In some instances, components mustwithstand rotational forces, stresses associatedwith press fitting or compression joining, andhave sufficient strength to accommodate thecopper winding process during assembly.Appropriate polymer types and process conditions permit adequate strength to supportapplication requirements.
AC Frequency Preferred applications involveoperating conditions of 200 Hz electrical frequency. This utilizes the benefits associatedwith the inherently low eddy current losses ofI.P. materials.
Core-Loss The two primary components ofcore-loss include eddy current and hysteresislosses. Greater core-loss values generallyincrease operating temperatures, which leads toadditional losses. Lower loss values translateinto greater electrical efficiencies. Losses can beminimized with proper particle coating, bindercombinations and stress relief.
Processing Conditions Various options existdepending upon the binder and/or lubricantcombinations. Warm compaction, with or without powder heating, or conventional compaction can be used for a variety of applications.
Base Iron Chemical composition and particlesize, along with component density, can bemanipulated to enhance specific magnetic performance characteristics.
Curing Temperature A secondary thermaltreatment enhances the binder strength andhelps minimize internal stress promoting recovery of the iron powder crystal structure.Temperature optimization is required to limitinternal stresses without destroying the bindercharacteristics.
MAGNETIC TERMINOLOGYInduction (B) is the magnetic flux per unit area,measured in Gauss. Sometimes referred to asflux density. This characteristic has a direct relationship with component density.Permeability (µ) essentially indicates the easewith which a material can be magnetized or itsmagnetic sensitivity – represents a ratio of fluxdensity to magnetizing force.Coercive Field Strength (Hc) is the demagnetizing force necessary to restore themagnetic induction to zero.Eddy Current Loss is the primary component of high frequency loss. Generally associatedwith electrical currents that create an opposingforce to the magnetic flux when exposed to ACfields. Higher resistivity values are beneficial inminimizing eddy current losses.Hysteresis Loss represents the primary loss factor at lower frequency, and is primarily attributed to magnetic friction in the core. Widerand taller B-H loop areas generally representgreater hysteresis loss for a given material.Intrinsic Saturation is the point at which all thedomains in the magnetic material become oriented in the same direction as the appliedfield energy.Magnetizing Force (H) is the applied energy toinduce magnetic flux, measured in Oersteds.Hysteresis Curve is the measurement technique representing the closed circuit of a magneticmaterial subjected to positive and negativemagnetizing forces – graphically represents the material’s magnetic characterization, i.e., saturation, residual induction and coercivefield strength.
Soft Magnetic components have the ability toboth store or strengthen magnetic energy andallow for easy conversion back into electricalenergy - often utilized to strengthen the magnetic flux of an electric device as a coreproduct. Hard Magnets represent greater coercivity levels and are difficult to demagnetize, typicallyreferred to as permanent magnets and represent a broad B-H curve band-width(>M.M.F.).Air Gap represents a low permeability gap (air space) in the flux path of a magnetic circuit,generally undesirable for energy transfer – however, can be beneficial to increase the ability to store energy in a core. Reluctance essentially represents magnetic circuit “resistance,” which is inversely proportional to permeability and directly proportional to magnetic circuit length. Ferrites are combinations of iron oxides withMn, Zn, Ni used when high permeability andlow eddy current losses are desirable, generallyexhibit low saturation induction – generally usedfor high frequency 10 KHz to 1 GHz applications.Laminations are low carbon steel or silicon-irongrades made in thin strips with insulation coating positioned between layered stacks,extensively used in low 60 Hz electric motorapplications because of low cost and designfamiliarity.Iron Powder Cores share some characteristicswith Insulated Powder grades. They are primarily used for energy storage, transformersand inductors in various consumer products.Q Factor is a means of determining the effectiveness of an iron core – represents a ratioof the increase in effective inductance to theincrease in the equivalent resistance of the magnetic circuit: Q = I / R (I= increase in testcoil inductance, R = core-losses).
Hysteresis curve representative of a soft magnet material
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