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Magnetics 2017 Orlando January 19th 2017

Permanent Magnets Produced by Cold Spray Additive Manufacturing

Funded by: Vehicle Propulsion Technologies PERD - Natural Resources Canada

Jean-Michel Lamarre & Fabrice Bernier Research Officers

Proposed Approach: Cold Spray Additive Manufacturing

Advantages vs powder pressing : • Very good control of the microstructure (process vs feedstock) • Ease to modify geometry • Reduce costly machining steps • No assembly

vs Current magnets are... 1) Complicated to install (glue, screws,

grooves) → expensive to install and low design flexibility

2) Brittle and difficult to machine → low design flexibility

Proposed Approach: Cold Spray Additive Manufacturing

Key features: • High deposition rate (several kg per hour is possible) • Complex patterns are possible • Thicknesses from microns to centimeters

M-NdFeB

M: metal • Increase deposition efficiency • Good thermal conductivity • Corrosion/oxidation protection

NdFeB: hard magnetic phase • Strongest magnets • Provide coercivity and

saturation

Objectives

• Reduce rare earth quantity • Improve heat management • Allow new motor topologies by

increasing fabrication geometrical flexibility

• Reduce part number • Reduce fabrication steps

• Automate fabrication • Protect magnets from the

environment

DOE Vehicle Technologies Program

Objectives

Producing a low cost M-NdFeB composite permanent magnet using cold spray

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Spray Parameters

Spray parameters: Plasma Giken 800 3 to 4.9 MPa 20 to 300 mm/s 400 to 800°C

Coating Adhesion/ cohesion: > 9000 psi Dense: negligible porosity. Thick: > millimeters deposited. Fv NdFeB: 30-65%

Magnetic powder: MQFP-B, 15 µm, irregular MQFP 14-12, 15 µm, irregular MQP-S-11-9, 25-75 µm, spherical Aluminum powder: Valimet 5 µm, 15 µm, spherical

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On the Improvement of Magnetic Loading

Fall 2013 Base powder and parameters

Winter 2017 Improved metallic binder granulometry and improved process parameters

Spring 2015 Improved process parameters

Fall 2015 Optimized magnetic powder granulometry and optimized magnet/binder ratio

Magnetic Characterization

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Powder type

Composition Size d50, μm

Morphology Br, mT Hc, kA/m

MQP-S-11-9

Nd-Pr-Fe-Co-TiZr-B

49.8 Spherical 745 710

MQFP-B Nd-Pr-Fe-B 10.2 Angular 880 752

MQFP-1412

Nd-Fe-Nb-B 10.7 Angular 817 961

H15 Aluminium 15 Spherical - -

Content of FeNdB: SEM image analysis to determine volume fraction of FeNdB in coating

Magnetic Characterization: Hysterisigraph Permagraph L from Magnet Physics Specimen: 10-25 mm diameter and 4 mm thickness, Provide: Br, Hc and BH

Effect of Powder Composition

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0

50

100

150

200

250

300

-1000 -800 -600 -400 -200 0

Ind

uct

ion

B, m

TDemagnetization field H, kA/m

75%MQFP B + 25%Al-H15

75%MQFP 14-12 + 25%Al-H15

920 952

715 709

0100200300400500600700800900

1000

75% MQFP 14-12 - 25% Al

MQP 14-12powder

75% MQFP B -25% Al

MQFP Bpowder

Hc

(kA/

m)

0.25 0.28 0.276 0.29

0

0.05

0.1

0.15

0.2

0.25

0.3

0.35

75% MQFP14-12 - 25% Al

MQP 14-12powder

75% MQFP B -25% Al

MQFP Bpowder

Br (

T)

* *

Coercivity

Remanence

* Normalized to coating volume fraction.

The process does not significantly degrade the magnetic properties!

• Coating remanence is 5 to 10 % lower than the calculated value.

• Coating coercivity is 3 to 5% lower than the reference value.

Effect of Magnetic Loading Mélange Carrier gas (°C) Hc (kA/m) Br (T) Brcoating/Brdata Fv*

90%MQFP 14-12 - 10%Al H15

400 917 0.337 39.8 43.1

600 898 0.364 43.0 47.3 75%MQFP 14-12 - 25%Al H15

600 930 0.257 30.3 33.1

MQP 14-12 - Data 952 0.847 * Measured by image analysis

0

0.05

0.1

0.15

0.2

0.25

0.3

0.35

0.4

-1000 -800 -600 -400 -200 0

J (T

)

H (kA/m)

90% MQFP 14-12 - 600°C

75% MQFP 14-12 - 600°C

Increasing the NdFeB content in the starting mixes from 75% to 90% 1) Increases volumetric fraction and hence

remanence by 40%. 2) Does not significantly decreases Hc (3%).

Effect of Temperature Mélange Carrier gas (°C) Hc (kA/m) Br (T) Brcoating/Brdata Fv*

75%MQFP 14-12 - 25%Al H15

400 + cooling 937 0.233 27.5 28.5 500 930 0.238 28.1 30.7

600 920 0.25 29.5 33.5 600 + cooling 924 0.255 30.1 32.9

600 + cooling and wait 924 0.253 29.9 32.9

MQP 14-12 - Data 952 0.847 * Measured by image analysis

Confidential

Increasing gas temperature from 400°C to 600°C 1) Increases volumetric fraction and hence remanence by

10%. 2) Does not significantly decreases Hc (2%). 3) Cooling of substrate and waiting period between passes

had no significant effect.

0

50

100

150

200

250

300

350

400

-1000 -800 -600 -400 -200 0

Ind

uct

ion

B, m

T

Demagnetization field H, kA/m

400°C+Cooling 500°C

600°C 600°C+Cooling

600°C+Cooling+Wait

Effect of Temperature

0

0.1

0.2

0.3

0.4

0.5

-800 -600 -400 -200 0

Indu

ctio

n B

, T

Demagnetization field H, kA/m

1608111, 90 MQFP, 10 H5, 600C

1609192, 90 MQFP, 10 H5, 800C

1609201, 90 MQFP, 10 H5, 700C

Increasing gas temperature from 600°C to 700°C Does not alter the magnetic content hence magnetic properties are unchanged.

Increasing gas temperature from 700°C to 800°C Does not alter the magnetic content but magnetic properties are slightly decreased.

Demagnetization Temperature

Coating: 90%MQFP-B - 10%Al H5

Powder datasheet

0

0.1

0.2

0.3

0.4

0.5

-800 -600 -400 -200 0

Indu

ctio

n B

, T

Demagnetization field H, kA/m

25°C 50°C

75°C 100°C

125°C 150°C

175°C 200°C

0 100 200 300 4000.20

0.22

0.24

0.26

0.28

Diff

usiv

ity (c

m2 /s

)

Temperature (oC)

Others Characterization Techniques

0

0.05

0.1

0.15

0.2

0.25

0.3

0.35

0.4

0.45

0.5

-800 -700 -600 -500 -400 -300 -200 -100 0

J (T

)

H (kA/m)

Original

300°C - 100h

500°C - 15 min

0

0.02

0.04

0.06

0.08

0.1

0.12

0.14

0.16

0.18

0.2

-900 -800 -700 -600 -500 -400 -300 -200 -100 0

J (T

)

H (kA/m)

Original

300°C - 100h

500°C - 15 min

Aging: Effect of aging treatment on magnetic performance for a) MQP-S-11-9 and b) MQFP-14-12 NdFeB powder.

Protective layer: SEM image showing a 2 layer-structure. Bottom layer is a composite NdFeB-Al while top layer is Al.

Laser flash diffusivity: 75% MQFP, 25% aluminium powder

Demonstrator Magnetization Testing

Validate magnetization and performance of an industrial component

Demonstrate machinability

Magnetization and measurement by Magnet-Physics

-100

-80

-60

-40

-20

0

20

40

60

80

100

0 50 100 150 200 250 300 350 400

B r

ad [

mT]

Rotational angle [°]

B radial - distance 1 mm from surface

Upper Line

Middle Line

Lower Line

-80

-60

-40

-20

0

20

40

60

80

0 50 100 150 200 250 300 350 400

B r

ad [

mT]

Rotational angle [°]

B radial - distance 3 mm from surface

Upper Line

Middle Line

Lower Line

Magnetic mapping for 90% NdFeB

magnet on steel

Magnetic mapping for 90% NdFeB

magnet on aluminium

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Outer Diameter

Key objectives: • Deposit thick and wide

magnet.

• Optimize spray parameters for fast deposition.

• Evaluate time and cost.

Outer diameter prototype with four strips design, diameter ≈ 17 cm

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Complex Inner Diameter

Key objective: • Use complex robot programming

to achieve complex design on inner diameter.

• Develop ability to spray at an angle with high deposition efficiency

• Adapt the spray geometry (gun size, spray distance and angle) to an inner diameter

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Vertical Walls

Key objectives: • Optimize robot programming and

process parameters to achieve vertical walls.

Cross-section optimization

Conclusions

• High density coating with high NdFeB content. Magnetic properties follow mixture law.

• High deposition efficiency. • Increase heat diffusivity.

• Interface adhesion exceeding industrial standard (> 65 MPa).

• Environmental sealing via appropriate top-coat use.

• Improved high temperature resistance.

250°C – 10h

Conclusions

1) Assembled rare earth permanent magnets were fabricated by cold spray 2) Complex shape rotor can be readily fabricated without assembly

Technology Development 2017-2020

Next steps • Integrate coating permanent

magnet technology to actual motor design.

• Explore design possibilities offered by the added manufacturing flexibility.

Project Team

Automotive and Surface Transportation Portfolio - Thermal Spray and Powder Forming groups. • Jean-Michel Lamarre, Project leader. • Fabrice Bernier, Task leader characterization. • Thermal spray: J.-F. Alarie, F. Belval, J. Sykes, J.-C.

Tremblay. • Characterization: S. Mercier, D. de Lagrave, D. Simard,

K. Théberge. • Robot toolpath programming: M. Martin.

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Questions?

Acknowledgment

The authors gratefully acknowledge financial support for this

project from Natural Resources Canada through its Energy

Research and Development Program and the National

Research Council through its Vehicle Propulsion

Technologies Program

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Thank you Jean-Michel Lamarre Research Officer Tel: 450-641-5386 jean-michel.lamarre@nrc-cnrc.gc.ca www.nrc-cnrc.gc.ca

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