February 20, 2018

Toyota Motor Corporation

Development of “Nd-reduced heat-resistant magnet”

ー 20-50% reduction of neodymium ー

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１．Research background:

Demand forecast of vehicle electrification and neodymium

２．Roles and characteristics of magnets in electric motors

３．Development of “Nd-reduced heat-resistant magnet”

1) Grain refinement of magnet

2) Two-layered high-performance grain surface

3) Specific alloying ratio of La (lanthanum) and Ce (cerium)

4. Future efforts

Conventional engine vehicle

1990 20502010 204020202000 2030

By 2020EV launched

2050 Zero CO2Challenge

1997 1st Priuslaunched

2014 FCV

2030Electrified vehicles⇒More than 5.5 million soldEV/FCV⇒more than 1 million sold

By 2025EV grade set in all models

PHV

HV

FCVEV

Milestones of Toyota vehicle electrification plan

As electrified vehicles become common globally, supply and demand of electric motors increase substantially

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Demand forecast of neodymium (Nd)

Even the most optimistic forecasts anticipate supply shortages of neodymium from 2025

Nd composes the majority of rare-earth elements used in magnets for electric motors in electrified vehicles

PHV

HV

EV

Reference：“Increasing Importance of Securing REEs due to Expansion of Electric Vehicle Market” JOGMEC, 2017*Estimate from vehicle sales forecast and assumed magnet volume per vehicle

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Production of electric motors needed for electrified vehicles will peak and costs are feared to rise

⇒ Nd-reduction technology needs to be developed

Research background of Nd-reduced heat-resistant magnet

Increase inelectr i f ied

vehic le uni tsNd supply shortage

Increase indemand for

e lectr ic motors

If we use neodymium (Nd) without developing Nd-reduction technology

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１．Research background:

Demand forecast of vehicle electrification and neodymium

２．Roles and characteristics of magnets in electric motors

３．Development of “Nd-reduced heat-resistant magnet”

1) Grain refinement of magnet

2) Two-layered high-performance grain surface

3) Specific alloying ratio of La (lanthanum) and Ce (cerium)

4. Future efforts

Role of magnets in electric motors

Rare-earth metals are essential for high performance magnets

- The motor generates rotational force through magnetic power (attraction and repulsion)

- When the motor turns slowly (e.g., when starting a car), a powerful magnet is necessary to efficiently produce high torque

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electrosteel

magnet

周期＼族 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 181 1 H 2 He

水素 ヘリウム

Hydrogen Helium

2 3 Li 4 Be 5 B 6 C 7 N 8 O 9 F 10 Neリチウム ベリリウム ホウ素 炭素 窒素 酸素 フッ素 ネオン

Lithium Beryllium Boron Carbon Nitrogen Oxygen Fluorine Neon

3 11 Na 12 Mg 13 Al 14 Si 15 P 16 S 17 Cl 18 Arナトリウム マグネシウム アルミニウム 珪素 リン 硫黄 塩素 アルゴン

Sodium Magnesium Aluminum Silicon Phosphorus Sulfur Chlorine Argon

4 19 K 20 Ca 21 Sc 22 Ti 23 V 24 Cr 25 Mn 26 Fe 27 Co 28 Ni 29 Cu 30 Zn 31 Ga 32 Ge 33 As 34 Se 35 Br 36 Krカリウム カルシウム スカンジウム チタン バナジウム クロム マンガン 鉄 コバルト ニッケル 銅 亜鉛 ガリウム ゲルマニウム 砒(ヒ)素 セレン 臭素 クリプトン

Potassium Calcium Scandium Titanium Vanadium Chromium Manganese Iron Cobalt Nickel Copper Zinc Gallium Germanium Arsenic Selenium Bromine Krypton

5 37 Rb 38 Sr 39 Y 40 Zr 41 Nb 42 Mo 43 Tc 44 Ru 45 Rh 46 Pd 47 Ag 48 Cd 49 In 50 Sn 51 Sb 52 Te 53 I 54 Xeルビジウム ストロンチウム イットリウム ジルコニウム ニオブ モリブデン テクネチウム ルテニウム ロジウム パラジウム 銀 カドミウム インジウム 錫(スズ) アンチモン テルル ヨウ素 キセノン

Rubidium Strontium Yttrium Zirconium Niobium Molybdenum Technetium Ruthenium Rhodium Palladium Silver Cadmium Indium Tin Antimony Tellurium Iodine Xenon

6 55 Cs 56 Baランタノイド

72 Hf 73 Ta 74 W 75 Re 76 Os 77 Ir 78 Pt 79 Au 80 Hg 81 Tl 82 Pb 83 Bi 84 Po 85 At 86 Rnセシウム バリウム ハフニウム タンタル タングステン レニウム オスミウム イリジウム 白金(プラチナ) 金 水銀 タリウム 鉛 ビスマス ポロニウム アスタチン ラドン

Cesium Barium Hafnium Tantalum Tungsten Rhenium Osmium Iridium Platinum Gold Mercury Thallium Lead Bismuth Polonium Astatine Radon

7 87 Fr 88 Raアクチノイド

104 Rf 105 Db 106 Sg 107 Bh 108 Hs 109 Mt 110 Ds 111 Rg 112 Cn 113 Nh 114 Fl 115 Mc 116 Lv 117 Ts 118 Ogフランシウム ラジウム ラザホージ

ウム ドブニウム シーボーギウム ボーリウム ハッシウム マイトネリ

ウムダームスタ

チウムレントゲニ

ウムコペルニシ

ウム ニホニウム フレロビウム モスコビウム リバモリウム テネシン オガネソン

Francium Radium Rutherfordium Dubnium Seaborgium Bohrium Hassium Meitnerium Darmstadtium Roentgenium Copernicium Nihonium Flerovium Moscovium Livermorium Tennessine Oganesson

ランタノイド57 La 58 Ce 59 Pr 60 Nd 61 Pm 62 Sm 63 Eu 64 Gd 65 Tb 66 Dy 67 Ho 68 Er 69 Tm 70 Yb 71 Lu

ランタン セリウム プラセオジム ネオジム プロメチウム サマリウム ユウロピウム ガドリニウム テルビウム ジスプロシウム ホルミウム エルビウム ツリウム イッテルビウム ルテチウム

Lanthanum Cerium Praseodymium Neodymium Promethium Samarium Europium Gadolinium Terbium Dysprosium Holmium Erbium Thulium Ytterbium Lutetium

アクチノイド89 Ac 90 Th 91 Pa 92 U 93 Np 94 Pu 95 Am 96 Cm 97 Bk 98 Cf 99 Es 100 Fm 101 Md 102 No 103 Lr

アクチニウム トリウム プロトアクチニウム ウラン ネプツニウム プルトニウム アメリシウム キュリウム バークリウム カリホルニウム アインスタイ

ニウム フェルミウム メンデレビウム ノーベリウム ローレンシ

ウム

Actinium Thorium Protactinium Uranium Neptunium Plutonium Americium Curium Berkelium Californium Einsteinium Fermium Mendelevium Nobelium Lawrencium

What are rare-earth elements (REE)?

lanthanum (La 57) and cerium (Ce 58)＝light-rare earth element (LREE)

neodymium (Nd 60)

Neodymium (Nd) is essential for production of high performance magnetsLanthanum (La) and cerium (Ce) are abundant and inexpensive

Group name of 17 elements, scandium (Sc 21), yttrium (Y 39), lanthanide (elements 57-71)

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57 La 58 Ce 59 Pr 60 Nd 61 Pm62 Sm 63 Eu 64 Gd 65 Tb 66 Dy 67 Ho 68 Er 69 Tm 70 Yb 71 Luランタン セリウム プラセオジム ネオジム プロメチウム サマリウム ユウロピウム ガドリニウム テルビウム ジスプロシウム ホルミウム エルビウム ツリウム イッテルビウム ルテチウム

Lanthanum Cerium Praseodymium Neodymium Promethium Samarium Europium Gadolinium Terbium Dysprosium Holmium Erbium Thulium Ytterbium Lutetium

terbium (Tb 65) and dysprosium (Dy 66)＝heavy rare-earth element (HREE)Application for high-temperature usage of magnets (critical materials)

What are critical materials?Defined as metals that are difficult to extract for technological and economic reasons or are found only in small amounts in the earth’s crust, but of which stable supply is politically important.

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*Definition of METI

Elemental Number

Inde

x of

abu

ndan

ce in

the

Eart

h’s

crus

t

Rare-earth elements

Abundance in the Earth’s crust

Critical materials

Ref: USGS Fact Sheet 087-02(2002)

Rare-earth element ratio of typical ore

・20% of rare-earth elements in magnets is categorized as critical materials・La and Ce are abundant in supply

Ce

LaNdPr

Tb/Dy

For magnets

Rare-earth element usage in heat-resistant magnets

Reduction of Dy usage has been achieved. From now, it is critical to reduce the usage of Nd, which is the main rare-earth element used in magnets.

Approximately 30％ of the elements in magnets are rare-earth

2nd and 3rd

generation Prius

4th generation Prius

Aimed direction of magnet development

in the future

0% 10% 50% 60% 70% 80% 90% 100%

Reduction of Nd:Boron

:Iron

Rare-earth elements

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:Tb/Dy

:Nd

:La/Ce

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１．Research background:

Demand forecast of vehicle electrification and neodymium

２．Roles and characteristics of magnets in electric motors

３．Development of “Nd-reduced heat-resistant magnet”

1) Grain refinement of magnet

2) Two-layered high-performance grain surface

3) Specific alloying ratio of La (lanthanum) and Ce (cerium)

4. Future efforts

Conventional neodymium magnet- The amount of rare-earth elements, including Nd, is

30% of the magnet- The size of the grains of the magnet is about 5 μm- In order to increase the heat resistance of the magnet and to

use the motor at high temperatures, Dy needs to be added

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5μm

5μm

Micro structure of conventional Nd magnet（Schematic image）

5μmN

S

NN

S

（Scanning electron microscope image）

S

Why are we developing a ”Nd-reduced heat-resistant magnet?”Nd usage reduction through substitution of Nd to abundant and inexpensive La and Ce (LREE)⇒ Anticipated effect of addressing Nd supply concern and allowing for cost

reductionOn the other hand, the problem is deterioration in performance

Ce/La: $5-7

Nd/Pr: $100

・Dy: $400・Tb: $900

Simple alloying of LREE deteriorates performance⇒To maintain high performance, further development is

required

（Oct. 2017 market price: per kg）

Performance of magnet

Conventional magnet

Nd-reduced magnet

Simple alloying deteriorates performance

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Development of “Nd-reduced heat-resistant magnet”１．Grain refinement in magnet２．Two-layered high-performance grain surface３．Specific alloying ratio of La (lanthanum) and Ce (cerium)

Magnet performance Heat-resistant magnet

with reduced Nd

Developed Nd-reduced magnet

Conventional Nd Magnet

Conventional Nd magnet

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Reduced Ndwithout optimization

Simple Alloying of La and Ce

Simple alloying LREE causeperformance deterioration

High performance exhibitby developed technology

Improved magnetization and coercivity through refinement of each grain of the magnet and enlarging the boundary area

Conventional Nd magnet (SEM image)

Development point 1: Grain refinement of magnet 15

5μm 0.25μm

0.25μm

Grain refined to 1/10th the size of a conventional magnet grain, enlarging the grain boundary area

- Magnets consist of numerous fine grains. Smaller grains have a larger boundary area for coercivity enhancement- As the motor load increases, the temperature of the magnet rises, and the magnetic force of magnet decreases

5μm

5μm

Grain-refined developed Nd-reduced magnet (SEM image)

Grain size⇒1/10th of the original size↓

Boundary area ⇒ 10 times larger

(Schematic figure) (Schematic figure)

(Patent filed in 2010）

Development point 2: Two-layered high-performance grain surface 16

Through the two-layered structure, both the reduction of Nd usage and maintenance of high performance are possible (Patent filed in 2013）

Two-layered structure by thickening of Nd at grain surface with surface-modification heat treatment- Simple substitution of Nd to LREE causes deterioration of properties (magnetization and coercivity)- Retention of magnetic force through the creation of a layer with a high density of Nd on the surface of the grain- Maintaining coercivity by thinning (reducing the amount of) the Nd inside the grain and mixing alternative LREE

Diluted Nd in the grain core

Concentrated Nd on the surface

Homogeneous distribution of Nd

Conventional magnet Two-layered structure magnet

Alloying La and Ce at the special ratio suppresses performance deterioration even with reduced Nd

Development point 3: Specific alloying ratio of La and Ce

Simple alloying of LREE deteriorates performance

Alloying La and Ce with special ratio enhances relative magnetization

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Special ratio of La:Ce=1:3

Alloying specific ratio of La and Ce suppresses performance deterioration- Usage of La and Ce, which are abundant and inexpensive- Simply alloying La and Ce reduces performance (heat resistance and magnetization)

Surface modified grain with simple LREE alloying Alloying specific La and Ce ratio at the grain core

(Patent filed in 2017）

0.25μm

Microscope images of the newly developed “Nd-reduced heat-resistant magnet”

Combining the three development points, we achieve nano-structural control⇒ The world’s first* realization of Nd-reduced heat-resistant magnet

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Nd concentrated at the grain surface

Special ratio of La and Ce in the grain core

Composition analysis mapping imageElectron microscope image

*January/ 2018 present, researched by Toyota

100 150 200Temperature（℃）

Coercivity

0 50 100 150 200Temperature （℃）

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Coercivity

Performance of the newly developed “Nd-reduced heat-resistant magnet

High coercivity at high temperatures is necessary for motor usage

Maintain high performance even with reduced Nd⇒ Can designate Nd reduction amount between 20-50％

Conventional Nd magnet (with Dy 4%)

Nd-reduced magnet（Nd -20％）

Nd-reduced magnet (simple, unoptimized LREE alloy ratio)

Nd-50％

Ability to designate performance by Nd amount

Note: This work was conducted as part of “Development of magnetic material technology for high efficiency motors” program commissioned by the New Energy and Industrial Technology Development Organization (NEDO)

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１．Research background:

Demand forecast of vehicle electrification and neodymium

２．Roles and characteristics of magnets in electric motors

３．Development of “Nd-reduced heat-resistant magnet”

1) Grain refinement of magnet

2) Two-layered high-performance grain surface

3) Specific alloying ratio of La (lanthanum) and Ce (cerium)

4. Future efforts

Future efforts• Continue further development to increase magnet

performance• Consider not only vehicle application (driving motors and

EPS, etc.) but also for many other applications, such as robot servo motors

• Continue efforts toward commercialization– Development of technology for the commercialization of motors

using the newly developed magnets– Development of mass production technology

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The new technology utilizing abundant and inexpensive LREE is important for supporting future popularization of electrified vehicles and robotics⇒ Promotion of technology development at an early stage

with the aim of practical application