DAI HOC QUOC
GIA
HA
NOI
TRl/CfNG
DAI HOC KHOA HOC
Tl/NHIEN
NGHIEN
CtJtJ
CHE TAO NAM CHAM DAT
HIEM
NdFeB
Sir
DUNG
BOT
VAT
LIEU
CHE
TAO BANG
PHUONG
PHAP HAP THU HYDRO
MA SO:
QT-06-15
CHU TRIDE
TAX:
PCS. TS.
LUtJ TUAN TAI
CAC CAN Bp TRAM GIA : TS.
LlTU HOAI
NAM
ThS.

4-
Chu
tri
de tai: PGS. TS.
Lim
Tua'n Tai
Phong
thi
nghiem vat
ly
nhiet do thap, trudng DHKH Tu nhien ,
Dai hoc qudc gia Ha Noi
5- Can bo tham gia de tai:
PGS.
TS. Luu
Tua'n
Tai
ThS.NCS. Ta Van Khoa
ThS.Pham thi
Thuong
TS.
Luu hoai Nam
Va cac cong tac vien khac
6- Muc tieu va noi dung nghien curu:
- Che tao he
ha'p
thu hydro don gian de ap dung cdng nghe HDDR
- Nghien
ciiu ,tim
ra cdng nghe HDDR thfch hop.

HDDR khdng di hudng va di
hudng.
- Mot quy
trinh
nhiet vdi nhiet do cao
han
va thdi gian dai hon da dugc
lira
chon
thich
hgp cho cac vat lieu cd pha tap mot lugng nhd Zr
(0.1%
Zr).
Ket qua la da
che'
tao dugc nam cham ket dmh tren ca sd bdt hgp kim
NdigFeys.gZroiBs
di hudng che tao bang phuong phap HDDR dat
tich
nang lugng
cue
dai
(BH)^,,
= 9.95 MGOe.
8-
Tinh
hinh kinh phi cua de
tai:
*T6ng
kinh phi dugc cap: 15 trieu dong Viet nam

Staff:
Dr. Luu hoai Nam
MA. Phs. Ta Van Khoa
MA. Phs. Pham thi Thuong
And some others
V. Aims and contents of the project:
- To investigate the influence of temperature and time of HDDR technology
condiSon
o^
the hard magnetic properties of the NdFeB bonded magnets m order to
find the good condition to produce NdFeB bonded magnets.
To investigate and fabricate the NdFeB bonded magnets use HDDR powder
VI.
Summary of Achievements of project:
- To set up the HDDR equipment
- To investigate the influence of temperature and
time
of HDDR technology
condition and addition effect of small amount of Zr
on
the hard magnetic
properties of the NdFeB bonded magnets
in
order to
find
the good condition to
produce NdFeB bonded magnets.
^ e
tu^
-

He mau hgp kim Nd,6Fe76.xZrxB8vaix =
0.1,0.2,0.3
va
0.5 22
IV.KETLUAN
28
V. TAI LIEU THAM KHAO
29
NOI DUNG BAO CAO
TONG
KET
I.
MCf
DAU
Viec che tao cac NCVC dua tren ca so cac hgp kim chua dat hiem
vao nhiing nam 70 da ma
dku
cho mot cuoc
each
mang mai trong
ITnh
vuc
dien va dien tu. Dac biet la loai nam cham
SmCos
va (SmPr)Co5 c6 ten tren
>
y
f
thi trudng la Recoma vdi day du cac dac tinh can thiet cua NCVC va nang
lugng tu dat dugc la

cuu tren the gidi. Cudi nam 1983, Sagawa va cac cdng su da thanh cdng
trong viec
chl
tao mot loai NCVC mdi tren co sd cua hgp kim Nd-Fe-B
bang
phuong phap bdt thieu ket vdi nang lugng tu cue dai dat
(BH)max
= 36
MGOe,
lire
khang tu theo cam ung tu
BHC
^
11
KOe,
lire
khang tu theo tu
do
MHC
=
12 KOe,
B,
=
12.3 KG (1.23 Tesla). Pha hgp kim chinh cua loai
7
vat lieu nay la hgp kim
Nd2Fei4B.
Vat lieu nay d nhiet do phdng cd mdmen
tu bao hda cao
Ms =

nang lugng tinh cho cac loai bdt nay vao
khoang 12 MGOe va trong dang nam cham ket dinh tich nang lugng
cue
dai
dat dugc chi vao khoang 10 MGOe. Cac dang nam cham
kk
dinh tao ra tu
bdt nam cham ngudi nhanh cd rat nhieu va tinh chat tu
cflng
nhu nang lugng
tu cua chung cung trai ra trong mot khoang nao dd, tuy nhien cd
th§
tdng
k^t
chung d ba loai khac nhau sau: cac nam cham
k§t
dinh tao ra
bSng
phuong
phap ep khudn, cac nam cham ket dinh tao ra bang phuong phap ep dun va
cac nam cham deo.
Cac bdt nam cham NdFeB che tao bang phuong phap ngudi nhanh
f
y
dung trdng ddng quay ma ta thuong goi la
MQI
d tren, sau khi ep ndng ta se
thu dugc mot loai san pham quen goi la
MQII,
sau dd ap dung cdng nghe ep

che do ddng nhat chat lugng san pham; mac du loai vat lieu nay da xuat hien
va chiem mot ty
le
nhd trong cac san pham nam cham ket dinh ndi chung.
Mot trong nhung nguyen nhan lam cho
ITnh
vuc nam cham ket dinh
phat trien manh me la do
sir
phat trien
ciia
cac loai bdt nam cham nhu: bdt
nam cham
Sm2Fei7Nx,
cac
bdt^nam
cham NdFeB che tao bang quy trinh
cdng nghe HDDR, cac bdt nam cham dang hudng loai
HIREM,
cac bdt nam
f
y
f
cham che tao bang phuong phap bien dang ndng
Phu-cng
phap tach va tai hgp trong hydro HDDR (Hydrogenation
Dispropotionation Desorption and Recombination)
Hieu ung tach pha trong khi hydro da dugc khao sat ti mi vdi
nhiJng
dieu kien cu the khac nhau nhu trong dieu kien ap suat khi hydro la 30 bar

Nagayama md ta qua trinh su dung xu ly nhiet trong hydro de che tao bdt
nam cham NdFeB vdi tich nang lugng
cue
dai cua vat lieu bdt la 95
KJ/m^
f f
If
(12 MGOe). Ho da dung bdt nay trdn vdi chat ket dinh de che tao nam cham
ket dinh NdFeB cd tich nang lugng la 8 MGOe va luc khang tu la
iHc
= 10
KOe.
Sir
phat trien mdi nay cd the canh tranh
true
tiep vdi ban quyen ve
nam cham
lanh
nhanh de san xuat cac nam cham ket dinh. Cflng can phai
luu y rang, cac bdt NdFeB tao ra
true
tiep tu hgp kim khdi NdFeB bang
phuong phap nghien thdng thuong hoac bang phuong phap tach vo trong
t •% f f
hydro (HD) cd the dung de che tao cac nam cham thieu ket nhung khdng du
y
f f f
do
Idn
ve

thiic
qua trinh nay, vat lieu dugc kiem tra bang kinh hien
VI
truyen qua TEM, cho thay vat lieu bao gdm cac hat tinh the rat nhd chi cd
0.3fim
cua hgp kim NdFeB, kich thudc nay cd the so sanh dugc vdi kich
thudc
ciia
don ddmen
ciia
pha sat tir NdFeB va giai thich dugc tai sao luc
khang tir
iHc
cdn
giu*
nguyen dugc do
Idn
trong cac hat.
Trong thdi gian dau nhiing nam
1990,
McGuiness
ciing
cac cdng
sir
da giai thich qua trinh hinh thanh cac hat rat min cd
c§u true
tinh
thi
NdFeB
trong hai cdng

dai
cuang ciia
quy trinh HDDR
Quy trinh HDDR tdng quat dugc dua ra trong hinh 1, nd chi
h\hu
dd
f "*,
dai cuong
ciia
cau true vi md sau mdi cdng doan cua quy trinh HDDR.
11
6
qua trinh
dhu
(hydrogenation) hydro tham nhap vao
viing
bien hat
(noi cd thanh
ph4n
pha giau Nd) cua
Nd2Fei4B
tao ra
NdH2.7.
Do cd su khac
nhau ve thdng sd mang
giiia
kim loai, hgp kim va hydrid cua chung, nen khi
cac nguyen tir hydro tham nhap vao cau true da lam gian mang
khien^mau
bi

••••• •• •
•«•
»
•
•
•
-50 0 200
250
50 100 150
thdi gian (phut)
Hinh 2,
Duang
cong ddng nhiet cua dien
traphu
thudc vao thai gian
cua quy trinh HDDR
tach vd thanh cac thanh phan be nhd.
Trong giai doan thu hai (Disproportionation), nguyen tu hydro tiep tuc
hap thu vao pha
NdaFe^B
trong cac hat lam cho cac hat nay phan ra thanh:
neodym hydrid, Fe va
Fe2B.
Do dd giai doan phan ra nay cd the dugc md ta
dudi dang phan ung nhu sau:
6
750°C:
NdzFeuB
+
(2±x)H2 02NdH2±x +12Fe

hudng tdi qua trinh
HDDDR
dd la ap
suk
khi hydro trong budng phan img,
Oliver Gutfleisch
ciing
cdng su da nghien cuu anh hudng nay thdng qua su
thay ddi dien trd mau trong qua trinh HDDR tai cac gia tri khac nhau
ciia
ap
suat khi hydro.
Sir
giam dien trd
chii ylu
la do su hinh thanh Fe, Neodymhydrid. Gia
tri dien trd dat trang thai can
bSng
sau qua trinh phan ra phu thudc vao ap
f ^
suat khi hydro
ciia
he. Tai ap suat cao hon, qua trinh phan ra xay ra nhanh
Id
han
Q,
00
jz
CL
o

Hinh 3. Do thi bieu thi phan
ung
phan
ra
phu thuoc vao thai gian.
f
>
hon, khien cho trang thai can bang dien tra dat dugc nhanh hon, nhu
duong
f
cong cham
tron
tren hinh 2 (tuong ung vai P = 0.7 bar) so vai duong cong
13
ch4m
sao (tuong ung vdi P = 0.2 bar). Gia tri dien trd tang khi Nd phan ung
ket hgp vdi Fe va
Fe2B
tao thanh
Nd2Fei4B.
Tir hinh 2 ta
thSy,
toe do phan
ung nay khdng phu thudc vao ap suat hydro ban dau.
m
Hinh 3 cho biet ty le
ciia
phan ung phan ra phu thudc vao
thoi gian
o

bang
phuong phap nguyen tu hda trong khi tro tai hang Rhone Poulenc d
New Jersey, USA. Nguyen tu hda trong khi tro la mdt phuong phap don
gian, cung dugc su dung de che tao cac bdt kim loai, hgp kim khac (vi du
•J ^
nhu cac thep, nhdm ) da dugc su dung de tao ra cac hat NdFeB dang cau
cd dudng kinh nhd hon
200|am.
Hgp kim NdFeB dugc nau chay rdi dap nhd
dua vao mot cai
dTa
cd mot vdi phun vdi dudng kinh vai milimet dat tai day
dTa quay. Vat lieu dugc nau chay va phun ra do ap suat nen cao bang khi Ar
dl
nhan dugc cac giot hgp kim sau khi hda ran roi xudng day cua thiet
bj
la
noi tap hgp de thu lai cac hat vat lieu. Cac hat vat lieu tao ra bang phuong
\
f
phap nay cd luc khang tir
[He -
287.7 KA/m
{-
3 KOe) va sau khi ddng nhat
tai
500°C
-
900°C
trong mot gid thi

chi
tao nam cham thieu kk tu bot
nay thi hau nhu khdng trd thanh nam cham do
sir Idn
len rat nhanh
ciia
cac
hat sieu nhd.
DI
nang cao chat lugng bdt vat lieu,
chn
phai lam
th^
nao
dk
bdt tao ra bang phuong phap nay trd thanh bdt di hudng.
Tai hoi nghi quoc te
\kn thii 11
(nam 1990), Takeshita va Nagayama
f
^
cdng bd hg da tao dugc bdt di hudng
ciia
hgp kim
Ndi2.6Fe7oCon 4B6
bang
hieu ung pha tap. Ho da thu nghiem tren mot
loat
cac nguyen td pha tap la:
Al,

qua trinh HDDR. Vat lieu tdt nhat de che tao nam cham ket dinh di
hudng chua 0.1% Zr vdi
lire
khang tir noi tai
iHc ^
700 KA/m
(-
9 KOe) va
(BH)max =
150
KJ/m^
( 13
MGOe). Ho gia
thiSt
r^ng
di hudng cua bdt vat
lieu la do ddng gdp uu tien dinh hudng cua cac hat NdFeB sau qua trinh tai
hgp cd kich thudc cd nhd hon micromet va
mire
do di hudng cua nam cham
f f
^
ket dinh phu thudc vao cau
triic
cua hgp kim due ban dau, phu thudc vao
kich thudc cua cac hat bdt, tir dd cac hat bdt tai hgp hinh nhu se
djnh
hudng
trong
viing

[He
= 744 KA/m (9.3 KOe) va tich nang lugng
cue
dai
(BH)^ax
= 98
Kj/m^
(~
12MG0e).
Phuong phap HDDR con dugc dung de
chi
tao cac nam cham
due
NdFeB vai gia tri
luc
khang tu cao.
Zhang cung cac cong
sir
(1991) da ap dung quy trinh HDDR trong
dieu kien khdng xay ra qua trinh tach vd (HD) cho cac mang mdng cua hgp
kim
Nd2.iFei4B
cd do day cd
4-^5mm.
Hieu ung tach vd khdng xay ra khi
>
t
f
hgp phan xung quanh hgp thuc 2:14:1 tai nhiet do phdng, tuy nhien de chac
f f

dai
Idn
hon 5MG0e
16
III.CAC KET QUA
C
HINH CUA DE TAI
Nhu da ndi trong
pfian
trudc,
viec nghien ciru chi tiet cac qua trinh vat
ly va tinh the xay ra
tronu
cong nghe HDDR da dugc thuc hien d nhieu noi
tren the gidi va cho cac
kci
qua kha tudng minh. Chinh vi vay d day chiing
tdi chi tap
truiig
vao
kliao sal
cac dieu kien va cac thdng sd cdng nghe nham
tim dugc quy trinh
cdny riyhe
thich hgp tuong irng vdi he thdng thiet bi hien
cd, cho phep che tao
duxic
cac nam cham ket dinh cd nang lugng cao, phan
ly giai chi
dii'ng

=
0, 0.1, 0.2, 0.3, 0.5 dugc
che tao bang phuong phap ndng chay hd quang, trong mdi trudng khi Ar tir
cac nguyen lieu ban
d4u
cd do sach tdi
thilu
la 99,9%. Hgp kim sau khi
n4u
cd mau xam sang, be ngang mau thay rd
c4u
true textua theo hudng vudng
gdc vdi day ndi. Kiem tra cau tnic ddmen
ciia
cac mat cat dgc theo phuong
textua (a) va vudng gdc vdi phuong textua (b)
bSng
chk
Idng
tir (ferrofluid)
f f
,
cho ta thay (hinh 1) d hinh (a) cau tnic ddmen tir cd dang dieu xi ga cdn d
hinh (b) cd dang cac bgt tir, cho thay ddmen tir ciing xap xep theo phuong
textua. Nhu vay cac hat tinh the dugc djnh hudng tuong ddi ddng nhk theo
mot phuong tinh the.
\
f f
it^
Sau khi dap nhd bang cdi sat, cac mau hgp kim cd kich thudc khoang

thay ddi theo mot chuong trinh nhiet xac djnh
tiiy
theo timg me mau.
3.1.
He mau hgp kim
Ndi6Fe76B8
He mau
NdieFcyeBg
da dugc xu ly nhiet theo cac quy trinh nhiet khac
nhau va dugc ky hieu tuong ung
la^Mla,
Mlb
va
Mlc.
Vdi he mau cd ky hieu
Mia,
quy trinh sir ly nhiet dugc thuc hien nhu
>
->
> >
tren so dd hinh
15.
O qua trinh
dau.
Id
boat ddng nang nhiet do budng phan
ung tir nhiet do phdng
Troom len
tdi
lOO'^C

rdi
dk
nhiet do tang theo id
nung len tdi
700°C;
nhiet do tiep tuc dugc tang len tdi
800°C
vdi tdc do tang
nhiet la
8°C/phut
va
giiJ
budng phan img tai nhiet do nay trong vdng 2.5 gid.
Sau qua trinh giir nhiet, budng phan img dugc giam nhiet do xudng
200°C
f f
\
tuong ling vdi tdc do
200°C/phiit
va cudi ciing budng phan ung dugc giam
r
f f
xudng den nhiet do phdng
Troom
vdi tdc do giam nhiet la
26°C/phut.
Quy trinh nhiet
ciia
mau Mlb, budng phan img dugc tang nhiet do tir
nhiet do phdng

lOOjim bang
may ray. Bdt vat lieu
HDDR dugc trdn vdi epoxy
r^n
vdi ty le 2% trgng lugng, roi dugc ep trong
' T(^C)
100=C
200=0^^
700X
^ *
800"'C
Giur
trong
2.5 gid
Ngupi
theo to
6^C/phut
20X/phiJt
Theo
16
8^C/phut
t
Hinh 3. Quy trinh nhiet cua mdu
Mlb.
r
f
'y
f
khudn thep
((t)12

5.7930
5.5367
5.7355
Br
[KG]
4.2
4.04
4.05
4.1
3.98
4.04
MHC
[KOe]
7.78
7.55
7.95
•
8.03
7.54
7.60
BHC
[KOe]
3.15
3.12
3.10
3.25
3.10
3.25
(BH)max
[MGOe]

lire
khang
tir
va gia
tri tir du ndi chung vdi d >
lOO^im dku Idn
hon.
Ta
cQng
nhan thay rang, cac ket qua
v^
nam cham da dugc cai thien
dang ke, tuy cac gia tri nay van cdn thap so vdi
cacjcet
qua da dugc cdng bo
la 5 MGOe ddi vdi loai HDDR ding hudng (cd mot ket qua da cdng bo cua
T(^C)
100=C
IOO'CJ/^
700=0
y^
X
= 750, 810 or
850'^C
•x>
\
en '^ \
m
O \
1

b,
c vdi thdi gian
giij
nhiet la 3 gid va do hat dugc
lira
chon bang may ray
cd: 100
|Lim
< d < 125
^m.
Cac ket qua cua he mau nay dugc tdng hgp trong
bang 2.
21
Bang 2. Cdc thong so cua he mdu M2.
MIU
M2a
M2b
M2c
P
[g/cm^]
5.8432
5.9107
5.8502
B.
[KG]
4.69
5.08
4.41
MHC
[KOe]

tang, cd
th§
la do do hat ddng deu hon, thdi gian tach pha va tai hgp dai hon
cho phep phan ung xay ra hdan tdan tren toan bd the tich mau. Nhu vay quy
trinh nhiet cho mau M2b la quy trinh nhiet thich hgp nhat vdi lugng mau
khoang 30 gam, dat dugc
(BH)niax ^
4.58 MGOe.
D§
nang cao
ch4t
lugng bdt vat lieu, can phai lam the nao dd de bdt
tao ra
bang
phuong phap nay trd thanh bdt di hudng, chimg tdi da chon
phuong phap pha tap vao hgp kim NdFeB mot lugng Zr de cd dugc hgp kim
Ndi6Fe76-xZrxB8
vai x = 0.1, 0.2, 0.3, 0.5. Cac ket qua cua cac he mau nay se
dugc
trinh bay trong phan sau.
3.2. He mau
ho-p
kim
NdieFeTe-xZr.Bg vdi
x = 0.1, 0.2, 0.3, 0.5
He mau
NdieFcye-xZrxBg
dugc xu ly nhiet tuong tu nhu quy trinh xu ly
nhiet cua he mau M2b va dugc ky hieu la M3a, M3b, M3c, M3d
tuomg

^
6=*C/phut 20=C/phut
Theo
16
8^'C/phut
|.
Hinh 5. Quy trinh nhiet cua mdu M3.
phan loai hat bang may ray cd dudng kfnh
lOOjim
< d <
125|im.
Bdt vat lieu
HDDR dugc trdn vdi epoxy
rSn
vdi ty le 2% trong lugng, rdi dugc ep trong
khudn thep
{^\3
mm) vdi ap suat 6
t§n/cm^
trong tir trudng 1 Tesla, song
song vdi phuong ep.
TiSp
theo dd la polymer hda trong nhiet do
125''C/gid,
cac mau dugc nap tir trong tir trudng xung 5 Tesla, sau dd dugc xac dinh cac
thdng sd
ciia
nam cham.
Cac thdng sd
ciia

0
Happ
= 1
Happ =
0
'"lapp ~ ^
Bang;
p[g/cm^]
5.9249
5.9197
5.8398
5.8429
5.8511
5.8609
5.8327
5.8617
3.
Cdc thong so
ciia
mdu M3
Br
[KG]
5.1
5.79
4.7
5.55
4.49
5.69
4.41
5.37

H/B
at
(BH)„ax
0.3
0.32
0.29
0.35
0.29
0.35
0.37
Do vay, he mau
M3a
da dugc chon de khao sat quy trinh nhiet ti mi
hon. Quy trinh nhiet cho he mau nay dugc chon nhu ban dau nhung thay ddi
nhiet do cao
nhat
la:
800°C
(M3al),
820°C
(M3a2),
830^C
(M3a3) va
850°C
(M3a4), thdi gian
giii
tai nhiet do cao nhat nay van la 3 gid. Cac ket qua cua
he mau nay dugc dua ra trong bang 4.
Tir cac kk qua d bang 4, ta nhan thay rang, ddi vdi viec pha tap Zr,
X =

Bang 4. Cdc thong so cua mdu
M3al,
M3a2, M3a3 vd M3a4
Mau
M3al
M3a2
M3a3
M3a4
Nhiet do
li
[°C]
800
820
830
850
p[g/cm^]
5.9202
5.9197
5.9257
5.9580
Br
[KG]
5.81
5.89
6.43
6.67
MHC
[KOe]
9.60
9.72

M3a41
(giij
trong 3 gid); M3a32, M3a42 (giir trong 3.5
gid);
M3a33, M3a43
(giij
trong 4 gid). Cac ket qua cua he mau nay dugc
dua ra trong bang 5.
X = 830 or
850'^C
6^C/phut
20^C/phut
Theo 16
8"C/phut
Hinh 7. Quy trinh xu ly nhiet
ciia
he M3a3 vd M3a4
25
Bang 5. Cdc thong so
ciia
mdu
M3a31,
M3a32,
M3a33,
M3a41, M3a42
vd^M3a43
MIU
M3a31
M3a32
M3a33

5.28
5.48
5.67
5.57
(BH)niax
[MGOe]
9.05
9.31
8.68
9.23
9.95
9.46
H/B
at
(BH)„ax
0.4
0.35
0.34
0'.35
0.35
0.38
f
r \
Tir cac ket qua dua ra trong bang 5 ta nhan thay rang, khi tang thdi
f
gian
giir
nhiet d nhiet do cao nhat len thi tinh tir cung
ciia
vat lieu da dugc

^im).
Do dd, anh hudng
ciia
muc do ghd ghe tren be mat mdi hat
giam di gdp phan cai thien gia tri tir du
Br ciia
he mau.
Tir cac ket qua
ciia
hgp kim NdFeB khi khdng cd pha tap va khi cd
pha tap Zr vdi
ph4n
tram khac nhau, ta thay rd anh hudng
ciia
viec pha tap
Zr vao he hgp kim. Hieu img pha tap nguyen td Zr da lam phuc hoi tinh dj
hudng cua vat lieu. Nguyen nhan la do vat lieu ban dau da cd tinh di hudng,
26