-  Yttria-Stabilized Zirconia(YSZ)  ZrO2

-  Yttria-Stabilized Zirconia(YSZ)  ZrO

-      

^†  ******

 

*
 

**   

*** 

(2000 1 11 , 2000 9 22 )

Synthesis of Yttria-Stabilized Zirconia and ZrO

-gel by Sol-Gel Method and the Crystallization Mechanism of Gel Powders

Un-Yeon Hwang^†, Seung-Gu Lee, Jung-Woon Lee, Hyung-Sang Park, Seung-Joon Yoo*, Ho-sung Yoon** and Yong-Ryul Kim***

Department of Chemical Engineering, Sogang University

*Faculty of Environmental and Chemical Engineering, Seonam University

**Division of Mineral Utilization and Materials, Korea Institute of Geology, Mining & Materials

***Department of Chemical Engineering, Daejin University (Received 11 January 2000; accepted 22 September 2000)



           ! "# YSZ $ ZrO2-%

 &' (). 0.4*[Acac]/[Zr-n-p]=R*0.6 '+ 1, - 3, ./01  ! "# ZrO2-%

 &' (23, R4 567 89 % ,: 56 (). ; R4: % <= '> ?1 01 @A B C). [Acac]/[Zr-n-p]=0.5 '+ D )E 46 '/ YSZ-% &' (23, Y2O₃ '/: YSZ-% ?1

FG @A BC). XRD HI  J 60^oC 24, +' %: '/ KLM NO P1Q RS23, 450^oC

 T  ! UV1L ?1'6 W/XS). 2.5YSZ> 4.5YSZ Y Z[ \\ 600^oC $ 1,000^oC 1V 1L ?1'D R]6 ^_`2a 6.5YSZ $ 8.5YSZ Y T bcd 1,000^oCe 56 !c ?1' ]

afa ghi ?1/j ARXS). T 01 450^oC =k afa lm: P1QR UV1LD ?1

> ZrOCO3(lattice), H₂O noi CO2 W/  p3, 850^oC=k afa lm: ?1' < qr  CO32−so tu pv  w xS).

Abstract−In this study, transparent yttria stabilized zirconia(YSZ)-gel and ZrO₂-gel were prepared by the alkoxide-acetyl- acetone chelation method of Zirconium-n-propoxide. Transparent ZrO₂-gel could be prepared through 1 hour reaction and three hours aging in the condition of 0.4*[Acac]/[Zr-n-p]=R*0.6. The gelation time was increased with increasing the molar ratio R. The molar ratio R had an important effect upon the inner structures of gel and the crystallization process. YSZ-gel of the four kinds of composition was prepared in the condition of [Acac]/[Zr-n-p] = 0.5. Crystallization behavior of these gels depended upon the concentration of Y₂O₃. All samples dried at 60^oC for 24 hr were amorphous by XRD analysis, and the first crystalline phase obtained beyond 450^oC from the dried samples was the cubic one. The 2.5YSZ and 4.5YSZ samples passed through the cubic phase were transformed into the tetragonal phase was at arround 600^oC and 1,000^oC, respectively. For 6.5YSZ and 8.5YSZ, cubic structure was developed continuously without transformation of crystal structure by 1,000^oC. An exothermic peak around 450^oC on DTA analysis associated with the crystallization to cubic phase and the formation of ZrOCO₃(lat- tice), H₂O, and CO₂. The third exotherm (about 850^oC) during the calcination was attributed to the liberation of CO₃²⁻. Key words: ZrO₂-Y₂O₃ Gel, Sol-Gel Process, Metal Alkoxide, Chemical Modification

†E-mail: hspark@ccs.sogang.ac.kr

 38 6 2000 12

1.  

     
  1899 Nernst [1]     .1937 Baur! Preis[2] 1,000^oC


"# $%& ' (   ) *+, . - .   /0 1234 56 789, :;< =>?

 @  ;A ZrO2, HfO₂, CeO₂, ThO₂! Bi2O₃B 4 C, 3aC, -
5bC D" EF GHI6 J KLMN EM

O(Cubic Crystal Structure, D C-EMOA P) QR 

D .

ST@  ; , UV OW# XY ZMS[ , O\ "# D" $ ]^[ 
,  $ _^[ ` . -
N3 3 aD " b cd6 e f^[ 

, $ gh& ' i6 M jk` O) $l[ ` . -mn o'` ZrO2 p q"# rsMN EMO(Monoclinic Crystal Structure, D M-EMOA P)) J
(9, 1,170^oC Dq

"# MLMN EMO(Tetragonal Crystal Structure, D T-E MOA P)A, 2,370^oC Dq "# C-EMOA tu, v w b S N3 a b$ nxy [3]. D! z0 3

a b ZrO2 {@ X|$ } . ~# € CaO, MgO, Y₂O₃, Sc₂O₃B 2$  3$ QRDn ‚ƒ„ +6 ZrO2!

…† ŠO ‹ $ ?Œ
( [4]. Ž ZrO2-Y₂O₃ (Yttria Stabilized Zirconia,D YSZ)N MgO-ZrO2, CaO-ZrO₂ B

N 1 C-EMO qcD 
, ‘"# ZM` EMO)

‰ & ' ( ’“ ”0 $ ?Œ
( .
 STA#

YSZ a•0 T-EMO – C-EMO) J $ ', Y₂O₃ mol%$ —$˜ ~ D" $ —$ * Y2O₃mol%

 —$ D"  {a ™ ) —$š[5], Y2O₃ OaD 20 mol%DqD ›, œA Zrh Y †4 Y4Zr₃O₁₂! Y6ZrO₁₁B D ža ’“
 STA# a•D Ÿ ` [6]. ~# ¡¢

39A Y2O₃mol%

$X '` a6 nx£ ¤9A =>l ( .

YSZ B Da¥N  ŠO (¦# $X §¨` I0 © a¥

D ª¡ˆ …†} «¥ ŠOD . ZrO2-Y₂O₃N p a¬

£ Y2O₃$ ª¡ˆ ¥­›   D" EF GHI ®v O aD ¯ˆ 
, D" $ ST # ª¡ f9°A

 ST ±²D ³¦ ˆ 
, O\"# EMqh N3

aD Y2O₃ Oa ”0 cd6 e ’“D .

´ # YSZ ZrO2! Y2O₃ µ5TA ¶¶ Zirconium- n-propoxide(D Zr-n-pA P)! Yttrium chloride hexahydrate(D

Y-c-hA P)) s@
, a¥N  ŠO (¦# ¢·R

O¸ ¹ VH'º ª¡` …†D $•` »-¼½[7]6 D@ 4$

Oa ¾¿` YSZ-¼6 ŠO9, OaD EMO b ¹ EM 7% «j cd À
Á . ª¡` Oa ¥­)

¢·R O¸D Ĩ, ¡¢39A µ5@Ã pH) O¸7n [8, 9], v¥$'¥S ¹ …†@Å) s@7n[10, 11], ZMŠ) Æ

$ L½D D@
( . -mn Ti-=ÇÈ, Al-=ÇÈ ¹ Zr-

=ÇÈ! zD QRD" v¥ É ÊD Ë =ÇÈ p

pH O¸  ¢·R) Š¦ ¦Ì
[12], v¥ $'¥S

¹ …†@Ž0 µ5TD Í© =ÇÈ4 p 3@} . ~#

´ # ¢·R$ ÎÏ ZrO2 µ5T4 Zr-n-p) Acetyl-

acetone(D AcacA P)9A ZMš L½6 D@ YSZ-¼

6 ŠO . ´ # ¾¿` YSZ-¼ ŠO Ð# [Acac]/[Zr-

n-p](D RA P) Ê6 0# 1< 0.05Ñ —$š›# o'`

ZrO₂6 ŠO
, R b$ ŠO}  ¬Ò! EMO b

 «j cd À
Á9, D! z0 ÓÔ Eh)  ÕA  ¾¿` YSZ-¼ ŠO) Â` R Ê6 EM .

2.  

´ # ZrO₂ µ5TA Zr-n-p(Zr(O(CH₂)₂CH₃)₄, 70 wt%

solution in propanol, Alfa)) s@9, Y2O₃ µ5TA Y-c-h (YCl₃Ö6H2O, Strem Chemicals, 99.9%)) s@ . Iso-propanol (C₃H₇OH, Carlo Erba Reagent, 99.0%)6 Zr-n-p ZM ¹ Y-c-h

@S ¢· @ÅA s@9, Zr-n-p ZMŠA Acac(CH₃- COCH₂COCH₃, Daejung, 99.7%)6 s@ . 0 2× —„ D

" ØU` ¤6 s@ .

2-1.
 ZrO2 

Zr-n-p) @Å4 iso-propanol @Sš
¢·OW ~ Acac6 Æ$ 30^oC# 1Y %Z 100 rpm RA Ø¢›# ZM ¢

·6 'Œ
, D @à [H2O]/[Zr-n-p]=4 SÙ h isopro- panol …† @Ã6 Æ$ 3Y %Z 200 rpm RA Ø¢›#

$'¥S ¹ چ§† ¢·6 ?Œš
1Y %Z ÛaÜ ¾¿`

ZrO₂-¼6 ŠO9, ŠO} ¼0 60^oC# 24Y WO .

2-2. YSZ 

Zr-n-p) @Å4 iso-propanol @SÝ . Acac6 Æ$ 30^oC

# 1Y %Z 100 rpm RA Ø¢Ü ZM} Zr-=ÇÈ

@Ã6 ŠO9, ¡MÞ YCl3ß6H2O$ @S} iso-propanol h D …†} @Ã6 Æ$ 200 rpm Ø¢RA 30^oC# 3

Y%Z Ø¢Ý . 1Y %Z ÛaÜ ¾¿` YSZ-¼6 ŠO

 . @Ã [Y-c-h]/[Zr-n-p] ÊD 0.025, 0.045, 0.065, -
0.085

$ à µ5T6 Æ$9(D 2.5YSZ, 4.5YSZ B9A P

), ¢· Æ$` 20 á1A Zr-n-p : Acac : H2O : iso-propanol=1 : 0.5 : 4 : 40D  É0 YCl3 ⦠( ¤6 ­˜ N

 . ŠO} ¼0 60^oC# 24Y WO . Dq ÓÔ ¸ã ) Fig. 1 nx£, .

Fig. 1. Flowchart for synthesis of YSZ-Gel.

2-3. 

  äM6 g ¬a} EMO)
Á Â Oah "

b À` Xå ׸ ¥æ(XRD, Rigaku, Interval 0.02, Scanning speed 0.5^o/min, Target=Cukα, Power=30 kV, 20 mA, 20^oç2θç80^o)6 'Œ

9, YSZ ¥ E† qÒ!   " b ~Ï ¥ £

E† qÒ b)
Á Â 3^oC/min è" RA é

` ¥) KBr pellet ½9A Vê¬ ë6 *+¦ FT-IR(MIDAC GRAMS/386) ¥ì) s@ 400-2,500 cm⁻¹ íî' ïÂ#

¥æ9, «¥! KBr ðˆ1 1 : 2009A
M . YSZ

¥ é¥S ¹ qb a6
Á  TG-DTA(DuPont 2000 Differential Thermal Analysis,è" R 3^oC/min, ¥Â Air) Ó Ô6  . ŠO} YSZ ¥ Oa0 1,000^oC# 1Y%Z 

}  ICP-AES(Inductively Coupled Plasma Atomic Emission Spectrophotometer, PERKIN ELMER/Plasma40, JOBIN YVON/JY 138 Ultrace)¥æ6 g ñò–ó .

3.  

3-1. 
 ZrO2    

R ÊDŠO} ZrO₂ ¬Ò «j cd À` ÓÔEh ›

Rô0.7 ïÂ# 24Y ¢·h 10¡ %Z ÛahM6 gS#

 žaD ŠO fó . 0.4çRç0.6 ïÂ# 3Y ¢·

h 1Y M ÛahM6 g ¾¿` ¼D ŠO,
, R ÊD

—$˜ ~ ¼ YD —$ . R<0.4 ïÂ# R ÊD

Ÿ &'à 10¥ D£ õ öD ža, .

Fig. 2 R Ê6 bÜ ŠO} ZrO2-¼ ¹ ö6 3^oC/min è" RA 500^oC<  `  À` XRD¥æ EhD . Fig. 2

 › Zr-n-p6 ZMš f0 R=04 OW# ŠO} ö

0 Àv¥ M-EMO) J
(6 = ' (
, R ÊD —$˜

# ŠO} ¼0 Àv¥ T-EMO) J
(6 = ' ( . ZrO₂-¼ ¹ ö £v O! EM «j ¢·R cd

 À` Ï H+ Eh[13-17] › ¢·R) øµ'à

ŠO} ¼0 0 ´ KH$ ùú39A ¥­¦ (9 C-  T-EMO! ‰s` £v O) J
(
, ~# D! z0 £v

O 4 500^oC M#    T-EMO$ ža }
5P .

-m°A R<4 OW# Zr-n-p$ ZM fó ’“ ¢

·R$ ί
, ~# Ë ´ KH$ ùúˆ ·û} öD

ža} ¤D, D! z0 ùú` £v O 4 500^oC#

    M-EMO$ ža,
s} . -
0.4ç

Rç0.6 ïÂ# ŠO} ¾¿` ZrO2-¼0 «KH$ ùú39A â

é¦ (9 T-  C-EMO! ‰s` £vO) J
( ’

“ 500^oC#    T-EMO$ ža,
s} . Fig. 30 R=0.54 OW# ŠO} ¼6 360^oC# 1,000^oC< 3^oC/

min è" RA  ` ¥ À` XRD¥æ EhD . ¡¢39A o'` ZrO2 p   äM  1MTq9Avü M-EMO

$ ža *[3], Fig. 3 › 400^oC#  `  p M-E MO$ ^ý T-EMO$ ža,9, 500^oC <  " —

$! þ¦ T-EMO$ 5ÿ˜6 = ' ( . -mn 600^oC#  

$ nx
.  ") 1,000^oC< —$š› T-EMO a0 Ÿ

3-2. YSZ

R ÊD ŠO} o'` ZrO2ža ¬Ò À` ÓÔEh) Õ Fig. 2. X-ray diffraction patterns of various ZrO₂ samples calcined at

500^oC(heating rate=3^oC/min).

Fig. 3. X-ray diffraction patterns of ZrO₂ calcined at various tempera- ture(heating rate=3^oC/min).

 38 6 2000 12

A  R=0.5, [H₂O]/[Zr-n-p]=4A
M
[Y-c-h]/[Zr-n-p] 1) O¸ 4$ Oa YSZ-¼6 ŠO9, Table 1 µ5T

Oa1! ICP-AES ¥æ Eh S ŠO} £ Oa1) nx

£, . Table 1 › ¢· Æ$} Y-c-h! Zr-n-p 1 1

 ŠO}  £ Y-c-h OaD 2Y ]ˆ nx
.

Fig. 4 2.5YSZ-¼ ) 3^oC/min è"RA 1,000^oC<

  ŠO} «¥ À` XRD¥æ EhD . 2.5YSZ-¼ p

 400^oC#    C-EMO$ nx
9,  "

—$ ~ EMaD —$
(9 600^oC#   

T-EMO$ nxn 9(“ › 2θ=35^o! 2θ=60^o v€ peakD ¶¶ (002), (200)› ¹ (113), (131)›9A ¥¦ n xn› T-EMO) J
(9 (200) ¹ (311)› n* nxn›

C-EMO) nx [18, 19]), 1,000^oC<   " —$! þ

¦ T-EMO$ 5ÿ˜6 = ' ( . -
, Fig. 3 R=0.5#

ŠO} o'` ZrO2 «¥! Fig. 4 2.5YSZ «¥) 500^oC#

 `  XRD ¥æ Eh) 1ØS–› o'` ZrO2«¥

T-EMO$ « Þ Y-c-h Æ$  C-EMOA U6

= ' ( .

Fig. 5 4.5, 6.5 ¹ 8.5YSZ  À` XRD ¥æ EhA Fig. 4

 2.5YSZ  600^oC#    T-EMO$ ža

, * 4.5YSZ  800^oC< C-EMO$ ‰ 
(9

1,000^oC#    (002)›h (200)› ¹ (113)›h (311)›

 À` peak$ ¥ ¤9A –^ T-EMO$ ža,6 = ' ( . 6.5YSZ! 8.5YSZ  1,000^oC<  "$ —$

 EMO biD C-EMO$ NR ‰ 6 = ' (9, D! z0 Eh! ICP ¥æ Eh › 6.7çYttrium mol%ç8.55 ï £v Oa6 J $
 STA# '` a6 nx

 ¤9A s} .

Fig. 60 #A Ï Y2O₃ Oa ) 450^oC#   ža } «¥ À` XRD ¥æ EhA Í  C-EMO) nx Fig. 4. X-ray diffraction patterns of 2.5YSZ calcined at various temper-

ature(heating rate=3^oC/min).

Table 1. Composition of YSZ determined by ICP-AES

Sample Yttrium added in

reactor(mol%)

Yttrium in the sample(mol%) 2.5YSZ

4.5YSZ 6.5YSZ 8.5YSZ

2.5 4.5 6.5 8.5

2.65 4.55 6.70 8.55

Fig. 5. X-ray diffraction patterns of various samples calcined at indi- cated temperature(heating rate=3^oC/min).

Fig. 6. X-ray diffraction patterns of YSZ calcined at 450^oC(heating rate=3^oC/min).

£
(9 Y2O₃ OaD Ÿ &'à EMaD —$
(6 = ' ( .

3-3. DTGA 

Fig. 70 2.5YSZ  À` 1,000^oC<  TGA ¥æ EhD (è

" R=3^oC/min). 100^oC v€# H2O —5 ` ðˆ Ÿ $ nx
9, 300-450<sup>o</sup>C ïÂ# ‰T ‰ ` ðˆ Ÿ  :qD nx

, 500^oCvü 1,000^oC< 0 " ïÂ# 2

4.3% M ðˆ Ÿ  :qD nx
.

Fig. 80 4$ Oa YSZ-¼ À` DTA ¥æ EhD . Í 

# 100^oC v€ "# '¥ —5 ` é peak$ nx

, 370^oCv€#  5é peak$ nx
. XRD ¥æ E h › 400^oC D "#  `  p Í© 1MT qD, ’“ 370<sup>o</sup>C v€# nxy 5é peak EM `

¤D ^ý
‰ ¥S ` Eh
s} . -
400-500^oC

 ïÂ# YSZ-¼0 © 5é peak$ nx

, 850-870^oC v

€#  5é peak$ nx
. D! z0 © $  5颷

0 ¡¢34 :qD * ^ ¿Ž Sæ¦ ( f . o'`

ZrO₂! MgO-ZrO2…† ŠO! EMa ‹` “6 gS Kundu [20] 400-500^oC

 EFI+D s  ’“ nxn :qD
Sæ
, Gu- inebretiere[13]0 ¼ ŠO ¢·OW ~ © 5颷 Âj!

÷$ b, D ¼ £v aD ¯ ’“D
Sæ . Zeng[21]0 AcacA Zr-n-p) ZMš äM S ŠO} o'`

ZrO₂-¼ ‹` ) g qb$ ¡¦n " v€# ZrO2

GH£ ¥H{%0 {5, ~#  h z0 ¢·6 g

HCO₃⁻D" CO3$ GHO R9A +¦$
H2O! CO2¹ O2−

$ ža}
5P .

(1)

` GH £v ; CO3

2− 900^oCv€# ‰}
5 P . -
Fig. 6 450^oC#  `  À` XRD ¥ æ › Y2O₃ OaD Ÿ &'à EMaD —$
(9n Fig. 8 DTA ¥æ Eh › Y2O₃ OaD —$&'à © 5颷 ÷$ —$
(6 = ' ( . -m°A Fig. 8

 400-500^oC ïÂ# nxy © 5颷0 1MTq C- EMOA Uh ˜  (1) ¢·D % ¡¦
 ’“D 
s} . Fig. 4! 5 XRD ¥æ Eh › 2.5YSZ!

4.5YSZ 800^oCDq "# EMO$ b9n, 6.5YSZ!

8.5YSZ 1,000^oC<  þ EMO b nxn f ó . -mn Fig. 8 › Í # 860^oCv€# 

¤D – q b hM# GH £vA +¦$ ( CO32−

 ‰ 4` ¤9A s} . -
Fig. 7 TGA ¥æ 

 500^oC D. ºŽ ¡¦y 2 4.3% M ðˆŸ  Â

 ¢·  ža} H2O, CO₂, O⁻₂ ¹ 860^oC v€#

CO²⁻₃ ‰ 4`
s} .

3-4. FT-IR 

Fig. 9 60^oC# 24Y WO` ! m "#  ` 2.5YSZ

 À` FT-IR ¥æ EhD . 2,300-2,400 cm⁻¹íî' ïÂ#

 'À CO2 ` ¤D
, 1,528, 1,620, 1,630, 1,645, -

1,655 cm⁻¹# 'À H2O ` ¤D . ` C=O E† 

` 'À 1,710, 1,528, 1,425 ¹ 1,025 cm⁻¹ íî'# nxn

( . 1,550h 1,453 cm⁻¹# 'À Zr-O-C E† ` ¤ D . CH2 E† ` 'À 1,440, 1,360 ¹ 1,377 cm⁻¹ íî '# nxn
( . 1,278 ¹ 933 cm⁻¹ íî'# 'À ¶

¶ C-O! C-C E† ` ¤D . 60<sup>o</sup>C# WO`  p

Àv¥ H2O! ZMŠA Æ$} Acac ` 'À$ nxn
( ¤9A –^ WO äM . ZMŠ$ Ž ¼ £v ;

˜6 = ' ( . -
450^oC#  `  p Acac B

‰Th H2O -
CO2 ` 'À$ Ÿ 6 = ' ( . -mn 500<sup>o</sup>C#  `  450^oC#  `  1

 CO2 ` 2,300-2,400 cm⁻¹ v€ 'À! 1,400-1,700 cm⁻¹ v€ íî'# 'À$ —$
600^oCDq9A   "

) —$š›  Ÿ ˜6 = ' ( . -
1,000^oC#  `

 p 470 cm⁻¹v€# ìïÂ` r¡ 'À$ nxy ¤9 A –^ T-EMO$ ža,6 = ' ( [22]. D! zD 2,300- 2HCO₃+OZrO lattice( )→ZrOCO₃(lattice)+H₂O ad( )

+CO₂+O²

Fig. 7. TGA curve of 2.5YSZ sample.

Fig. 8. DTA curves of various YSZ samples.

 38 6 2000 12

2,400 cm⁻¹ ¹ 1,400-1,700 cm⁻¹ v€ íî'# 'À$  

" —$! þ¦ Ÿ   —$  Ÿ  äM6 7jˆ } ¤0 Fig. 7h 8 TGA ¹ DTA ¥æ#
Á` t! zD C-EMOA

 EM hMh  (1) ¢· 4`
s} . , 450^oCv

€ EM hM# ža} CO2  2,300-2,400 cm⁻¹v€

'À$ —$` ¤D
H2O ¹ ZrCO3  1,400-1,700 cm<sup>−1</sup> v€ íî'# 'À$ —$` ¤D . -
600^oC Dq9A

  ") —$š› H2O, CO₂ ¹ GH£v ; CO−3$

‰ ’“  Ÿ ` ¤D
s} .

4.  

´ # ¢·R$ Å ÎÏ Zr-n-p) Acac9A ZMÝ , Y2O₃ µ5T4
qÒ YCl3ß6H2O) propanol @S

Ü ŠO` @Ã6 Æ$ ¢·9A YSZ) ŠO9

h z0 E6 , .

(1) ¾¿` ZrO2-¼6 ŠO) Â` [Acac]/[Zr-n-P] Ê6 M

Â` ÓÔEh › Rô0.7 ÓÔ OW# ¢·D ?Œ

fó9 R<0.44 OW# Å ÎÏ ¢·6 gS öD ža

,
Æ$} Acac ÉD —$&'à ¢·YD —$ . -

0.4çRç0.64 OW# 3Y M ¢·h 1Y M Ûaä M6 g ¾¿` ZrO2-¼6 ŠO& ' (, .

(2) [Acac]/[Zr-n-P] Ê6 bÜ ŠO`  XRD ¥æ6 g S, 500<sup>o</sup>C#  ` p Acac9A ZMš f0  M- EMO) nx£,9 Acac Æ$ÞD —$&'à T-EMO

a6 nx£ peak ÷$ —$9, ZMŠA Æ$}

Acac É0 Zr-n-p ¢·R* ^ý ža ¬Ò! £vO

 cd6 «j, £v O  ¥ EMO Ë cd6

«ö6 = ' (, .

(3) ŠO} 4$ Oa YSZ  À` 1,000^oC<   

~Ï EMa b À`
Á6 g 2.5YSZ! 3.5YSZ p

1MTKLMMLM rN) 7j›# EM,
, 6.5YSZ!

8.5YSZ p 450^oC v€#vü C-EMO$ ža 

9 1,000^oC<  ") —$šþ EM¬Ò D iD NR EMa*D —$ .

(4) TGA ¥æ Eh › 500^oC Dq# 2 4.5% ðˆ

Ÿ $ ¡¦6 = ' (,
, DTA ¹ XRD ¥æ Eh 

D! z0 :q0 500^oC v€# EM äM# ža} H2O, CO₂ ¹ EM £v ( CO32−¥S ` Eh6 4 . -
DTA ¥æ © 5颷0 1MT q EM!  (1)

 ¢·D ˜ ¡¦6 = ' (,
, 850^oCv€# nxy  5颷0 EMO £ CO32−‰ ` ¤6 = ' (, . -
Â! z0 EM äM# nxn :q0 FT-IR ¥æ6 gS# 4& ' (, .



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Fig. 9. FT-IR spectra of 2.5YSZ calcined at various temperature.