Shonan Institute of Technology
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ShonanInstitute of Technology
MEMolRs oF SHoNAN
INenTvTs oF THcHNoLoGy
Vol.es,No.1,I991
Wettingand
Interface
Pb<Zr,Ti)O,Reaction
of
BaTi03
andby
Ag
Metal
SunaoSUGIHARA'
10r:NIO'3 Pa ofige-tSlueJr:',
iin'
,Eig.E[t'1:fi
ib:5ea-
tr-rmaea
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frLk. -t!7i v e.xOgasE: Lv(, BaTi03 2:Pb(Zr,Ti)03 tztwreLk.
t'ib
E)a)-tr7E ・ycrJkig
Ag Vlj f)TC,maiLVkhs-)k.
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ve PbO cDRRb:ge<
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PbOtscdea)ges2
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tk,
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BaTi03 vc-.L・-cigerveL,
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Lka1. Introduction
In
applications of ele¢tronic ceramlcs, theelectrodes are essentially
important.
The
improvement
of bondability can beimpre-mented by an addition of a glass to an
electrode metal, and the
basic
studyfor
theinterfaces
is
necessary.There
have been afew
studies on wettingfor
leadborosilicate
glass-precious metali) and
Na2Si?Os
glass
tometals likeAu,
Pt
andFe!'
as thebasic
ones,in
which a wettinghas
mainlybeen
discussed
from a
view
point of redox reaction.Fur-thermore, a role of adherence oxides
in
chemical
bonding
at glass-metalinterfaces
were
discussed
as wel13).
In
this study, leadborosilicate
glass-addedAg was
put
onBaTiO,
(BT)
and also onPb(Zr,Ti)O,
(PZT)
ceramics to study theirinterfaces.
The another samples were threekinds
of barium titanatesfor
a semiconductor.The
order ofthe
processing toform
thesemiconductors isan as-sintered
BT
first,
thesecond one
is
the reduced sample, BaTi03u6and the
final
is
the surface oxidized onedescribed
asBaTi03-j,x.
The
systems wereprovided
for
cross sectional analysis with aSEM
and anEPMA,
and the rnechanisms ofwetting are discussed as well.
* Stge}][:\geLMXst
gnbR 2 {F 10 Jl 16 Hee"l
2.
Experiments
The wetting experiments of silver
contain-ing
5,20 and 40 weight%
oflead
borosilicate
glass on BT and PZT was performed
in
avacuum of
10-2"ulO-3
Pa
in a temperaturerange up to1000aC.
Wetting
behaviors
wereobserved
by
a telescope and contact angleswere measured at the elevating temperature.
The
semiconductors, as-sintered BTs werereduced at 9500C
in
thereducing atmosphere,and then these were oxidized at the same
temperature in an air.
These
three kindsof
barium
titanateswere provided toinves-tigate the surface condition with an
XPS
analysis. For wetting study of the
semi-conductors, silver was put on each of them
under the same conditions as
described
above.After wetting experirnents, the superficial
and cross sectional interfaces were
inves-tigated using a
SEM
and anEPMA.
3.
Resuks and Discussion1)
Effect
of Glass Frit on Wetting
Photograph.
1 shows the wetting of silveronly on
BT
andPZT.
The
contact angleswere
90
degrees
for two cases.Silver
wasnot
detected
at the interfacesof the ceramics.However,
BT
andPZT
were wettedby
theglass-added silver. The contact angles were
46 and 43
degrees
on theBT
and PZT,-59-NII-Electronic Library Service
湘南工 科 大 学紀要 第 25 巻 第 1 号
(
a
)
(
b
)
白
Photo 1.
Wetting
of BaTiOs (a)and Pb(Zr, Ti)Os(b)byAgat 1000°C.
(
a
)
」
L
(
b
)
凸
Photo 2. Wetting of Ag十40% glass on
(a)and Pb(Zr, Ti)03 (b)at 980°C . BaTio3 3.2 2.4 〈 1.6 」 0β 0900 920 940 960 980 1000 (℃}
Fig .1. Temperature dependence of contact
leロgth !height ratio for Ag 十frit!BaTiO3
system (40F ; 40 weight % frit・added snver ,
and so on). 4.o ρ 3 工 丶 」 2ρ 1.0900 920 940 960 980 1000 (℃ )
Fig.2. Temperature dependence of contact
length!height ratio for Ag十frit!Pb(Zr, Ti)03
system (40F:40 weight % frit・added silver,
and so on)・ 「
「
Frit
一 一 .02 、( ⊃, ’. ・バ’・盞
誌
1
・ ト. ル鹽・卩 ・,, 崇 「 続. ” 詳
黴
鑼
の ご,, 卩 . ・ °〆9 頭 尊 書、 ヂ … . . . ● ” ・ 》・ ∵. 『 闘 箆へ 〔 堕 ’ . 岬 .. ’ρ ゐ ゜ ’ ■ , ‘. ’ . ° 吻 “ ム ∴ ・ ∴ . . 更 曾 ’灘
誹
T
Photo 3. EPMA analysis for the cross sectiQnal interfaces of Ag 十40% frit!BaTiOs .
一 60 一
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ShonanInstitute of Technology
Wbttingand JntetzfaceReaction
of
BaTi03 and Pb(th,71)03byAg Mlatalspectively,
in
the case of 40 weight%
glass,is
shownfor
the 40%frit+Ag/PZT
systemfor
instance,
as shown in Photo. 2. Figures in Fig.3.
The place of 40% frit+Agis
land2illustratetheratios of contact
length,
hatched
and some elementsin
theglass
L
andheight,
H on the BT and PZT, re- diffuses concentrically into the PZT baserespectively,
The
LfH
ratiosin
thebase
of which presented thedifferent
colorfrom
theboth
BT
andPZT
showed the minimurn at original PZT after the wetting experiment.9550C and
9500C,
respectively.This
mayThe
dotted
parts
illustratetheg!assdiffusing
be
explainedby
that the llquidlvapor inter- regions inthis figure. Lead was notdetected
face
tension will be the largest among otherin
the regionbetween
a,rtva2 whereasit
wastensions when silver
begins
to melt at 950"" detectedin
the region between aorvai.It
is
9600C, and then becomes wetted.
After
the explained by that PbO providedfrom
theminimum, HIL ratios increase with tempera- glass diffuses
into
thedeMcient
part ofPbO
tures.
The
reasons are assumed tobe
due
in
the PZTbase.
These
phenomena willbe
to the vaporization of PbO from the glass elucidated as shown
in
Fig.
4.As
thefirst
for
both
cases, anddue
to the oxygen gas stage,PbO
is
vaporizedfrom
PbZr03
in
aby
the chemical reactions especiallyin
the vacuum sincePbZr03
is
easierdecomposed
BT system, given as follows, than PbTiO,5)
in
thePZT,
thenPbO
is
vided from the glass to react with
Zr02,
andPbO[gl]+BaTiO, ->
PbTiO,[int]+Ba+1!2
0"
finallythe complete
PbZrO,
canbe
formed.
where
[gl]
istheglassphase and[int]
indicates
the
interface.
Photograph.
3
shows anEPMA
analysisfor
A
g + 4O
%
f r i tthecross sectional
interfaces
of the 40%frit+
i
Ag/BT
system.As
the result, titanium waspbo
detected
in
the glass region.It
is
suggestedf22
tas
thattitaniums react with
PbO
toform
PbTi03
p bz
ro
in
theinterfaces
asdescribed
above.4) 3The superficial analysis
by
using aSEM
(1)
:,
i//ls
rtN
s
\
't/$,Iil,b,;,
uPZTN"g
la2;
f,,s
i/"
i
i
ti'
S
l-
i
---';tX,,,(2'XAg+4o%frit
: i lae ai
{mm)
a:PbZr03
Superficialdistancesfrom the center of the base
Fig. 3. SEM analysis of each element of the
(3)
surfaceofPZTafterwetting.
(aDNai:
glass Fig.4. Interfacereaction of Pb(Zr,Ti)Os withdiffusionlayer,dotted) Ag+40% glass assembly.
NII-Electronic Library Service
muwtIaJS(\kee
ar
25ig
ew
1 £-e1etpent. .Ti2pPISSEsi5eVsbepE=.leV"ile:ott saltprec:
Al-Hl-kVwwNo-'isee-cheent tt tteee e o ca N e e c = e o e
xt't't
goIJ2
f
s
f
L..is5s` s,1 s obtSurface
exidizBaT
NX
rb2edueed
BaTi03
xl12 47"7e 170 150 130 110 90 469 Fig. -68 5. 467 xps 466 46S analysis cs=opex-[eo 464 463 462 46t "l6e 459 4SS 457 456 ・-5545d- 4S3152Binding
Energy
(eV)
oi titanium in the three types of BaTi03.
2}
Effect
efSurface
Oxides
The
binding
energies relating to titanium
(Ti
2P)
of the surface oxidizedBT
in
parti-.
o
.
×
i
XXo
Agg,S t Flg. 3-rf 3-cs+x 3 Oxygencontent
6. Change of contact angle with relative
oxygen content in BaTi03 (BaTi03-e,
BaTiOa-fi+x)・
62
cular were
different
from the other BTs asshown in Fig.5. The surface oxidized layer
was amounted to approximate 4oA
by
anEPMA
analysis. Fig.6
shows therelation-ships among contact angles, relative oxygen
content, and wetting behaviors corresponding
to each oxide as well.
The
contact anglesreduced with the relative oxygen content or
TilO binding characteristics. It
is
suggestedthat oxygen effects on the
interface
reactionto be wetted through
formation
of silveroxides although silver
does
notdiffuse
into
the
base.
4. Summarys
(1)
Neither
BT
norPZT
was wettedby
silver with the contact angle of about
90
degrees.
Whereas
both
BT
andPZT
wereShonan Institute of Technology
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ShonanInstitute of Technology
Wtrtting and intet:fuceReaction
of
BaTi03wetted
by
thefrit-added
silver although thewetting mechanisms of BT is
different
fromthose of
PZT.
(2)
Titanium diffused into the glass to 2)react with PbO initat the interfacesbetween
glass-silverand BT.
In
the glass-silver-PZTsystem, PbO provided from the glass diffused 3)
into the
deMcient
part ofPbO
in
thePZT
base
toform
complete PbZrO,.
(3)
The surface oxides on BT of thesemi-conductor affected the wetting
behavior
of 4)silver metal.
Acknowledgement
5)
I
would appreciate the support on the XPSanalysis
by
Dr.
T.
Amano.
Referenees
1) V.K. Nagesh, A.P. Tomsia and
J.A.
Pask:and I'b(Zr,71)Os b.v.Ag Mketal
"Wetting
and reactions in th leadborosilicate glass-precious rnetal systems," J.Mater. Sci.,
18,2173-80
(1983).
J.
A. Pask and R.M. Fulrath: "Fundamentalsof Glass-to-Metal Bonding: VIII, Nature of
Wetting and Adherence," J. Amer. Ceram.
Sci.,45,592-96(1962).
M.P. Borom and
J.A.
Pask: "Role ofAd-herence Oxides inthe Development of Chemical
Bonding at Glass-MetalInterface," J.Amer,
Ceram. Sci.,49,1-6
(1966).
S.Sugihara and K. Okazaki: Poster session
in the 7th InternationalSymposium on the
Application of Ferroelectrics,
Urbana-Cham-paign, IL.,
June
6-8, 1990.K. Okazaki: Cerarnic Engineering for
Di-electrics (3rded.
Japanese).
Tokyo Gakkensha,1983.