$ZnCr_2O_4$'in nem algılama davranışlarının $K_2CrO_4$ eklenerek geliştirilmesi

(1)

~ .ı.\ C ı

re

n 13 i I i n 1 1 c r i En s t i t üs ü Der g i s i 9 .

c

:

i I t. 1 . Sa\· ı 2 O() 5

~ . ZnC r2O-ı 'in Neı11 ı\lgilaıı1n Davraıı i ~iııin 1( 2(.'r() ₁ Eklenerek C3eliştirilnıl!sİ. . l~u\ aS()_....§lu

"'

ZnCr

₂

O.t 'in NEM ALGILAMA

DAVRANIŞININ

K

₂

CrO.t EKLENEREK

GELİŞTİRİLMESİ

N. K~ı\

V ASü('"'; L

l

J

1 ,

M. BA YHAN

2

,

S. KAV

ASOĞ

L l

J

1

1-lacetteıJe Uııiv., Mi.ilı. Fak., Fizik Mülı. B ö lüıııü, Beytepe, Ankara

M Lığ 1 ~1 U 11 i v . , Fen E d e L1 . , Fal< . ,

r

i z

i

k B ö I i.i 111 i.i • l( öte I< l i , M u ğ I a , T e l : 2 5 2 2 1 1 1 5 9 2 , E-ın a i 1 : 111 l1 a lı a n@ 111 u . e d u . t r

~

-••

OZET

S J) i ııe I Zn Cr ~ O -1 sera 111 iğ i ne çeş itli y•i.izdese I oraıı !arda potasyLı 111 kro ıııa t I a )ıap ı l,lıı katkı I a ııd ı r111a n ı n ne nıe karş ı

da\1_raııış _ı _il_e _il_g_{ili etl}_, _il _e_ri _{çalı~ılııı} _ı_ş_{tır. NüıııLıııeler aras1ııda}_sa_d_ece 0_/4₂₀ 1(

2

Cr0..ı _i_çe_ren _ZnCr

2

0 ~

1 seranıik sensörün

0

o7 5 ile 9() ara~ıııda değişe n göreli ııeııı (Rf--l) aralığıııdak i cf .L~. direnci. üç nıertebe değişiııı göstereıı üstel bir

davra11 1ş serg il e ıııiştir. Yük ileti111iniıı c~ ase rı protonik oldLığu ve il etiıııin tane yüzcy lcrincie soğurtı lan ince su tab~ık,ı ları a ra~ ırıdaıı 111ctal ko nt,ıklara d oğru )'ap ılaıı )1ük transfer i ile koı1trl1l edi l(i iğ i so ııuctıııa arılnı ı~tır. cı.L· .

eıııı1elian s ö lçüııı so ııtıç ları ı şı ğ ıııc.la RC paralel de re ine seri bağ lı sal1 it faz e lcnıaıı larııı d· ın c1 ltı şan lıir devre sen (ir

e~cJ cğer c.ic\'rc~ i t> larak t)ııcrilnıektedir.

A ııal1tar l<.cli111clcr - Ncııı scnsörü~ ZııCr .O .-l( __ CrO.ı Eıııpcdaııs spektrosk o ıJ is i

.,

-IMPROVEMEN

T OF

THE HUMIDITY-SENSING

BERA VIOUR

OF ZnCr

₂

0_. BY ADDITION OF K

₂

CrO ...

ABSTRACT

·rııc cffccts or thc acid iti o ıı ot~ varioLıs J)erceııtages of JJotass iuııı c lıro ııı c1te as ,1 s interiııg c1id c111 tlıe response tc1 air

nı t) İsttıre

o

r

ZnCr~O _I spiııel cerarn ic body were studied . Only· tlıe ıııaterial con tai ııing 2()~ o K2Cr0..ı- in ZnCr"'O~

ex lıilıi tcd aıı eXJJC.)rıential l,ehaviour to hL1111idity, which sl1ows abo ut tlıree order clıange iıı the cl.L· . resi tance c)ver

thc rclati vc lıu ıı1idity (

RH)

raı1ge betvveen 25 and

90~

1_0. _it _wasconc lLıded tlıat co ı1duct i oıı _is dtıe ıııainl)' _t_o_protonic

tı1<) li o n and is co ııtrolled through the ttıiıı layers of' \Vater, adso rbcd oıı tlıe surface ot· the gra iııs. wittı charge trarıs fer

to tlıc nıct,1llic clectrodes. Based 0 11

a.c.

impedance ı11easurements, an eqtıiva lent c ircLıit assoc iated \Vİ th a network of RC J)arallel circ Lıit in series \Vİtlı constant plıase e lcınents (CPEs) lıa beeıı sLıggested.

Keywords

-

Huınidity sensors, ZnCr

₂

0ı.ı-K~Cr0

₄

, lınpedance spectroscopy

(2)

S. C' I'en Bitin1leri En~titüsü Dergisi <).C'ilt. '·· a) ı 1 005

1. INTRODUCTION

The _...growing _{' -} deınand for the ın easureınent a11d co ııtro l of

hunı id it., v in an iı1dLıstrial or hoLısehold enviroııııı ent lıas led to co ıısiderable interest in tlıe researclı devoted to the de e lo pnıeııt of ne~, ınaterials for huıııidity seııso rs [ 1,2].

T he re I ati ve hum i d it y (

R H

) ,

\ıV h i c lı is t he r at i o of a c t Lt al

,,aJJ0 ur pressure ata particular tenıpcrature, is cc.)111ıno ı1ly

u. eci to ı11easLıre hLııııidity. Coınnıerc ia lly dcve lo ı)ed ~en sor 111ateria Is a re e itlıer po ly111cric or poro u ce raın ic, each ot· \vhich lı ave its O\Vn ııı erits aııd prov ide a direct clcctric signal _... asa fLınctioıı of lıtııııidit₁' iıı the atnıo - phere. Ceranıic t)·pe of hun1idit)' seııso rs based on

. intered ox ilies via so lid state reac ti o ııs are iıı general su J)e r i o r i 11 perf o rıı1a ııce to rJ<.) ly nı eri c types, d ue to tlıe i r

hi _~oh tlı er11ıal stal, ilit _, arıd 11ı eclıanica l stre ıı_~trtlı to\vards a ,, itic raııge of OJ)cratiıı g tenıpcraturcs, fa. t res r,o rıse to

thc c lıa ııges ot' lıLı ıııidity, resistance to contaıı1iııaııts and i rrad iati o ıı and tlıe ease witlı \Vhich it ınay be prodLıced in thin filııı forııı

r

3].

f-Iowever , they are to a ce rtaiıı extent 11ot fully satisfactory iıı terıııs ot'

th

e

need for periodic

tl1crı11a l cyc liııg to recover tl1eir lıuıııi dity-seıısitive properti es. Iıı receııt years, nanostrLıctLıred ceraıııic fi lıııs ha c l1ee ıı id e ııtified as a o ptinıa l c,ındidates to r lıLııııidity

s

c

n

s

i rı g d Lı

e

t

o

t lı

e

11 i g lı

s

ur

fa

c

e a

r

e a e x

pos

e

d f

o

r

ad orptioıı of' water ın o lec Lıles l4] .

·rııe priııcip le ot' lıu ıııid it ıııeasurenıeııt is the variations i rı t lıe e lectrica I cond Lıction and capacitance due to water

cheıııisorptioııs aııd/or capillary water co ndLıctio n with in the pores [5.6J . Wheıı adsorJ)ti o ıı starts 011 the clean oxide sLırface, a la., er of lı)1_dr_ox _I_g_r_o_up_s _i_s _f_o_rn_1ed. _T_lı_e

,vater apour ıııo lec Lıles are clıe ıııi sorbed tlıroLıgh a dis ·ociati

e

nıeclıaııi sı11 by· ,,vhicl1 t\ o surface 11:droxy·ls

per \\·ater ıııo lecLıl e are fo rnıed . Th i la)'er, once forı11ed

is not furt her ,rftectecl by ex1Jc.1sure to hL1111idity. Oııce the

tırst layer is l<.1rıııed, subseq u eııt layers of \Vater

ıııo lccLıl es are plıys ical ly adsorbed . Many 111ore

phy isorbed layers will be joiııed as l1tııııidity gets

lıi glıer . Tlıese pl1ys isorbed layers are easi ly aııd

'

-revers i b ly re ııı oved by decreas iıı g the hLıınidity.

Plıys i so rbed water ıııo lecu les dissociate, becaLıse of the

tı i _~o lı e le c tr i c fi e I d s i ıı tlı e c lı e 111 is o r be d w ate r la yer. T he

charge trarı spo rt occurs wlıe n hyd roııiurıı ioıı s release a proton to neiglıboLıring water nıo lecules, wh iclı accepts it

wlı ile re leasi11g aııotlıer proton and so on (G rot11ıuss's

chai n reactio rı). ,~ı, is proto ıı 111oves freely along the water laycr aııd tlıLıs cieterıııiııes the sensor conductivity [7] . Finallv. at hi glı lıLııııidity, liquid water co ııdenses iıı the

capill; r)' po~·es.

acc

o

rdiıı

g

to

K

e

l

viıı's

la\v. and electrolytic coııdLıcti on occurs siınultaneoLıs ly 'A' İth

protoni c transı)ort.

Materials based 0 11 zinc chron1ite, as aı1 exaıııı) lc ofa ternar .. ıııetal ox ide piııel lıa e loı1g been id e ntifıed asa

canclidate to r aıı acti e 111ate rial in che ıııical se1ıs i11g

app lications f 8,9] . Ho\vever air ıno istLıre serı siti ve

2

Z ıı ( ' r ₂( )-t 'in "\ c 111 .Alg i I a 111 a f) a, ra n i ~in ı n 1, ( r( ) :

Eklenerek (ıcli~Liriln1c ·i. "\. l,a, a~c)plu

ceraınic seııso rs based on pLıre zinc clıronıitc arc

ratlıer poor iıı perforı11arıce aııd a a re ·ult

co ınpos ites with TiO2 or LiZnVO-ı ha c been studied iııstead [ 1

O]

.

Ad ditionally, cer,ııııi c

coıııposites coııta inin g l( ~CrO_₁ or ZnO in z iııc

chro ın ite Jıave bee ıı suggestcd as cand idate

ınaterial s tor hLıııı idity sc rıs iııg [ l 1, 12]. in tlıi s article, the response to relative huın idit)' (R//) ot' porous ceraıııics \Vith co ıı1pc1s itio11 Zn(~r:O

~-K,CrO4 prepared b)1 S()lid stcıte reaction at

elevated teıııpcratures. _\\_'_a_s_s_tu(i_i_c_d.

2. EXPERJM ENTAl.ı PROCE DURI~

Higlıest jJLı rity co ıı1 111 erciall~>' ava ilal1lc po\,vdcrs of

ZrıO aııd Cr O . ~1ere useci tıs J)rectırso rs. l ntinıate

ıııixtLıre of ZııO:Cr .O. \V İtl1

a

ıııo lar ratio of 1: 1

- '

was crLıshed iıı an agate pestle arıd ıııortar fo r 30

ıııiıı . fo llowed by calc iııati o n at teınperatures

ranging betweeıı 800 aııd I l OOl1C witlı a heatirıg rate of 500')C ıı-' iıı a ıııtıfflc fLırııace (Carl1o lite

R WF 12/5 ). Ttıe coıııp()Sitioıı _a_nd tlıe plıase _\_Ve_re

assessed by X-ray diffractio n (Jatterı1s ( himadztı

XRD-600 diffractoıııeter e111ploying a Cu target with iro n-fı ltered rad iat ioıı of wave length

1.54 18A).

The seııso r _rnatcri_a_l_s_\\1erc fab ricated by adding in

various pcrcentages (l1y wc igl1t) of potassİLını

chroınate ₍I<. ,CrO.ı) _to _th_e ZııCr,O

_.

rflıe nıixtLıre

- 1

vvas gro uııd fc)r 30 ıııin ancı co ııııJacted into pellets

( \ı\' it lı a 1 3 111111 i n d i a ııı

c

t

c

r a ıı d l -3 111 m i n t h i c k)

'

at a pressure <.)f 1-2 toıı~ c ııı _, wlıi c lı _\_,_ve_r_e _then

fireci at a te ınpcrate (1 f 1 1 ()()' C to r abo Lıt 12 hours.

The sLırface aııd fractured 111orpl1ologies of tlıe

pel lets were ob erved l1y scanı1 _in_g _e_l_ectro_n ınicroscopy ₍_J_eol JSM IC848). Eleı11eııtal _s_pecies

present iıı tlı t; _p_e_ll_{ets \}_V_{ere a}_l_so _a_nal_ysed u s iııg

eııergy d ispersive aııalys is l1y X-rays ( ED X).

Tlıe d.c. resistance as a fLıııction of relative

lıuıııidity ııı easure ıııe ııts _we_re _c_arried oLıt _u_s_in_g

two po iııt _pr_o_be techııiqLıe. _To _thi_s _purp_ose, _a

l(eithley-236 source and ıııeasure tınit _w_as Lısed .

Tlıe sanıp les wcre iıı iti al ly 111 oLıııted in a custoın

btı ilt clı a ıııbcr, wlıere tlıe l1Lıınidity _{was cont}_r_o_ll_ed

by pass i ng a carrier gas throLıgh water at J)re(i eterıııiııed _rat_es. _{The relat}_iv_e l1L111ıidity _in tlıe cl1an1ber was ıııo nito re(I Lıs in_...g _{a T}_es_t_o ₆₂₅

refereııce l1L1111idity ın etcr . Mctallic contact were

nı ade t'ro nı ga lliuııı \Vhic lı _was fotınd _t_{o g}_iv_e

O lı 111 i c be lı a \1 i o ur . T h e cı. c . i ııı p e d a n c e

nı eas ureııı ents \ ere perforıııed Lısiııg a He,,,ıett

(3)

s ,.\(·ı F'cıı B i linıl e ri Enstitü_ rı D r_~2:i. i 9.C ilt. 2 . Sa,_~·ı ?00 ~

rre lıLıenc range bet\ e ıı 5Hz- l "MJ-lz tı ı . llb an

c. citatio n sigı1al of <50 111V aıııpl itu de.

3. RESUL TS AN D DISCUSSION

,,, l t !1 o Lı g h t he d i

tr

r

a c ti ıı p e a I at 2 O u ( (J ₁₁ : B r a g g

1 \ 1 f 1 0 _c _'' 1 '1 9' "7 ~ ı• 4J-ı _ 5 ''_ 54.011

• <;7_5''_

ı ı ı ı .~ . e _I a 11 g es L) _) . _ı • J _ . . -' . , _ . _ . _ 7

;.r:1,i 63 .2' ()l1tain ed fro n1 tlıc rJ owd r of ?Z11O : 1 Cr,O,

.. ~!ter fi ri 11g <it te ıı1ı)c ratLıres l1et\v~e n 80()- 1 l00''C lor

:·' ,J1 12 hoLırs are 21sSl)C İ c1ted with corre IJ nd iııg r1l aııes

· • --:-n C r ₂O -1 • t lı e JJ e ,l k s a t 2 f) ₁₁ a n g I s o t· 3 4 . 5 l' 4 7 . 7' ·,

·. , 68. 1 '', 69 .21

' are as ociat d witl1 ZııO and tlıe peal<

.• ang le of., 1.9" w itlı Cr₂O,. Tlıese re ults iııdi cated

tespite th e stoicl1İl) 111ctri ratio cl10 eı1 to p rod Lıce a

con1J)ou11d 01· Zı1Cr.:O .. , tlı c for111atio ı1 of Zı1C r2O ..

rıt gone to co ı111Jlet i o ıı tlı r idLı a l ot' botlı ZnO

, , which ,1re videıı t iıı th X-ray patte rns. - .

~ ı;;e 1 ~ , the B rag(J ~Je,ıl< · i rı th

X-

r

a

diffracto ııı t r

r O. fı red at 800 -,1 0 111 tlı po,\.ıd r of 1 n :1 - ' at ,fJ11 ").., 9 1 (I - _) . , 1 f- ı 8 .., ,, ,

o , -,

,,

-,

5 74° , 7 .., 8° aıı-. _... es c.) <. J , J _ _)_) .J . _) . .J 57.4711 , 6, .1 2' 1 , 7l. 63 '\ ,1nd 74.70° ali

ond to plzıııe s )!' Zrı r.0 ₁ iıııpl y iııg the fo rııı ation

·nl) ntı phasc cLıbi c b<.1d)· (. ee F' i sLıre 1 ). T l1e Miller

a rı d the Brc1_g6 JJeal rat ios esti111ated a ı-e iıı detail

· d I wh 're

l

13

l.

Tl1c l::1ttice co ıı stant, an

d

fro

n1

::ızıclı d iffı·acti o n

p

e

a

l

< wa

s

J

Jl

o

tted

aga

in

st

) ,· siı1 () ( not slıL)W tı lı re) aı1d _tl1e extrapolatio n _of

. ta to ()

=

TT / 2 y i e ld d tlıe I attice coııstaııt as

ı, [14] .

2 sho,;y tyJJi cal s coııdary electro11 m icrograplı

he a -fir d . tırface

o

t·

Z11Cr₂0.ı- l(₂CrO.ı (20% ) fireci at 1 0l)01 \C fo r aboL1t 12 h oLırs. Tlı e ceraınic I porou nd a _C'oreat • 111 l13tllf 11u ıııb er w ith of a grain size about

1-po

r

es,

i.nd icative of'

zatio11 ot· o ııe or ınore of tlıe coıı11Jo nents

)

1.,

p ta · iuııı) at lı igJ1 t ınp ratLı res .

Mo

r

eove

r

,

ç,caıı o\ıer tlıe r _Do-i ıı

ot'

_Dara iıı aı1d _~crrai11

1r i re aled tl1at potassiLıın coııtent of graiıı

·.l·ır ie \~a si gııi fica ntJy l1igl1er a coıııpa red ta that

\; _....erain as i · slıc \ n iıı tlı Fi~L~ ıre 3.

-

....

(/) C :::::ı Q.) > ·

_....

-('O

-

Q.) ı... C

----(/) C QJ ... C

ZnCr2()• 'in Ne nı A l gila n1 ,ı Da rani ş iııi ıı l(~( 'r()_~

Eklenerek Ge !i ~tirihııes i , . l(avaso ğ lu

• 1Zn0:1Cr 2 O 3

-•

-

1100°C '-

,

_& _l _ı

.

.. , l ' i _•• _{• 1} '- _- _... _• _l .. ... • ₁ • • . ~ .

-

, • 800°C LI -ı ] - ı_ _- ·ı _-__..__ --~ ..l....~-7 • ₍₁_{11 )} ₍₂₂₀₎₍₃₁ ₁_{) (}₄₀₀_{) (}₄₂₂_{) (}₅₁_{1 ~440}₎₍₆₂₀₎₍₅₃₃₎ . ₁ . ' . 1 -' . _' . _' . _' -' . o 1 O 20 30 40 50 60 70 80 90 Figure 1. X- ray dill'raction patt crııs

or

IZn< - 1 'r,(J, po,\·dcr - ' () ubtaiıı ed alter fi rin_~g in thc ran_~ec 800- 1 100 C' ror about 12 lıour, in air.

Figurc 2. Thc as-fired surlace secnndary electron nıicrograph

o

of ZnC'r, - K,

· ·ro

(2011/0) anıple sintered at l000

c

·

tor

- -

..

about 12 lı ours.

-

,.,,

-·-_C: ~ QJ >

· .,

-m

-

QJ L. C:

-~

z.

· -

V) C: QJ

....

C:

o

K 50 Grain Pores Cr ~ . . • Zn 100 150 200 Energy ( eV)

Fi0 ure 3. Typical EDX pectra recorded froııı the pellet conta in ing 20% K~ rO ... in the in set the potass iuın peak i- re

(4)

..

.', l l Fen Bili111leri En ·titü Li D~rgi.'i 9.l-- ilt. 2 .. a,·ı 2

-F igLı re 4 slı ows d .c. re ista11ce as a fL111ct i on ot· r lati v

lıL1111 idi ty for ZnCr=O• - l( ₂CrO-1 c raıııic y t e ııı ':lt variou

percent21ges of IJOtassİ Lllll c lıro ııı ate. rrh cl.c·. r İ ·tance

\ a a strong fLıııctioıı ot· tlı lıLırııidity for all

'O ıııpositiorı s, decrea iııg b v-ra l rd r f ıııagnitude

LqJ n iııcreasiııg hLııııidity al lıoLı ~ lı on ! nıat rial

c ııtairıir1g 20o/o K, rO di play d aıı xpon ntial belıaviotır as fuııction of

RH.

Thi i br adly coıısistent

\Vİth , hat is ııor111al '~' report d nd i geııeral ly

u rıderstood i 11 terıııs of th r uglı aıı d rb d \ at r plıase

[15 16]. Tlıe co nduction ın clıani 111 ııcluded froı11 tlı

e ideııce given abo e i ioııi and tlıat protoııs ar

p roba b 1 ' t lı do 111 in a ıı t c lı ar g ar r i r l 7] . A I e a t

-quare best fit to th alue ·

f

/.c·. re istaııce verstı

r lativ lıLııııidit for tlı aıııpl c o ntainiı1~ 20°/o l(~CrO

yi ld d lc>g(R) = l0.22 - 0.0 (Rl-f), (fı rR iııolıııısaDıd RH in o/o). 1 o 10 A • ...

..

_ZnCr _O_:_K _C_rO • 2 4 2 4 109 • •

..

...

-

_C

-

_..

-

Jı,.. eı:::

•

108 • •

..

- ~ a.ı . . . . . . . .

..

u . . . . . ••

..

C .. • . . ro . . +-' 107 • •• . . . ... . 1/) ı..

'

.

-1/) • _K_CrO (10%) • ... • (l) ,

.

• • •

....

,.

. ı,_ • K₁Cr0, (20%) •

..

• . 106 K CrO (30%) u _. ... 1 • •

....

"'O . . . Precursor • 20 40 60 80 100 Relative humidity RH (%)

Figure -1. (/.c. re i.-ırınc -· ver·u · rı::l atiYc huıı1idit,~ · charactcri tic of

Z11 ·r_ ₁- K::. ·ro -1 ceranıı c sy:ıeıı1 at var iou~ perccntages of potas iıııı1 c h ro nıa le.

111 aıı atteııııJt to in r a. e oııdLıcti it . Cu.O ,;vas added to

·0111 a nıp le CC)11tai ııiııg 2 · 0_/ _o J)Otas İLıırı chrc1111ate. he

corre poı1di ı1g l.c·. re ·i taııce v rsLı r lati\ıe lıu111idity

clıaracter i ·tic~· ar giv 11 in Fi!.!.ure 5 and _... revea] tlıat the

add iti 11 of LıÜ lıad draıııat ic effect 011 tlıe lıuıııidity

d pen lence. ~rıı add i t ion of oıı 1 1 '~1_o CLı O red uced the resistaııce at low l1Lııııi d ity ( Rf-1 <40o/o) by ap proxiıııately

a ıı o r d r o f I11 a b n i t Lı d e. \V lı i I e at 11 i g lı e r h u ın i el i ty it

a1Jpcar d to lıav.e ııo t~ et. 1 ncrea in g tlıe !eve I of CLıÜ

doJ)İ11 ₆ n t on! red Lıced the low l1uı11idity resistance

ven 111 r it rev r d the slope of the clıaracteristic, so

th t for

RH

<40o/o r i taııce increased witlı i11creasi11g

lı u 111 i d i t . T lı r , ıı

f

o r t h is re ver sa I o

f

s I o p e ar e 11. ot at

pr 11t l r.

lıe arıatıon . .

f

th ıııagnittıde of iınpedaııce ( Z )

r LI fr qLl n - (

.

r

for th a111ple coı1taiııing 20%

K., r ( e F i _Ou re 6) u ıı der a d r

11

u 111 i d a ın b i en t s h o,

a

lıiglı

fr qu ney fail-aft' of Z as

f

-

o.&, \Vhic}1 is due

4

ZnCr20• 'in e nı . Igi lanıa Da,·rani; ini11 I(~ 'r( )

- h:.lenerck Gc li ti ril nıe~· i. . l<. a, u_·llQlu

ıııaiııly to capac ıtı ve effects '" itlıin tlı · 1:t ₁₁₁

froııı cal,les tlı e equip ııı e ııt irır>ut capac itan c and

p lı. s i c a I g_e o ııı et r y

o

t

t h e c on t <1 c t ~ . t fr q u

e

n · i .

b ·low l

o

"

Hz, ıııagn i tLıd e ot- iıııp d n, \ ari ,

very ~ ıowl)1 _\Vİtlı_._/ _· _iııdi _~(_ıtin _g_tlıat _rc_·_i_·_tive-t. _'_J_J

behav ior is n1ore cloııı i ıı aıı t. -r~h is typ of be h ·ı io r

is reported widely in s iınilar ceraıııic syst rrı

[18, 19]. Tlıe Col - Cole plot of coıııfJlex

1, "

i 111 p edan c e ( i . . ,

Z

v r us

Z

w here

Z

a 11 d

,

Z correspond to co ıııı) l e ✓ and r-al ıJart of the

i111pedaı1ce) i also di play d iıı tlı in t of FigLır

6. It consist

f

a d pr s d nıicircl

corresponding to 8 par, llel coınbi11ati n ofa cl.c· .

coı1d Lıctance arı d a · l i glıt l d i p r iv capac itance

togeth er \ itlı a so-call d p · Lıdo-iııdLıctaııc I p

[20]. 109 • 1% CuO • _• _• ₂_% _Cu0 • 108 •

-

5%Cu0 C: • _•

-

_eı::: _• • ~ ·ı '.J 1 D QJ _C: o ₁₀7 _u _• _o C ll C: C'll rı ... ... ... ... 9'.-1 1/) Ll A

..

....

..

·-_1/) ... ...

..

_..

~

-(1) _ı.._ı ı... ... • 106 ... D • Ü ... • 'ti ... 1051---,1"""""'-T" __ ""'I""'"" _ _ ,..."""""' _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ . O 1 O 20 30 40 50 60 70 80 90 100 RH (%) J.~ i o u re S. , /. c. r · i .s t ı1 ıı c ı; r su re I at ive lı un 1 i el it\ (20°/4 ) ceran1ic systenı ch aracteri ·tic ol" the 7n r _:'.O _.J- K C_~ rO at various pcrccntagı:s

o

r

'u(). 1Q5T""ffll ... ""l""l"l . . . . r"""""',._~'l'lll...,,.._ ...

l"l'II_."'"'_

-

_...C N 104 10°

• ••••••

\ 1 1 1

• ••

•

• • • • • • • • • ı_ • ı_ 1 • 'ı . .ı.

-

., 1 -· f ı.10· · • •

-

• . 1 • _• N

•

• • . ~ • 1 • <ti h 10'" .. C _• • _• . o, _• ıı:ı • E • _V -G . n _2:ı1•• ıh,,U ' ı;;.10· B'ıı:10· Re.al Z (U) 102 ₁₀4 ₁₀6 Frequency, f (Hz) 1

'

. 1 . 1 1 1

•

1 ' 108

l,i~urc (L A plot

o

r

Z ver. us frcquenc_; for the sanıple

nııtaining 20<1/o K :C' rO.ı undcr 22r1/ı> RH . in the in et Cnlc

-c·oıc plot I' th iıı1ped ·ııı e ıııeasurecl for tlıis sanıple i. also

(5)

~ .. \( ' ı ·cn Bilinılcri Cnstitüsü Dergisi 9.C'il t. 2.S,t) ı 2()05

,.\ lıoıııe-nıad e ZnC r_O :- l<._CrO.(1 ₀_°0 ₎ _ce_r_a_nıi_c_lıuııı _ic_l _i_t_y

ı...cn.:;ı.1r \\a ' also satisfactoril)' cal ibratcd Ll ing a rcfereııce

J₁Lıtııiciit) seıı ·or

S

HT

75 .

obtained frt) tıı .. · en s iri oıı . To

lhut c1iııı. a nt1vc l _circu _i1r_y_· Cl,ns isti ııg ofa 11 l1it A D.

s ı I 1·7) iııtc rfacc ci rcLıi t aııti I to V l1ri tlgc aıııı, lifi cr \:vas

Lit'\ ell)ped. rrlıc t);pical sanıı,ling rale () r de el()jJell ı\ 'D

circuit i~ alıl)Ut l () kl-17. aııd it works 0-5 V rangc \Vİtlı an

aı,ı1rL) \ İnıatcl ₁ 1.25 111V reso luti o ıı . ·1·1ıc c ircu it is

•~n1trt)llec.i l,\· a ()l1asic rl1 ut iııe t)tl tlıc l)(' \Vlıic h all <1\\ s to

-

-!LClU i re (.)tlC hu ııllrcd dat~l ~1er SCC()llCI. ·r•ııc

S

i rr

7:

i . a

1

-in~lc chi11 ıııulti se ııso r ııı ()dtılc iııc luclin g a ca ı)ac iti e

~

... l\111\~r _, lıunıi(lity' sc ııs iııg c lc ıne llt aııtl a l1anli gap

_ , 1 11 ı.: r 8 t u r c ~ c il s o r .

4. CONC LUSION

ıı1cıı'ıtL1rc sensitive ZııCr C) , ccraııı ic l1t1dy jJ rodLıced

- -,

+h~ ~olid ~lale rcnctio11 lJCl\vccıı 1.inc c)x idc aııd

1ııl,~ L) :-<İdc at c lcvc_ltcd tt:ı1111cratu rcs cli sıJ la)·eci a

, 11 )t1r scıı~ iıı g 11erfc)r11ınncc tt1 lıLııııid it: . l l o \Ve\ıer.

~ı~taııct.' a~ a ftıııctioıı l1f rclati e huııı idity slıO\\:ed g clc11cnlicncc, <.iccrcasing l) \1er se\'Cra l or(i ers 01·

udL \\ itl1 iı1c rca~i 11~ _{._} lıtııııidi t\_•' l)ci n_{' -}~ c.l s nıooth

~ 1 nli~ıl in thc ense t11· tlıe sanııı lc ı) reıJarccl using

ı) (.., ()0 o) iıı /nl"r () ,. 1·11e cıJ (Iİtİ c) n C) f ( .,u() rc sulted

•

İliC rL·~t"ıC 111 tlıc cc1 ıı c.lu cti\.ıit,· l,u t lıuti a tie leteric)us

r

·Ll ()11 tlıc lıu ıııillİt\ . · ı he~~ rc~uıt ~ İn (l ic,1te Llıat

)

1,

( 'rt)

_.

~_.,,·~tc ıı1 c1 ıı cc calc iı1 ccl , c<.1 1111Jactc<.i aııd L'Ll uııdcr 11r()pcr t.:()11<.l it İ<1 11s ha · 1Jote11ti'11 Lıse as aıı

111tılcrinl lt)r tlıc· lıtııııiclit\_-' scnsors.

ACKN OWLEDGEM~:NTS

ıu tlll)rs like tc) acl(tlC) \Vlcdge fiııan c ial SLIJ)port l1y tlıe

ı , ers ıı}· t)I' Muğla, Researc lı Project Fc)Ltn(iation (AF~P

ı

).

1 lı C \ . n r C t! r at C

r

LI I t o A .

w

.

B r i il k 111 a 11 f o r l1 e I p fı.ı l

.

'-.; e

til111s antl c.i i sc tıssioııs. Tlı ank.s are also dtıe to Ş .

1k lt)r lıi~ ct1ııtiı1tı0Lıs supp ort of tlıis \Vork.

5

ZnC 'r₂C)-ı 'in 1c111 ,'\lgilan1a Oa,·rani ~inin l( :( 'r() ₁

f-:klcncrek Cicli~tiriln1~si. . 1<.n, a~<)ğlu

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[ 2 O ] . A . K . J

o

rı

s

c

he r,

D

i e

I

e c t r i c·

R

e

/

cı.Y cı l i c) ı 1 i 11

.

'

,c>li(

/

s

(Chelsea Dielectric Pres , Londotı