Low-temperature combustion synthesis of Bi4Ti3O12 plate-like structure and some of its characteristics.

lv{alm,sian Joumal of ivlicroscopl' Vol 6 (20 ]0) pg. 69-74

LOW-TEMPERATURE COMBUSTION SYNTHESIS OF Bi,rTi:Ore
PLATE.LIKE STRUCTURE AND SOME OFITS CHARACTERIZATION
A. Umar Al-Amani, S. Srimala-, M.N. Ahmad Fauzi and A.R. Khairunisak
School of Material and Mineral Resow'ces Engineering, Universiti Sains Malaysia, 14300
Seberang Perai Selatan, Nibong Tebal, Penang

Bismuth titanate, BiaTiiOp was prepared at different hydrolysis temperatules ond
characterized with XRD, Rietveld analysis, TG-DTA, FESEM and TEM. The results
indicated that the pure bismuth titanate was obtained after combtrstion at lo*et
temperature of about 260 "C. Interestingly, no calcination step involved to obtain
bisrnuth-strtrctured layered. The effect of hydrolysis temperatttre at 4A ''C, 50 ''C'
oC
on phase.fotmation, lattice parameter, crystallite size, thennal behavior
and 60
as well as grain morphologies was investigated.

Keywords: Bi+Tr:Or:; Low-temperature combustion; Chmacterization

INTRODUCTION


used

Bismuth titanate, (Bi4TirOr2) has been
access memory

for ferroelectric tandort

to its

glycol-assisted hydrothermal rnethod

at

200

oC. However, there are some lirritations in

fenoelectricity [1]. This compound has been


both processes such as the difficulty to
understand the phase evolution and rnechanical

prepared using a rvet chemicai technique such
as sol-gel, hydrothamal, precipitation aud

hydrothermal process in terms of experimentai

(FRAM) devices due

outstanding

Wet chemical
molten-salt synthesis
technique is preferred because a single phase
Bi4Ti3Or2 can be obtained at low temperature
[3]. In early stage, Bi.rTirOrz has been prepared
using conventional solid state which often

l2l.


results

in high

aggiomeration

and

low

sinterability of powders because of high
oC and repeated
calcination beyond 1000

grinding [4].
Several studies have emerged as the
leading techniques to lorm BiaTi3Or2 have been
produced
reported. Han and


Ko t5l

nanocrystalline Bi4Ti3Or2 powder using an
intense meehanical activation of a rnixtr::'e of
o-BizO: and TiO2 after a milling time of 9
hours. Gu et al. [6] reported that BiaTi3O12

activation condition and the courplexity of
set up.

Therefore, in this wort we use the
combustion method to produce Bi+Ti:Oi:. The
current approach offers great advantages such
as simple experimental set up, capability to
produce high purity powder with excellent
homogeneity, eliminate calcination step and
relatively low fonnation ternperature of a
single phase [7-9]. However, comprehensive


investigation on the processing parameter
needs to be conducted in order to r.mderstand
the relation between processing parameter with
properties of the BiqTiror2. In this paper, the
the
effect
hydrolysis temperahre
formation of BirTi:Orz is reported.

of

nanopiates were synthesized by polyethylme

* Correspondingauthor: Tel. +6 (04) 5995255; Fax+6 (04) 5941011
E-mail. [email protected] (5. Sreekantan)

on

i


\II

-r

----. i -i-::r:

iJ \, -4hmad Faci

and A.R.

Khoinnisak

solutron. After that, the temperuture rvas raised
rnixture,

TH OD S .1.\D \I-A,TERL{LS

to 80 'C to form a dried powder

::.:::: :':=1.--:- f\', riop:oporide iiere used

:: :=-::t: ::ia.:IrarS. Inlialll', bismuth nitrate
:=-:r11i::. u'as added rnto a conical tlask

subsequently, gently crushed using an agate
mortar pestle. 'Ihe crushed powder was placed
back on a hot plate to cornplete the cornbustion
process. The combustion temperatue was then
recorded by thermocouple.

:e:ce:a:r:e \las confolled at 40 0c under
;lrjia:i sILnng. Simultaneously, citric acid
+ai di.solr.ed in distilled rvater and stirred at
rcc:n :arnperarure. After that, citric aqueous

combustion)

3,s:.-.-:: :t:::=r: oe;rrlahldrale, citric

::a: r.rl2neii drstilled wata-. The conical flask
n:s -:i:r placed in a water bath and the


u.ere added to bismuth aqueous and constantly
sired to iorm bismuth mixture. Separately,
titanium (IV) isopropoxide rvas dissolved in 2)Iethaoxyethanol (Sigma-Aldnch, ?_99 %) to
torm aqueous solution of Tia- ion. Then, the
.lqueous of Ti'- ion rvas slowly added into
bismuth mxflue. The obtained mixture (which
aiso knou.ri as precursor soiution) was adjusted
to pH 7 by usLng NFIaOH (29 % solution). The
precusor solution with milky color lvas
oC,
hldrolyzed at 40
50 'C, and 60 'C and
stirred for 24 h to obtain more homogeneous

t3,?141 Bi4Ti3Ol

The dried powders

(belbre

il
thennal analysis

were anaiyzed using

thermogravimetry-differential

(TG-DTA). On the other hand, the ascombusted powders were characterized by
using X-ray diffraction (XRD), fie1d emission
scanning electron microscopy (FESEN{) aad
transmission electron microscope (TEM). The
lattice parameter aad crystallite size of the ascombusted powders were calculated using
High-Score Pluss softrvare and Schener's
formula, respectively.

-

N
c
o


30

10

40

50

20 (o!

Fig.

1.

XRD profile
temperature.

for the


as-combusted powders prepared

70

at different

hydrolvsis

LOIY-TEMPERATURE COMBUST]ON SYNTHESIS OF Bi'Ti30II PLATE-I}KE S?RUCTURE AND SOME OF ITS
CHARACTENZATION

RESULTS AND DISCUSSIONS
XRD arulysis
The XRD profile for the as-combusted
porvders prepared at different hydrol;sis
temperatue is shown in Fig. 1. The result show
that all ttre difliaction peaks are corresponding
to BiaTi3O12 phase and matched well with PDF
# 73-2181. The absence of any other peak
confinaing a single phase of BiqTir0rz was

successfully obtained

at

lorv-temperature

combustion synthesis. Besides that, it was also
noticed that the hydrolysis temperature had

significimt influence
characieristic.

It

on diftaction

peak

was noted that the broadness

of the peak reduced with

increasing of

crystallinity degree. Based

or

hydrolysis temperature, indicating
arralysis, the variation

'I'able

1.

high
Rietveld

of lattice parameter was

clearly affected by hydrolysis temperanre. We
also found that a- and b-parameters rvere not

always close; thereiore

it

confirmed that

Bi4Ti3Orz compounds matched well with
pseudo- orlhorhombic strucnrre. With the
hcrease of this parameter, the volume of
orthorhombic sfiuctwe of BiaTi3012 also
siightly increased and the result obtained at 60
oC
was considered very close to the standard
file. As mentioned in the experimental section,
the crystallite size at the peak position (i17)
was calculated using Scherrer's equation [10]
and the result is shown il Table 1. The result
showed that the crystallite size was strongly
dependent on the hydrolysis temperature. This
was attribute.d by the increase of grain size.

Lattice parameter and crystallite size of the as-combusted powder at different
hydrolysis temperature calculated fiom XRD data

400c

50nc

600c

al A.

5.4i50(1)

5.4140( 1)

b/A

5.4400(1)
32.7730(6)

s.4440( 1)

5,420(2)
5.447(2)

32.7840(6)

32;/75(8)

96s.3 804

956.2748

967.s442

Space group (No.)

Fmmm(69)

Fmmm(69)

Fmmm(69)

R (expected)/ %

4.62321

4.32741

4.92416

R (profile)/ %

10.458s

lt.86494

11.96359

14.20051

14.25008

Lattice pararneters

cl A

V/

i06 pm3

R (weighted proftle)/

o/o

Density (calculated)/ g/cm
Crystallite size (nm)

1

t2.3113
8.06

8.052s

8.0419

24.1

26.4

26.5

TG-DTA analysis

The thermal behavior of the dried
porvder rvith dilferent hydrolysis temperatures
is shorvn in Fig. 2. As seen the decomposition

process can be divided into hvo distinct stages
in the TG plot (Fig. 2(a)). This trend was

shown by three different

hydrolysis

A. Umar Al-Amani, S. Srimala, M.N. Ahmad Fauzi and A.R. Khairunisak

temperatures. The first weight loss took place
at temperature rangc at temperatrue range

of50

- 181 "C. This causes to the vaporization of the

residual water, organic solvent such as 2methaoxyethanol, isopropoxide and hy&oxyl
groups. It lvas correlated with thg small
endothermic peak at 121 "C and 151 "C (not

shown here) The second rveight ioss
accompanied by a sharp exothermic peak took
piace at different temperahrres i.e, 242 'C,244

'C ard 246 "C for 40 oC, 50 oC and 60 'C,
respectively. Large exothermic peak was due to
vigorous oxidation-reduction reaction or
cornbustiq! between dgqoryposed citric acid

and nikate ions which then led

to

crystallization of bismuth tiianate.

This frrding confirmed that the
oombustion reaction dependent on the
hydrolysis temperatures of the precursor
solution. It was wor& to note that no further

the temperature ofbelow 260 "C represents a
srtfficient temperature for the formation r,rf a

crystalline Bi+Ti:Or: from the con-rbuslion
reaction.

Micro stru cture analysis

The FESEM (Fig.

3(a))

microstructures of the cornbusted powders
hydrolyzed at 60 "C are shown in Fig. 3, The
images for 40 "C and 50 "C rvere not shorvn as
the change in terms of size and shape were not
so obvious. The Bi+TirOrz povvder was mostly

composed

of

plate-like grains and

the

approximate diameter of grains was about 200
nrn. Since the size was quite fine, the particles
formed with high agglomeration as clezrly
observed by TEM (Fie. 3(b)).

weight changes and heat effects were observed
nC,
indicating
in the TG-DTA cun/e up to 500

{b}

50'c

40'c i

{a}
60'c

teo

:-3
3-4

50"c

40'c

200

300

Temp€rature

Fig.2, Thermal behavior

locl

240

femperatun (ocl

of as-combusted poxders with different hydrolysis temperatur.e:

(a) TC and (b) DTA.

LO'Y.TETIPERAN]RE COJI{BUSTION SYNTHESIS OF BiILOTJ PLATE'I,IKE STRUCTUKE AND SOME OF IT'S
CTTARACTENZATION

Fig.

3.

Plate-like grains of as-comtrusted powder hydrolyzed at 60 "C: (a) FESEM and (b)

TEM,

CONCLUSION

tLl

Bi+Tirorz powder rvas successfully
obtained by a combustion synthesis at very low
temperature. It rvas confirmed by XRD and

TG-DTA. Siudy on hydrolysis temperaure
showed the variation of structure lattice
parameter that was confirmed by Rietveld

Bismuth Tiianate Ceramics,

t3l

f

E

ternp emhrre was essenlial paralneter

Slr.lvl ano I

1919.

t4l

-ts.lVI.

ACKNOWLEDGMENT
The authors appreciate the technical
sripport provided by the School of Materials
and lvlineral Resources Engineering, USM.
This research was suppofled by the E-science
Fund 305/Pbahx1601,3357, Short term USM
304.PBahan.6035267 and USM-RU grant
100l,PBahan/8042018.

Pookmanee, P., BoonphaPk, P.,
Phanichphant, S. (2004). Chemical

synthesis oF bismuth titanate
microparticles, Ceram. Int., 30 1917-

to

produce Bi4TilOt2 powder. Nano-platey
stnlchrre of BirTi:Or: rvas clearly observed by

t5l

Kan, Y., Jin. X., Wang, P., Li, Y., Cheng,
Y.B., Yan, D. (2003). Anisorropic grain
grorvth of Bi+Tirorz in moiten salt fluxes,
lvlateL Res. Bull.,38 567-576.

Han,

I(,

Ko, T. (2009).

phase formation

nanoporvder

t6l

Gu, H.,

Zou,

by mechanicai alloying, J
490495.

Hu,2., Hu, Y., Yuan, Y., You, J.,
(2008). The structure aild

W.

photolurninesoence
Chen, M., Liu, Z.L.,Wang,

Y.,

735-739.

of

Bi4Ti3Or2

nanoplates sl,nthesized by hydrothennal
nrethod, Colloid Sutfaces A., 315 294298.

Wang,

C.C., Yang, X.S., Yao K.L. (2004).
Ferroelectric properties of Pr6O11-doped
BiaTi3Ol2, Solid State Commun., \30

SYnthesis and

of ferroelectric Bi4TiiO12

Allo1, Q6sO6., 473

REFER.ENCES

t1l

Sci.

Sintering,3T 199-216.

analysis.Dii-ferent exothennic telnperanres
were aiso recorded in DTA, intlicating tlte
hydrolysis

Lazarevii, 2., Stojanovi6, B.D., Varela"
J.A. (2005). An Approach to Analyzing
Synthesis, Structure and Properties of

t7l

Patil, K.C., Aruna, S.T., Mimani, T.
(2002). Combustion synthesis: an update,
Cun'. Opin. Solid State tVat Sci., 6 50'1
512.

A. umar Al-Anani, S. Srinala, lrf.N. Ahnad Fqilzi ctld A.R. Khaintnisak

t8l

Luo, S., Tang, 2., Yao, W., Zhang, Z.

(2003). lrw-temperature combustion
synthesis and characterization of
nanosized tetragonal barium titanate
powders, Mio'oelectron. Eng., 66 141152.

[9]

Franco Junior, de Olivera Lima, E.C,
Novak, M.A., Wells Jr, P R. (2007)'
Synthesis of nanopadicles of Co,Fe13-'yO.r
by combustion reaction method, J. Iulagn.
Magn. Mater., 308 198--202.

[10] Burton, A.W., Ong, K., Rea, T., Chan,
I.Y. (2009). On the estirnation of average
crystallite size of zeolites from the
Scherrer equation: A critical evaluation of
its application to zeolites lvith onediraensional pore systems, Micropor.
Mesopor. Mater., 117'1 5-90.