Sains Malaysiana 39(4)(2010): 621–626
Kelakuan Pengesanan Tekanan Bagi Seramik
Natrium Bismut Titanat
(Pressure Sensing
Behaviour of Sodium Bismuth Titanate Ceramics)
Mohammad Hafizuddin Haji Jumali*, Mohd Riduan Mt Said, Ngoi Yung
Wee & Muhammad Yahaya
Pusat Pengajian Fizik Gunaan, Fakulti Sains dan Teknologi
Universiti Kebangsaan Malaysia, 43600 UKM Bangi, Selangor D.E.,
Malaysia
Muhammad Mat Salleh
Institut Kejuruteraan Mikro dan Nanoelektronik (IMEN)
Universiti Kebangsaan Malaysia, 43600 UKM Bangi, Selangor D.E.,
Malaysia
Diserahkan: 16 September 2009 / Diterima: 5 Januari 2010
ABSTRAK
Satu kajian
bagi menentukan kesan suhu ke atas mikrostruktur dan kelakuan pengesanan
tekanan seramik Na0.45Bi0.55TiO3 (NBT) sebagai bahan piezoelektrik bebas plumbum telah
dilakukan. Seramik NBT disediakan
secara tindak balas keadaan pepejal daripada campuran serbuk Na2CO3, Bi2O3 dan TiO2. Campuran serbuk disinter pada tiga suhu yang berlainan
iaitu 1100 oC, 1200 oC dan 130 0oC selama 12
jam. Selepas disinter, serbuk NBT dikisar
dan dimampatkan menjadi pelet berdiameter 13 mm diikuti pemanasan selama 2 jam
pada 700 oC.
Mikrostruktur dan morfologi sampel masing-masing dikaji dengan menggunakan XRD dan SEM. Sifat
pengesanan tekanan NBT diuji
dengan menggunakan kebuk tekanan pneumatik. Analisis pembelauan sinar-X
menunjukkan semua sampel mengandungi lebih 70% NBT berstruktur rombohedral sebagai fasa utama dan bakinya
merupakan fasa sekunder Bi2Ti2O7 (BTO). Kenaikan suhu sinteran didapati meningkatkan kandungan
fasa NBT di dalam
sampel. Mikrograf SEM menunjukkan
saiz butiran dan ketumpatan sampel semakin meningkat dengan pertambahan suhu
sinteran. Ujian sifat pengesanan tekanan menunjukkan kesemua sampel memberi
sambutan apabila voltan pemula diberikan. Berdasarkan faktor ketumpatan,
kestabilan dan kebolehulangan sifat pengesanan tekanan, seramik NBT yang disinter pada suhu 1200oC merupakan seramik yang terbaik dan berpotensi digunakan
sebagai sensor tekanan.
Kata kunci:
Natrium bismut titanat; perovskit; piezoelektrik; sensor tekanan
ABSTRACT
A study to
determine the microstructure and pressure sensing behaviour of Na0.45Bi0.55TiO3 (NBT) as
lead-free ceramics has been conducted. NBT ceramics were prepared using the solid state reaction
technique from stoichiometric mixture of Na2CO3, Bi2O3 and TiO2 powders. The mixture was sintered at three different
temperatures namely 1100 oC, 1200 oC, 1300 oC for 12 hours. After sintering, the NBT powders were ground and pressed into pellet with 13 mm
diameter and subsequently heated at 700 oC for 2 hours. Microstructure and morphology of the
samples were determined using XRD and SEM, respectively. Customized pressure chamber using
pneumatic load was employed for pressure sensing behaviour of the samples.
X-ray diffraction analysis revealed that all samples consist of more than 70%
of polycrystalline, rhombohedral NBT phase, with bismuth titanate, Bi2Ti2O7 (BTO) as the
secondary phase. The increment in sintering temperature has resulted in the formation
of higher NBT content in
the sample. SEM micrographs
showed that grain size and bulk density of the samples increased with the
increment of sintering temperature. Pressure sensing test showed that all
samples were responsive toward pressure variations only when initial voltage
was applied to the ceramics. Based on density, stability and repeatability in
pressure sensing behavior, NBT ceramic
sintered at 1200 oC
was the best ceramic with great potential as lead free pressure sensing
material.
Keyword:
Piezoelectric; pressure sensor; perovskite; sodium bismuth titanate
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*Pengarang untuk surat-menyurat; email: hafizhj@ukm.my
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