The Effects Of PVA Binder On The Structural And Dielectric Properties Of BNT-BT Ceramics

• Main Author: Mohamad, Nurul Jannah
• Format: Thesis
• Language: English; English
• Published: 2020
• Subjects: Q Science (General); QC Physics
• Online Access: http://eprints.utem.edu.my/id/eprint/25394/1/The%20Effects%20Of%20PVA%20Binder%20On%20The%20Structural%20And%20Dielectric%20Properties%20Of%20BNT-BT%20Ceramics.pdf; http://eprints.utem.edu.my/id/eprint/25394/2/The%20Effects%20Of%20PVA%20Binder%20On%20The%20Structural%20And%20Dielectric%20Properties%20Of%20BNT-BT%20Ceramics.pdf; http://eprints.utem.edu.my/id/eprint/25394/; https://plh.utem.edu.my/cgi-bin/koha/opac-detail.pl?biblionumber=119680

Bismuth Sodium Titanate – Barium Titanate (BNT-BT) is known as a lead-free piezoelectric ceramic with perovskite structure. In this work, the preparation of BNT-BT with different PVA (Poly vinyl alcohol) binder contents using solid state reaction was done. This work is mainly to study the effectiveness of PVA binder on the structural and dielectric properties of BNT-BT ceramics with different sintering temperature. Good sintering temperature can improve the density of material at times. In general, the PVA binder agent is used to form the shape of green body and bind the granules together that can help the materials achieved densification through changes in particle shape with high sintering temperature. The main problem of the BNT-BT ceramic is to have a high density and low porosity, whereby the weight percentage of PVA binder to be added is important. Preparation of BNT-BT with different composition of PVA binder (0.0, 0.1, 0.3, 0.5 and 0.7 wt%) was initially carried out by conventional milling methods; the starting materials of (Barium carbonate- Sodium carbonate- Bismuth oxide- Titanium Oxide) BaCO3-Na2CO3- Bi2O3-TiO2 are subsequently milled, calcined and sintered. In this work, X-Ray diffraction (XRD) is used to analysed the phase formation of material. Based on phase analysis using XRD technique, single phase of BNT and BT powder was successfully synthesized at calcination temperature of 950oC with 4 hours soaking time. After that, single phase of BNT-BT was successfully synthesized for all different compositions with three different sintering temperatures. The peak shifted towards lower angle and get broaden when increasing the composition of PVA content, indicating that the crystallite size is decreasing. Among all of the sample, the BNT-BT with 0.1 wt% composition of BNT-BT has exhibits single phase and has clear distinctive peak of both rhombohedral and tetragonal peak. It also has the highest density when the sintering at 1170oC which is 96.08%. The sample is also dense and uniform in grain size and turn into spherical in shape indicating a complete BNT-BT perovskite structure. BNT-BT with 0.1 wt% composition of PVA binder also has the highest dielectric constant and lowest dielectric loss at room temperature. Therefore, the lowest PVA amount is simply the good composition in this case. Hence, the dielectric performance of materials can be increased.