Arnon Chaipanich

Effect of Poling Temperature on Piezoelectric Properties of 0-3 PZT-Portland Cement Composites

Lead zirconate titanate (PZT)-Portland cement (PC) composites were produced and the effect of poling time on the piezoelectric properties such as piezoelectric coefficient (d33) and electromechanical coupling coefficient (Kt) of 0–3 connectivity PZT-Portland cement (PC) composites were investigated. PZT-PC composites were produced using PZT of 60% by volume and the poling time of 15, 30, 45, 60 and 90 minutes were used. The results showed that when using the poling time at 45 minutes, the d33 and Kt values were found to be highest at 28 pC/N and 19.87%, respectively.

Ferroelectric Hysteresis Behavior in 0-3 PZT-Cement Composites: Effects of Frequency and Electric Field

Lead zirconate titanate (PZT)-cement composites of 0-3 connectivity were produced and the effects of the frequency and electric field on the ferroelectric polarization-electric field (P-E) hysteresis of the composites were investigated. It was found that there was an increase in both the instantaneous remnant polarization (P ir ) and coercive field (E ic ) when the applied field increased. The instantaneous remnant polarization (P ir ) was found to reduce when the frequency was increased. The ferroelectric hysteresis loops only existed when the composites were subjected to lower frequency; i.e. at 20 and 40 Hz. At higher frequency, the loops tended to stretch out, showing more of a lossy characteristic.

Effect of PZT particle size on the electromechanical coupling coefficient of 0-3 PZT-cement composites

PZT-cement composites were produced using PZT ceramic of different particle size (3.8 μ m to 620 μ m). The effect of PZT particle size on the electromechanical coupling coefficient (Kt) of the composites was then investigated. The results showed that the particle size of PZT used to produce the composite has a noticeable effect on the Kt values. The electromechanical coupling coefficient was found to increase with the particle size of PZT used where Kt values are found to be at 16.1% and 20.5% for composites with median particle size of 3.8 μ m and 620 μ m respectively. Enhanced piezoelectricity can be explained when PZT ceramic particle increased since there would exist a more functioning ceramic (accompanying more PZT grains) and less contacting surfaces between the PZT ceramic and the cement matrix. These would lead to better piezoelectric properties of the composites.

EFFECTS OF PZT CONTENT AND PARTICLE SIZE ON FERROELECTRIC HYSTERESIS BEHAVIOR OF 0–3 LEAD ZIRCONATE TITANATE—PORTLAND CEMENT COMPOSITES

Lead Zirconate Titanate (PZT)-cement composites of 0–3 connectivity were produced and the effects of PZT particle size and PZT content on the ferroelectric hysteresis behavior were investigated. It is clear from the hysteresis measurements that the particle size has a strong influence on the polarization-electric field loop of composites with smaller particle sizes of 75 μm and 212 μm the loops were found to exhibit a lossy characteristic. At 425 μm particle size, the composite exhibits a more typical ferroelectric hysteresis loop. There is also a significant increase in the remnant polarization with increasing particle size where the composite of 425 μm was found to have a significantly higher instantaneous remnant polarization (Pir ) in comparison to the composites with smaller particle sizes. Furthermore, Pir was found to increase as PZT volume increases from 40–60%, while coercive field (Eic ) decreased and reached a saturated value when PZT volume content is 60%.

Dielectric Properties of Lead-Free Composites from 0-3 Barium Zirconate Titanate-Portland Cement Composites

The dielectric properties of lead-free composites from 0-3 barium zirconate titanate-Portland cement composites were investigated. 0-3 BZT-PC composites were produced using BZT content at 30–70% by volume. The dielectric properties at various frequencies with difference BZT content were investigated. Parallel, cube and series models were also compared to the dielectric measurement results. The results showed that the dielectric constant of BZT-PC composites increased with increasing BZT content where ϵr values at 1 kHz are 225 and 549 for composites with 30 and 70% by volume respectively. The dielectric properties of BZT-PC composites were also found to depend on the frequency tested.

Microstructure and Characterizations of Portland-Carbon Nanotubes Pastes

This research studied microstructure and characterizations of Portland cement with carbon nanotubes (CNTs) which were used as an additive material at 0 %, 0.5 % and 1 % by weight of cement. The compressive and flexural strength tests of mixes were conducted using water/cement ratios (w/c) of 0.5. Samples of mixes were selected for SEM analysis and then ground for TGA analysis. The results show that the compressive strength and flexural strength at all aging time of Portland-CNTs cement composites was higher than that of control mix. Microstructure results show that CNTs was filled in pores between matrix phases to show denser phase and TGA graphs show similar phases to PC mix.

Effect of Carbon Addition on Dielectric Properties of 0-3 PZT-Portland Cement Composite

The dielectric properties of the 0-3 lead zirconate titanate (PZT)-portland cement (PC) composite with carbon addition were investigated. Lead zirconate titanate (PZT), Portland cement (PC) composite and carbon powder were fabricated using 50% of PZT, and varying addition of carbon 1, 2 % by volume. The dielectric properties were measured under room temperature at different frequency from 1kHz-20kHz. Carbon addition was found to slightly increase the dielectric constant of PZT-PC composite at room temperature. The results also show that both the carbon powder addition and frequency affected the dielectric constant and dielectric loss tangent of 0-3 all PZT-PC composites.

Acoustic and Piezoelectric Properties of 0-3 Barium Zirconate Titanate-Portland Cement Composites-Effects of BZT Content and Particle Size

Lead-free 0-3 Barium zirconate titanate (BZT)-Portland cement (PC) composites, environmentally friendly piezoelectric materials, which are expected to find applications in smart concrete structures due to their good compatibility with the host concrete, are studied. The results indicate that the composites can be tuned to a compatible value to match the requirement of concrete structure. For 425 μm BZT particle size used for the range tested at the same volume led to optimum piezoelectricity in composites. The electromechanical coupling coefficient was found to be ≈17% for 70% BZT composite. Several mathematical models are applied for the calculation of the piezoelectric coefficient of the composites and the experimental results were closest to those calculated from the cube model.

Effect of Polarization on the Microstructure and Piezoelectric Properties of PZT-Cement Composites

Lead zirconate titanate (PZT)-Portland cement (PC) composites were produced and successfully poled at different poling field and time. The effect of polarization on the microstructure and piezoelectric properties were then investigated. It was found that, at a fixed poling field up to 2 kV/mm, the piezoelectric coefficient (d33) was found to increase with poling time. The optimum poling time was found at 45 minutes where d33 value is 42 pC/N. The optimum and most practical poling field found for the composite was at 2 kV/mm. Lower poling field would give the composite lower piezoelectricity and poling field that is too high would result to breakdown of samples. Therefore, from these results, a poling field of 2 kV/mm at 45 minutes would be the ideal polarization condition used in poling PZT-PC composites.

Effect of Particle Size on Dielectric and Ferroelectric Properties of 0–3 Lead Magnesium Niobate Titanate-Portland Cement Composites

The effect of lead magnesium niobate titanate (PMNT) particle size on the dielectric and ferroelectric properties of PMNT- Portland cement (PC) composites was investigated. PMNT of various particle sizes (75–425μm) were used at 50% by volume to produce the composites using the mixing and pressing method. Dielectric properties at various frequencies (0.1–20 kHz) and ferroelectrics behavior of the PMNT-Portland cement composites were investigated at room temperature. The results show that the dielectric constant of PMNT- Portland cement composite are found to increase ( = 154 for particle size 75 μm and = 275 for particle size 425 μm (at 1 kHz)), while dielectric loss decreased with increasing particle size of ferroelectric PMNT ceramics. Furthermore, the “instantaneous” remnant polarization (Pir ) of composites was found to increase with increasing PMNT particle size.