Ruamporn Potong

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.

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 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.

Ferroelectric Hysteresis Properties of 0–3 Lead-Free Barium Zirconate Titanate-Portland Cement Composites

Cement-based 0–3 type lead-free piezoelectric composites, made from barium zirconate titanate (BZT) ceramic particles and Portland cement (PC) are developed for smart or intelligent structure in civil engineering. Ferroelectric hysteresis properties of the composites with different BZT contents at 40–70% by volume were then investigated. The results showed that the ferroelectric hysteresis loops can be seen for all composites. The “apparent” remnant polarization (Pr′ ) was found to increase with increasing BZT content. The “apparent” coercive field (Ec′ ) was found to decrease with increasing BZT content from 11.0 to 7.30 μC/cm2 at 15 kV/cm when BZT volume content used was 40% and 70% respectively.

Effect of Temperature on the Dielectric Properties of 0-3 PZT-Cement Composites

In this work, 0-3 lead zirconate titanate (PZT) was mixed with normal Portland cement to produce 0-3 connectivity composites. The effect of temperature on the dielectric properties such as the dielectric constant and dielectric loss was determined. It was found that with increasing PZT content the Tc increases where the optimum dielectric constant was observed and that at the temperature up to 100°C there is a significant change in the dielectric properties in PZT-cement composites. This is due to the loss of water molecules at up to 100°C. At above 100°C, the dielectric properties of the composites were found to have a similar behavior to that of PZT ceramic with Tc being ≈420°C.

Acoustic, dielectric and piezoelectric properties of 1-3 connectivity barium titanate-portland cement composites

The 1–3 barium titanate (BT)-Portland cement (PC) Composites were fabricated using dice and fill method for smart materials applications in civil engineering structure. The acoustic, dielectric and piezoelectric properties of composites were studied. The results show that the acoustic impedance of the composites can be tailored to match that of the host structure, concrete. Moreover, the dielectric constant (ϵ r) and piezoelectric coefficients (d 33) of the composites increased with the increase of BT volume content. The d 33values were found to be 63 pC/N and 128 pC/N for composites with BT volume content of 30% and 70%, respectively. Therefore, this new kind of lead-free piezoelectric ceramic-Portland cement composite has potential to be used for smart structure in the civil engineering field.

Effect of Particle Size on Dielectric Properties and Hysteresis Behavior of 0-3 Barium Zirconate Titanate-Portland Cement Composites

In this work, the effect of barium zirconate titanate (BZT) particle size on the dielectric properties and hysteresis behavior of 0-3 Barium zirconate titanate- Portland cement composites was investigated. BZT of various particle sizes (75, 212 and 425 μm) were used at 50% by volume to produce the 0-3 lead-free composites. The results showed that the dielectric constant at 1 kHz of composite was ≈ 350, while dielectric loss decreased with increasing particle size of BZT ceramics. It is clear from the hysteresis measurements that the particle size has a strong influence on the polarization-electric field loop of composites. The composite at 425 μm particle size was found to exhibit a more typical ferroelectric hysteresis loop.

Effect of Particle Size on the Dielectric Properties of Sodium Potassium Niobate -Portland Cement Composites

In this research, the effect of sodium potassium niobate, (Na0.5K0.5)NbO3 (NKN) particle size on the dielectric properties of 0-3 non lead based piezoelectric cement based composites were investigated. NKN of various particle sizes (75, 225 and 450 μm) were used at 50% by volume to produce the composites. Dielectric properties at various frequencies (0.1–20 kHz) were investigated. The results showed that the dielectric values of NKN-PC composites increased with increasing NKN particle size where ϵ r at 1 kHz are 158.60 and 191.21 for composites with 75 μm and 450 μm NKN particle size respectively. The dielectric loss (tanδ) was found to reduce with increasing NKN particle size and the tan δ value was lowest at 0.39 for composite with 450 μm NKN particle size.

Dielectric Properties of 2–2 PMN-PT/Cement Composites

Dielectric properties of 2–2 connectivity lead magnesium niobate-lead titanate (PMN-PT)/Cement composites were investigated at 0.1–20 kHz. PMN-PT of 60–80% by volume was used. The composites were fabricated using a dice and fill technique and cured in 98%RH curing chamber for 7 days before measurements. Dielectric constant (ϵr) at 1 kHz increased with PMN-PT volume, having values of 1504, 1645 and 2390 respectively. Dielectric loss (tanδ) values are 0.382, 0.185 and 0.188 at 1 kHz. In addition, the dielectric constant was found to decrease with an increase in the frequency tested having value of 1692, 1504 and 1322 for 0.1, 1 and 20 kHz respectively. The dielectric loss was found to be less with increasing frequency at 0.702, 0.382 and 0.179 for 0.1, 1 and 20 kHz respectively.