In this research, waste gypsum (CaSO4·2H2O), a by-product material from industrial factory, was upgraded and then used as raw material for building materials. The by-product gypsum possessed a high acidic value of 3-point pH scale and moisture content of 40 %. The two properties had an impact on setting reaction and hardening of gypsum. Therefore, the studies of gypsum phase transformation to calcium sulfate hemihydrate (CaSO4·0.5H2O) were focused on washing process and amount of calcium carbonate (CaCO3) added at 0, 1, 3 and 5 % wt. After washing, waste gypsum and washed water were reduced from high acidic value to neutralization (pH = 7) as a result of CaCO3. Next, the neutralized gypsum was heated to the optimal temperature at 160 °C for 2 hours and transformed to hemihydrate gypsum phase observed by XRD. Finally, the relationship of amount of CaCO3-mechanical property such as bending strength will be investigated.
Nowadays, the concept of harvesting energy from the environment, for example, thermal, wind, sun, vibration and human activities is much of interest. PZT is one of the materials which show an ability to harness vibration energy and then change to electrical energy. Therefore, the PZT (Pb(Zr0.53Ti0.47)O3) doped with 0.02 mol% BYF (Bi(Y0.7Fe0.3)O3) piezoelectric ceramics has been studied to improve the figure of merit (d33*g33). The PZT and BYF powder systems were prepared by solid state reaction with calcination temperature of 800 and 850 °C for 2 h, respectively. XRD results showed that both powders exhibited pure perovskite phase for PZT and single phase of BYF without pyrochlore phase. Then, the two calcined powders (PZT and BYF) were mixed according to the composition of 0.02 mol% BYF doped PZT by two different milling techniques called conventional ball-milling (CBM) and high energy ball-milling (HBM) for 10 h. The result showed that average particle size obtain from HBM was 1 µm which was smaller than from CBM shown up to a few microns in bimodal mode. The PZT-BYF-HBM ceramics showed higher physical and electrical properties but lower K value. Thus promoting to higher g33 which was equal to 36.89 * 10-3(Vm/N) and FOM was 11,632*10-15(m2/N), while PZT-BYF-CBM had g33 of 26.86* 10-3(Vm/N) and FOM at 8,016*10-15(m2/N), respectively.
Recently, Lead Zirconate Titanate (PZT) has been attracted for energy harvesting (EH) devices because of their excellent piezoelectric properties at the morphotropic phase boundary (MPB). The EH devices require high energy density related to high figure of merit (FOM: g33 x d33). As a result, the improvement of piezoelectric voltage coefficient (g33) and piezoelectric charge coefficient (d33) to better energy density property obtained should be searching for. Therefore, PZT-BYF system was chosen for piezoelectric energy harvester by focusing to study on the composition of 0.99PZT-0.01BYF (0.99Pb(Zr0.53Ti0.47)O3-0.01Bi(Y0.7Fe0.3)O3). In this study, PZT and BYF systems were calcined separately and then 0.99PZT-0.01BYF powders were prepared by solid state method and mixed via high-energy ball milling in various milling time (2, 4, 10 and 16 hrs). The effect of milling time on the physical and electrical properties, figure of merit and microstructure were investigated.
The effect of manganese doping on microstructure, piezoelectric and electromechanical properties of Pb0.94Sr0.06(Zr0.52Ti0.48)O3 (PSZT) ceramics has studied. The PSZT ceramics doped MnCO3 concentration in the region of 0-1.0 mol% were prepared by a solid-state reaction and conventional sintering process. Phase identification showed the formation of single phase perovskite structure in all compositions. Microstructure and fracture behavior were observed by scanning electron microscopy (SEM). The fracture behavior demonstrated the change of fracture type from trangranular to mix of trans-and inter-granular type with increasing the amount of MnCO3. Dielectric constant (K), d33 and kp were increased when higher amount of MnCO3 was doped. In addition, the mechanical quality factor (Qm) was highest at 0.1 mol% MnCO3 doping in PSZT ceramics.
The PSZTM ceramics from Pb0.94Sr0.06(Zr0.52Ti0.48)O3doped with 0.1 mol% Mn were prepared by a solid state reaction and. Two different methods were used to calculate the amount of Mn-dopant into PSZT powder. One was calculated rely on B-site precursor represented byBmethod. The other was computed based on the amount of calcined PSZT calledCmethod. This study was to investigate the effect of the two different calculating formulations of Mn doped PSZT ceramics by B and C methods on phase formation, microstructure, physical and electrical properties. The results were observed that phase identification showed the formation of perovskite structure in both cases. Besides, the mechanical quality factor (Qm) of the PSZTM ceramics derived fromBmethod was two times higher than those fromCmethod. Nevertheless, the dielectric constant (K), piezoelectric coefficient (d33) and planar coupling coefficient (kp) of the PSZTM ceramics fromBmethod were slightly lower than those of derived fromCmethod. This could be drawn the conclusion that PSZTM with 0.1 mol% Mn prepared byBmethod can be used as hard-type piezoelectric material.
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