Suchittra Inthong

Effects of NiO Nanoparticles on Physical and Mechanical Properties of BNKT Lead-Free Ceramics

In this research, The effects of NiO nanoparticles on the physical and mechanical properties of Bi0.5(Na0.81,K0.19)0.5TiO3 (BNKT) were investigated. The ceramics were synthesized by solid state reaction technique. The powder of BNKT was calcined at 850 °C for 4 h. The ceramics of BNKT/x NiO vol.% ( i.e. x= 0.0, 1.0, 2.0 and 3.0) were sintered at 1000-1150 °C for 2 h for optimize condition. Densification, phase formation, microstructure and micro hardness of samples were characterized via Archimedes method, X-ray diffraction techniques (XRD), scanning electron microscope (SEM) and Vickers micro hardness tester. The X-ray diffraction analysis of the ceramics suggests that all samples exhibited a perovskite structure. Densification of samples tended to increase with increasing amount of NiO content with minimun at 1.0 vol.% NiO additive. The NiO additive influenced densification as well as the mechanical properties of the samples. The results of this research suggest that NiO nanoparticles have influence on physical and mechanical properties of BNKT ceramics.

Phase Formation, Microstructures and Mechanical Properties of Lead-Free BNKT Ferroelectric Ceramics Doped with BZZ

In this research, the effects of bismuth zinc zirconate (BZZ) additive on phase formation, microstructural and mechanical properties of bismuth sodium potassium titanate (BNKT) ceramics were investigated. The BZZ-doped BNKT ceramics were prepared using solid state reaction technique. The pure phase of BZZ-doped BNKT powders were achieved for a calcinations temperature of 850 °C for 4h. The obtained powders were pressed into small pellets and sintered at optimum temperature to from dense ceramics. The XRD analysis of the ceramics shows that all ceramic samples exhibited a pure phase perovskite structure. The bulk densities of samples were about 5.82-6.03 g/cm3 which measured using the Archimedes method. The mechanical properties were measured using micro hardness tester. The microstructural of sintered surface was investigated using scanning electron microscopy (SEM). Average grain size increased with increasing BZZ content. The relations of these results were discussed and compared to the previous works.

Effects of B-site doping on piezoelectric and ferroelectric properties of Pb0.88Sr0.12(Zr0.54Ti0.44Sb 0.02)(1-y)-(Zn1/3Nb2/3) yO3 ceramics

Pb0.88Sr0.12(Zr0.54Ti0.44Sb0.02)(1-y) – (Zn1/3Nb2/3)yO3 ceramics where y = 0.00–0.10 were prepared by a solid state reaction method. Doping of Zn and Nb (co-doped) at B-site produced a phase transformation from tetragonal to rhombohedral phase. Highest piezoelectric coefficient d33 of 632 pC/N was recorded for the y = 0.04 sample. The piezoelectric result was correlated with the phase formation and the ferroelectric properties. Dielectric constant and loss tangent slightly increased with increasing the co- doped content. However, loss tangent values were less than 0.06 for all samples. These results indicated that the piezoelectric and dielectric properties of the ceramics could be improved by the co-doping.

Effects of Rate-Controlled Sintering on Phase Formation, Dielectric and Ferroelectric Properties of Cobalt Oxide Doped BNKT Ceramics

Lead-free powders of Bi(Na0.81K0.19)O3 doped 0.3 wt.% CoO were prepared by a conventional mixed oxide technique. The sintering process was controlled with various rate up and down temperature. The samples were sintered at 1,050 °C for 4 h which difference heating rate controlled i.e. 100, 300, and 600 °C/h. The XRD pattern analysis of all studied samples showed a single phase perovskite structure Dielectric and ferroelectric properties of the ceramics were investigated as a function of rate controlled sintering temperature. The sample heating rate at 600 °C/h showed maximum dielectric constant (~5961) at Tm. In addition, the ferroelectric properties were analyzed and discussed.

Effects of Sintering Temperature on Physical and Mechanical Properties of HA/YSZ Nanocomposites

In the present work, the effects of sintering temperature on physical and mechanical properties of HA/YSZ nanocomposites were investigated. The obtained results have been proved that the sintering temperature contributed greatly to densification and the compressive strength with the highest at 4.80 g/cm3 and 74.20 MPa for 80 wt.% of YSZ content in nanocomposites, respectively. The densification increased with increasing sintering temperature, where the compressive strength value was related with densification for the same ratio amount of YSZ. The higher the YSZ contents also significantly produced the ascendant of densification and the compressive strength.

Characterization Nanocrystalline of Hydroxyapatite Synthesized by a Co-Precipitation Method

In the present work, we demonstrated that hydroxyapatite (HAp) fine powder could be synthesized by a coprecipitation method. Diammonium hydrogen phosphate and calcium nitrate solutions were used as starting precursors. The pH of solution was adjusted to be 10 by ammonium hydroxide solution and the mixture solution was kept constant at a temperature at 70 °C though the precipitation. After the reaction completed, the product slurry was aged. The obtained powder was calcined at different temperatures up to 900 °C. Phase composition and microstructure of the resulting powders were characterized by X-ray diffraction technique (XRD), scanning electron microscope (SEM) and transmission electron microscope (TEM). The results showed that the obtained powder was a pure HAp phase for the calcination temperature of 900 °C. The powder also exhibited very fine particles with an average particle size of ∼110 nm.

Preparation and electrical properties of (1-x)Ba0.9Sr 0.1[Ti0.8(Fe0.5Nb0.5) 0.2]O3-xBiZn0.5Ti0.5O3 ceramics

The (1-x)Ba0.9Sr0.1[Ti0.8(Fe1/3Nb2/3)0.2]O3–xBiZn1/2Ti1/2O3 solid solution ceramics were synthesized via a solid-state reaction method where x = 0.02, 0.04, 0.06, 0.08 and 0.10. The structural and electrical properties of these ceramics system were investigated as a function of the BZT content by X-ray diffraction (XRD) and dielectric measurement techniques. The XRD analysis demonstrated that with increasing BZT content in (1-x)BSTFN–xBZT, the structural change occurred from the rhombohedral to the tetragonal phase at room temperature. Changes in the dielectric behavior were found to depend on the BZT content.