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1.
This study aimed to fabricate and characterize new complex-structured ceramics with formula (1-x)Pb(Zr0.52Ti0.48)O3–xSrBi2Nb2O9 or (1-x)PZT–xSBN (where x=0, 0.1, 0.3 and 0.5 weight fraction). The ceramics were prepared by a solid-state mixed-oxide method and sintered at temperatures between 1000 and 1250 °C. Optimum sintering temperature for this system was found to be 1050 °C for 3 h dwell time. X-ray diffraction patterns of (1-x)PZT–xSBN powders showed peak intensities of two-phase mixture corresponding to the relative amount of each phase as a result of SBN addition. Microstructure of (1-x)PZT–xSBN ceramics showed a variation in grain shape and grain size. The small addition of SBN (x=0.1) was also found to improve ferroelectric properties of pure PZT ceramic. 相似文献
2.
Anucha Wannagon Watcharee Sornlar Pattarawan Choeycharoen 《Ceramics International》2012,38(6):4485-4494
Ceramic stoneware body has been modified with ceramic and glass industrial wastes by replacing 25–100% as flux in the formula. The effects of solid wastes added to the bodies were studied after firing in the temperature range 950–1280 °C. The physical properties of linear shrinkage, bulk density, apparent porosity, water absorption and 3-point bending strength were determined. A composition which related to the general stoneware properties was found when using soda-lime cullet and glaze sludge. It had a firing range lowered to 1050–1100 °C. SEM results demonstrated the sintered microstructure increased in density with increase in solid waste in the modified body. XRD results after firing showed the crystalline phases comprised of mullite, albite calcian and quartz. Thermal expansion was measured in the range 6.53–6.67 × 10?6 K?1 at 30–500 °C. The modified bodies were capable of forming prototype products by slip casting and jiggering. 相似文献
3.
Bismuth sodium zirconate titanate ceramics with the formula Bi0.5Na0.5Zr1-xTixO3 [BNZT], where x = 0.3, 0.4, 0.5, and 0.6, were prepared by a conventional solid-state sintering method. Phase identification was investigated
using an X-ray diffraction technique. All compositions exhibited complete solubility of Ti4+ at the Zr4+ site. Both a decrease of unit cell size and phase transition from an orthorhombic Zr-rich composition to a rhombohedral crystal
structure in a Ti-rich composition were observed as a result of Ti4+ substitution. These changes caused dielectric properties of BNZT ceramics to enhance. Microstructural observation carried
out employing SEM showed that average grain size decreased when addition of Ti increased. Grain size difference of BNZT above
0.4 mole fraction of Ti4+ displayed a significant increase of dielectric constant at room temperature. 相似文献
4.
Nopsiri Chaiyo Anucha Ruangphanit Rangson Muanghlua Surasak Niemcharoen Banjong Boonchom Naratip Vittayakorn 《Journal of Materials Science》2011,46(6):1585-1590
Crystalline lead-free piezoelectric potassium niobate (KNbO3) powders have been synthesized through a modified solid-state reaction method. The thermal behavior of the K2C2O4·H2O and Nb2O5 raw material mixture was investigated by thermogravimetric analysis (TGA) and differential thermal analysis (DTA). The X-ray diffraction technique (XRD) was used to investigate the phase formation and purity. The morphology of the powder obtained was characterized using a scanning electron microscope (SEM). The XRD pattern showed that the monophasic perovskite phase of KNbO3 could be synthesized successfully at a temperature as low as 550 °C for 240 min, with an average crystallite size of 36 ± 8 nm. The SEM images suggested that the average particle size of the powder obtained was 278 ± 75 nm. 相似文献
5.
Highly filled graphite polybenzoxazine composites for an application as bipolar plates in fuel cells
Highly filled graphite polybenzoxazine composites as bipolar plate material for polymer electrolyte membrane fuel cell (PEMFC) are developed. At the maximum graphite content of 80 wt % (68 vol %), storage modulus was increased from 5.9 GPa of the neat polybenzoxazine matrix to 23 GPa in the composite. Glass transition temperatures (Tg) of the composites were ranging from 176°C to 195°C and the values substantially increased with increasing the graphite contents. Thermal conductivity as high as 10.2 W/mK and electrical conductivity of 245 S cm?1 were obtained in the graphite filled polybenzoxazine at its maximum graphite loading. The obtained properties of the graphite filled polybenzoxazine composites exhibit most values exceed the United States department of energy requirements for PEMFC applications. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 3909–3918, 2013 相似文献
6.
Anucha Wannagon Sitthisak Prasanphan Samunya Sanguanpak 《Journal of the European Ceramic Society》2013,33(4):653-660
Ceramic glaze containing Li2O and ZnO was prepared at a low firing temperature of 1100 °C. Addition of 0–30 wt.% iron oxide content developed brown color with a metallic sparkling effect from crystallization after soaking at 980–1080 °C. Using XRD, SEM/EDS and Raman microscopy the crystalline phases were determined as lithium zinc ferrite (LixZn1?2xFe2+xO4 where x = 0.05–0.20), hematite (α-Fe2O3) and anorthite (CaAl2Si2O8). The most preferable metallic sparkling effect was caused by the lithium zinc ferrite phase obtained from the glaze containing 10 wt.% of iron oxide. Thermal analysis by STA after heat treatment indicated that crystallization temperature of lithium zinc ferrite and the effective soaking temperature depended on the iron oxide content in the glaze. The influence of excessive iron oxide content on the crystallization behavior of lithium zinc ferrite, anorthite and hematite phases is discussed. 相似文献
7.
Methee Promsawat Jenny Y.Y. Wong Anucha Watcharapasorn Sukanda Jiansirisomboon 《Materials Chemistry and Physics》2013
The structural, dielectric and ferroelectric properties of Pb(Mg1/3Nb2/3)0.9Ti0.1O3 (PMNT) ceramics prepared with CuO as a sintering aid at various sintering temperatures between 950 °C and 1150 °C are investigated. The lattice parameters slightly increase with the sintering temperature >1050 °C. A significant increase in the grain size is observed when the sintering temperature is increased from 1000 °C to 1050 °C. The maximum dielectric constant reaches the highest value of ∼22,000 for the ceramic sintered at 1050 °C. For the ceramics sintered at >1050 °C, the temperature of maximum dielectric constant and the diffuseness parameters tend to increase with the increasing sintering temperature. The optimal sintering temperature for this ceramic is 1050 °C, which displays significant improvements in ferroelectric properties at room temperature, i.e. the increase in the remanent polarization and the ferroelectric loop squareness. 相似文献
8.
9.
In this work, nanocrystalline M–Zn ferrites (M=Ni; Mn; Cu) with compositions of M1?xZnxFe2O4 (x=0.0, 0.2 and 0.4) were synthesized from metal nitrate precursors by rapid the sol–gel combustion method using diethanolamine (DEA) as the fuel. As-synthesized powders were calcined at 1000 °C for 4 h. The crystal structures and morphologies of these compounds were characterized by X-ray diffraction (XRD) and field-emission scanning electron microscopy (FE-SEM), respectively. The chemical interaction of ferrite powders was investigated by Fourier transform infrared spectroscopy (FTIR). The magnetic properties of after-calcined nanoparticles were measured at room temperature using a vibrating sample magnetometer (VSM). The single phase spinel cubic structure formation is confirmed by XRD and FTIR results. Meanwhile FE-SEM micrographs show the appearance of both undoped and Zn-doped ferrite ceramic samples. In addition, the VSM analyses indicate that the Zn content has a significant influence on the magnetic properties such as saturation magnetization (Ms) and coercivity (Hc). 相似文献
10.
Anucha Wonglert Pornkasem Jongpradist Pitthaya Jamsawang Stefan Larsson 《Soils and Foundations》2018,58(2):446-461
This research aims to clarify and gain an insight into the impact of the length of the stiffened core and the strength of the deep cement mixing (DCM) socket on the behaviors of floating stiffened deep cement mixing (SDCM) columns. The observed behaviors include the axial ultimate bearing capacity, settlement and failure mode. The study begins by conducting a series of physical model tests as a preliminary investigation. The results reveal that the strength of the DCM socket can be reduced to a certain value by inserting a sufficiently long reinforced core to achieve the highest possible load-carrying capacity, indicating an optimum length of the stiffened core for a specific DCM socket strength. For a parametric study on the actual scale condition, full-scale load tests on a floating DCM and an SDCM column with eucalyptus wood as a core in the thick soft clay layer area were carried out to provide a reference case. The extended numerical analysis results suggest that the modes of failure depend on the length of the stiffened core and the strength of the DCM socket. The results from the numerical parametric study were used to establish a guideline chart for suggesting the appropriate length of the core in accordance with the strength of the DCM socket of the floating SDCM columns. The field pile load test results also confirm that core materials with a lower strength and stiffness, such as eucalyptus wood, could potentially be used as a reinforced core. 相似文献