Effect of Excess PbO on Crystal Structure, Microstructure and Phase Transition of Lead Titanate Ceramics

2008 ◽  
Vol 55-57 ◽  
pp. 193-196 ◽  
Author(s):  
W. Tangkawsakul ◽  
Panadda Sittiketkron ◽  
Theerachai Bongkarn
Keyword(s):  
Crystal Structure ◽  
Phase Transition ◽  
Lead Titanate ◽  
Raw Materials ◽  
Lead Dioxide ◽  
Average Particle ◽  
Particle Sizes ◽  
Sintering Process ◽  
Sintered Ceramic ◽  
Titanate Ceramics

In this work, we studied the effect of excess PbO on crystal structure, microstructure and phase transition of lead titanate (PT). PT was prepared via a mixed oxide method with various PbO levels (0, 1, 3 and 5 wt.%). The raw materials were calcined at 750 oC for 2 h and sintered at 1225 oC for 2 h. The characteristics of PT were analyzed by a X-ray diffractometer (XRD), scanning electron microscopy (SEM) and differential scanning calorimeter (DSC). It was found that calcined powders and sintered ceramics indexed in a tetragonal structure. For PT powders, the impurity phases of lead oxide (PbO) and lead dioxide (PbO2) were detected in 3 and 5 wt.% of excess PbO samples, but they were not detected in all sintered ceramic samples. The increase of excess PbO levels resulted in a decreased c/a ratio in both calcined powders and sintered ceramics. Average particle sizes increased from 0.64 to 4.24 µm when excess PbO levels increased from 0 to 5 wt.%. It was also clearly seen that the liquid phase of the sintering process was obtained in the PT calcined powders which had an excess of PbO. The DSC result indicated that the phase transition temperature, from a ferroelectric to a paraelectric phase with a high PbO content (5 wt.%), was higher than those with low PbO contents (0, 1 and 3 wt.%).

Effect of ZrO2 Doping on Crystal Structure, Microstructure and Phase Transition of Lead Titanate Ceramics

2008 ◽  
Vol 55-57 ◽  
pp. 169-172 ◽  
Author(s):  
Panadda Sittiketkron ◽  
S. Sukkho ◽  
Theerachai Bongkarn
Keyword(s):  
Crystal Structure ◽  
Phase Transition ◽  
Lead Titanate ◽  
X Ray ◽  
Zro2 Phase ◽  
Ceramic Samples ◽  
Average Grain Size ◽  
Titanate Ceramics ◽  
Pbtio3 Ceramics ◽  
Scanning Electron

In this work, the effect of ZrO2 doping on the properties of PbTiO3 ceramics was investigated. PbTiO3 powders were prepared via a mixed oxide method with a calcination temperature of 750 °C for 2 h. The various amounts of ZrO2, between 0 and 2 wt.%, were added to the calcined powders to decrease the c/a ratio. The mixed powders were sintered at 1225 °C for 2 h. The samples were characterized using X–ray diffractrometer (XRD), scanning electron microscopy (SEM) and differential scanning calorimeter (DSC). It was showed that the ZrO2 phase was not detected in all of the powder and ceramic samples. The highest density in the ceramics was found in the sample with 0.5 wt.% of ZrO2. The average grain size slightly increased with the increase of ZrO2. The phase transition temperature from tetragonal ferroelectric to cubic paraelectric was about 465 to 466 °C for all sintered samples.

Barium Strontium Titanate Ceramics Prepared by a Reaction-Sintering Process

2004 ◽  
Vol 848 ◽  
Author(s):  
Yi-Cheng Liou ◽  
Jen-Hsien Chen ◽  
Chi-Ting Wu
Keyword(s):  
Strontium Titanate ◽  
Barium Strontium Titanate ◽  
Sintering Temperature ◽  
Raw Materials ◽  
Reaction Sintering ◽  
Sintering Process ◽  
Barium Strontium ◽  
Bst Ceramics ◽  
Titanate Ceramics

ABSTRACTBarium strontium titanate (Ba0.7Sr0.3TiO3, BST) ceramics prepared by a reaction-sintering process were investigated. The mixture of raw materials of stoichiometric Ba0.7Sr0.3TiO3 was pressed and sintered into ceramics without any calcination stage involved. Perovskite BST ceramics were obtained after sintered at 1330–1370°C for 2–6 h. For 6 h soak time, a density value 5.68g/cm3 (99.8% of the theoretic value) was obtained at 1350°C sintering. Grains of sizes between 2μm and 15μm were formed after 1330–1370°C sintering for 2–6 h. A diffused ferroelectric-paraelectric transition was observed in pellets sintered at 1330°C for 2 h and disappeared at a longer soak time or a higher sintering temperature.

scholarly journals The influence of mechanical activation on sintering process of BaCO3-SrCO3-TiO2 system

2012 ◽  
Vol 44 (3) ◽  
pp. 271-280 ◽  
Author(s):  
Darko Kosanovic ◽  
N. Obradovic ◽  
J. Zivojinovic ◽  
A. Maricic ◽  
V.P. Pavlovic ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Mechanical Activation ◽  
Ball Mill ◽  
Sintering Process ◽  
Electrical Measurements ◽  
Air Atmosphere ◽  
Titanate Ceramics ◽  
Scanning Electron

In this article the influence of mechanical activation on sintering process of bariumstrontium-titanate ceramics has been investigated. Both non-activated and mixtures treated in a planetary ball mill for 5, 10, 20, 40, 80 and 120 minutes were sintered at 1100-1400?C for 2 hours in presence of air atmosphere. The influence of mechanical activation on phase composition and crystal structure has been analyzed by XRD, while the effect of activation and sintering process on microstructure was investigated by scanning electron microscopy. It has been established that temperature of 1100?C was too low to induce final sintering stage for this system. Electrical measurements have been conducted for the densest ceramics sintered at 1400?C for 2 hours.

Synthesis of Aluminium Titanate Ceramics from Waste Sludge of Aluminium Factory

2008 ◽  
Vol 368-372 ◽  
pp. 1538-1540
Author(s):  
Yang Shen ◽  
Yu Zhong Ruan ◽  
Yan Yu ◽  
Yun Hong Zheng
Keyword(s):  
Crystal Structure ◽  
Aluminum Oxide ◽  
Raw Materials ◽  
Pure Tio2 ◽  
Target Product ◽  
Tio2 Powder ◽  
Aluminium Titanate ◽  
Waste Sludge ◽  
Crystal Phases ◽  
Titanate Ceramics

Aluminium titanate was synthesized using waste aluminium sludge and chemical pure TiO2 powder as raw materials. Effect of different compositions on crystal structure and contents of target product was discussed. XRD results showed that four crystal phases, aluminium titanate, perovskite, rutile and aluminum oxide, are formed in the sintered samples. The content of aluminium titanate increases first and then decreases with the decrease of the content of waste aluminum sludge. When the content of the sludge is 65.52wt%, the content of aluminium titanate reaches the maximum of 86.1wt%.

The Effect of Excess PbO on Crystal Structure and Microstructure of (Pb0.925Ba0.075)TiO3 Ceramics

2008 ◽  
Vol 55-57 ◽  
pp. 177-180 ◽  
Author(s):  
Theerachai Bongkarn ◽  
R. Sumang
Keyword(s):  
Crystal Structure ◽  
Barium Titanate ◽  
Lead Oxide ◽  
Lead Dioxide ◽  
Average Particle Size ◽  
Impurity Phase ◽  
Average Particle ◽  
Ceramic Samples ◽  
Average Grain Size ◽  
Structure And Microstructure

In this work, we studied the effect of excess PbO doping on lead barium titanate [(Pb0.925Ba0.075)TiO3; (PBT)] ceramic. PBT was prepared via a mixed oxide method with various PbO levels (-3, 0, 1, 3, 5 and 10 wt.%). The excess PbO was added to compensate the loss from evaporation during calcination and sintering at 800 oC and 1150 oC. It was found that lead barium titanate powders indexed in a tetragonal structure. Impurity phases of lead oxide (PbO), titanium oxide (TiO), and lead dioxide (PbO2) were detected in the calcined powders with higher than 1 wt% of excess PbO. The impurity phase was not obtained in any ceramic samples. The c/a ratios decreased with an increasing excess of PbO in both calcined powders and sintered pellets. The average particle size and the average grain size of the PBT increased with the increase of PbO. The shrinkage plots showed a maximum peak for the 1 wt.% sample which was also the most dense sample.

scholarly journals Sintering of mechanically activated magnesium-titanate and barium-zinc-titanate ceramics

2011 ◽  
Vol 43 (2) ◽  
pp. 145-151 ◽  
Author(s):  
N. Obradovic ◽  
S. Filipovic ◽  
V.B. Pavlovic ◽  
A. Maricic ◽  
N. Mitrovic ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Mechanical Activation ◽  
Ball Mill ◽  
Sintering Process ◽  
Zinc Titanate ◽  
Magnesium Titanate ◽  
Titanate Ceramics ◽  
Scanning Electron

In this article the influence of mechanical activation on sintering process of magnesium-titanate and barium-zinc-titanate ceramics has been investigated. Both nonactivated and mixtures treated in planetary ball mill for 80 minutes were sintered at 1100?C and 1300?C. The influence of mechanical activation on phase composition and crystal structure has been analyzed by XRD, while the effect of activation and sintering process on microstructure was investigated by scanning electron microscopy. It has been established that temperature of 1100?C was to low to induce final sintering stage for both systems. Moreover, we concluded that barium-zinc-titanate ceramics exhibited better sinterability than magnesium-titanate ceramics.

Preparation of Barium Strontium Titanate Ceramics via Combustion Method

2008 ◽  
Vol 55-57 ◽  
pp. 185-188
Author(s):  
Theerachai Bongkarn ◽  
C. Wicheanrat
Keyword(s):  
Crystal Structure ◽  
Perovskite Phase ◽  
Average Particle Size ◽  
Combustion Method ◽  
Cubic Phase ◽  
Average Particle ◽  
X Ray Diffraction ◽  
Pure Perovskite Phase ◽  
Average Grain Size ◽  
Titanate Ceramics

This study concentrated on the crystal structure and microstructure of [(Ba0.75Sr0.25)TiO3; (BST)] ceramics at different firing temperatures. The BST powders were prepared by a combustion method. (CO(NH2)2) was used as a fuel. Crystallinity of the calcined powders was improved by increasing the calcining temperature, as indicated by the increase in intensity of the X-ray diffraction peak. The pure perovskite phase of BST powders was obtained with a calcinations condition of 1200 oC. The a axis lattice constant of BST calcined powders and sintered ceramics were calculated and it was found that the crystal structure is a cubic phase. The microstructure of BST calcined powders and sintered ceramics were analyzed by a scanning electron microscope (SEM). The SEM result indicated that the average particle size and average grain size increased with the increase of calcinations and sintering temperatures, respectively. The apparent density of the samples was measured by the Archimedes method.

Dynamic low-dose electron diffraction and imaging of phase transitions in polymers

1993 ◽  
Vol 51 ◽  
pp. 890-891
Author(s):  
David C. Martin ◽  
Jun Liao
Keyword(s):  
Crystal Structure ◽  
Phase Transition ◽  
Electron Diffraction ◽  
Low Dose ◽  
Dark Field ◽  
Continuous Change ◽  
Selected Area Electron Diffraction ◽  
Resolution Electron ◽  
Chain Axis ◽  
High Resolution Electron Micrographs

By careful control of the electron beam it is possible to simultaneously induce and observe the phase transformation from monomer to polymer in certain solid-state polymcrizable diacetylenes. The continuous change in the crystal structure from DCHD diacetylene monomer (a=1.76 nm, b=1.36 nm, c=0.455 nm, γ=94 degrees, P2l/c) to polymer (a=1.74 nm, b=1.29 nm, c=0.49 nm, γ=108 degrees, P2l/c) occurs at a characteristic dose (10−4C/cm2) which is five orders of magnitude smaller than the critical end point dose (20 C/cm2). Previously we discussed the progress of this phase transition primarily as observed down the [001] zone (the chain axis direction). Here we report on the associated changes of the dark field (DF) images and selected area electron diffraction (SAED) patterns of the crystals as observed from the side (i.e., in the [hk0] zones).High resolution electron micrographs (HREM), DF images, and SAED patterns were obtained on a JEOL 4000 EX HREM operating at 400 kV.

crystal structure and phase transition in the compound [C6H5CH2NH2CH3]10Sb6Cl28

2006 ◽  
Vol 31 (1) ◽  
pp. 39-48
Author(s):  
Najla Vix-Gurtel ◽  
Chaari Dentzer ◽  
Slaheddine Chaabouni ◽  
Jean-Michel Savariault ◽  
Abdelhamid ben Salah
Keyword(s):  
Crystal Structure ◽  
Phase Transition
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