Fabrication of Textured SrBi2Nb2O9 Ceramics by Templated Grain Growth

2007 ◽  
Vol 26-28 ◽  
pp. 239-242 ◽  
Author(s):  
Chun Wei Cui ◽  
Jin Liang Huang ◽  
Lin Hua Gao ◽  
Xing Hua Yang ◽  
Xiao Wang
Keyword(s):  
Relative Density ◽  
Molten Salt ◽  
Grain Growth ◽  
Grain Orientation ◽  
Sintering Temperature ◽  
Molten Salt Method ◽  
Templated Grain Growth ◽  
Increasing Temperature ◽  
Lotgering Factor ◽  
Peak Value

Textured SrBi2Nb2O9 (SBN) ceramics were fabricated by templated grain growth (TGG) method. The plated-like SBN particles with shape anisotropy prepared by molten salt method were used as the templates. The SBN powders prepared by conventional solid (CS) reaction were used as matrix powders. It was found that the textured SBN ceramics can be obtained by TGG method. The grain orientation (Lotgering factor, f) increased with the increase of sintering temperature and content of the templates. The textured SBN ceramics with f=0.86 could then be obtained after sintering at 1300 °C for 3 h with 20wt.% templates. The relative density keeps rising with increasing temperature until it reaches a peak value 91.22% at the sintering temperature 1300°C, after which it decreases.

Texture Development in Na1/2Bi1/2TiO3-BaTiO3 Ceramics by Reactive-Templated Grain Growth

2007 ◽  
Vol 336-338 ◽  
pp. 121-124
Author(s):  
Yong Ke Yan ◽  
He Ping Zhou ◽  
Wei Zhao ◽  
Dan Liu ◽  
Shan Shan Liu
Keyword(s):  
Molten Salt ◽  
Grain Growth ◽  
Microstructure Evolution ◽  
Grain Orientation ◽  
Texture Development ◽  
Molten Salt Method ◽  
Templated Grain Growth ◽  
Important Impact

High <001>-textured Na1/2Bi1/2TiO3-BaTiO3 (6mol%BaTiO3) ceramics were fabricated by reactive-templated grain growth (RTGG), using plate-like Bi4Ti3O14 particles prepared by a molten salt method as the templates. The effect of template concentration on the texture development and microstructure evolution was studied, and the mechanisms of grain orientation and densification were also discussed. The design of Bi element reaction has important impact on the texture development.

Effects of Starting Materials on Molten Salt Synthesis of Bi4Ti3O12

2008 ◽  
Vol 55-57 ◽  
pp. 165-168
Author(s):  
Paisan Setasuwon ◽  
S. Kijamnajsak
Keyword(s):  
Molten Salt ◽  
Grain Growth ◽  
Grain Orientation ◽  
Crystal Size ◽  
Raw Materials ◽  
Piezoelectric Materials ◽  
Molten Salt Synthesis ◽  
Chloride Salt ◽  
Templated Grain Growth

Na0.5Bi0.5TiO3 is one of the potential candidates for non-lead piezoelectric materials to replace existing lead-based ones. Properties of BNT could be enhanced by reactive templated grain growth (RTGG) technique through induction of grain orientation with crystals of Bi4Ti3O12. Controlling the size of Bi4Ti3O12 crystals during the synthesis with molten salt is a major factor in optimizing RTGG. It was found that molten salt synthesis of Bi4Ti3O12 crystals with NaCl-KCl yielded larger particles, compared with Na2SO4-3K2SO4. Varying the proportion of chloride salt did not produce noticeable changes in crystal size. Bi4Ti3O12 crystals were significantly affected by raw materials treatment. Non-milling of starting powders could approximately double the crystal size

Preparation and Characterization of High Textured KSr2Nb5O15 Lead-Free Piezoelectric Ceramics

2008 ◽  
Vol 368-372 ◽  
pp. 1905-1907
Author(s):  
Li Jin Xie ◽  
Gao Jie Xu ◽  
Zhi Xiang Li
Keyword(s):  
Solid State ◽  
Molten Salt ◽  
Grain Orientation ◽  
Sintered Density ◽  
Raw Materials ◽  
Piezoelectric Ceramics ◽  
Lead Free ◽  
Molten Salt Method ◽  
Templated Grain Growth

Anisometric KSr2Nb5O15 (KSN) particles were synthesized by molten salt method with SrCO3, Nb2O5 and KCl as raw materials. With K2CO3, SrCO3 and Nb2O5 starting materials, KSN lead-free piezoelectric ceramics were prepared by conventional ceramics technique and reactive templated grain growth (RTGG) method, respectively. In the RTGG process, green compacts were fabricated by tapecasting using anisometric KSN as template particles. The KSN particles prepared by molten salt method were rodlike in shape and dense. The KSN ceramics prepared by RTGG not only had higher degree of grain orientation but higher sintered density compared with that prepared by solid-state reaction.

Fabrication and evaluation of CA-doped SrTiO3 thermoelectric materials by molten salt method

2021 ◽  
pp. 2140040
Author(s):  
Kei-Ichiro Murai ◽  
Takuya Nishiura ◽  
Ryutaro Nagata ◽  
Toshihiro Moriga
Keyword(s):  
Electrical Conductivity ◽  
Relative Density ◽  
Molten Salt ◽  
Electric Conductivity ◽  
Thermoelectric Materials ◽  
Simple Synthesis ◽  
Molten Salt Method ◽  
Mixed Salt ◽  
Mild Conditions ◽  
Increasing Temperature

In this study, we focused on the molten salt method and attempted a simple synthesis of SrTi[Formula: see text]Co[Formula: see text]O3. It was clarified that SrTi[Formula: see text]Co[Formula: see text]O3 can be obtained under relatively mild conditions by using the molten salt. In all samples, the electrical conductivity increased with increasing temperature. Compared with the sample without the molten salt, the electric conductivity of the samples with the molten salt was greatly improved. The sample using the KCl-NaCl mixed salt showed the highest electrical conductivity of 83 S/cm at 973 K. The relative densities of all the samples using the molten salt were above 85%. It is considered that the improvement in the electrical conductivity is partly due to the increase in the relative density.

Influence of Sintering Conditions on Electric Performance of Textured 92BNT-6BT-2KNN Ceramics

2012 ◽  
Vol 512-515 ◽  
pp. 1380-1384 ◽  
Author(s):  
Cheng Gen Ye ◽  
Fang Fu ◽  
Bo Shen ◽  
Ji Wei Zhai
Keyword(s):  
Phase Transformation ◽  
Volume Change ◽  
Temperature Increase ◽  
Grain Orientation ◽  
Sintering Temperature ◽  
Sintering Process ◽  
Templated Grain Growth ◽  
Soaking Time ◽  
Sintering Conditions ◽  
Lotgering Factor

0.92(Bi0.5Na0.5)TiO3-0.06BaTiO3-0.02(K0.5Na0.5)NbO3(92BNT-6BT-2KNN) is a high-stain material due to the volume change which come from antiferroelectric-ferroelectric (AFE-FE) phase transformation. Textured 92BNT-6BT-2KNN with a Lotgering factor of 67% was obtained by templated grain growth (TGG) method using plate-like (Bi0.5Na0.5)TiO3（BNT）particles as templates. The influences of sintering process on Lotgering factor and strain were investigated. It was found that the Lotgering factor increased as sintering temperature increase and then decreased with further temperature increase. The changing tendency of polar and unipolar strain did not keep the same accordance with that of Lotgering factor. The maximum of Lotgering factor (79%) and polar strain (0.36%) was obtained when the sintering temperature was 1240°C and 1220°C, respectively, due to the decrease of density when high sintering temperature was employed. Also it was found that the lotgering factor and polar strain reached its highest values when the soaking time was 4h. All these proved that the density and grain orientation codetermined the strain of 92BNT-6BT-2KNN ceramics.

Mechanical Properties of WC-Co Cemented Carbide Prepared via Vacuum Sintering

2013 ◽  
Vol 275-277 ◽  
pp. 1917-1920
Author(s):  
Bing Liang Liang ◽  
Yun Long Ai ◽  
Chang Hong Liu ◽  
Nan Jiang
Keyword(s):  
Mechanical Properties ◽  
Phase Composition ◽  
Relative Density ◽  
Sintering Temperature ◽  
Rupture Strength ◽  
Cemented Carbide ◽  
Vacuum Sintering ◽  
Transverse Rupture Strength ◽  
Temperature Range ◽  
Peak Value

WC-Co cemented carbide specimens were prepared via vacuum sintering. The influences of composition and sintering temperature on phase composition, microstructure and mechanical properties of WC-Co cemented carbide were investigated. The results show that dense specimens were obtained in the sintering temperature range of 1280~1400°C and the relative density reached over 95%. Only WC and Co3W3C (-phase) were detected by XRD without any else phases, even though Co. With the ascended sintering temperature, hardness increased and the transverse rupture strength (TRS) ascended to peak value and then descended. WC-Co cemented carbide with excellent mechanical properties (HRA>90, TRS~700MPa and KIC>10MPa•m1/2) were obtained.

Effect of Small Amount BaTiO3 on Properties of K0.02Na0.98NbO3 Ceramics with Various Sintering Temperature Prepared by Molten Salt Method

2016 ◽  
Vol 718 ◽  
pp. 129-132
Author(s):  
Chompoonuch Warangkanagool
Keyword(s):  
Molecular Weight ◽  
Dielectric Constant ◽  
Dielectric Properties ◽  
Barium Titanate ◽  
Molten Salt ◽  
Sintering Temperature ◽  
Maximum Density ◽  
Molten Salt Method ◽  
Sodium Niobate ◽  
Potassium Sodium Niobate

In the research, the properties of potassium sodium niobate – barium titanate [(1-x)K0.02Na0.98NbO3–(x)BaTiO3: (1-x)KNN–(x)BT] ceramics prepared by molten salt method with various molecular weight of BT or x are 0 and 0.05 were investigated. The calcined powders of pure K0.02Na0.98NbO3 and (0.95) K0.02Na0.98NbO3-(0.05) BaTiO3 were pressed and sintered at 1250 – 1325 °C and 1225 – 1300 °C for 2h, respectively. It was found that, the samples showed phase structure changing from monoclinic to orthorhombic with small amount BaTiO3 addition. The densification of K0.02Na0.98NbO3 ceramics and dielectric properties were improved with the addition of BaTiO3. The (0.95)K0.02Na0.98NbO3–(0.05)BaTiO3 ceramics sintered at 1250 °C showed maximum density and dielectric constant (∼8035), which was even comparable with that of K0.02Na0.98NbO3 ceramics sintered at 1225 – 1300 °C.

Enhanced Densification and Grain-Size Refinement in Cation-Doped Tetragonal Zirconia

2010 ◽  
Vol 62 ◽  
pp. 227-231
Author(s):  
Keijiro Hiraga ◽  
Hidehiro Yoshida ◽  
Koji Morita ◽  
Byung Nam Kim
Keyword(s):  
Grain Size ◽  
Relative Density ◽  
Grain Growth ◽  
Sintering Temperature ◽  
Initial Density ◽  
Tetragonal Zirconia ◽  
The Other ◽  
Size Refinement ◽  
Grain Sizes ◽  
Materials Used

In tetragonal zirconia, possibility is investigated of densification with finer grain sizes under the combination of doping and sintering in air. The materials used are CIP'ed compacts of 3-mol%-yttria-stabilized tetragonal zirconia (3Y-TZP) doped with a small amount of cations. For a given sintering temperature and initial density of the compacts, while the doped cations enhances densification in the latest stage of sintering, the effect is different in grain growth during densification: a doped cation tended to enhance grain growth, whereas the other cations tended to suppress grain growth. As a result, the doping of the latter cations brings about a grain size finer than that of the undoped 3Y-TZP for a given relative density.

scholarly journals Giant Grain Growth in (K,Na)NbO3 Ceramics

Ceramist ◽  
2021 ◽  
Vol 24 (3) ◽  
pp. 286-294
Author(s):  
Seonhwa Park ◽  
Jung Woo Lee ◽  
Kyung-Hoon Cho ◽  
Yuho Min ◽  
Cheol-Woo Ahn
Keyword(s):  
Single Crystal ◽  
Molten Salt ◽  
Single Crystals ◽  
Grain Growth ◽  
Abnormal Grain Growth ◽  
Molten Salt Synthesis ◽  
Topochemical Reaction ◽  
Templated Grain Growth ◽  
Interesting Phenomenon

In this manuscript, an interesting phenomenon is reported. It has been reported that the growth of single crystals is observed in donor-doped (K,Na)NbO3 (KNN)-based ceramics. It is very interesting that the growth happens without the addition of a seed. The growth of huge grains (single crystal, approximately 30 mm,) occurs due to the abnormal grain growth (AGG) in KNN-based ceramics. In the AGG compositions, moreover, the seed plates can be synthesized by not topochemical reaction but simple molten salt synthesis (SMSS) which is a simple-and-cheap process. They can be a good candidate for the seeds at reactive templated grain growth (RTGG) or templated grain growth (TGG) process.

Physical, Dielectric Properties and Micro-Hardness of the (Ba0.90Ca0.10)0.90(Na0.50Bi0.50)0.10TiO3 Ceramics Prepared by Molten Salt Method

2018 ◽  
Vol 283 ◽  
pp. 132-139
Author(s):  
Chompoonuch Warangkanagool
Keyword(s):  
Dielectric Properties ◽  
Molten Salt ◽  
Heating Rate ◽  
Sintering Temperature ◽  
Molten Salt Method ◽  
Micro Hardness ◽  
Fluid Medium ◽  
Grain Sizes ◽  
Knoop Indentation ◽  
Lcr Meter

In this study, the physical properties, dielectric properties, and micro-hardness of (Ba0.90Ca0.10)0.90(Na0.50Bi0.50)0.10TiO3 or BCT-NBT ceramics prepared by molten salt method with various sintering temperatures were investigated. The powders were calcined at 500-1100°C for 4 h with heating rate of 5°C/min. It was found that the optimum calcination condition was 1000°C for 4 h. These powders were pressed and sintered at 1200-1400°C for 3 h with a heating rate of 5°C/min. The microstructure was examined by scanning electron microscope (SEM). The density of the sintered samples was measured by Archimedes method with distilled water as the fluid medium. Dielectric properties were examined by LCR meter. The micro-hardness of the BCT-NBT ceramics was determined using the Vickers and Knoop indentation techniques. The results showed that the average grain sizes increased with increasing sintering temperatures. At sintering temperatures higher than 1200°C, the fracture mode changed from partial intra-granular to mainly intra-granular. The sintering temperature at which the density, dielectric and hardness properties were maximal was 1350°C. The highest density was about 5.4 g/cm3, and the Vickers and Knoop micro-hardnesses were 6.6 and 6.4 GPa, respectively. The dielectric constant at the Curie temperature was 3682 and the dielectric loss was 0.01 at 1 kHz frequency.

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