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.

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

SINGLE CRYSTAL GROWTH AND TEXTURING OF LEAD-BASED PIEZOELECTRIC CERAMICS VIA TEMPLATED GRAIN GROWTH PROCESS

2008 ◽  
Vol 01 (02) ◽  
pp. 127-132 ◽  
Author(s):  
THOMAS RICHTER ◽  
CARSTEN SCHUH ◽  
RALF MOOS ◽  
ENDER SUVACI
Keyword(s):  
Crystal Growth ◽  
Single Crystal ◽  
Single Crystals ◽  
Grain Growth ◽  
High Performance ◽  
Piezoelectric Materials ◽  
Secondary Recrystallization ◽  
Single Crystal Growth ◽  
Templated Grain Growth ◽  
Textured Ceramics

In the field of high-performance piezoelectric materials, PMN-PT single crystals and textured ceramics have been attracting increased research interest for several years. On the other hand, the growth of single crystals from melt for PZT-based compositions is impossible due to its incongruent melting behavior. In order to obtain the characteristics of pure single crystal PZT as closely as possible, the PZT must be textured by secondary recrystallization of introduced seeds in a fine-grained matrix. Zirconium was therefore added to a PMN-PT-ceramic with 32 mol% PT ( Pb ( Mg 1/3 Nb 2/3)0.68 Ti 0.32 O 3) in order to obtain a PMN-PZT-ceramic with 37 mol% PT and 21 mol% PZ ( Pb ( Mg 1/3 Nb 2/3)0.42( Ti 0.638 Zr 0.362)0.58 O 3). Initially, the growth mechanism of (001)-oriented BaTiO 3 (BT) single crystals in those matrices was investigated. The piezoelectric single crystals were produced via a process that starts with the hot pressing of a BT single crystal in cold isostatically pressed ceramics, followed by an additional sintering step in order to achieve a secondary recrystallization. The measured growth lengths in PMN-PT and PMN-PZT matrices were up to 140 μm and 65 μm, respectively. Having developed this understanding, both ceramics were textured via the templated grain growth (TGG) process by using (001)-oriented BT templates. Sintering of templated grain bodies resulted in template growth into the matrix to produce textured ceramics with Lotgering factors up to 0.99 for both compositions. In textured samples unipolar strain s33 was enhanced by a factor of up to 1.8 compared to randomly oriented ceramics. By contrast, BT single crystal growth in an alternative PZT matrix with NdMn doping was not successful. Hence, in the present work, growth experiments in this NdMn -doped PZT were first performed using PZT fibers of similar composition as seeds. Growth of the fiber diameter of up to 100 μm was observed in that matrix.

scholarly journals Effect of Composition on the Growth of Single Crystals of (1−x)(Na1/2Bi1/2)TiO3-xSrTiO3 by Solid State Crystal Growth

Materials ◽  
2019 ◽  
Vol 12 (15) ◽  
pp. 2357 ◽  
Author(s):  
Le ◽  
Fisher ◽  
Moon
Keyword(s):  
Growth Rate ◽  
Crystal Growth ◽  
Solid State ◽  
Single Crystal ◽  
Single Crystals ◽  
Grain Growth ◽  
Ceramic Powder ◽  
Single Crystal Growth ◽  
Crystal Growth Rate ◽  
Mixed Control

The (1−x)(Na1/2Bi1/2)TiO3-xSrTiO3 (NBT-100xST) system is a possible lead-free candidate for actuator applications because of its excellent strain vs. electric field behaviour. Use of single crystals instead of polycrystalline ceramics may lead to further improvement in piezoelectric properties but work on single crystal growth in this system is limited. In particular, the effect of composition on single crystal growth has yet to be studied. In this work, single crystals of (NBT-100xST) with x = 0.00, 0.05, 0.10 and 0.20 were grown using the method of Solid State Crystal Growth. [001]-oriented SrTiO3 single crystal seeds were embedded in (NBT-100xST) ceramic powder, which was then pressed to form pellets and sintered at 1200 °C for 5 min–50 h. Single crystal growth rate, matrix grain growth rate and sample microstructure were examined using scanning and transmission electron microscopy. The results indicate that the highest single crystal growth rate was obtained at x = 0.20. The mixed control theory of grain growth is used to explain the single crystal and matrix grain growth behaviour.

Low-cost Cu-based shape memory single crystals obtained by abnormal grain growth showing excellent superelasticity

Materialia ◽  
2019 ◽  
Vol 5 ◽  
pp. 100200 ◽  
Author(s):  
Shuiyuan Yang ◽  
Jixun Zhang ◽  
Mengyuan Chi ◽  
Yuhua Wen ◽  
Xinren Chen ◽  
...  
Keyword(s):  
Shape Memory ◽  
Single Crystals ◽  
Grain Growth ◽  
Low Cost ◽  
Abnormal Grain Growth

Templated Grain Growth of Barium Titanate Single Crystals

2004 ◽  
Vol 83 (11) ◽  
pp. 2654-2660 ◽  
Author(s):  
Paul W. Rehrig ◽  
Gary L. Messing ◽  
Susan Trolier-McKinstry
Keyword(s):  
Barium Titanate ◽  
Single Crystals ◽  
Grain Growth ◽  
Templated Grain Growth

Microwave dielectric properties of oriented BaLa4Ti4O15 ceramics fabricated by templated grain growth

2004 ◽  
Vol 833 ◽  
Author(s):  
Yuko Fukami ◽  
Kensuke Wada ◽  
Ken-ichi Kakimoto
Keyword(s):  
Dielectric Properties ◽  
Grain Growth ◽  
Microwave Dielectric Properties ◽  
Molten Salt Synthesis ◽  
X Ray Diffraction ◽  
Templated Grain Growth ◽  
Solid State Method ◽  
Microwave Dielectric ◽  
Growth Method ◽  
Large Anisotropy

ABSTRACTDense and highly textured BaLa4Ti4O15 (BLT) ceramics was fabricated by templated grain growth method. Plate-like BLT particles prepared via a molten salt synthesis using NaCl flux were mixed with B LT powders obtained by the conventional solid state method. X-ray diffraction and scanning electron microscope studies of the textured ceramics showed plate-like BLT grains aligned parallel to the casting direction. Large anisotropy was found in the dielectric properties.

Molten salt synthesis of single-crystal Co3O4 nanorods

2007 ◽  
Vol 61 (18) ◽  
pp. 3901-3903 ◽  
Author(s):  
Xingfei Ke ◽  
Jieming Cao ◽  
Mingbo Zheng ◽  
Yongping Chen ◽  
Jinsong Liu ◽  
...  
Keyword(s):  
Single Crystal ◽  
Molten Salt ◽  
Molten Salt Synthesis ◽  
Co3o4 Nanorods

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.

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