Structure and Properties of Zn-Ti0.2-Cu0.15 Single Crystal Containing Eutectic Precipitates

2013 ◽  
Vol 58 (4) ◽  
pp. 1019-1022 ◽  
Author(s):  
G. Boczkal

Abstract Some structure observations for the Zn-Ti0.2-Cu0.15 single crystal obtained by the Bridgman method are presented. The structure contains (Zn) - phase with inclusions of Zn16Ti inter-metallic compound. The Zn16Ti intermetallic compound is localized within the eutectic precipitates. A morphology of the Zn16Ti compound varies according to the solidification condition imposed during the single crystal growth. The block, great size particles are a characteristic element for the alloy which composition is situated nearly the eutectic point in the phase diagram. These particles were not observed previously in the hypoeutectic Zn-Ti alloys. Mechanical properties of the obtained single crystals are also investigated. Critical resolved shear stress (CRSS) during deformation in a basal slip system (0001)<11-20>is determined. The changes of the CRSS for the Zn-Ti0.2-Cu0.15 single crystals within the range of temperatures from 200K to 370K are presented. The obtained data are compared with previously investigated results for the (Zn) single crystals containing lower (hypoeutectic) titanium addition

Crystals ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 378
Author(s):  
Li Zhao ◽  
Zhiwei Hu ◽  
Hanjie Guo ◽  
Christoph Geibel ◽  
Hong-Ji Lin ◽  
...  

We report on the synthesis and physical properties of cm-sized CoGeO3 single crystals grown in a high pressure mirror furnace at pressures of 80 bar. Direction dependent magnetic susceptibility measurements on our single crystals reveal highly anisotropic magnetic properties that we attribute to the impact of strong single ion anisotropy appearing in this system with TN∼33.5 K. Furthermore, we observe effective magnetic moments that are exceeding the spin only values of the Co ions, which reveals the presence of sizable orbital moments in CoGeO3.


Author(s):  
Phan Gia Le ◽  
Huyen Tran Tran ◽  
Jong-Sook Lee ◽  
John G. Fisher ◽  
Hwang-Pill Kim ◽  
...  

AbstractCeramics based on (Na1/2B1/2)TiO3 are promising candidates for actuator applications because of large strains generated by an electric field-induced phase transition. For example, the (1−x)(Na1/2Bi1/2)TiO3-xSrTiO3 system exhibits a morphotropic phase boundary at x = 0.2–0.3, leading to high values of inverse piezoelectric constant d*33, which can be further improved by the use of single crystals. In our previous work, single crystals of (Na1/2B1/2)TiO3-SrTiO3 and (Na1/2B1/2)TiO3-CaTiO3 were grown by the solid state crystal growth technique. Growth in the (Na1/2B1/2)TiO3-SrTiO3 system was sluggish whereas the (Na1/2B1/2)TiO3-CaTiO3 single crystals grew well. In the present work, 0.8(Na1/2Bi1/2)TiO3-0.2(Sr1−xCax)TiO3 single crystals (with x = 0.0, 0.1, 0.2, 0.3, 0.4) were produced by the solid state crystal growth technique in an attempt to improve crystal growth rate. The dependence of mean matrix grain size, single crystal growth distance, and electrical properties on the Ca concentration was investigated in detail. These investigations indicated that at x = 0.3 the matrix grain growth was suppressed and the driving force for single crystal growth was enhanced. Replacing Sr with Ca increased the shoulder temperature Ts and temperature of maximum relative permittivity Tmax, causing a decrease in inverse piezoelectric properties and a change from normal to incipient ferroelectric behavior.


CrystEngComm ◽  
2015 ◽  
Vol 17 (13) ◽  
pp. 2682-2689 ◽  
Author(s):  
Pascal Schouwink ◽  
Adrien Ramel ◽  
Enrico Giannini ◽  
Radovan Černý

Single crystals of mixed-metal perovskite-type borohydride KCa(BH4)3 are prepared by using an easily generalized flux melting procedure based on eutectic borohydride systems.


1981 ◽  
Vol 7 ◽  
Author(s):  
C. J. Mchargue ◽  
H. Naramoto ◽  
B. R. Appleton ◽  
C. W. White ◽  
J. M. Williams

ABSTRACTSingle crystals of Al2O3 were implanted with chromium and zirconium to fluences of 1 × 1016 to 1 × 1017 ions cm−2. Rutherford backscattering-channeling studies showed the surface layers to be damaged but crystalline with the implanted ions randomly distributed. The microhardness and indentation fracture toughness were higher for the random solutions than for conventionally formed solid solutions. Changes in structure and properties caused by annealing in air at temperatures up to 1800°C were studied.


Materials ◽  
2019 ◽  
Vol 12 (15) ◽  
pp. 2357 ◽  
Author(s):  
Le ◽  
Fisher ◽  
Moon

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.


1991 ◽  
Vol 251 ◽  
Author(s):  
T. Miyatake ◽  
T. Takata ◽  
K. Yamaguchi ◽  
K. Takamuku ◽  
N. Koshizuka ◽  
...  

ABSTRACTWe investigate the crystal growth of YBa2Cu4O8 (124) and Y2Ba4Cu7O15 (247) in Al2O3 crucibles at an oxygen partial pressure of 20MPa employing an O2- HIP apparatus in a mixed gas environment of Ar-20%O2. Various melts compositions, rich in Ba and Cu, are explored to optimize crystal growth of 124. Large 124 single crystals up to a size of 1×0.5×0.05mm3 are obtained from compositions with about 65˜67%CuO. 247 single crystals having a maximum size of 3×1.5×0.05mm3 are grown from the same composition of melts. 124 crystals exhibit superconductivity at 75K. 247 crystals show Tc of 20K.


2008 ◽  
Vol 01 (02) ◽  
pp. 127-132 ◽  
Author(s):  
THOMAS RICHTER ◽  
CARSTEN SCHUH ◽  
RALF MOOS ◽  
ENDER SUVACI

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.


Crystals ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 56
Author(s):  
Lkhagvasuren Baasandorj ◽  
Zibin Chen

Numerous investigations on the development of the relaxor-PbTiO3 ferroelectric crystals have been carried out since their extraordinary properties were revealed. Recent developments on these crystals have offered further advances in electromechanical applications. In this review, recent developments on relaxor-PbTiO3 crystals and their practical applications are reviewed. The single crystal growth methods are first discussed. Two different strategies, poling and doping, for piezoelectric improvement are surveyed in the following section. After this, the anisotropic features of the single crystals are discussed. Application perspectives arising from the property improvements for electromechanical devices are finally reviewed.


1988 ◽  
Vol 02 (02) ◽  
pp. 571-575 ◽  
Author(s):  
Y.F. YAN ◽  
C.Z. LI ◽  
J.H. WANG ◽  
Y.C. CHANG ◽  
Q.S. YANG ◽  
...  

We have prepared two kinds of single crystals in Bi-Sr-Ca-Cu oxides by flux method;plate-like single crystals which exhibit metal to superconductor at 93 K, being the high-Tclayered compound BiSr (Ca 0.35 Sr 0.25 Bi 0.40)2 Cu 2Oy with orthorhombic structure with a=5.42 Å, b=5.44 Å and c=30.78 Å respectively, and another kind of bar-shapedbismuth-poor single crystals which is superconducting at the temperature below 82K whilebeing semiconducting above this temperature.


Sign in / Sign up

Export Citation Format

Share Document