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In this paper, single-phase chemically homogeneous high-entropy ceramics (HEC) were synthesized from a mixture of pre-mechanically alloyed CrNbMoWV high-entropy alloy (HEA) powders and carbon. High-entropy CrNbMoWV carbides were obtained for the first time. Mechanical alloying (MA) of a CrNbMoWV alloy with different process inputs times made it possible to obtain a single-phase powder with a body-centered cubic lattice and a uniform distribution of chemical elements. During the sintering of the mixture of pre-mechanically alloyed HEA powders with carbon by SPS single-phase HEC with the MeC chemical formula was formed. The XRD and SEM/EDX results are consistent between themselves. The obtained HEC are characterized by high wear resistance and hardness, with an average value of hardness for carbide sintered at 1400 °C of 1260 HV.

Magnetic and transport properties of iron nitride compounds are closely related to the ratio of Fe:N. In this letter, we report a successful growth of pure single-phase N-rich iron nitride (e-Fe2–3N and γ″-FeN) films on Al2O3. e-Fe2–3N shows a ferromagnetic behavior while γ″-FeN shows a nonmagnetic behavior. Same with other N-poor iron nitrides, e-Fe2–3N presents metallic transport nature. In particular, weak localization in quantum interference effects (QIEs) and spin-dependent scattering phenomena are observed in e-Fe2–3N. Different with other known iron nitrides, γ″-FeN shows semiconductor-like transport property. These findings offer great opportunities for designing magnetoelectronic devices based on iron nitride compounds.

Ti-substituted CuGaS2 (Ti-CGS) thin film, a well candidate intermediate band (IB) material, has been successfully synthesized via a well synthetic route by alternate sputtering. The results revealed that the film have a compact morphology and are comprised of a crystalline chalcopyrite single phase Ti-CGS. Due to the presentation of Ti atoms, the IBs were introduced and additional sub-band-edge responses were directly observed in absorption spectroscopy. In the Ti-CGS thin film, except an intrinsic band-edge response observed at 510 nm (‘A’, 2.31 eV), two distinct sub-band-edge responses are observed at 856 nm (‘B’, 1.45 eV) and 1418 nm (‘D’, 0.87 eV). Besides, one weak sub-band-edge responses are found at 1102 nm (‘C’, 1.13 eV), which is in accord with theoretical prediction. The present report might provide a promising fabrication process for discovering the multiple IBs in the Ti-CGS film.

Mg4Nb2O9 ceramics have been prepared by B-site precursor method in this work. Experimental results demonstrate that the uniform particles-size distribution of Mg4Nb2O9 powders can be obtained, which exhibit high reactivity to promote the grain growth of Mg4Nb2O9 ceramics. Moreover, the Mg4Nb2O9 ceramics via B-site precursor method can be sintered at a wide range of sintering temperature from 1275 to 1375 °C with single phase Mg4Nb2O9 composition and high crystallinity. Compared to the conventional solid-state method, the Mg4Nb2O9 ceramics prepared by B-site precursor method exhibit excellent Q × f value by above 168,756 GHz.

M2BiLi2V3O12 (M = Ca, Zn) low temperature co-fired ceramics were investigated in the present work. The ceramics could be densified at 625–675 °C for 4 h. X-ray diffraction (XRD) patterns of ceramics shown that Ca2BiLi2V3O12 was a single phase with cubic garnet structure, but Zn2BiLi2V3O12 displayed multiple phases. Both ceramics exhibited good comprehensive performances (Ca2BiLi2V3O12: optimized sintering temperature Ts = 650 °C, er = 24.7, Q × f = 6436 GHz, τƒ = 57 ppm/°C. Zn2BiLi2V3O12: Ts = 675 °C, er = 17.0, Q × f = 17,522 GHz, τƒ = −154 ppm/°C), indicating that they are the candidates for LTCC device applications.

The single phase Fe-doped NiTiO 3 samples were fabricated by sol-gel method. The reduction in both direct and indirect optical band gap from 2.34 eV to 1.82 eV and from 2.02 eV to 0.94 eV, respectively, were obtained due to the presence of Fe substitution at Ni site in ilmenite structure of NiTiO 3 materials. The NiTiO 3 powders exhibited weak-ferromagnetism at room temperature while the Fe-doped NiTiO 3 showed strong-ferromagnetism with the strong enhancement in magnetization. We expected that our work was further to understand the role of interaction in A -site in ilmenite structure to increase the room temperature magnetic ordering for electronic application.

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Eu2+/Eu3+-doped fluorophosphate Na5Al(PO4)2F2 was synthesized by the high-temperature solid-state reaction. The structural XRD refinement was used to investigate the phase formation and structure. The photoluminescence (PL) excitation and emission spectra were measured. The host accommodates two kinds of Eu-centers in the lattices, i.e., Eu3+ and Eu2+, which were confirmed by the emission spectra and decay curves. Under the excitation of UV and near-UV light, the broad emission peaked at 420 nm and 530 nm from the 4f65d–4f7 transition of Eu2+ and narrow peaks at 592 nm, 615 nm from the 4f–4f transitions of Eu3+ ions were detected. The luminescence color could shift from blue to white and red by mixing the luminescence from the coexistence of Eu2+/Eu3+ ions in the single-phase phosphor.

Most recently, a host of irradiation experiments conducted on single-phase concentrated solid-solution alloys has been lacking interpretations from first principles. Here, the formation energetics and migration kinetics of interstitial defects in pure Ni and two Ni-based alloys (NiCo and NiFe) have been investigated by first principles calculations, based on which we are able to provide significant insights into two key aspects of experimental observations concerning the radiation-induced segregation and the enhanced radiation tolerance.

The high densified single phase ceramics Gd 2 Zr 2 O 7 have been successfully manufactured by spark plasma sintering (SPS) for the first time. The effects of sintering temperature and holding time on the phase and microstructure were investigated in detail. The XRD studies reveal that the Gd 2 Zr 2 O 7 ceramics with a single phase can be obtained at 1700 °C beyond 3 min, and the intensity is found to increase with increasing holding time. From the fracture surface observation and density measurement, the SPS processed samples have higher densities than conventional one. This work offers a novel approach to a high densified single phase ceramic Gd 2 Zr 2 O 7 in a much shorter time.

LiSmTa4O12 ceramics were prepared via the conventional solid-state method, and their microwave dielectric properties were studied. The ceramics could be densified at 1425 °C–1525 °C. X-ray diffraction (XRD) analysis suggested that LiSmTa4O12 is single phase with A-site deficient perovskite structure a, whereas the impact from sintering temperature is weak. The excellent microwave dielectric performances of er = 59.60, Q × f = 7 760 GHz (at 5.065 GHz), and τf = +41.8 ppm/°C were achieved when the ceramics were sintered at 1500 °C for 4 h, which means that the ceramics are suitable for miniaturized electronic devices.

In this study, we report the synthesis of Cu(Zn,Sn)Se2 (CZTSe) nanoparticles by hot-injection method for application to the absorber layer in solar cells. The composition of elements in the CZTSe nanoparticles depends mainly on the injection speed of the Se precursor. By controlling the injection speed, we obtained complete single-phase CZTSe nanoparticles with high crystallinity and copper-poor composition. The nanoparticle diameter mainly ranged from ~ 7 nm to 18 nm. The obtained CZTSe nanoparticles were used to fabricate a light absorber layer in the CZTSe solar cells. The cell exhibited performance, with short-circuit current density of ~ 30.8 mA/cm2, open-circuit voltage of 0.39 V, fill factor of 0.47 and conversion efficiency of 5.8%.

A series of W-type hexagonal ferrites with the composition Ba 1 - x Sr x Fe 2 2 + Fe 16 3 + O 27 (0≤x≤1) were prepared by the ceramic process in a reducing atmosphere during the whole process of pre-sintering and sintering. The phase composition, micro-morphology, and magnetic properties of the particles were investigated by XRD, SEM, and VSM. The results of XRD show that the single phase was observed in the W-type ferrites with different Sr content. The micro-morphology of the particles exhibits the uniform plane hexagonal structures of W-type ferrites with different Sr content. The coercivity (Hc) of the particles increases with the increase of Sr content (x), while the saturation magnetization (Ms) of the particles first decreases with x from 0 to 0.2, and then begins to increase when x continues to increase.

Spherical Li 4 Ti 5 O 12 (LTO) anode materials were synthesized by spray drying, followed by calcination at different temperatures. A well-crystallized LTO in a single phase was obtained at 750 °C. The spherical LTO particles had polyhedron-shaped grains with dimensions of 200×200×200 nm 3 assembled from ~29 nm nanosized grains. The obtained sample at 750 °C had initial discharge capacities of 209.69 and 193.16 mA h g −1 at 1 C and 2 C rates, respectively. After 20 cycles, the as-prepared LTO retained 99.68% and 99.72% of its initial discharge capacities at 1 C and 2 C rates, respectively.

To make SnO 2 –CoO–Nb 2 O 5 –Cr 2 O 3 –Y 2 O 3 –Bi 2 O 3 ceramics suitable for low voltage varistor applications, the amount of Bi 2 O 3 addition to a well-known SnO 2 -based composition for high voltage varistors was optimized. The addition of 0.15 mol% Bi 2 O 3 has resulted in a single phase ceramic material with the average grain size of 30 μm and electrical properties useful for low voltage varistors. The obtained SnO 2 low voltage varistors exhibit excellent electrical properties as surge absorbers.

Two new high Curie temperature piezoelectric ceramics were reported for the first time. The PbTiNb2O8 and PbZrNb2O8 samples show single phase with space group of Am m 2 and C2 2 2, respectively. With the sintering temperature of 1120 °C and 970 °C, PbTiNb2O8 ceramics and PbZrNb2O8 ceramics have the highest Tc of 700.1 °C and 559.6 °C, respectively. The thermal depoling effects study shows that the depoling temperature of PbTiNb2O8 and PbZrNb2O8 ceramics is around 560 °C and 480 °C, respectively. The typical piezoelectric properties of PbTiNb2O8 and PbZrNb2O8 ceramics are: d33=16 pC/N, kp=0.11, Qm=102 and d33=20 pC/N, kp=0.16, Qm=42, respectively. All PbTiNb2O8 and PbZrNb2O8 samples are have low dielectric loss with ~10−4, which is good for the application of devices.

In the present work we report the synthesis, crystal structure and charge transport properties of BaSnO 3 . The powder X-ray diffraction showed the formation of single phase with cubic structure. The total conductivity was measured using complex impedance analysis. The maximum conductivity was found to be 3.63×10 −3 S cm −1 at 650 °C. The total conductivity was found to increase with increase in temperature.

Phase formation of NiTi via solid state diffusion from Ni–Ti and Ni–TiH2 powders under a CaH2 reducing environment were investigated. Elemental powder sintering of Ni–Ti at equiatomic composition did not result in single phase TiNi, but rather in multi-phases, including Ti2Ni, TiNi, and TiNi3. In this work, we show evidence that powder sintering of Ni–TiH2 produces single phase NiTi with good transformation heat both on cooling and heating with ΔHA–M=26.04 J/g and ΔHM–A=25.53 J/g, respectively. The use of CaH2 as the in situ reducing agent and of TiH2 to replace Ti as the starting powder, protected the sample successfully from oxidation.

Single phase gyrolite – cation exchanger, has been successfully synthesized in the CaO–SiO2–Na2O–H2O system. It is the first successive attempt, when the single phase gyrolite was synthesized using quartz as siliceous material. It has been found that the content of NaOH is crucial for gyrolite crystallization. The results indicate that optimum amount of NaOH is in narrow range between 0.75% and 1.00%. Decreasing or increasing its amount does not allow to obtain gyrolite in pure form and in final products unreacted quartz was observed.

In this work, a nanotwinned structure of a two-phase titanium (TC21) alloy was prepared via the martensitic phase transformation method. The TC21 alloy forms initially a single phase β when the temperature reaches 1050 °C. Then, it transitions into an orthorhombic martensite (α″) material when quenched in water. After tempering at 500 °C, the martensite transforms into a high-density nanotwinned α phase material. The hardness of the nanotwinned alloy is 25% higher than that of the TC21 raw material.

The compositionally up- and down-graded BaZr x Ti 2− x O 5 ( x =0, 0.01, 0.02, 0.03 and 0.04) thin films normal to Pt/Ti/SiO 2 /Si substrates were prepared by the sol–gel method. Their microstructure, dielectric and ferroelectric properties were investigated. The single phase compositionally graded thin films were obtained, and the upgraded thin film had better crystallization. The polarization enhancement of the compositionally graded BaZr x Ti 2− x O 5 thin films was observed. Compared with the downgraded film, the upgraded BaZr x Ti 2− x O 5 thin film showed better properties of dielectric constant ( e r =75, at 1 MHz) and remnant polarization (2 P r =0.66 μC cm −2 ) due to the BaTi 2 O 5 seeding layer.

A single phase perovskite, Y x Sr 1− x Ti 0.6 Fe 0.4 O 3− δ ( x= 0.07, 0.08, 0.09), was synthesized at 1350 °C by the sol–gel method. The effects of Y-doping on the electronic and ionic conductivities of Y x Sr 1− x Ti 0.6 Fe 0.4 O 3− δ were investigated. The ionic conductivity of SrTiO 3 -based materials can be significantly improved by Y-doping on the A-site and Fe-doping on the B-site. We report in this paper a remarkable enhancement of ionic conductivity of Y, Fe co-doped SrTiO 3 by the increase in Y-doping amount on the A-site. The total electrical conductivity and ionic conductivity were 0.135 S/cm and 0.017 S/cm for Y 0.07 Sr 0.93 Ti 0.6 Fe 0.4 O 3− δ at 800 °C, respectively, while were 0.056 S/cm and 0.02 S/cm for Y 0.09 Sr 0.91 Ti 0.6 Fe 0.4 O 3− δ .

Novel single-phased white-light-emitting Ca 2.96 (P 0.99 B 0.01 O 4 ) 2 :0.04Dy 3+ phosphors for light-emitting diode (LED) applications were synthesized by conventional solid-state reactions. The phases and luminescent properties of the obtained Ca 2.96 (P 0.99 B 0.01 O 4 ) 2 :0.04Dy 3+ phosphors were well characterized. The results show that the excited bands of Ca 2.96 (P 0.99 B 0.01 O 4 ) 2 :0.04Dy 3+ phosphor centered at wavelengths of 324 nm ( 6 H 15/2 → 4 M 17/2 ), 350 nm ( 6 H 15/2 → 4 M 15/2 , 6 P 7/2 ), 366 nm ( 6 H 15/2 → 4 I 11/2 ), 387 nm ( 6 H 15/2 → 4 I 13/2 , 4 F 7/2 ), 427 nm ( 6 H 15/2 → 4 G 11/2 ), and 448 nm ( 6 H 15/2 → 4 I 15/2 ). On excitation at 350 nm, the emission transitions of Dy 3+ consisted of double emission bands, which can be assigned to the transition emissions of 4 F 9/2 → 6 H 15/2 (480 nm) and 4 F 9/2 → 6 H 13/2 (572 nm). One mol% B 3+ dopant improved the luminescence intensity of Ca 2.96 (PO 4 ) 2 :0.04Dy 3+ phosphor, and the reason was proposed. The developed phosphor has great potential as a single-component white-light-emitting phosphor for UV-light-emitting diodes.

An electrodeposition process to obtain Cu–Li alloy as a function of the temperature is studied. The optimal temperature for producing sheets of a single phase of copper with lithium in solid solution, without inclusions nor voids, is determined. In fact, when the electrodeposition process is performed at a temperature of 923 K, a single phase alloy of Cu–1.4 wt.% Li with a cubic Fm3m structure with a=3.624 A is obtained.

Magnetoelectric composites with compositions xBa0.8Pb0.2TiO3+(1−x)Ni0.5Co0.5Fe2O4 in which x varies as 0, 0.55, 0.70, 0.85 and 1.0 were prepared by double sintering method. The presence of single phase in x=0 and x=1 as well as two phases in x=0.55, 0.70 and 0.85 composites has been confirmed by XRD. The dielectric constant and loss tangent were studied as a function of frequency and temperature. The static value of the magnetoelectric conversion factor, i.e. d.c. (ME)H was studied as a function of the magnetic field. The maximum value of ME coefficient was observed for x=0.85 composite, whereas minimum for x=0.55 composite.

Using CaO/CaCO3 (blend) and NH4Cl as the respective calcium and chloride sources, we have succeeded in the synthesis of single-phase Ca2SiO3Cl2:Eu2+ powder phosphor via solid-state-reaction. Indeed, two emission bands due to Eu2+ should be observed in Ca2SiO3Cl2:Eu2+, since there are two Eu2+ luminescence centers substituting for two Ca2+ sites. However, interestingly, only one emission band centered at 495 nm is observed. This is explained based on the uniform covalency and crystal field of two Eu2+ sites. The excellent thermal stability and the intense emission upon near-ultraviolet (UV) light excitation suggest that Ca2SiO3Cl2:Eu2+ can be used as a potential bluish-green phosphor for near-UV white LEDs. (C) 2012 Elsevier B.V. All rights reserved.

White light emission (Sr0.85Mg0.14)3(P1−xSixO4)2: Dy3+ phosphors applied for white light emitting diodes (LEDs) were synthesized by the solid state reaction process. The phases and luminescence properties of the obtained (Sr0.85Mg0.14)3(P1−xSixO4)2: Dy3+ phosphors were well characterized. The presented results demonstrate that the (Sr0.85Mg0.14)3(P1−xSixO4)2: Dy3+ particles emit an intensive white light emission under excitation at 350 nm. Additionally, the effect of Si4+ incorporation concentration on the luminescence properties of (Sr0.85Mg0.14)3(PO4)2: Dy3+ was investigated in detail.

Sinter-forging technique was applied to produce high efficiency e-Zn 4 Sb 3 bulk specimens. Near single phase Zn 4 Sb 3 with a remnant ZnSb was obtained using nominal stoichiometric powder mixtures. Thermoelectric properties in sinter-forged specimens as a function of temperature were investigated up to 600 K and compared with results of other studies. Transport properties at room temperature were also evaluated. Thermoelectric properties of Zn 4 Sb 3 processed by sinter-forging are comparable to the published data. Sinter-forging offers a potential processing route to produce a bulk Zn 4 Sb 3.

The effect of HCl additions on the formation of precipitates by hydrolysis of FeCl3 solutions at 90 jC has been investigated using X-ray powder diffraction (XRD), FT-IR spectroscopy and transmission electron microscopy (TEM). In the precipitation systems with 0.1 M FeCl3, the concentration of HCl varied between 0.005 and 0.1 M, whereas the maximum time of hydrolysis was 35 days. At the beginning of the hydrolytic process, the formation of precipitate was strongly suppressed with an increase in HCl concentration. h-FeOOH was found as a single phase in the precipitates for the concentration 0.1 M FeCl3+0.01 M HCl after 1 and 3 days of hydrolysis. For the concentrations [HCl]z0.05 M, the precipitates also contained a small amount of a-FeOOH. FT-IR spectroscopy was proved to be a useful technique in the detection of a-FeOOH. After 35 days of hydrolytic process, a-Fe2O3 was found as the end product of precipitation, whereas some precipitates also contained small amounts or traces of a-FeOOH. The size and shape of the particles strongly depended on the HCl concentration. Forced hydrolysis of 0.01 M FeCl3+0.005 M HCl solution for 35 days yielded small and uniform a-Fe2O3 particles (f0.08 Am). D 2004 Elsevier B.V. All rights reserved.

The paper presents a simple technique for synthesis of La 1− x Sr x CoO 3 ( x =0–0.3) nanopowders by calcining maleate-based precursors. The complex precursors were characterised by chemical analysis, electronic and FT-IR spectra and DTA–TG analysis. The XRD data for La 1− x Sr x CoO 3 show that the samples are single phase with rhombohedral distorted perovskite structure. Specific surface area results of La 1− x Sr x CoO 3 samples indicated values in the range 30–38 m 2 /g, which are high values for perovskite-type oxides.

A new heteronuclear (NH 4 ) 2 Sr[Fe II (CN) 6 ] complex having a tetragonal phase was synthesized from Sr(NO 3 ) 2 and (NH 4 ) 4 [Fe II (CN) 6 ]·nH 2 O. A single phase of the heteronuclear (NH 4 ) 2 X La 1 − X Sr X [Fe(CN) 6 ]•nH 2 O complex was synthesized by the coprecipitation of two heteronuclear hexacyano complexes of La[Fe III (CN) 6 ]•5H 2 O and (NH 4 ) 2 Sr[Fe II (CN) 6 ]. The X value (Sr content) for the complex was lower than that of the starting material. The perovskite-type La 1 − X Sr X FeO 3 − α phase was directly formed by the thermal decomposition even at 250 °C for 1 h.

We synthesized and analyzed single-phased white light emitting phosphors, Na(Sr,Ba)PO4:Eu2+, Mn2+, and found that the energy transfer from the Eu2+ to the Mn2+ activator followed by the photoemission was more efficient in Na(Sr0.5Ba0.5)PO4 than in the Ba-free host composition, NaSrPO4. Combining a near UV 390 nm chip and the given Na(Sr0.5Ba0.5)PO4:Eu2+, Mn2+ phosphor produced a bright white light illuminating phosphor converted-light emitting diodes (pc-LEDs), demonstrating CIE chromaticity coordinates of (0.36, 0.31). The emission intensity was substantially changed with an increase of the injection current from 5 to 90 mA, while the shifts of chromaticity coordinates were nearly negligible. Those results suggest that Na(Sr,Ba)PO4:Eu2+, Mn2+ can be a promising single component phosphor for cost effective white emitting pc-LEDs.

Skutterudite compounds Co 4 Sb 12-x Te x (0.1 ≤ ×≤0.8) was synthesized successfully by high temperature and high pressure (HTHP) method and characterized with X-ray diffractometry and thermoelectric properties measurements. The samples prepared by HTHP are nearly with the single phase CoSb 3 . The electrical resistivity, Seebeck coefficient and thermal conductivity were all depending on synthetic pressure and the Te content of the Skutterudite compounds were performed at room temperature. As our expected, the Seebeck coefficient increased with an increase of the synthetic pressure and the thermal conductivity decreased with an increase of the synthetic pressure. These results indicated that HTHP technique may be helpful to prepare thermoelectric materials with enhanced thermoelectric properties.

Two different ferromagnetic phases of the perovskites RMn 0.5 Co 0.5 O 3 (R=Pr, Nd, Sm) have been synthesized in single phase forms by a low-temperature method. For each compound, a phase with a higher ferromagnetic transition temperature is obtained for samples heated at 700°C, whereas a second phase having a lower ferromagnetic transition temperature is obtained for samples heated at 1350°C. Samples heated in the temperature range 700–1350°C showed mixed phase behavior.

Single crystalline Mg 2 B 2 O 5 nanorods have been synthesized by a two-step process involving the mechano-chemical technique and sintering method. Using MgCl 2 ·6H 2 O and NaBH 4 powders as the starting materials, the mixture was firstly milled for 120 h, and then sintered at 800 °C for 2 h. The X-ray diffraction indicates the final product is monoclinic Mg 2 B 2 O 5 . SEM and TEM results show that the Mg 2 B 2 O 5 is nanorod with the diameter about 200–400 nm and the length up to 5 μm. SAED analysis shows that the nanorod is single crystalline and twinned structure. The by-product NaCl is necessary for the formation of the single phase Mg 2 B 2 O 5 .

Two distinct single phases of ferromagnetic LaMn 0.5 Co 0.5 O 3 have been synthesized by the low-temperature glycine-nitrate method. Sample heated to 700°C shows a single well-defined ferromagnetic transition at T c ≈225 K whereas the sample heated to 1300°C shows a sharp ferromagnetic transition at T c ≈150 K. Mixed phase behavior is observed for samples heated in the temperature range 700–1300°C.

An X-ray study of the solid solution Cs x Cu (1− x ) Cl was carried out to determine the powder diffraction peaks ( hkl indices) pertaining to the intermediate compound CsCu 2 Cl 3 . This phase forms at 623 K and can be retained at room temperature as a single phase.

The effects of preparation condition on structure and superconductivity of LaBa2Cu3Oy (LaBCO) system have been investigated, and the optimum preparation condition and superconductivity of Tc(0)=97 K and Tc(onset)=101 K, which are the best results at present, have been achieved. The optimum preparation condition is A-B-C3-D-E. Investigations show that keeping LaBa2Cu3Oy, being of tetragonal structure before oxygenation, at 305°C is a key procedure to obtain a single phase LaBa2Cu3Oy sample with the best superconductivity.

Polycrystalline samples of KTi1−xNb1+xO5 (x=0.1, 0.2, 0.3) were synthesized by solid-state reactions. The synthesized compounds were blue-colored, suggesting reduced oxidation states. Single phase KTi1−xNb1+xO5 was obtained for 0≤x

In this letter, p-type pseudo-binary AgSbTe2–Ag2Te thermoelectric alloys with the composition of (AgSbTe2)1 − x(Ag2Te)x (x = 0~0.2) were prepared by high pressure and high temperature (HPHT) method. The samples are near single phase AgSbTe2 with a small quantity of impurities including Sb2Te3 and Ag2Te. The electrical properties including the Seebeck coefficient and the electrical resistivity depending on synthetic pressure and the Ag2Te content x were studied at room temperature. The measurement results show that the Seebeck coefficient and the electrical resistivity for (AgSbTe2)1 − x(Ag2Te)x decrease with an increase of the synthetic pressure and x which indicate that high pressure combining alloying with Ag2Te could modulate the electrical properties of Ag–Sb–Te system effectively.

Ultrafine single phase potassium tantallate (KTaO3) powders were successfully synthesized through the reaction of Ta2O5 and concentrated KOH solution under atmospheric pressure at the temperature of 150 and 200 degrees C. The samples were characterized by XRD and FESEM. It is shown that the concentration of KOH has a great effect on the morphology and particle size of KTaO3 powders. The morphology of KTaO3 powders changed from cubic particles to spherical particles and the particle size decreased from 200-250 nm to 30-50 nm as the KOH concentration increased from 55 to 75 wt.%. (C) 2007 Elsevier B.V. All rights reserved.

A simple co-precipitation technique has been successfully used for the preparation of pure ultrafine single phase BiTaO 4 . A standard ammonium hydroxide solution was used to precipitate Bi 3+ and Ta 5+ cations as hydroxides simultaneously under basic conditions. This precursor, on heating at 600 °C, produced product phase. This is the lowest temperature for the formation of BiTaO 4 phase so far reported in the literature. For comparison BiTaO 4 powders were also prepared by the traditional solid state method. The phase contents and lattice parameters were studied by the powder X-ray diffraction (XRD).

A new method was provided to synthesize three kinds of potassium titanates, namely K4Ti3O8, K(2)Ti(2)O(5)(.)xH(2)O and KTiO2(OH), by treating TiO2 with concentrated KOH solution under atmospheric pressure. The effects of reaction temperature and KOH concentration on the morphology and species of potassium titanates were determined by XRD, FESEM and ICP-OES. On the basis of the experimental results, a formation diagram has been constructed for the products synthesized in the TiO2-KOH-H2O system under atmospheric pressure with KOH concentration ranging from 55 to 80 wt.% and temperature ranging from 100 to 280 degrees C. From the experimental results, it can be concluded that well crystallized and single phase potassium titanates can be obtained under the certain temperature and KOH concentration. (c) 2005 Elsevier B.V. All rights reserved.

An X-ray study of the solid solutions CsxAg(1 − x)I was carried out from which all of the powder diffraction peaks (hkl indices) pertaining to the intermediate compound CsAg2I3 were determined. This phase forms at 210 °C and can retained to room temperature as a single phase.

Single-phase bulk Al-Fe(Mo,Si,B) nanostructured alloy was prepared by heating a material consisting of alternate layers of amorphous (Fe0.99Mo0.01)(78)Si9B13 ribbons and pure aluminum sheets for 20 min under a pressure of 3 GPa at a temperature of 1073 K. Its mean grain size is about 22 nm and its crystal structure is orthorhombic. The formation mechanism of the bulk nanostructured alloy is discussed.

Creep data of single-phase γ-TiAl alloys from different sources can be explained by a single deformation mechanism that incorporates a threshold stress. It is suggested that the creep behavior of single-phase γ-TiAl alloys is controlled by a dislocation climb process (n≈ 4.5) with an activation energy for creep of about 313 kJ/mol. © 1994.

We have found that thermolysis of the heteropolymetallic transmetalation product (μ4-O)L4Cu2(Ni(H2O))2Cl6 (L  N,N-diethylnicotinamide) in argon at 350°C is a direct, low-temperature route to the single-phase copper-nickel alloy Cu0.50Ni0.50. Homologous heteropolymetallic precursors also give other stoichiometric copper-nickel alloys under the same conditions.