scholarly journals Synthesis of the superfine high-entropy zirconate nanopowders by polymerized complex method

2021 ◽  
Vol 11 (1) ◽  
pp. 136-144
Author(s):  
Yangjie Han ◽  
Renwang Yu ◽  
Honghua Liu ◽  
Yanhui Chu
Keyword(s):  
Particle Size ◽  
High Purity ◽  
Phase Evolution ◽  
Synthesis Temperature ◽  
Fluorite Phase ◽  
Complex Method ◽  
Crystallinity Degree ◽  
High Entropy ◽  
Polymerized Complex Method ◽  
Compositional Uniformity

AbstractThe high-purity and superfine high-entropy zirconate nanopowders, namely (Y0.25La0.25Sm0.25Eu0.25)2Zr2O7 nanopowders, without agglomeration, were successfully synthesized via polymerized complex method at low temperatures for the first time. The results showed that the crystallinity degree, lattice strain, and particle size of the as-synthesized powders were gradually enhanced with the increase of the synthesis temperature from 800 to 1300 °C. The as-synthesized powders involved fluorite phase in the range of 800–1200 °C while they underwent the phase evolution from fluorite to pyrochlore at 1300 °C. It is worth mentioning that the as-synthesized powders at 900 °C are of the highest quality among all the as-synthesized powders, which is due to the fact that they not only possess the particle size of 11 nm without agglomeration, but also show high purity and good compositional uniformity.

Influence of Synthesis Temperature on the ZnNb2O6 Powders Prepared via Co-Precipitation Method

2014 ◽  
Vol 1033-1034 ◽  
pp. 1044-1047
Author(s):  
Yong Du ◽  
Jin Liang Huang ◽  
Yong Jun Gu
Keyword(s):  
Particle Size ◽  
Phase Composition ◽  
Chemical Composition ◽  
High Purity ◽  
Raw Materials ◽  
Particle Morphology ◽  
Synthesis Temperature ◽  
Coprecipitation Method ◽  
Precipitation Method ◽  
Co Precipitation

ZnNb2O6powder was successfully synthesized via coprecipitation method with Nb2O5、Zn(NO3)2·6H2O as raw materials and ammonia as precipitant agent. This precursor on heating at750°C, produced ZN powders. Phase composition, morphology and chemical composition were studied via a combination of XRD, TEM and EDS technique. The effects of synthesis temperature on phase composition and particle morphology were investigated in this paper. The results showed that with the increase of the synthesis temperature, the particle size decreases. We could get the ZnNb2O6powder with high purity, fine crystalline when the synthesis temperature is at 50°C.

scholarly journals Synthesis of High-purity YBa2Cu3O7-d Superconductors by Polymerized Complex Method.

1993 ◽  
Vol 40 (10) ◽  
pp. 982-986 ◽  
Author(s):  
Masato Kakihana ◽  
Hirotaka Fujimori ◽  
Masatomo Yashima ◽  
Masahiro Yoshimura ◽  
Hiromasa Mazaki ◽  
...  
Keyword(s):  
High Purity ◽  
Complex Method ◽  
Polymerized Complex Method

scholarly journals Mining Wastes of an Albite Deposit as Raw Materials for Vitrified Mullite Ceramics

Minerals ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 232
Author(s):  
Pedro J. Sánchez-Soto ◽  
Eduardo Garzón ◽  
Luis Pérez-Villarejo ◽  
George N. Angelopoulos ◽  
Dolores Eliche-Quesada
Keyword(s):  
Particle Size ◽  
Raw Materials ◽  
Phase Evolution ◽  
Particle Size Analysis ◽  
Size Analysis ◽  
Mining Wastes ◽  
X Ray Diffraction ◽  
X Ray ◽  
Maximum Value

In this work, an examination of mining wastes of an albite deposit in south Spain was carried out using X-ray Fluorescence (XRF), X-ray diffraction (XRD), particle size analysis, thermo-dilatometry and Differential Thermal Analysis (DTA) and Thermogravimetric (TG) analysis, followed by the determination of the main ceramic properties. The albite content in two selected samples was high (65–40 wt. %), accompanied by quartz (25–40 wt. %) and other minor minerals identified by XRD, mainly kaolinite, in agreement with the high content of silica and alumina determined by XRF. The content of Na2O was in the range 5.44–3.09 wt. %, being associated with albite. The iron content was very low (<0.75 wt. %). The kaolinite content in the waste was estimated from ~8 to 32 wt. %. The particle size analysis indicated values of 11–31 wt. % of particles <63 µm. The ceramic properties of fired samples (1000–1350 °C) showed progressive shrinkage by the thermal effect, with water absorption and open porosity almost at zero at 1200–1250 °C. At 1200 °C, the bulk density reached a maximum value of 2.38 g/cm3. An abrupt change in the phase evolution by XRD was found from 1150 to 1200 °C, with the disappearance of albite by melting in accordance with the predictions of the phase diagram SiO2-Al2O3-Na2O and the system albite-quartz. These fired materials contained as main crystalline phases quartz and mullite. Quartz was present in the raw samples and mullite was formed by decomposition of kaolinite. The observation of mullite forming needle-shape crystals was revealed by Scanning Electron Microscopy (SEM). The formation of fully densified and vitrified mullite materials by firing treatments was demonstrated.

scholarly journals A Study of Thin Film Resistors Prepared Using Ni-Cr-Si-Al-Ta High Entropy Alloy

2015 ◽  
Vol 2015 ◽  
pp. 1-7 ◽  
Author(s):  
Ruei-Cheng Lin ◽  
Tai-Kuang Lee ◽  
Der-Ho Wu ◽  
Ying-Chieh Lee
Keyword(s):  
Annealing Temperature ◽  
Phase Evolution ◽  
Amorphous Structure ◽  
High Entropy Alloy ◽  
X Ray Diffraction ◽  
Temperature Coefficient Of Resistance ◽  
X Ray ◽  
High Entropy ◽  
Transmission Electron ◽  
Thin Film Resistors

Ni-Cr-Si-Al-Ta resistive thin films were prepared on glass and Al2O3substrates by DC magnetron cosputtering from targets of Ni0.35-Cr0.25-Si0.2-Al0.2casting alloy and Ta metal. Electrical properties and microstructures of Ni-Cr-Si-Al-Ta films under different sputtering powers and annealing temperatures were investigated. The phase evolution, microstructure, and composition of Ni-Cr-Si-Al-Ta films were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), and Auger electron spectroscopy (AES). When the annealing temperature was set to 300°C, the Ni-Cr-Si-Al-Ta films with an amorphous structure were observed. When the annealing temperature was at 500°C, the Ni-Cr-Si-Al-Ta films crystallized into Al0.9Ni4.22, Cr2Ta, and Ta5Si3phases. The Ni-Cr-Si-Al-Ta films deposited at 100 W and annealed at 300°C which exhibited the higher resistivity 2215 μΩ-cm with −10 ppm/°C of temperature coefficient of resistance (TCR).

Synthesis of high‐purity high‐entropy metal diboride powders by boro/carbothermal reduction

2019 ◽  
Vol 102 (12) ◽  
pp. 7071-7076 ◽  
Author(s):  
Da Liu ◽  
Honghua Liu ◽  
Shanshan Ning ◽  
Beilin Ye ◽  
Yanhui Chu
Keyword(s):  
High Purity ◽  
Carbothermal Reduction ◽  
High Entropy

scholarly journals Hierarchical phase evolution in a lamellar Al0.7CoCrFeNi high entropy alloy involving competing metastable and stable phases

2021 ◽  
Vol 204 ◽  
pp. 114137
Author(s):  
K. Srimark ◽  
S. Dasari ◽  
A. Sharma ◽  
P. Wangyao ◽  
B. Gwalani ◽  
...  
Keyword(s):  
Phase Evolution ◽  
High Entropy Alloy ◽  
High Entropy

scholarly journals Phase evolution, characterisation, and performance of cement prepared in an oxy-fuel atmosphere

2016 ◽  
Vol 192 ◽  
pp. 113-124 ◽  
Author(s):  
Liya Zheng ◽  
Thomas P. Hills ◽  
Paul Fennell
Keyword(s):  
Particle Size ◽  
Compressive Strength ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Carbon Capture ◽  
Raw Materials ◽  
Carbon Capture And Storage ◽  
Phase Evolution ◽  
Chemical Compositions ◽  
Phase And Elemental Compositions

Cement manufacture is one of the major contributors (7–10%) to global anthropogenic CO2 emissions. Carbon capture and storage (CCS) has been identified as a vital technology for decarbonising the sector. Oxy-fuel combustion, involving burning fuel in a mixture of recycled CO2 and pure O2 instead of air, makes CO2 capture much easier. Since it combines a theoretically lower energy penalty with an increase in production, it is attractive as a CCS technology in cement plants. However, it is necessary to demonstrate that changes in the clinkering atmosphere do not reduce the quality of the clinker produced. Clinkers were successfully produced in an oxy-fuel atmosphere using only pure oxides as raw materials as well as a mixture of oxides and clay. Then, CEM I cements were prepared by the addition of 5 wt% gypsum to the clinkers. Quantitative XRD and XRF were used to obtain the phase and elemental compositions of the clinkers. The particle size distribution and compressive strength of the cements at 3, 7, 14, and 28 days' ages were tested, and the effect of the particle size distribution on the compressive strength was investigated. Additionally, the compressive strength of the cements produced in oxy-fuel atmospheres was compared with those of the cement produced in air and commercially available CEMEX CEM I. The results show that good-quality cement can be successfully produced in an oxy-fuel atmosphere and it has similar phase and chemical compositions to CEM I. Additionally, it has a comparable compressive strength to the cement produced in air and to commercially available CEMEX CEM I.

Sign in / Sign up

Export Citation Format

Share Document