scholarly journals Effects of Sintering Temperature on the Morphology and Photoluminescence of Eu3+ Doped Zinc Molybdenum Oxide Hydrate

2018 ◽  
Vol 2018 ◽  
pp. 1-10 ◽  
Author(s):  
Bao-gai Zhai ◽  
Qing-lan Ma ◽  
Long Yang ◽  
Yuan Ming Huang
Keyword(s):  
Low Temperature ◽  
Molybdenum Oxide ◽  
Large Scale ◽  
Sintering Temperature ◽  
Diffuse Reflectance Spectroscopy ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Oxide Hydrate ◽  
Rare Earth Doped

Synthesis of shape controlled and rare-earth doped ZnMoO4 nanostructures on a large scale with low costs is a present challenge in nanotechnology. The precursor of Eu3+ doped zinc molybdenum oxide hydrate (Zn5Mo2O11·5H2O) was synthesized at room temperature via the coprecipitation method. The influences of the sintering temperature on the microstructures and photoluminescence (PL) of the precursor were investigated by means of X-ray diffraction, scanning electron microscopy, thermal gravimetry, differential scanning calorimetry, energy dispersive X-ray spectroscopy, diffuse reflectance spectroscopy, and PL spectrophotometry. It is found that Eu3+ doped ZnMoO4 nanostructures can be derived by sintering the precursor at a relatively low temperature of about 400°C. Our results have demonstrated that Eu3+ doped ZnMoO4 nanostructures can be cost-effectively derived by sintering the precursor at a relatively low temperature.

scholarly journals Effects of Sintering Temperature on Densification, Microstructure and Mechanical Properties of Al-Based Alloy by High-Velocity Compaction

Metals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 218
Author(s):  
Xianjie Yuan ◽  
Xuanhui Qu ◽  
Haiqing Yin ◽  
Zaiqiang Feng ◽  
Mingqi Tang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
High Velocity ◽  
Sintered Density ◽  
Sintering Temperature ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Transmission Electron ◽  
High Velocity Compaction ◽  
Sintered Temperature

This present work investigates the effects of sintering temperature on densification, mechanical properties and microstructure of Al-based alloy pressed by high-velocity compaction. The green samples were heated under the flow of high pure (99.99 wt%) N2. The heating rate was 4 °C/min before 315 °C. For reducing the residual stress, the samples were isothermally held for one h. Then, the specimens were respectively heated at the rate of 10 °C/min to the temperature between 540 °C and 700 °C, held for one h, and then furnace-cooled to the room temperature. Results indicate that when the sintered temperature was 640 °C, both the sintered density and mechanical properties was optimum. Differential Scanning Calorimetry, X-ray diffraction of sintered samples, Scanning Electron Microscopy, Energy Dispersive Spectroscopy, and Transmission Electron Microscope were used to analyse the microstructure and phases.

A new low-loss microwave dielectric ceramic for low temperature cofired ceramic applications

2010 ◽  
Vol 25 (7) ◽  
pp. 1235-1238 ◽  
Author(s):  
Huanfu Zhou ◽  
Xiuli Chen ◽  
Liang Fang ◽  
Dongjin Chu ◽  
Hong Wang
Keyword(s):  
Dielectric Properties ◽  
Low Temperature ◽  
Sintering Temperature ◽  
Microwave Dielectric Properties ◽  
Microwave Dielectric Ceramic ◽  
X Ray Diffraction ◽  
Low Loss ◽  
Dielectric Ceramic ◽  
X Ray ◽  
Microwave Dielectric

A new low sintering temperature microwave dielectric ceramic, Li2ZnTi3O8, was investigated. X-ray diffraction data show that Li2ZnTi3O8 has a cubic structure [P4332(212)] with lattice parameters a = 8.37506 Å, V = 587.44 Å3, and Z = 4 when the sintering temperature is 1050 °C. The Li2ZnTi3O8 ceramic exhibits good microwave dielectric properties with εr about 26.2, Q×f value about 62,000 GHz, and τf about −15 ppm/°C. The addition of BaCu(B2O5) can effectively lower the sintering temperature from 1050 to 900 °C without degrading the microwave dielectric properties. Compatibility with Ag electrode indicates this material can be applied to low temperature cofired ceramic devices.

Low-temperature instability of Ti2SnC: A combined transmission electron microscopy, differential scanning calorimetry, and x-ray diffraction investigations

2009 ◽  
Vol 24 (1) ◽  
pp. 39-49 ◽  
Author(s):  
J. Zhang ◽  
B. Liu ◽  
J.Y. Wang ◽  
Y.C. Zhou
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Differential Scanning Calorimetry ◽  
Low Temperature ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Temperature Instability ◽  
X Ray ◽  
Transmission Electron ◽  
Ceramic Microstructure

Transmission electron microscopy (TEM), differential scanning calorimetry (DSC), and x-ray diffraction (XRD) investigations were conducted on the hot-pressed Ti2SnC bulk ceramic. Microstructure features of bulk Ti2SnC ceramic were characterized by using TEM, and a needle-shaped β-Sn precipitation was observed inside Ti2SnC grains with the orientation relationship: (0001) Ti2SnC // (200) Sn and Ti2SnC // [001] Sn. With the combination of DSC and XRD analyses, the precipitation of metallic Sn was demonstrated to be a thermal stress-induced process during the cooling procedure. The reheating temperature, even as low as 400 °C, could trigger the precipitation of Sn from Ti2SnC, which indicated the low-temperature instability of Ti2SnC. A substoichiometry Ti2SnxC formed after depletion of Sn from ternary Ti2SnC phase. Under electron beam irradiation, metallic Sn was observed diffusing back into Ti2SnxC. Furthermore, a new Ti7SnC6 phase with the lattice constants of a = 0.32 and c = 4.1 nm was identified and added in the Ti-Sn-C ternary system.

scholarly journals Synthesis and characterization of graphene oxide flakes for transparent thin films

2021 ◽  
Vol 22 (3) ◽  
pp. 595-601
Author(s):  
R.G. Abaszade ◽  
S.A. Mamedova ◽  
F.G. Agayev ◽  
S.I. Budzulyak ◽  
O.A. Kapush ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Graphene Oxide ◽  
Indium Tin Oxide ◽  
Electromagnetic Interference ◽  
Large Scale ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Scanning Electron

We have synthesized large scale, thin, transparent graphene oxide (GO) flakes by Hummer’s method and investigated their suitability for fabrication of transparent nanocomposites. The GO flakes were comprehensively characterized by X-ray diffraction, Scanning Electron Microscopy (SEM), Energy Dispersive X-ray analysis (EDX), Raman spectroscopy and Differential Scanning Calorimetry (DSC). X-ray diffraction displayed the peak of graphene oxide at 9°degree, which is characteristic peak of GO in agreement with the literature results. Scanning Electron Microscopy images revealed that thin, transparent, flake form GO with 14,8 µm lateral size and 0,31µm thickness were synthesized. The comparison with literature results show that for the first time, our group could synthesize large scale, thin and more transparent GO flakes by simple Hummer’s method using simple dispersed graphite. EDX measurements indicate the formation of layered structure with oxygen containing functional groups. The intensity ratio between D and G peaks in the Raman spectra proves that less defective GO flakes have been synthesized. The solution ability of the synthesized material indicate that high quality GO flakes were synthesized, which make them effective soluble material due to oxygen containing groups formed on the graphene plane during synthesis process.DSC results shows that these flakes are thermally stable till 200°C.  Due to high solubility properties, large scale and transparency they can be very useful in fabrication of high optical transparent nanocompoties for replacement indium tin oxide transparent conductors in solar panels, biomedical applications and microwave absorbers for electromagnetic interference (EMI) environmental protection.

Room Temperature Synthesis of Cu2O Nanospheres: Optical Properties and Thermal Behavior

2014 ◽  
Vol 21 (1) ◽  
pp. 108-119 ◽  
Author(s):  
Daniela Nunes ◽  
Lídia Santos ◽  
Paulo Duarte ◽  
Ana Pimentel ◽  
Joana V. Pinto ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Thermal Behavior ◽  
Room Temperature ◽  
Diffuse Reflectance Spectroscopy ◽  
Ion Beam ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Transmission Electron

AbstractThe present work reports a simple and easy wet chemistry synthesis of cuprous oxide (Cu2O) nanospheres at room temperature without surfactants and using different precursors. Structural characterization was carried out by X-ray diffraction, transmission electron microscopy, and scanning electron microscopy coupled with focused ion beam and energy-dispersive X-ray spectroscopy. The optical band gaps were determined from diffuse reflectance spectroscopy. The photoluminescence behavior of the as-synthesized nanospheres showed significant differences depending on the precursors used. The Cu2O nanospheres were constituted by aggregates of nanocrystals, in which an on/off emission behavior of each individual nanocrystal was identified during transmission electron microscopy observations. The thermal behavior of the Cu2O nanospheres was investigated with in situ X-ray diffraction and differential scanning calorimetry experiments. Remarkable structural differences were observed for the nanospheres annealed in air, which turned into hollow spherical structures surrounded by outsized nanocrystals.

Electrical and optical studies on tungsten-substituted bismuth molybdates

2020 ◽  
Vol 111 (7) ◽  
pp. 546-551
Author(s):  
Satish J. Naik ◽  
Puzy A. Pavaskar ◽  
Arun V. Salker
Keyword(s):  
Diffuse Reflectance Spectroscopy ◽  
Sol Gel ◽  
Visible Region ◽  
Green Emission ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Rietveld Refinements ◽  
X Ray ◽  
Bismuth Molybdates ◽  
Infrared Techniques

Abstract This manuscript highlights the structural, electrical and optical properties of Bi2Mo1-xWxO6 (x = 0.0, 0.2, 0.4, 0.6, 0.8 and 1.0) compounds. These compounds were prepared employing the citrate sol-gel method. These compositions were characterized using thermo-gravimetric and differential scanning calorimetry, X-ray diffraction and infrared techniques. The Rietveld refinements of X-ray powder diffraction data determined and confirmed the crystal structure of the compositions. DC electrical conductivity indicated the conduction behaviour and diffuse reflectance spectroscopy confirmed the semiconducting nature of the compounds. Room temperature photoluminescence results exhibited two type of emission namely blue-green and green emission in the visible region.

Low Temperature Sintering of (Ba0.98Ca0.02)(Sn0.04Ti0.96)O3 Ceramics Using CuO-B2O3 as a Sintering Additive

2014 ◽  
Vol 602-603 ◽  
pp. 813-816
Author(s):  
Jian Qiang Zhou ◽  
Ke Pi Chen
Keyword(s):  
Low Temperature ◽  
Piezoelectric Properties ◽  
Sintering Temperature ◽  
Solid State Reaction Method ◽  
Low Temperature Sintering ◽  
X Ray Diffraction ◽  
Conventional Solid State Reaction ◽  
X Ray ◽  
Sintering Additive ◽  
Precision Impedance Analyzer

The effects of CuO-B2O3(CBO) additive on densification, microstructure, and electrical properties of (Ba0.98Ca0.02)(Sn0.04Ti0.96)O3(BCST) cermaics were investigated. The phase compositions, microstructure, dielectric, ferroelectric and piezoelectric properties of BCST ceramics were studied by X-ray diffraction (XRD), scanning electron microscopy (SEM), precision impedance analyzer, ferroelectric tester and quasi-static piezoelectric constant testing meter, respectively. The results show that CuO-B2O3(CBO) frit can improve the densification and promote low-temperature sintering of BCST ceramics prepared by a conventional solid-state reaction method. Dense BCST ceramics with CBO can be sintered at temperatures as low as 1175 °C, which is approximately 275 °C less than the sintering temperature of pure BCST. When sintered at 1200 °C, the optimized properties of the BCST ceramics with 0.5 wt% CBO were obtain asε= 1206,d33= 346 pC/N,kP= 0.39, tgδ = 0.009.

Mechanical Alloying Influence on the Sintering of Cu-Fe Compound Powders

2007 ◽  
Vol 353-358 ◽  
pp. 1350-1353 ◽  
Author(s):  
Jin Feng Sun ◽  
Ming Zhi Wang ◽  
Xiao Pu Li ◽  
Zhan Wen He ◽  
Yu Cheng Zhao
Keyword(s):  
Activation Energy ◽  
Mechanical Alloying ◽  
Sintering Temperature ◽  
Sintering Process ◽  
Stored Energy ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Structure Strength ◽  
Activation Energy Of Diffusion

In this paper, X-ray diffraction (XRD), differential scanning calorimetry (DSC) and sintering process were used to characterize Cu-Fe compound powders milled for different times. The increment of defects and the change of granularity, grain size and crystal structure were discussed. Mechanical Alloying (MA) influence on the sintering of Cu-Fe compound powders was analyzed. The results showed that, the refinement of the powders and the increment of defects such as interface and dislocation induced the energy storage. The stored energy released in the sintering process, which reduced the activation energy of vacancy and the activation energy of diffusion. So the sintering temperature was reduced and the structure, strength and hardness of specimens were improved.

scholarly journals Tailoring Upconversion and Morphology of Yb/Eu Doped Y2O3 Nanostructures by Acid Composition Mediation

Nanomaterials ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 234 ◽  
Author(s):  
Daniela Nunes ◽  
Ana Pimentel ◽  
Mariana Matias ◽  
Tomás Freire ◽  
A. Araújo ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Diffuse Reflectance Spectroscopy ◽  
Homogeneous Distribution ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Host Matrix ◽  
X Ray ◽  
Transmission Electron ◽  
Scanning Transmission ◽  
Subsequent Calcination

The present study reports the production of upconverter nanostructures composed by a yttrium oxide host matrix co-doped with ytterbium and europium, i.e., Y2O3:Yb3+/Eu3+. These nanostructures were formed through the dissociation of yttrium, ytterbium and europium oxides using acetic, hydrochloric and nitric acids, followed by a fast hydrothermal method assisted by microwave irradiation and subsequent calcination process. Structural characterization has been carried out by X-ray diffraction (XRD), scanning transmission electron microscopy (STEM) and scanning electron microscopy (SEM) both coupled with energy dispersive X-ray spectroscopy (EDS). The acid used for dissociation of the primary oxides played a crucial role on the morphology of the nanostructures. The acetic-based nanostructures resulted in nanosheets in the micrometer range, with thickness of around 50 nm, while hydrochloric and nitric resulted in sphere-shaped nanostructures. The produced nanostructures revealed a homogeneous distribution of the doping elements. The thermal behaviour of the materials has been investigated with in situ X-Ray diffraction and differential scanning calorimetry (DSC) experiments. Moreover, the optical band gaps of all materials were determined from diffuse reflectance spectroscopy, and their photoluminescence behaviour has been accessed showing significant differences depending on the acid used, which can directly influence their upconversion performance.

Low-Temperature Reduction of Graphene Oxide Using the HDDR Process for Electrochemical Supercapacitor Applications

2020 ◽  
Vol 1012 ◽  
pp. 141-146
Author(s):  
F.G. Benitez Jara ◽  
P. D. V. Cruz ◽  
Lusinete Pereira Barbosa ◽  
J.C.S. Casini ◽  
S. K. Sakata ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Low Temperature ◽  
Large Scale ◽  
Oxide Powder ◽  
Processing Temperature ◽  
Scale Production ◽  
X Ray Diffraction ◽  
Promising Alternative ◽  
X Ray ◽  
Large Scale Production

In the present work, attempts of reducing a graphene oxide powder using a low temperature hydrogenation disproportionation desorption and the recombination process (L-HDDR) has been carried out. A lower processing temperature in large scale production is significant when costs are concerned. Graphite oxide was prepared using a modified Hummers’ method dispersed in ethanol and exfoliated using ultrasonication to produce Graphene Oxide (GO). Investigations have been carried out by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The experimental results of L-HDDR processing graphene oxide powder, using unmixed hydrogen at 400°C and relatively low pressures (<2 bars) have been reported. X-ray diffraction patterns showed a reduction of graphene oxide with the L-HDDR process. The results showed that both processes, the L-HDDR as well as the standard HDDR, may be applied to the reduction of graphene oxide in order to produce supercapacitor materials. The advantage of employing the L-HDDR process is a relatively low temperature reducing the cost of treatment, what is a very important factor for producing a large amount of material. Thus, the L-HDDR process has been considered a promising alternative method of reducing graphene oxide with efficiency, with the possibility of large scale production.

Sign in / Sign up

Export Citation Format

Share Document