High pressure sintering of TiB2 ceramics at different temperatures

In this paper the effect of high-pressure sintering (HPS) temperature on the microstructure, physical and mechanical properties of TiB2 ceramics has been investigated. Initial TiB2 powder with the average particle size of 5 ?m was sintered in a modified high-pressure anvil-type apparatus under static pressure of 4 GPa in the temperature range of 1400-1800?C. It is shown that HPS allows preparing full-dense TiB2 ceramics with fine-grained structure. The density of samples rises with increasing the sintering temperature up to 1800?C while the maximal microhardness is observed on samples prepared in the temperature range of 1500-1600?C. XRD analysis has shown that this fact is connected with an increase of the level of internal stresses in these samples.

Download Full-text

Synthesis of Cu Loaded TiO2 Nanoparticles for the Improved Photocatalytic Degradation of Rhodamine B

International Journal of Nanoscience ◽

10.1142/s0219581x16600024 ◽

2016 ◽

Vol 15 (05n06) ◽

pp. 1660002 ◽

Cited By ~ 9

Author(s):

V. Kavitha ◽

P. S. Ramesh ◽

D. Geetha

Keyword(s):

Titanium Dioxide ◽

Rhodamine B ◽

Sol Gel ◽

Average Particle Size ◽

Visible Spectrum ◽

Xrd Analysis ◽

Bandgap Energy ◽

Average Particle ◽

Titanium Tetraisopropoxide ◽

Photoexcited Electron

Copper doped Titanium dioxide TiO2 nanoparticles were synthesized by sol–gel method using titanium tetraisopropoxide and copper sulfate as precursors. The synthesized nanoparticles were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), Scanning electron microscopy (SEM), UV-Visible spectroscopy (UV-Vis), Photoluminesce spectroscopy (PL) and atomic force microscopy (AFM). XRD analysis confirms the formation of anatase titanium dioxide and average particle size was 35[Formula: see text]nm. Cu– TiO2 exhibits a shift in the absorption edge toward visible spectrum. The rate of recombination and transfer behavior of the photoexcited electron–hole pairs in the semiconductors was recorded by photoluminescence. From SEM spherical shaped nanoparticles was observed. Comparing with pure TiO2 nanoparticles, Cu doped TiO2 photocatalyst exhibited enhanced photocatalytic activity under natural sunlight irradiation in the decomposition of rhodamine B aqueous solution. The maximum 97% of degradation efficiency of Rhodamine B was observed at 0.6% Cu–TiO2 within 180[Formula: see text]min. The photocatalytic efficiency of Rhodamine B of Cu doped TiO2 nanoparticle was higher than the pure TiO2, which could be attributed to the small crystallinity intense light absorption in Sunlight and narrow bandgap energy of Copper.

Download Full-text

A Comparative Study of Nanostructures of CuO/Cu2O Fabricated via Potentiostatic and Galvanostatic Anodization

Journal of Nanomaterials ◽

10.1155/2021/5533845 ◽

2021 ◽

Vol 2021 ◽

pp. 1-8

Author(s):

S. Mary Margaret ◽

Albin John P. Paul Winston ◽

S. Muthupandi ◽

P. Shobha ◽

P. Sagayaraj

Keyword(s):

Thermal Stability ◽

Comparative Study ◽

Aqueous Electrolyte ◽

Average Particle Size ◽

Xrd Analysis ◽

Molecular Vibration ◽

Synthesis Process ◽

Average Particle ◽

Good Crystallinity ◽

Cu Foil

A detailed comparative study on the synthesis process of coral-like CuO/Cu2O nanorods (NRs) and nanopolycrystals (NPCs) fabricated on Cu foil employing aqueous electrolyte via potentiostatic (POT) and galvanostatic (GAL) modes is discussed. The structural, morphological, thermal, compositional, and molecular vibration of the prepared CuO/Cu2O nanostructures was characterized by XRD, HRSEM, TG/DTA, FTIR, and EDX techniques. XRD analysis confirmed the crystalline phase of the formation of monoclinic CuO and cubic Cu2O nanostructures with well-defined morphology. The average particle size was found to be 21.52 nm and 26.59 nm for NRs (POT) and NPCs (GAL), respectively, and this result is corroborated from the HRSEM analysis. POT synthesized nanoparticle depicted a higher thermal stability up to 600°C implying that the potentiostatically grown coral-like NRs exhibit a good crystallinity and well-ordered morphology.

Download Full-text

Sintesis Nanopartikel Perak Menggunakan Ekstrak Daun Kluwak Pangium edule Reinw Sebagai Bioreduktor dan Uji Aktivitasnya Sebagai Antioksidan

Jurnal Ilmu Alam dan Lingkungan ◽

10.20956/jal.v10i1.6557 ◽

2019 ◽

Vol 10 (1) ◽

Author(s):

Indrawati Patabang ◽

Syahruddin Kasim ◽

Paulina Taba

Keyword(s):

Antioxidant Activity ◽

Particle Size ◽

Silver Nanoparticles ◽

Leaf Extract ◽

Average Particle Size ◽

Xrd Analysis ◽

Average Particle ◽

Result Show ◽

Ic50 Values ◽

Show Result

Silver nanoparticles have been synthesized using kluwak leaf extract (Pangium edule Reinw) as bioreductor and antioxidant activity assay. The nanoparticles formed were monitored by observing UV-Vis absorption and characterized by using FTIR, PSA, XRD and SEM instruments. The result of functional group characterization with FTIR show that the functional groups OH, C = O, C-O and CH2 act as Ag+ reducing agent. The size of silver nanoparticles was determined by using Particle Size Analyzer (PSA) and the result show average particle size distribution of 93.2 nm. Morphology of AgNp were observed by Scanning Electron Microscope (SEM) and X-Ray Difraction (XRD) analysis show result of 51,78 nm. The antioxidant activity was shown by in kluwak leaf extract and silver nanoparticles with IC50 values respectively 831,33 ppm dan 1493,09 ppm.

Download Full-text

Fe3O4 Magnetic Preparation by Bauxite Ore Washing Fine Mud

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.1010-1012.961 ◽

2014 ◽

Vol 1010-1012 ◽

pp. 961-965

Author(s):

Jian Qiang Xiao ◽

Guo Wei He ◽

Yan Jin Hu

Keyword(s):

Particle Size ◽

Aging Time ◽

Average Particle Size ◽

Xrd Analysis ◽

Test Methods ◽

Raw Material ◽

Molar Ratio ◽

Average Particle ◽

Experimental Conditions ◽

Particle Size Analyzer

Bauxite waste sludge as a raw material, the use of reverse chemical coprecipitation synthesize Fe3O4. Researching temperature, precipitation concentration, aging time and Fe2+/Fe3+ molar ratio effect on the particle size, morphology. Optimal experimental conditions: temperature 70 °C, the precipitant NaOH mass ratio of 10%, aging time 3h, Fe2+/Fe3+ molar ratio of 2:3. Test methods using a laser particle size analyzer, XRD analysis of the products were characterized, the product is Fe3O4, the average particle size of 0.11mm.

Download Full-text

Experimental Study on the Effects of Internal Erosion on the Physical and Mechanical Properties of Tailings Under Unsteady Seepage

10.21203/rs.3.rs-515346/v1 ◽

2021 ◽

Author(s):

Rong Gui ◽

Guicheng He

Keyword(s):

Mechanical Properties ◽

Particle Size ◽

Shear Strength ◽

Average Particle Size ◽

Physical And Mechanical Properties ◽

Internal Erosion ◽

Average Particle ◽

Sand Column ◽

Sedimentary Characteristics ◽

Seepage Erosion

Abstract In this paper, the hydraulic sedimentary model was established to investigate the effects of dry beach slope on the sedimentary characteristics of tailings, and the sand column model was built to investigate the effects of seepage erosion on the physical and mechanical properties of sedimentary tailings under unsteady seepage.The results show that the slope of dry beach have a great effect on the sedimentary characteristics of tailings, the average particle size of tailings decreases along the slope of dry beach, and the larger the slope, the more obvious the stratification of the tailings. The migration of fine-grained tailings caused by seepage erosion increases the permeability of the tailings and reduces the shear strength of the tailings. After seepage erosion,the average particle size of 1#tailings sample, 2#tailings sample and 3#tailings sample increased by 6.4%, 12.0% and 2.4% respectively, the hydraulic conductivity of 1# tailings sample, 2# tailings sample and 3# tailings increased by 27.2%,17.9%, and 15.3% respectively after internal erosion, and the shear strength of 1#tailings sample, 2#tailings sample and 3#tailings sample tailings sample decreased by 20.9 %, 15.1% and 12.4% respectively.

Download Full-text

Synthesis of Green Copper Nanoparticles Using Medicinal Plant Hagenia abyssinica (Brace) JF. Gmel. Leaf Extract: Antimicrobial Properties

Journal of Nanomaterials ◽

10.1155/2020/3924081 ◽

2020 ◽

Vol 2020 ◽

pp. 1-12 ◽

Cited By ~ 1

Author(s):

H. C. Ananda Murthy ◽

Tegene Desalegn ◽

Mebratu Kassa ◽

Buzuayehu Abebe ◽

Temesgen Assefa

Keyword(s):

Medicinal Plant ◽

Copper Nanoparticles ◽

Leaf Extract ◽

Energy Gap ◽

Spectral Band ◽

Average Particle Size ◽

Antimicrobial Properties ◽

Xrd Analysis ◽

Average Particle ◽

Hagenia Abyssinica

Indigenous medicinal plant of Ethiopia has been applied for the first time to investigate the synergistic influence of phytoconstituents in green copper nanoparticles (g-Cu NPs) towards the enhancement of antimicrobial properties of NPs. We report the green synthesis of Cu NPs using Hagenia abyssinica (Brace) JF. Gmel. leaf extract. The synthesized g-Cu NPs were characterized by UV-visible, UV-DRS, FT-IR, XRD, SEM, EDXA, TEM, HRTEM, and SAED techniques. The maximum absorbance, λmax, was found to be 403 nm for g-Cu NPs due to surface plasmon resonance. The energy gap, Eg of NPs, was found to be 2.19 eV. FTIR spectra confirmed the presence of polyphenols, tannins, and glycosides in the leaf extract of Hagenia abyssinica. The spectral band at 740 cm-1 is a characteristic of interaction between Cu and biomolecules of the extract. The XRD analysis revealed that the g-Cu NPs appears to be more crystalline in nature. SEM and TEM micrographs showed a mix of spherical, hexagonal, triangular, cylindrical, and irregularly shaped Cu particles. The average particle size of NPs was found to be 34.76 nm by ImageJ analysis. EDX analysis confirmed the presence of copper in the g-Cu NPs. In addition, the SAED pattern of g-Cu NPs presented concentric circular patterns for 4 major planes of crystalline copper and its oxides. The experimental and calculated d-spacing values of one of the crystal planes (111) were found to be 0.2432 nm and 0.2444 nm, respectively. The d-spacing values of 0.2444 nm and 0.2040 nm correspond to d111Cu2O and d111Cu lattice fringes, respectively. The antibacterial test conducted on E. coli, Pseudomonas aeruginosa, Staphylococcus aureus, and Bacillus subtilis showed good zone of inhibitions 12.7, 12.7, 14.7, and 14.2 mm, respectively, proving potentiality of g-Cu NPs as a remedy for infectious diseases caused by tested pathogens.

Download Full-text

Facile Microemulsion Synthesis of Vanadium-Doped ZnO Nanoparticles to Analyze the Compositional, Optical, and Electronic Properties

Materials ◽

10.3390/ma12050821 ◽

2019 ◽

Vol 12 (5) ◽

pp. 821 ◽

Cited By ~ 2

Author(s):

H.S. Ali ◽

Ali Alghamdi ◽

G. Murtaza ◽

H.S. Arif ◽

Wasim Naeem ◽

...

Keyword(s):

Zno Nanoparticles ◽

Average Particle Size ◽

Xrd Analysis ◽

Attenuated Total Reflection ◽

Lattice Parameters ◽

Average Particle ◽

Structural Morphology ◽

Wurtzite Phase ◽

X Ray ◽

Doped Zno

In this work, microemulsion method has been followed to synthesize vanadium-doped Zn1−xVxO (with x = 0.0, 0.02, 0.04, 0.06, 0.08, and 0.10) nanoparticles. The prepared samples are characterized by several techniques to investigate the structural, morphology, electronic, functional bonding, and optical properties. X-ray diffractometer (XRD) analysis confirms the wurtzite phase of the undoped and V-doped ZnO nanoparticles. Variation in the lattice parameters ensures the incorporation of vanadium in the lattice of ZnO. Scanning electron microscopy (SEM) shows that by increasing contents of V ions, the average particle size increases gradually. X-ray Absorption Near Edge Spectroscopy (XANES) at the V L3,2 edge, oxygen K-edge, and Zn L3,2 edge reveals the presence and effect of vanadium contents in the Zn host lattice. Furthermore, the existence of chemical bonding and functional groups are also asserted by attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR). UV–Visible analysis shows that by increasing V+ contents, a reduction up to 2.92 eV in the energy band gap is observed, which is probably due to an increase in the free electron concentration and change in the lattice parameters.

Download Full-text

Influence of Physical Properties of B4C Powder on the Strength Properties of the Ceramics Manufactured by SPS Sintering

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.1085.312 ◽

2015 ◽

Vol 1085 ◽

pp. 312-315

Author(s):

Oleg L. Khasanov ◽

Edgar S. Dvilis ◽

Zulfa G. Bikbaeva ◽

Valentina V. Polisadova ◽

Alexey O. Khasanov ◽

...

Keyword(s):

Physical Properties ◽

Boron Carbide ◽

Physical And Mechanical Properties ◽

High Strength ◽

Strength Properties ◽

Carbide Powder ◽

Fine Grained ◽

Fine Grained Structure ◽

Determining Factor ◽

Sps Sintering

Ceramics samples in the form of a parallelepiped with high strength characteristics have been made. For the manufacture of the ceramics samples a powder mixture from submicron В4С powder with additives (1 wt%, 5 wt%, 10 wt%) of boron carbide nanopowder was used. The physical properties of the powder mixtures and strength properties of sintered ceramics have been studied. It was shown that the use of submicron fractions of the boron carbide powder together with nanoadditives is a determining factor in the formation of dense fine-grained structure providing improved physical and mechanical properties of the ceramics.

Download Full-text

Dynamic High-Pressure Microfluidization-Treated Pectin under Different Ethanol Concentrations

Polymers ◽

10.3390/polym10121410 ◽

2018 ◽

Vol 10 (12) ◽

pp. 1410 ◽

Cited By ~ 2

Author(s):

Cheng-Mei Liu ◽

Lu Liang ◽

Xi-Xiang Shuai ◽

Rui-Hong Liang ◽

Jun Chen

Keyword(s):

High Pressure ◽

Average Molecular Weight ◽

Average Particle Size ◽

Suitable Condition ◽

Uv Spectra ◽

Average Particle ◽

Dynamic High Pressure Microfluidization ◽

Dynamic High Pressure ◽

Ethanol System ◽

Induced Aggregation

We previously reported that dynamic high-pressure microfluidization (DHPM) can degrade pectin in aqueous solution. In this study, we further investigated the effect of DHPM on pectin in water-ethanol systems. In the absence of DHPM treatment, it was found that pectin exhibited increased average particle size and unchanged average molecular weight, but a decline in reducing-sugar-ends content with the increase of ethanol concentrations (0–10% v/v). These results indicated that the addition of ethanol induced aggregation of pectin. During DHPM treatment, pectin underwent disaggregation and degradation under all measured ethanol concentrations. Disaggregation was enhanced but degradation was weakened with the increase of ethanol concentration. FT-IR and UV spectra indicated that demethylation but no β-elimination occurred in the water-ethanol system during DHPM. Finally, the mechanism of DHPM-induced disaggregation and degradation of pectin under a water-ethanol system was updated. This work may help us to find a suitable condition for reducing the degradation of pectin during the process of homogenization.

Download Full-text

PREPARATION OF NANO-TATB BY SEMIBATCH REACTION CRYSTALLIZATION

NANO ◽

10.1142/s1793292013500550 ◽

2013 ◽

Vol 08 (05) ◽

pp. 1350055 ◽

Cited By ~ 6

Author(s):

XUE-RONG TAN ◽

XIAO-HUI DUAN ◽

CHONG-HUA PEI ◽

HONG-LIN XU

Keyword(s):

Grain Size ◽

Average Particle Size ◽

Reaction System ◽

Xrd Analysis ◽

Differential Scanning Calorimetric ◽

Average Particle ◽

Bet Method ◽

Close Relationship ◽

Dsc Curves ◽

Semibatch Reaction

The 1,3,5-triamino-2,4,6-trinitrobenzene (TATB) nanoparticles were prepared by using semibatch reaction crystallization method, and the influencing factors in close relationship with the grain size and crystal morphology control, such as the concentration of reaction system and categories of surfactants, were studied in this paper. The synthesized nano-TATB particles had been characterized by SEM, XRD, thermo gravimetric/differential scanning calorimetric (TG/DSC) and N 2 physisorption. The grain size of TATB particles using nonionic surfactant as the additive ranged from 30 nm to 65 nm with a shape of spheres or ellipsoids. The broadening of the peaks and the weakening of the strength for nano-TATB were observed by XRD analysis. The corrected average particle size of nano-TATB was calculated using the Debye–Scherrer equation and the range was from 18 nm to 50 nm. TG and DSC curves revealed that thermal decomposition of nano-TATB occurred in the range of 361.5°C–385.0°C and its peak temperature was 373.7°C with a decrease of approximately 7°C compared with original TATB. Furthermore, the specific surface area (21.54 m2/g) of nano-TATB was calculated by BET method using N 2 physisorption (at 77°C).

Download Full-text