scholarly journals Consolidation of Amorphous Powders by Hot Pressing

2012 ◽  
Vol 2012 ◽  
pp. 1-10 ◽  
Author(s):  
M. Tavoosi ◽  
F. Karimzadeh ◽  
M. H. Enayati ◽  
H. S. Kim
Keyword(s):  
Electron Microscopy ◽  
Hot Pressing ◽  
Intermetallic Phase ◽  
Average Crystallite Size ◽  
Bulk Sample ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Transition Electron Microscopy ◽  
Amorphous Powders ◽  
Transition Electron

The current study investigates the feasibility of fabricating amorphous Al80Fe10Ti5Ni5powders by mechanical alloying and consolidating them into bulk samples by a hot-pressing technique. As-milled and hot-pressed samples were examined by X-ray diffraction, scanning electron microscopy, transition electron microscopy, and differential scanning calorimetry. The results showed that milling of Al80Fe10Ti5Ni5powder for 40 h and hot pressing at 550°C under 600 MPa led to a fully dense bulk sample. During consolidation, an AlTi intermetallic phase with average crystallite size of 10 nm precipitates in the amorphous matrix.

Strengthening of CP-Ti by Rolling at Room Temperature

2010 ◽  
Vol 667-669 ◽  
pp. 737-741
Author(s):  
Jian Hua Jiang ◽  
Yi Ding ◽  
Ai Dang Shan
Keyword(s):  
Electron Microscopy ◽  
Room Temperature ◽  
Mechanical Test ◽  
Commercial Purity ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transition Electron Microscopy ◽  
Microstructure Observation ◽  
Cp Ti ◽  
Transition Electron

The effects of asymmetric and symmetric rolling at room temperature on mechanical properties and microstructure of the commercial purity Ti were investigated by means of mechanical test, optical microscopy, X-ray diffraction and transition electron microscopy. The results show that through asymmetric and symmetric rolling processes the ultimate tensile strength is substantially increased from 450 MPa to 960 MPa. Microstructure observation illustrates this variation in mechanical property is caused by the grain refinement and work hardening.

Synthesis and Characterization of Hierarchical Zeolite with High Mechanical Stability

2011 ◽  
Vol 217-218 ◽  
pp. 368-371 ◽  
Author(s):  
Xu Ling ◽  
Rui Liu Zong ◽  
Bin Kan Qiu
Keyword(s):  
Electron Microscopy ◽  
Self Assembly ◽  
Mechanical Stability ◽  
Three Dimensions ◽  
X Ray Diffraction ◽  
Polystyrene Spheres ◽  
Hierarchical Zeolite ◽  
Transition Electron Microscopy ◽  
Transition Electron

A hierarchical zeolite was synthesized by self-assembly of ZSM-5 nano-crystals colloid and polystyrene spheres coated with cationic poly (diallyldimethylammonium chloride). The colloidial ZSM-5 nano-crystals were first bound onto the polyelectrolyte-modified PS by electrostatic attraction, followed by centrifugation to form PS/ZSM-5 close-packed composite. After being dried and calcined to remove the organic components, the hierarchical zeolite was obtained. The X-ray diffraction, scanning electron microscopy, transition electron microscopy and N2 adsorp-tion-desorption techniques were employed to characterize the hierarchical zeolite. The results showed that the material prepared by this method was well crystallized and possessed uniform ma-cropores interconnected in three dimensions through windows. Furthermore, the hierarchical zeolite was rather mechanically stable.

WO3 Nanostructures Synthesized by a Sonochemical Strategy

2009 ◽  
Vol 60-61 ◽  
pp. 16-21 ◽  
Author(s):  
Shi Bin Sun ◽  
Zeng Da Zou ◽  
Guang Hui Min
Keyword(s):  
Electron Microscopy ◽  
Tungsten Trioxide ◽  
Selective Adsorption ◽  
Morphological Evolution ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transition Electron Microscopy ◽  
Tungsten Hexachloride ◽  
Solvent Molecules ◽  
Transition Electron

A simple sonochemical synthesis of tungsten trioxide hydrate with various morphologies has been developed by using tungsten hexachloride (WCl6) as precursor and water, ethanol and their mixture as solvent, followed by annealing in a tube furnace. The resulting products were structurally characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transition electron microscopy (TEM) and differential thermal analysis (DTA). Results show that nanowhiskers emanating from the core of nanoparticles have been obtained with ethanol as solvent, and that nanoplates and nanosheets were formed when water and/or mixed ethanol and water was used as the solvent, respectively. The continuous changing supersaturation of tungsten trioxide may account for the formation of nanowhiskers. The formation of nanoplates or nanosheets may be associated with the selective adsorption of solvent molecules on the WO3 crystals. Due to a combination of the loss of chemical bonded water and crystal growth, the as-synthesized tungsten trioxide hydrate underwent apparent morphological evolution during thermal processing.

Effect of Annealing Temperature on Structural and Optical Properties of Ceria Nano Particles

2014 ◽  
Vol 1035 ◽  
pp. 366-372
Author(s):  
Chu Chuan Hong ◽  
Zheng Hong Qian ◽  
Jian Ping Li ◽  
Ying Zi Peng
Keyword(s):  
Band Gap ◽  
Crystallite Size ◽  
Annealing Temperature ◽  
Average Crystallite Size ◽  
Nano Particles ◽  
X Ray Diffraction ◽  
Characterization Methods ◽  
Transition Electron Microscopy ◽  
Indirect Band Gap ◽  
Transition Electron

Pure and single-phase ceria particles were synthesized by an anodic electrochemical method followed by annealing at 500-900°C for 2h. Many characterization methods have been used to study the ceria nanostructures and electronic structures, including X-ray diffraction, transition electron microscopy and UV-vis spectrophotometer. The average crystallite size was estimated to be the scale of nanometers. While annealing at a low temperature, ceria particles are a little agglomeration and are termed as mesocrystal. It is observed to increase the crystallite size in addition to increase the crystalliminty of the nanoparticles while increasing the annealing temperature. The absorption spectra show that the ceria nanoparticles have direct and indirect band gap structures. There is a red shift of the absorption peak for the particles after annealing. Both the direct and indirect band gap energies are found to decrease with the annealing temperature.

scholarly journals Studies on PEBAX/organoclay nanocomposites by meltintercalation process: Effect of organoclay surface

e-Polymers ◽  
2009 ◽  
Vol 9 (1) ◽  
Author(s):  
Somayeh Mohamadi ◽  
Naser Sharifi Sanjani
Keyword(s):  
Electron Microscopy ◽  
Tensile Modulus ◽  
Melt Flow Index ◽  
Xrd Analysis ◽  
Flow Index ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Transition Electron Microscopy ◽  
Clay Concentration ◽  
Alkyl Ammonium

AbstractIn this study, the polyetherblock amide (PEBAX)® nanocomposites with 2.5 % and 5 wt.% organoclay, based on Cloisite 30B (montmorillonite intercalated with dimethyl, 2-ethyl hexyl hydrogenated tallow alkyl ammonium cation), were prepared by the melt-intercalation process. The structural properties, thermal behaviors and the mechanical properties were characterized using the X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), melt flow index (MFI), differential scanning calorimetry (DSC), thermogravimetry analyses (TGA), transition electron microscopy (TEM), scanning electron microscopy (SEM) and the tensile test. The XRD analysis indicated the formation of intercalated PEBAX nanocomposites. The TGA results revealed that the addition of 2.5 wt.% nanoclay improved the thermal properties, while the nanocomposite with 5 wt.% nanoclay did not enhance the thermal stability. The DSC analysis indicated that, in the case of PEBAX with 2.5 wt.% organoclay, each peak was related to the fusion of the crystalline fraction of the poly ether and poly amide affected blocks. On the contrary, regarding the PEBAX with 5 wt.% nanoclay, only the peak related to polyamide was changed. Interestingly, the tensile modulus increased with the incorporation of 2.5 wt.% clay, but it decreased in PEBA 5. The elongation at break reduced with the incorporation of the clay, attaining a minimum value at the clay concentration of 2.5 wt.%, and followed by an increase at the clay concentration of 5 wt.%.

Research on compatibility and surface of high impact bio-based polyamide

2021 ◽  
pp. 095400832110055
Author(s):  
Yang Wang ◽  
Yuhui Zhang ◽  
Yuhan Xu ◽  
Xiucai Liu ◽  
Weihong Guo
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Scanning Electron Microscopy ◽  
Differential Scanning Calorimetry ◽  
Crystallization Behavior ◽  
High Impact ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Scanning Electron

The super-tough bio-based nylon was prepared by melt extrusion. In order to improve the compatibility between bio-based nylon and elastomer, the elastomer POE was grafted with maleic anhydride. Scanning Electron Microscopy (SEM) and Thermogravimetric Analysis (TGA) were used to study the compatibility and micro-distribution between super-tough bio-based nylon and toughened elastomers. The results of mechanical strength experiments show that the 20% content of POE-g-MAH has the best toughening effect. After toughening, the toughness of the super-tough nylon was significantly improved. The notched impact strength was 88 kJ/m2 increasing by 1700%, which was in line with the industrial super-tough nylon. X-ray Diffraction (XRD) and Differential Scanning Calorimetry (DSC) were used to study the crystallization behavior of bio-based PA56, and the effect of bio-based PA56 with high crystallinity on mechanical properties was analyzed from the microstructure.

scholarly journals Effect of Surfactant Addition on Bi2Te3 Nanostructures Synthesized by Hydrothermal Method

2017 ◽  
Vol 62 (2) ◽  
pp. 1005-1010 ◽  
Author(s):  
Peyala Dharmaiah ◽  
C.H. Lee ◽  
B. Madavali ◽  
Soon-Jik Hong
Keyword(s):  
Electron Microscopy ◽  
Hydrothermal Method ◽  
Figure Of Merit ◽  
Bulk Sample ◽  
The Other ◽  
X Ray Diffraction ◽  
X Ray ◽  
Coarse Grains ◽  
Scanning Electron ◽  
Nanostructured Sample

AbstractIn the present work, we have prepared Bi2Te3nanostructures with different morphologies such as nano-spherical, nanoplates and nanoflakes obtained using various surfactant additions (EG, PVP, and EDTA) by a hydrothermal method. The shape of the nanoparticles can be controlled by addition of surfactants. The samples were characterized by x-ray diffraction (XRD) and scanning electron microscopy (SEM). It is found that the minority BiOCl phase disappears after maintained pH at 10 with EG as surfactant. SEM bulk microstructure reveals that the sample consists of fine and coarse grains. Temperature dependence of thermoelectric properties of the nanostructured bulk sample was investigated in the range of 300-450K. The presence of nanograins in the bulk sample exhibits a reduction of thermal conductivity and less effect on electrical conductivity. As a result, a figure of merit of the sintered bulk sample reached 0.2 at 400 K. A maximum micro Vickers hardness of 102 Hv was obtained for the nanostructured sample, which was higher than the other reported results.

scholarly journals Development of an Oxcarbazepine Solid Dispersion Using Skimmed Milk to Improve the Solubility and Dissolution Profile

2019 ◽  
Vol 11 (05) ◽  
Author(s):  
M. Shah ◽  
D. Patel
Keyword(s):  
Electron Microscopy ◽  
Solid Dispersion ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Infra Red ◽  
Crystalline Nature ◽  
Skimmed Milk ◽  
Scanning Electron

Oxcarbazepine has low solubility and low oral bioavailability, so it’s a challenge to formulate suitable dosage form. In this present investigation, to improve the dissolution rate and solubility, skimmed milk is used as a carrier. Physical mixers were prepared using various drugs to carrier ratio and spray drying technology was used to develop solid dispersion with the carrier. Various techniques were used to characterize the solid dispersion immediately after they were made which includes differential scanning calorimetry, scanning electron microscopy, fourier transform infra- red spectroscopy, X-ray diffraction and in-vitro dissolution profiles. The differential scanning calorimetry thermograms of raw drug indicated of its anhydrous crystalline nature. In thermograms of solid dispersion, the characteristic peak was absent suggesting the change from crystalline nature to amorphous form. X-ray diffraction confirmed those results. X-ray diffraction results of raw drug showed highly intense peak characteristic of its crystalline nature where solid dispersion showed less intense, more diffused peak indicating the change in crystalline form. Fourier transforms infra-red spectroscopy studies showed there was no interaction between drug and carrier. Scanning electron microscopy support the amorphous nature of mixer. The whole formulation showed distinct enhancement in the drug release behavior and solubility. The optimum oxcarbazepine to skimmed milk ratio 1:3 enhances the in-vitro drug release by 3.5 fold and also show distinct increase in solubility. It was concluded that for improvement of solubility of poorly water soluble oxcarbazepine, skimmed milk powder as a carrier can be utilize very well.

Evolution of microstructure and wear-friction behavior of W-30 wt.% Cu nanocomposite produced via a mechanochemical synthesis route

2020 ◽  
Vol 111 (6) ◽  
pp. 491-503
Author(s):  
K. Zangeneh-madar ◽  
H. Abbaszadeh ◽  
E. Salahshour-rad ◽  
S. Seyyedin ◽  
M. Ahangarkani
Keyword(s):  
Electron Microscopy ◽  
Chemical Reduction ◽  
Hydrogen Atmosphere ◽  
Liquid Phase Sintering ◽  
X Ray Diffraction ◽  
Friction Behavior ◽  
Transition Electron Microscopy ◽  
Micro Cracks ◽  
Copper Phase ◽  
Evolution Of Microstructure

Abstract W-30 wt.% Cu nanocomposites were prepared by chemical reduction of a ball-milled WO3-CuO powder mixture under a hydrogen atmosphere. The prepared samples were analyzed by means of X-ray diffraction, transition electron microscopy, scanning electron microscopy and energy dispersed spectroscopy. Microstructural studies revealed higher density of the composite sintered at 1300 °C compared to 1 050 °C and 1 150 °C due to activated liquid phase sintering as well as the solution-reprecipitation mechanism at 1300 °C. Density and hardness of the W-Cu composite samples measured in the range of 87.5- 97.3 g cm-3 and 22 - 63 Rockwell A, respectively. It was also found that the wear mechanism of the composite includes the following steps: chipping of tungsten particles, plastic deformation of copper phase and formation of some Cu-free pores and micro-cracks, pulling out of tungsten particles and plastic strain and deformation of tungsten particles and formation of a mechanically mixed layer on the surface.

scholarly journals Standard Hot Pressing as a Possible Solution to Obtain Dense K0.5Na0.5NbO3 Ceramic Doped by Er2O3 and Yb2O3

Materials ◽  
2019 ◽  
Vol 12 (24) ◽  
pp. 4171 ◽  
Author(s):  
Paweł Rutkowski ◽  
Jan Huebner ◽  
Adrian Graboś ◽  
Dariusz Kata ◽  
Dariusz Grzybek ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Rare Earth ◽  
Phase Composition ◽  
Powder Mixture ◽  
Hot Pressing ◽  
X Ray Diffraction ◽  
X Ray ◽  
Ultrasonic Methods ◽  
Scanning Electron

In this study, the influence of the addition of rare earth oxides on the phase composition and density of KNN piezoelectric ceramics was investigated. The initial powders of Na2CO3 and K2CO3 were dried at 150 °C for 2 h. Then, a powder mixture for synthesis was prepared by adding a stoichiometric amount of Nb2O5 and 5 and 10 wt % overabundance of Na2CO3. All powders were mixed by ball-milling for 24 h and synthesized at 950 °C. The phase composition of the reaction bed was checked by means of X-ray diffraction (XRD). It had an appearance of tetragonal and monoclinic K0.5Na0.5NbO3 (KNN) phases. Then, 1 and 2 wt % of Er2O3 and Yb2O3, were added to the mixture. Green samples of 25 mm diameter and 3 mm thickness were prepared and sintered by hot pressing at 1000 °C for 2 h under 25 MPa pressure. The final samples were investigated via scanning electron microscopy (SEM)-energy-dispersive X-ray spectroscopy (EDS), XRD, Rietveld, and ultrasonic methods. Phase analysis showed tetragonal and orthorhombic KNN phases, and a contamination of (K2CO3·1.5H2O) was present. The obtained KNN polycrystals had a relative density above 95%. Texturing of the material was confirmed as a result of hot pressing.

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