scholarly journals Rheology and Consolidation of Colloidal Suspension of Ultrafine SiO2-Al2O3 Powder

1990 ◽  
Vol 98 (1141) ◽  
pp. 951-956 ◽  
Author(s):  
Yoshihiro HIRATA ◽  
Ichiroh HARAGUCHI ◽  
Yoshimi ISHIHARA
Keyword(s):  
Colloidal Suspension ◽  
Al2o3 Powder ◽  
Ultrafine Sio2

scholarly journals Tandem selective photothermal absorbers based on EPD of CuO colloidal suspension coupled with dip-coated silica

2021 ◽  
pp. 126818
Author(s):  
S. Shehayeb ◽  
X. Deschanels ◽  
L. Ghannam ◽  
I. Karamé ◽  
G. Toquer
Keyword(s):  
Colloidal Suspension

scholarly journals Characterization of Al2O3 Samples and NiAl–Al2O3 Composite Consolidated by Pulse Plasma Sintering

Materials ◽  
2021 ◽  
Vol 14 (12) ◽  
pp. 3398
Author(s):  
Katarzyna Konopka ◽  
Marek Krasnowski ◽  
Justyna Zygmuntowicz ◽  
Konrad Cymerman ◽  
Marcin Wachowski ◽  
...  
Keyword(s):  
Fracture Toughness ◽  
Mechanical Alloying ◽  
Ceramic Composites ◽  
Pulse Plasma ◽  
High Plasticity ◽  
Composite Powders ◽  
Microstructural Investigation ◽  
Al2o3 Powder ◽  
Plasma Sintering ◽  
Pulse Plasma Sintering

The paper describes an investigation of Al2O3 samples and NiAl–Al2O3 composites consolidated by pulse plasma sintering (PPS). In the experiment, several methods were used to determine the properties and microstructure of the raw Al2O3 powder, NiAl–Al2O3 powder after mechanical alloying, and samples obtained via the PPS. The microstructural investigation of the alumina and composite properties involves scanning electron microscopy (SEM) analysis and X-ray diffraction (XRD). The relative densities were investigated with helium pycnometer and Archimedes method measurements. Microhardness analysis with fracture toughness (KIC) measures was applied to estimate the mechanical properties of the investigated materials. Using the PPS technique allows the production of bulk Al2O3 samples and intermetallic ceramic composites from the NiAl–Al2O3 system. To produce by PPS method the NiAl–Al2O3 bulk materials initially, the composite powder NiAl–Al2O3 was obtained by mechanical alloying. As initial powders, Ni, Al, and Al2O3 were used. After the PPS process, the final composite materials consist of two phases: Al2O3 located within the NiAl matrix. The intermetallic ceramic composites have relative densities: for composites with 10 wt.% Al2O3 97.9% and samples containing 20 wt.% Al2O3 close to 100%. The hardness of both composites is equal to 5.8 GPa. Moreover, after PPS consolidation, NiAl–Al2O3 composites were characterized by high plasticity. The presented results are promising for the subsequent study of consolidation composite NiAl–Al2O3 powder with various initial contributions of ceramics (Al2O3) and a mixture of intermetallic–ceramic composite powders with the addition of ceramics to fabricate composites with complex microstructures and properties. In composites with complex microstructures that belong to the new class of composites, in particular, the synergistic effect of various mechanisms of improving the fracture toughness will be operated.

scholarly journals Light Confinement with Structured Beams in Gold Nanoparticle Suspensions

Photonics ◽  
2021 ◽  
Vol 8 (6) ◽  
pp. 221
Author(s):  
Argelia Balbuena Balbuena Ortega ◽  
Felix E. Torres-González ◽  
Valentin López López Gayou ◽  
Raul Delgado Delgado Macuil ◽  
Gaetano Assanto ◽  
...  
Keyword(s):  
Colloidal Suspension ◽  
Laser Wavelength ◽  
Gaussian Beams ◽  
Optical Vortices ◽  
Complex Structures ◽  
Plasmonic Resonance ◽  
Dark Solitons ◽  
Experimental Campaign ◽  
Nanoparticle Suspensions ◽  
Light Beams

We carry out an experimental campaign to investigate the nonlinear self-defocusing propagation of singular light beams with various complex structures of phase and intensity in a colloidal suspension of gold nanoparticles with a plasmonic resonance near the laser wavelength (532nm). Studying optical vortices embedded in Gaussian beams, Bessel vortices and Bessel-cosine (necklace) beams, we gather evidence that while intense vortices turn into two-dimensional dark solitons, all structured wavepackets are able to guide a weak Gaussian probe of different wavelength (632.8 nm) along the dark core. The probe confinement also depends on the topological charge of the singular pump.

scholarly journals Appearance of a Solitary Wave Particle Concentration in Nanofluids under a Light Field

Nanomaterials ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 1291
Author(s):  
Abram I. Livashvili ◽  
Victor V. Krishtop ◽  
Polina V. Vinogradova ◽  
Yuriy M. Karpets ◽  
Vyacheslav G. Efremenko ◽  
...  
Keyword(s):  
Solitary Wave ◽  
Wave Velocity ◽  
Light Field ◽  
Particle Concentration ◽  
Colloidal Suspension ◽  
Type Equation ◽  
Concentration Wave ◽  
Nanoparticle Concentration ◽  
Constant Intensity ◽  
Concentration Convection

In this study, the nonlinear dynamics of nanoparticle concentration in a colloidal suspension (nanofluid) were theoretically studied under the action of a light field with constant intensity by considering concentration convection. The heat and nanoparticle transfer processes that occur in this case are associated with the phenomenon of thermal diffusion, which is considered to be positive in our work. Two exact analytical solutions of a nonlinear Burgers-Huxley-type equation were derived and investigated, one of which was presented in the form of a solitary concentration wave. These solutions were derived considering the dependence of the coefficients of thermal conductivity, viscosity, and absorption of radiation on the nanoparticle concentration in the nanofluid. Furthermore, an expression was obtained for the solitary wave velocity, which depends on the absorption coefficient and intensity of the light wave. Numerical estimates of the concentration wave velocity for a specific nanofluid—water/silver—are given. The results of this study can be useful in the creation of next-generation solar collectors.

Stability of a Binary Colloidal Suspension and its effect on Colloidal Processing

1989 ◽  
Vol 155 ◽  
Author(s):  
Wan V. Shih ◽  
Wei-Heng Shih ◽  
Jun Liu ◽  
Ilhan A. Aksay
Keyword(s):  
Particle Size ◽  
Hard Sphere ◽  
Colloidal Particles ◽  
Colloidal Suspension ◽  
Fluid Phase ◽  
Ceramic Processing ◽  
Colloidal Processing ◽  
Interparticle Interactions ◽  
The Stability ◽  
Binary Suspension

The stability of a colloidal suspension plays an important role in colloidal processing of materials. The stability of the colloidal fluid phase is especially vital in achieving high green densities. By colloidal fluid phase, we refer to a phase in which colloidal particles are well separated and free to move about by Brownian motion, By controlling parameters such as pH, salt concentration, and surfactants, one can achieve high packing (green) densities in the repulsive regime where the suspension is well dispersed as a colloidal fluid, and low green densities in the attractive regime where the suspensions are flocculated [1,2]. While there is increasing interest in using bimodal suspensions to improve green densities, neither the stability of a binary suspension as a colloidal fluid nor the stability effects on the green densities have been studied in depth as yet. Traditionally, the effect of using bimodal-particle-size distribution has only been considered in terms of geometrical packing developed by Furnas and others [3,4]. This model is a simple packing concept and is used and useful for hard sphere-like repulsive interparticle interactions. With the advances in powder technology, smaller and smaller particles are available for ceramic processing. Thus, the traditional consideration of geometrial packing for the green densities of bimodal suspensions may not be enough. The interaction between particles must be taken into account.

Low temperature synthesis of ultrafine α-Al2O3 powder by a simple aqueous sol–gel process

2006 ◽  
Vol 32 (5) ◽  
pp. 587-591 ◽  
Author(s):  
Jiang Li ◽  
Yubai Pan ◽  
Changshu Xiang ◽  
Qiming Ge ◽  
Jingkun Guo
Keyword(s):  
Low Temperature ◽  
Sol Gel ◽  
Low Temperature Synthesis ◽  
Temperature Synthesis ◽  
Al2o3 Powder ◽  
Sol Gel Process ◽  
Α Al2o3

Stable Semiconducting Ink Based on a Polypyrrole/Carbon-Quantum-Dot Aqueous Colloidal Suspension: A Potential Sensor for Volatile Organics Present in Food

2017 ◽  
Vol 2 (6) ◽  
pp. 2139-2143 ◽  
Author(s):  
Lopamudra Bhattacharjee ◽  
Kallol Mohanta ◽  
Joghee Ravichandran ◽  
Rama R. Bhattacharjee
Keyword(s):  
Quantum Dot ◽  
Colloidal Suspension ◽  
Volatile Organics ◽  
Carbon Quantum Dot
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