Growth mechanism of hydrous chromium(III) oxide spherical particles of narrow size distribution

1974 ◽  
Vol 78 (25) ◽  
pp. 2621-2625 ◽  
Author(s):  
Alexander Bell ◽  
Egon Matijevic
Keyword(s):  
Size Distribution ◽  
Growth Mechanism ◽  
Spherical Particles ◽  
Narrow Size Distribution

Synthesis of Submicron, Narrow Size Distribution Spherical Zincite

1986 ◽  
Vol 73 ◽  
Author(s):  
Robert H. Heistand ◽  
Yee-Ho Chia
Keyword(s):  
Size Distribution ◽  
Surface Area ◽  
Systematic Study ◽  
Spherical Particles ◽  
Narrow Size Distribution ◽  
Crystallite Sizes ◽  
Hydrolysis Of ◽  
Controlled Hydrolysis

ABSTRACTZincite has been produced by the controlled hydrolysis of an alkylzinc alkoxide (ethylzinc-t-butoxide) resulting in ∼0.2 μm spherical particles with a narrow size distribution consisting of 150 Å crystallites. The surface area is 30 m2/g. Variation of the concentration of the water drastically affects the particle and crystallite sizes. The results of a systematic study of the hydrolysis parameters are reported here.

scholarly journals Structure investigations of nanocrystalline glass ceramics by ASAXS

2014 ◽  
Vol 70 (a1) ◽  
pp. C744-C744
Author(s):  
Armin Hoell ◽  
Vikram Raghuwanshi ◽  
Christian Rüssel
Keyword(s):  
Heat Treatment ◽  
Size Distribution ◽  
Glass Ceramics ◽  
Growth Effect ◽  
Spherical Particles ◽  
Diffraction Measurement ◽  
Narrow Size Distribution ◽  
Laser Materials ◽  
X Ray ◽  
Fluoride Crystals

Glass ceramics containing fluoride crystals such as BaF2 or CaF2 with crystallite sizes in the range from 5 to 100 nm are potential candidates for numerous photonic applications. Glass ceramics containing rare-earth-doped fluoride crystals are candidates for laser materials. The size distribution plays an important role and often a narrow size distribution is required for photonic applications. In the last years a hindered growth effect leading to a more narrow size distribution was observed during the crystallization of BaF2 as well as CaF2 nanocrystals in oxy-fluoride glasses. The aim of this study is a detailed quantitative structural and nano-chemical analysis of the formation of BaF2 or CaF2 in two glass ceramics by Anomalous Small-Angle X-ray Scattering (ASAXS) to reveal and understand the mechanism of hindered growth. Nanocrystals of BaF2 precipitate during heat treatment of a silicate glass of composition 69.6SiO2-7.52Al2O3-15.04K2O-1.88Na2O-4BaF2-2BaO. X-ray diffraction measurement proved the formation of BaF2 crystals in the glass matrix. High resolution TEM showed the formation of spherical particles of sizes in range from 10-40 nm surrounded by a layer enriched with SiO2. SAXS reveal the growth of nanocrystals with increasing annealing time and temperatures. ASAXS experiments are done at four energies close to the Ba-L3 X-ray absorption edge (5247eV). The ASAXS curves for the sample annealed at 5400C for 20h revealed a spherical core-shell model. It turned out that the layer surrounding the BaF2 crystals is enriched with SiO2. Sizes and compositions of these layers are analyzed quantitatively. Furthermore, the ASAXS analysis reveals the presence of very small nucleates of size of about 3 nm in the as melted glass sample already [1]. A precipitation of CaF2 nanoparticles takes place during heat treatment of glasses of composition 7.65Na2O–7.69K2O–10.58CaO–12.5CaF2–5.77Al2O3–55.8SiO2 up to 40 hours. SAXS experiments and especially ASAXS near the Ca-K edge proves the formation of CaF2 nanoparticle surrounded with SiO2 enriched layers, quantitatively. The ASAXS effect is very pronounced at this untypical low energy for ASAXS studies at the Ca-K edge. The ASAXS result reveals crystal sizes between 10-20 nm surrounded by a shell of lower electron density. Additional very small heterogeneities are found after long annealing with diameters of about 1.6 nm [2].

Macrostructure and microphysics of Saturn's E-ring

1984 ◽  
Vol 75 ◽  
pp. 607-613 ◽  
Author(s):  
Kevin D. Pang ◽  
Charles C. Voge ◽  
Jack W. Rhoads
Keyword(s):  
Size Distribution ◽  
Spherical Shape ◽  
Mie Scattering ◽  
Narrow Size Distribution ◽  
Electrostatic Levitation ◽  
Volcanic Origin ◽  
Micron Diameter

Abstract.All observed optical and infrared properties of Saturn's E-ring can be explained in terms of Mie scattering by a narrow size distribution of ice spheres of 2 - 2.5 micron diameter. The spherical shape of the ring particles and their narrow size distribution imply a molten (possibly volcanic) origin on Enceladus. The E-ring consists of many layers, possibly stratified by electrostatic levitation.

Note: Engineering of crosslinked poly(isothiouronium methylstyrene) microparticles of narrow size distribution for antibacterial applications

2017 ◽  
Vol 28 (5) ◽  
pp. 568-568
Author(s):  
Sarit Cohen ◽  
Inna Laitman ◽  
Tammy Lublin Tennenbaum ◽  
Michal Natan ◽  
Ehud Banin ◽  
...  
Keyword(s):  
Size Distribution ◽  
Narrow Size Distribution

Stranski-Krastanov Growth of InAs Quantum Dots with Narrow Size Distribution

2000 ◽  
Vol 39 (Part 2, No. 12A) ◽  
pp. L1245-L1248 ◽  
Author(s):  
Koichi Yamaguchi ◽  
Kunihiko Yujobo ◽  
Toshiyuki Kaizu
Keyword(s):  
Quantum Dots ◽  
Size Distribution ◽  
Narrow Size Distribution ◽  
Inas Quantum Dots

Colloidal synthesis of monodisperse trimetallic IrNiFe nanoparticles as highly active bifunctional electrocatalysts for acidic overall water splitting

2017 ◽  
Vol 5 (47) ◽  
pp. 24836-24841 ◽  
Author(s):  
Luhong Fu ◽  
Gongzhen Cheng ◽  
Wei Luo
Keyword(s):  
Synergistic Effect ◽  
Size Distribution ◽  
Water Splitting ◽  
Average Diameter ◽  
Colloidal Synthesis ◽  
Synthetic Method ◽  
Alloy Nanoparticles ◽  
Narrow Size Distribution ◽  
Acidic Media ◽  
Highly Active

Monodisperse IrNiFe alloy nanoparticles with an average diameter of 2.2 nm have been synthesized by a colloidal synthetic method. By taking advantage of the synergistic effect between Ir, Ni and Fe and the ultrasmall NPs with narrow size distribution, the as-synthesized IrNiFe catalyst exhibits superior HER/OER performances in acidic media.

Sign in / Sign up

Export Citation Format

Share Document