Influence of the particle size distribution on the CRTA curves for the solid-state reactions of interface shrinkage type

1997 ◽  
Vol 49 (3) ◽  
pp. 1477-1484 ◽  
Author(s):  
N. Koga ◽  
J. M. Criado
Keyword(s):  
Particle Size ◽  
Solid State ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Solid State Reactions

The Investigations on Luminescence Characteristics and Influence of Doping and Co-Doping Different Rare Earth Ions in White Phosphorescence Materials Having Different Luminescent Centers

2014 ◽  
Vol 90 ◽  
pp. 133-140
Author(s):  
Erkul Karacaoglu ◽  
Bekir Karasu ◽  
Esra Öztürk
Keyword(s):  
Particle Size ◽  
Rare Earth ◽  
Solid State ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Rare Earths ◽  
Solid State Reaction ◽  
Solid State Reaction Method ◽  
Reaction Method ◽  
Luminescence Characteristics

The Akermanite type alkaline earth silicate Ca2MgSi2O7 activated by different types of rare earths was prepared by the conventional solid state reaction method under weak reductive atmosphere. The phase formation, particle size distribution, particle morphologies and photoluminescence properties of the samples have been investigated respectively. The comparative results of SEM and laser particle size analysis revealed that the relatively regular morphology, smaller particle size distribution could be achieved for the phosphors synthesized by the solid state reaction method including dry-ground after which powders were sieved below 170 meshes. The effects of rare earth oxides; Nd2O3, Pr6O11, Ce2O3 and Sm2O3 on the luminescence properties of the host material, Ca2MgSi2O7, were studied. Remarkable enhancement and novel color emitting including white in luminescence characteristics of host material were observed as a result of doping the mentioned rare-earths were doped.

Low-temperature and rapid solid-state synthesis of YAG:Ce powders using oxides with narrow particle size distribution

2006 ◽  
Vol 3 (8) ◽  
pp. 2713-2716 ◽  
Author(s):  
Toshihiro Moriga ◽  
Takashi Kunimoto ◽  
Yuta Sakanaka ◽  
Tatsuro Yoshida ◽  
Kei-ichiro Murai ◽  
...  
Keyword(s):  
Particle Size ◽  
Solid State ◽  
Low Temperature ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Solid State Synthesis ◽  
Narrow Particle Size Distribution

scholarly journals Relevance of Particle Size Distribution to Kinetic Analysis: The Case of Thermal Dehydroxylation of Kaolinite

Processes ◽  
2021 ◽  
Vol 9 (10) ◽  
pp. 1852
Author(s):  
Juan Arcenegui-Troya ◽  
Pedro E. Sánchez-Jiménez ◽  
Antonio Perejón ◽  
Luis A. Pérez-Maqueda
Keyword(s):  
Particle Size ◽  
Particle Size Distribution ◽  
Kinetic Analysis ◽  
Size Distribution ◽  
Kinetic Models ◽  
Solid State Reactions ◽  
Intermediate Species ◽  
Real Samples ◽  
The Common ◽  
Step Mechanism

Kinetic models used for the kinetic analysis of solid-state reactions assume ideal conditions that are very rarely fulfilled by real processes. One of the assumptions of these ideal models is that all sample particles have an identical size, while most real samples have an inherent particle size distribution (PSD). In this study, the influence of particle size distribution, including bimodal PSD, in kinetic analysis is investigated. Thus, it is observed that PSD can mislead the identification of the kinetic model followed by the reaction and even induce complex thermoanalytical curves that could be misinterpreted in terms of complex kinetics or intermediate species. For instance, in the case of a bimodal PSD, kinetics is affected up to the point that the process resembles a reaction driven by a multi-step mechanism. A procedure for considering the PSD in the kinetic analysis is presented and evaluated experimentally by studying the thermal dehydroxylation of kaolinite. This process, which does not fit any of the common ideal kinetic models proposed in the literature, was analyzed considering PSD influence. However, when PSD is taken into account, the process can be successfully described by a 3-D diffusion model (Jander’s equation). Therefore, it is concluded that the deviations from ideal models for this dehydroxylation process could be explained in terms of PSD.

Influence of particle size distribution of precursor oxides on the synthesis of cordierite by solid-state reaction

2005 ◽  
Vol 153 (1) ◽  
pp. 34-42 ◽  
Author(s):  
J.R. González-Velasco ◽  
R. Ferret ◽  
R. López-Fonseca ◽  
M.A. Gutiérrez-Ortiz
Keyword(s):  
Particle Size ◽  
Solid State ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Solid State Reaction

Preparation of Delaminated Nano-Kaolinite by Intercalation of Chemical Assistants

2006 ◽  
Vol 11-12 ◽  
pp. 441-444 ◽  
Author(s):  
Mei Na Niu ◽  
Can Xiong Guo
Keyword(s):  
Particle Size ◽  
Solid State ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Solid State Nmr ◽  
Thermal Analyses ◽  
Potassium Acetate

A process for preparing of the delaminated kaolinite was developed with intercalation of hydrazine, urea or potassium acetate followed by removing the chemical assistants. Delaminated kaolinite was characterized by XRD, solid-state NMR, thermal analyses, particle-size distribution analyses, etc. The particle size was reduced to ca. 440 nm in diameter and ca.15 nm in thickness in contrast to about 7 μm and 800 nm for untreated precursor respectively. The dehydroxylation temperature of kaolinite was shifted from 514°C to 490°C by the delamination. Additionally, a greater mass lost was also observed for the delaminated particles by dehydroxylation.

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