Estimation of the activation energy of sintering in KNN ceramics using master sintering theory

2014 ◽  
Author(s):  
Rajan Singh ◽  
P. K. Patro ◽  
Ajit R. Kulkarni ◽  
C. S. Harendranath
Keyword(s):  
Activation Energy ◽  
Activation Energy Of Sintering

scholarly journals Preparation of Apatite-Wollastonite-Phlogopite glass-ceramic composites by powder sintering method

2013 ◽  
Vol 45 (3) ◽  
pp. 331-339
Author(s):  
A. Faeghi-Nia
Keyword(s):  
Activation Energy ◽  
Particle Size ◽  
Glass Ceramic ◽  
Ceramic Composite ◽  
Ceramic Composites ◽  
Powder Sintering ◽  
Powdered Glass ◽  
Activation Energy Of Sintering ◽  
Sintering Method ◽  
Glass Ceramic Composite

An Apatite-Wollastonite-Phlogopite glass-ceramic composite, was developed by sintering and crystallization of the powdered glass. The non-isothermal and isothermal sintering kinetics were studied for this glass-ceramic. Hot-stage microscopy (HSM) measurements demonstrated that it is possible to sinter and crystallize this glass-ceramic with 80% relative density. The activation energy of sintering was analyzed using previously reported model of sintering and it was obtained Q=193.83 KjmolK-1. Also it was shown that the microstructure of sample is a function of particle size distribution.

scholarly journals The Effect of Calcium Doping on the Surface and Catalytic Properties of Cobaltic Oxide Catalysts

2003 ◽  
Vol 21 (3) ◽  
pp. 229-243 ◽  
Author(s):  
Nasr-Allah M. Deraz
Keyword(s):  
Activation Energy ◽  
Calcination Temperature ◽  
Calcium Oxide ◽  
Total Pore Volume ◽  
Textural Properties ◽  
Peroxide Decomposition ◽  
Cobaltic Oxide ◽  
Adsorption Of Nitrogen ◽  
Activation Energy Of Sintering ◽  
Calcium Doping

The effects of calcium oxide doping (0.75, 1.5 and 3 mol% CaO) and calcination temperature (400, 500, 600 and 700°C) on different surface properties of Co3O4 were investigated. The structural properties of pure and doped oxide samples were determined by XRD methods, the textural properties were investigated via the adsorption of nitrogen at −196°C while the hydrogen peroxide decomposition activity of the investigated solids was determined by oxygen gasometric measurement of the reaction kinetics at 20–40°C. The dissolution of calcium ions in the Co3O4 lattice at temperatures in the range 400–600°C was accompanied by a marked decrease in the mean hydraulic radii (rh) and an increase in the surface area (SBET) and total pore volume (Vp) of the prepared oxide samples. In contrast, doping at 700°C brought about a decrease in the SBET and Vp values of the investigated solids. The catalytic activity for H2O2 decomposition on cobaltic oxide calcined at 400–700°C was found to decrease considerably on doping with CaO. The activation energy for sintering (ΔEs) of the pure and doped solids was determined from the variation in their SBET values as a function of the calcination temperature of these solids. Calcium oxide treatment resulted in a 50% increase in the activation energy of sintering of cobaltic oxide solid calcined at 400–600°C. This increase reflects the role of CaO doping in hindering the sintering of cobaltic oxide.

On the evaluation of the activation energy of sintering

2003 ◽  
Vol 80 (1) ◽  
pp. 108-113 ◽  
Author(s):  
Tsang-Tse Fang ◽  
Jyh-Tzong Shiue ◽  
Fuh-Shan Shiau
Keyword(s):  
Activation Energy ◽  
Activation Energy Of Sintering

Glass transition temperature and activation energy of sintering by optical dilatometry

2013 ◽  
Vol 553 ◽  
pp. 1-7 ◽  
Author(s):  
Alexander Karamanov ◽  
Boris Dzhantov ◽  
Mariano Paganelli ◽  
Davide Sighinolfi
Keyword(s):  
Activation Energy ◽  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Activation Energy Of Sintering

On the activation energy of sintering non-stoichiometric uranium oxide

1964 ◽  
Vol 11 (2) ◽  
pp. 229-235 ◽  
Author(s):  
I Amato ◽  
R.L Colombo ◽  
A.M Protti
Keyword(s):  
Activation Energy ◽  
Uranium Oxide ◽  
Activation Energy Of Sintering

scholarly journals Effects of Li2O Doping on the Surface and Catalytic Properties of Co3O4–Fe2O3 Solids Precalcined at Different Temperatures

2000 ◽  
Vol 18 (3) ◽  
pp. 243-260 ◽  
Author(s):  
G.A. El-Shobaky ◽  
M.A. Shouman ◽  
M.N. Alaya
Keyword(s):  
Activation Energy ◽  
Catalytic Activity ◽  
Mixed Oxides ◽  
Catalytic Properties ◽  
Nitrogen Adsorption ◽  
Surface Characteristics ◽  
Oxidation Of Co ◽  
Surface Areas ◽  
Different Temperatures ◽  
Activation Energy Of Sintering

The effects of Li2O treatment on the solid–solid interactions and the surface and catalytic properties of the Co3O4–Fe2O3 system have been studied using TG, DTA and XRD methods, nitrogen adsorption studies at −196°C and the catalytic oxidation of CO by O2 at 150–350°C. The results obtained showed that Li2O doping followed by precalcination at 500–1000°C enhanced the formation of cobalt ferrite to an extent proportional to the amount of dopant added (0.52–6.0 mol% Li2O). The solid–solid interaction leading to the formation of CoFe2O4 took place at temperatures ≥700°C in the presence of the Li2O dopant. Lithia doping modified the surface characteristics of the Co3O4–Fe2O3 solids, both increasing and decreasing their BET surface areas depending on the amount of dopant added and the precalcination temperature employed for the treated solids. The activation energy of sintering (ΔES) of cobalt/ferric mixed oxides was determined for the pure and doped solids from the variation in their specific surface areas as a function of the precalcination temperature. Both an increase and a decrease in the value of ΔES due to Li2O doping occurred depending on the amount of lithia added. The doping of Co3O4–FeO solids, followed by precalcination at 500°C, effected a significant increase (144%) in their catalytic activity towards CO oxidation by O2. Precalcination at 700–1000°C of the mixed oxide solids doped with Li2O (0.52 and 0.75 mol%) resulted in an increase in their catalytic activity which decreased upon increasing the amount of Li2O added above this limit. The activation energy of the catalyzed reaction was determined for the pure and variously doped solids studied.

scholarly journals Determination of activation energy of sintering of ThO2-U3O8 pellets using the master sintering curve approach

2003 ◽  
Vol 35 (3) ◽  
pp. 125-132 ◽  
Author(s):  
T.R.G. Kutty ◽  
K.B. Khan ◽  
P.V. Hegde ◽  
A.K. Sengupta ◽  
S. Majumdar ◽  
...  
Keyword(s):  
Activation Energy ◽  
Solid Solution ◽  
High Temperature ◽  
Constant Heating Rate ◽  
Heavy Water Reactor ◽  
Activation Energy Of Sintering ◽  
Constant Heating ◽  
Kinetics Of ◽  
Powder Metallurgy Route

ThO2 containing around 2 to 3 % U233O2 is considered as fuel for the forthcoming Indian Advanced Heavy Water Reactor (AHWR). High-density ThO2-UO2 pellets have been fabricated by powder metallurgy route using ThO2 and U3O8 powders as the starting materials. U3O8 decomposes to UO2 during high temperature sintering and forms a solid solution with ThO2. The densification behaviour and sintering kinetics of the above were evaluated using a high temperature dilatometer using constant heating rate experiments. To evaluate the activation energy of sintering, a master sintering curve approach has been used. The activation energy for sintering for the above composition in air was found to be 500 kJ/mol.

High Temperature n- and p-type Doped Microcrystalline Silicon Layers Grown by VHF PECVD Layer-by-Layer Deposition

2003 ◽  
Vol 762 ◽  
Author(s):  
A. Gordijn ◽  
J.K. Rath ◽  
R.E.I. Schropp
Keyword(s):  
Activation Energy ◽  
High Temperature ◽  
High Temperatures ◽  
Continuous Wave ◽  
Hydrogen Plasma ◽  
Silicon Layer ◽  
Dark Conductivity ◽  
High Deposition Rate ◽  
Layer By Layer ◽  
Microcrystalline Silicon

AbstractDue to the high temperatures used for high deposition rate microcrystalline (μc-Si:H) and polycrystalline silicon, there is a need for compact and temperature-stable doped layers. In this study we report on films grown by the layer-by-layer method (LbL) using VHF PECVD. Growth of an amorphous silicon layer is alternated by a hydrogen plasma treatment. In LbL, the surface reactions are separated time-wise from the nucleation in the bulk. We observed that it is possible to incorporate dopant atoms in the layer, without disturbing the nucleation. Even at high substrate temperatures (up to 400°C) doped layers can be made microcrystalline. At these temperatures, in the continuous wave case, crystallinity is hindered, which is generally attributed to the out-diffusion of hydrogen from the surface and the presence of impurities (dopants).We observe that the parameter window for the treatment time for p-layers is smaller compared to n-layers. Moreover we observe that for high temperatures, the nucleation of p-layers is more adversely affected than for n-layers. Thin, doped layers have been structurally, optically and electrically characterized. The best n-layer made at 400°C, with a thickness of only 31 nm, had an activation energy of 0.056 eV and a dark conductivity of 2.7 S/cm, while the best p-layer made at 350°C, with a thickness of 29 nm, had an activation energy of 0.11 V and a dark conductivity of 0.1 S/cm. The suitability of these high temperature n-layers has been demonstrated in an n-i-p microcrystalline silicon solar cell with an unoptimized μc-Si:H i-layer deposited at 250°C and without buffer. The Voc of the cell is 0.48 V and the fill factor is 70 %.

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