EFFECT OF COBALT OXIDE ADDITION ON ALUMINA
sintering additive for alumina. 3-5 The role of sintering additive is not only to enhance densification but also to provide uniform microstructure free from flaws so that the properties of the matter can also be improved. In the present work effect of cobalt (II) oxide as a sintering additive on alumina
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Improvement in the Low-Temperature Sintering Performance
For the purpose of lowering the sintering temperature of alumina with a CuO-TiO 2-Nb 2 O 5 additive effects induced by changes in the firing atmosphere in particular oxygen partial pressure (pO 2) were studied was confirmed that sintering was promoted in regions where the pO 2 was lower than that in the air atmosphere 0.21 atm. Our analysis of the additive using TG-DTA and XRD methods
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Effect of sintering atmosphere on the pore-structure
T1Effect of sintering atmosphere on the pore-structure stability of cerium-doped nanostructured alumina. AUKumar Krishnankutty-Nair P. AUTranto Janne. AUBalagopal N. AUNair Balagopal N. AUKumar Jalajakumari. AUHoj Jacob W. AUEngell John E. PY1994. Y11994
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Surface interaction in the platinum-.gamma.-alumina system
Surface interaction in the platinum-.gamma.-alumina system. V. Effects of atmosphere and fractal topology on the sintering of platinum. Walter G. Rothschild
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Effects of firing atmosphere on low temperature sintering
Jul 24 2017 · In particular effects of three kinds of firing atmosphere N 2 air and O 2 on sintering behavior of alumina with the CuO-TiO 2-Nb 2 O 5-Ag 2 O additives were investigated. At the firing temperature of 800 °C start of densification was observed in all samples. The sintering density was in the order of N 2 ≒ air > O 2.
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Alumina sintering and optical properties
The formation energy of alumina is about 400 kcal/mol only exceeded by the oxides of some rarc earth metals like La. Consequences are an extremely low vapour pressure and a high melting point (2045 °C). The deviation from the stoichiometric composition of alumina at normal atmospheric conditi(ms is < 5 x 10 even at 1600 °c ).
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(PDF) Formation and sintering of spinels (MgAl 2O 4) in
The reducing character of the atmosphere does not affect the formation up to 1300 • C. During sintering an increase of weight loss is observed with the temperature and with the reducing character of the atmosphere.The use of CO causes Mg volatilization producing microporosity. The magnesia-rich spinels reach the higher densities.
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Improvement in the Low-Temperature Sintering Performance
For the purpose of lowering the sintering temperature of alumina with a CuO-TiO 2-Nb 2 O 5 additive effects induced by changes in the firing atmosphere in particular oxygen partial pressure (pO 2) were studied was confirmed that sintering was promoted in regions where the pO 2 was lower than that in the air atmosphere 0.21 atm. Our analysis of the additive using TG-DTA and XRD methods
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Effect of Sintering Atmospheres on the Microstructure
Alumina/Alumina SiC laminate composites were fabricated by the pressureless sintering method. Although the laminate defect such as channel crack was observed under the sintering of oxidation atmosphere laminate defects were eliminated by the sintering of non-oxidation atmospheres. Among various atmospheres the vacuum atmosphere was effective in the elimination of laminate defects
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SinteringWikipedia
Sintering or frittage is the process of compacting and forming a solid mass of material by heat or pressure without melting it to the point of liquefaction.. Sintering happens naturally in mineral deposits or as part of a manufacturing process used with metals ceramics plastics and other materials.The atoms in the materials diffuse across the boundaries of the particles fusing the
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Sintering Behaviour of Aluminium in Different Atmospheres
of the sintering atmosphere on the dimensional changes of aluminium compacts during solid state sintering. To eliminate the effect of alloying additions and of a liquid phase on the sintering behaviour the pure aluminium powders were used. 2. Experimental procedure As starting materials were used − air atomized 99.5 purity aluminium powder
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Effect of Copper Oxide on the Sintering of Alumina
The effect of adding small amounts of copper oxide (CuO) on the sintering and mechanical properties of alumina ceramic was studied. Samples were prepared and fired in air atmosphere at temperatures ranging from 1400oC to 1600oC. Sintered samples were characterized to determine phase present bulk density hardness and grain size. The results indicated that all the doped samples could be
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Effects of Milling Atmosphere and Increasing Sintering
The TEM and FeSEM images of the 30 h milled samples in different atmospheres sintered at 500°C with their corresponding grain size distribution histograms are shown in Figures 2 and 3 respectively to better display the effects of milling atmospheres.TEM images showed almost circular ultrafine particles with some agglomerated particles for milled samples in argon atmosphere after sintering
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Alumina sintering and optical properties
The formation energy of alumina is about 400 kcal/mol only exceeded by the oxides of some rarc earth metals like La. Consequences are an extremely low vapour pressure and a high melting point (2045 °C). The deviation from the stoichiometric composition of alumina at normal atmospheric conditi(ms is < 5 x 10 even at 1600 °c ).
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Influence of processing parameters and sintering
Sintering is never performed in air or in an oxygen-rich atmosphere. The basic function of a sintering atmosphere is to protect metal parts from the effects of air contact. The final properties of the material using P/M technique are very dependent on the atmosphere where their sintering has
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Method of sintering translucent aluminaGTE Laboratories
What is claimed is 1. A process for producing a translucent polycrystalline alumina body comprising sintering a prefired shaped compacted green body at a maximum sintering temperature in an atmosphere containing nitrogen and an amount of hydrogen greater than or equal to about 2.5 volume percent and less than or equal to 35 volume percent for a period of time sufficient to produce a
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Effects of Milling Atmosphere and Increasing Sintering
The TEM and FeSEM images of the 30 h milled samples in different atmospheres sintered at 500°C with their corresponding grain size distribution histograms are shown in Figures 2 and 3 respectively to better display the effects of milling atmospheres.TEM images showed almost circular ultrafine particles with some agglomerated particles for milled samples in argon atmosphere after sintering
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Effect of carbon contamination on the sintering of alumina
Jan 01 2018 · The commercially available alumina was coated with carbon and sintered at different atmospheres to investigate the effect of carbon presence on alumina sintering behaviour. The sintering conditions were heating/cooling rates 5 °C/min and 1.7 °C/min until the maximum temperature of 1400 °C and a dwell time of 2 h.
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Surface interaction in the platinum-.gamma.-alumina system
Surface interaction in the platinum-.gamma.-alumina system. V. Effects of atmosphere and fractal topology on the sintering of platinum. Walter G. Rothschild
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Effect of Sintering Atmospheres on the Microstructure
Alumina/Alumina SiC laminate composites were fabricated by the pressureless sintering method. Although the laminate defect such as channel crack was observed under the sintering of oxidation atmosphere laminate defects were eliminated by the sintering of non-oxidation atmospheres. Among various atmospheres the vacuum atmosphere was effective in the elimination of laminate defects
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USAMethod of sintering translucent alumina
An improved process for producing a translucent polycrystalline alumina body comprising sintering a prefired compacted green body of alumina of predetermined shape is disclosed. The green body of alumina includes alumina doped with one or more sintering aids. The method of the present invention comprises sintering the prefired compacted green body of predetermined shape at a maximum sintering
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Influence of processing parameters and sintering
Sintering is never performed in air or in an oxygen-rich atmosphere. The basic function of a sintering atmosphere is to protect metal parts from the effects of air contact. The final properties of the material using P/M technique are very dependent on the atmosphere where their sintering has
Chat OnlineEffects of Interfacial Properties between Molten Iron and
2.1. Sintering of Alumina Balls under Ar Gas Atmosphere. Alumina balls (Al 2 O 3 92 SiO 2 5 ) which were prepared by tumbling granulation were used in the experiments. For simplicity we assumed that this material was pure alumina. Each ball is a sintered body which composed of the particles of several hundred nm to several μm.The average diameter of the alumina balls was 500 μm.
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The sintering behavior of ultrafine alumina particles
Warble sin- tered UFPs of alumina at atmosphere at 1150 °C for 48 h and noted that the 7-phase particles had transformed to the a-phase in a "plate and block" arrangement. In all of the preceding discussion no mention was made concerning the role of impurities on the prop- erties of these materials.
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2.1. Sintering of Alumina Balls under Ar Gas Atmosphere. Alumina balls (Al 2 O 3 92 SiO 2 5 ) which were prepared by tumbling granulation were used in the experiments. For simplicity we assumed that this material was pure alumina. Each ball is a sintered body which composed of the particles of several hundred nm to several μm.The average diameter of the alumina balls was 500 μm.
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24 Effects of the Microstructure Induced by Sintering on the Dielectric Properties of Alumina Zarbout Kamel 1 Moya Gérard 2 Si Ahmed Abderrahmane 2 Damamme Gilles 3 and Kallel Ali 1 1Sfax University LaMaCoP BP 1171 Sfax 3000 2Aix-Marseille University Im2n p UMR-CNRS 6242 Marseille 3Commissariat à l Energie Atomique DA M Ile-de-France Bruyère-le-Châtel
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EFFECT OF SINTERING ATMOSPHERE ON THE
The influence of sintering atmosphere on the microstructure of high Cr-alloyed sintered stainless steel was investigated. Two regimes using three sintering atmospheres were applied. Sintering in pure hydrogen was evaluated as unsatisfactory due to the strong decarburization of the compact surface. Sintering in mixed N2-H2 atmosphere resulted in
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Effect of sintering atmosphere on the pore-structure
The ionic size effect was studied by heat treating the Ce-alumina system in both oxidizing and reducing atmospheres to have Ce4 (87 pm) and Ce3 (106 pm) respectively. No compound formation between Ce and alumina was observed. In the case of pure alumina there is a drastic reduction in porosity during the transformation to α-alumina.
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2.1. Sintering of Alumina Balls under Ar Gas Atmosphere. Alumina balls (Al 2 O 3 92 SiO 2 5 ) which were prepared by tumbling granulation were used in the experiments. For simplicity we assumed that this material was pure alumina. Each ball is a sintered body which composed of the particles of several hundred nm to several μm.The average diameter of the alumina balls was 500 μm.
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Effects of Sintering Atmosphere and Sintering Time on Gas
Summary In this paper effects of sintering atmosphere and prolonged annealing on gas emission behavior of high purity Al2O3 were investigated to clarify the behavior of gases in the material and t
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