scholarly journals Effect of TiO2 on the sintering behavior and microstructure of stoichiometric spinel (MgAl2O4)

2019 ◽  
Vol 15 (34) ◽  
pp. 114-122
Author(s):  
Baker F. Hassen
Keyword(s):  
Sintering Temperature ◽  
Spinel Phase ◽  
Spherical Shape ◽  
Sintering Behavior ◽  
Magnesium Aluminate Spinel ◽  
Soaking Time ◽  
Sem Image ◽  
Single Firing ◽  
Spinel Mgal2o4 ◽  
The Impact

In this work, magnesium aluminate spinel (MA) (MgO 28 wt%, Al2O3 72 wt%) stoichiometric compound , were synthesized via solid state reaction (SSR) Single firing stage, and the impact of sintering on the physical properties and thermal properties as well as the fine structure and morphology of the ceramic product were examined. The Spinel samples were pressed at of (14 MPa) and sintering soaking time (2h). The effect of adding oxide titania (TiO2) was studied. The obtained powders were calcined at a temperature range of 1200 and 1400 °C. The calcined samples spinel were characterized by XRD, it showed the presence of developed spinel phase end also showed that the best catalyst is titania. The SEM image showed the high sintering temperature increased the regularity of the grain growth, as well as minutes from the acquisition of the spherical shape of the minutes spinel.

Effect of In Situ Formed Spinel Phase on the Mechanical Properties of Zirconia Ceramics

2007 ◽  
Vol 345-346 ◽  
pp. 1573-1576
Author(s):  
Z. X. Yang ◽  
Jeong Bae Yoon ◽  
Kyu Hong Hwang ◽  
J.K. Lee ◽  
B.S. Jun
Keyword(s):  
Mechanical Properties ◽  
Spinel Phase ◽  
Sintering Behavior ◽  
Reaction Sintering ◽  
Stabilized Zirconia ◽  
Homogeneous Microstructure ◽  
Fine Grain ◽  
Firing Shrinkage ◽  
Spinel Mgal2o4

The reaction-sintered zirconia-alumina and zirconia-spinel ceramics having low firing shrinkage were prepared from ZrO2(Ca-PSZ)/Al and ZrO2(Baddellyite)/MgAl powder mixtures via the attrition milling and the effect of the characteristics of used raw powders was investigated. Flaky Al powders mixed with coarse Ca-PSZ powders was not effectively comminuted due to lower hardness of zirconia powders. So by using the alumina ball media or coarse Al2O3 powders rather than Al, the milling efficiency could be much more increased. When fused Ca-PSZ powder was reaction-sintered with Al at 1550 for 3 hours, the reaction-sintering and densification were somewhat difficult because the Ca-PSZ/Al powder mixture was not effectively comminuted. And the Ca ion in Ca-PSZ grains diffused into alumina grains during sintering so that the unstabilization of Ca-PSZ body was occurred which gave the cracks in the specimens. But when MgAl alloy powder was added to monoclinic zirconia, Mg and Al became to oxide at first and subsequently converted to spinel(MgAl2O4) during heating and finally unreacted MgO seemed to stabilize the zirconia. The oxides which formed at the oxidation process would have very fine grain size so that the reaction sintering was more effective to densification and homogeneous microstructure. The mechanical properties of reaction-sintered stabilized zirconia/spinel composite were better than only MgO stabilized zirconia. Sintering behavior in reaction and mechanical properties of sintered body were examined, with emphasis on the relations between spinel formation and mechanical properties.

scholarly journals Sintering behavior of Y2O3 doped Bi2O3 ceramics

2007 ◽  
Vol 39 (3) ◽  
pp. 215-221 ◽  
Author(s):  
M. Alizadeh ◽  
A. Maghsoudipour ◽  
F. Moztarzadeh ◽  
K. Ahmadi ◽  
M. Saremi
Keyword(s):  
Relative Density ◽  
Sintering Temperature ◽  
Stable Phase ◽  
Sintering Behavior ◽  
X Ray Diffraction ◽  
Time Duration ◽  
Soaking Time ◽  
Density Measurements ◽  
X Ray ◽  
Different Temperatures

Influence of sintering temperature and soaking time on densification of Bi2O3 samples doped with 25%mol Y2O3 was investigated by shrinkage and relative density measurements. Samples were sintered in air at different temperatures in the range of 800 to 1000?C for 24 hr. The results showed that samples sintered at 950?C have the maximum relative density. Several samples were sintered at 950?C for duration of 0 to 36 hr in order to evaluate the effect of soaking time on densification of samples. It was found that the samples were sintered at 950?C for 36hr had higher relative density than others did for smaller time duration X-ray diffraction (XRD) analyses detected ? -Bi2O3 as the sole stable phase in all samples. Scanning Electron Microscopy (SEM) investigation of fractured surface of the samples showed that porosities decrease by increasing of sintering temperature and grow by further increasing of temperature.

Microstructure and Sintering Behavior of Mullite-Zirconia Composites

2010 ◽  
Vol 638-642 ◽  
pp. 979-984 ◽  
Author(s):  
F. Sahnoune ◽  
N. Saheb ◽  
M. Chegaar ◽  
P. Goeuriot
Keyword(s):  
Sintering Temperature ◽  
Water Immersion ◽  
Spherical Shape ◽  
Average Crystallite Size ◽  
Tetragonal Structure ◽  
Sintering Behavior ◽  
Zro2 Content ◽  
Immersion Method ◽  
Mullite Phase ◽  
Zirconia Composites

In the present work, the structure and sintering behaviour of mullite-zirconia composites were investigated. The composites were prepared by reaction sintering of Algerian kaolin, α-Al2O3, and stabilized zirconia (3Y-TZP). The raw materials were wet ball milled in a planetary ball mill followed by attrition. The green samples shaped using a uniaxial press were sintered between 1100°C and 1600°C for 2 hours. The density was measured by the water immersion method. Phases present and change of the average crystallite size of the mullite phase as a function of sintering temperature and ZrO2 content were characterized through X-ray diffraction. Mulite grains had whiskers' shape; however, the increase of ZrO2 content changed the morphology of grains to near spherical shape. The microstructure of the samples revealed uniform distribution of ZrO2 particles; also, aluminium was uniformly distributed on all grains exception on zirconia grains. At least a relative density of 95 % was achieved for all samples at a relatively lower sintering temperature of 1500°C. In composites containing up to 16 wt. % ZrO2, the zirconia phase retained its tetragonal structure and the transformed part did not exceed 3 %. However, with the addition of 32 wt. % ZrO2 around 66 % of the tetragonal structure changed to monoclinic structure.

Effect of TiO2 and MgO on Microstructure of α-Alumina Ceramics and its Sintering Behavior

2015 ◽  
Vol 1112 ◽  
pp. 519-523 ◽  
Author(s):  
Jarot Raharjo ◽  
Sri Rahayu ◽  
Tika Mustika ◽  
Masmui ◽  
Dwi Budiyanto
Keyword(s):  
Mechanical Properties ◽  
Sintering Temperature ◽  
Physical And Mechanical Properties ◽  
Basic Material ◽  
Sintering Behavior ◽  
Pressureless Sintering ◽  
Alumina Ceramics ◽  
Density Measurements ◽  
Technical Alumina ◽  
Platelet Structure

Observation on the effect of adding titanium oxide (TiO2) and magnesium oxide (MgO) on the sintering of α-alumina (Al2O3) has been performed. In this study, technical alumina used as basic material in which the sample is formed by the pressureless sintering/cold press and sintered at 1500°C which is lower than alumina sintering temperature at 1700°C. Elemental analysis, observation of microstructure, hardness, fracture toughness and density measurements were carried out to determine the physical and mechanical properties of alumina. The results indicate a change in the microstructure where the content of the platelet structure are much more than the equilateral structure. At sintering temperature of 1500°C, neck growth occurs at ceramics grain, supported by the results of the density test which indicate perfect compaction has occurred in this process.

Effect of Spark Plasma Sintering on the Microstructure Evolution and Properties of M3:2 High-Speed Steel

2014 ◽  
Vol 788 ◽  
pp. 329-333
Author(s):  
Rui Zhou ◽  
Xiao Gang Diao ◽  
Jun Chen ◽  
Xiao Nan Du ◽  
Guo Ding Yuan ◽  
...  
Keyword(s):  
Powder Metallurgy ◽  
Spark Plasma Sintering ◽  
High Speed ◽  
Bending Strength ◽  
Sintering Temperature ◽  
High Speed Steel ◽  
Continuous Heating ◽  
Plasma Sintering ◽  
Spark Plasma ◽  
The Impact

Effects of sintering temperatures on the microstructure and mechanical performance of SPS M3:2 high speed steel prepared by spark plasma sintering was studied. High speed steel sintering curve of continuous heating from ambient temperature to 1200°C was estimated to analyze the sintering processes and sintering temperature range. The sintering temperature within this range was divided into groups to investigate hardness, relative density and microstructure of M3:2 high-speed steel. Strip and quadrate carbides were observed inside the equiaxed grains. SPS sintering temperature at 900°C can lead to nearly full densification with grain size smaller than 20μm. The hardness and bending strength are higher than that of the conventionally powder metallurgy fabricated ones sintered at 1270°C. However, fracture toughness of the high speed steel is lower than that of the conventional powder metallurgy steels. This can be attributed to the shape and distribution of M6C carbides which reduce the impact toughness of high speed steels.

Effect of Sintering Behavior on Microwave Properties of (Ca0.8Sr0.2)ZrO3 Ceramics for Resonators

2014 ◽  
Vol 787 ◽  
pp. 338-341
Author(s):  
Cheng Hsing Hsu ◽  
Chia Hao Chang ◽  
Wen Shiush Chen ◽  
Jenn Sen Lin ◽  
Chun Hung Lai
Keyword(s):  
Dielectric Constant ◽  
Sintering Temperature ◽  
Microwave Dielectric Properties ◽  
Sintering Behavior ◽  
Passive Components ◽  
Suitable Candidate ◽  
Solid State Route ◽  
Microwave Dielectric ◽  
Microwave Ceramic ◽  
Conventional Solid State Route

Microwave dielectric properties and microstructures of (Ca0.8Sr0.2)ZrO3 ceramics prepared by the conventional solid-state route have been studied. The values of the dielectric constant (εr) were 22-26. The Q×f values of 10400–11500 GHz were obtained when the sintering temperatures were in the range of 1400–1490°C. The temperature coefficient of the resonant frequency τf was not sensitive to the sintering temperature. The εr value of 26, the Q×f value of 11500 GHz, and the τf value of-9 ppm/°C were obtained for (Ca0.8Sr0.2)ZrO3 ceramics sintering at 1490°C. The ceramic, (Ca0.8Sr0.2)ZrO3 is proposed as a suitable candidate material for application in highly selective microwave ceramic passive components.

Flash-sintering of magnesium aluminate spinel (MgAl2O4) ceramics

2016 ◽  
Vol 100 (2) ◽  
pp. 554-562 ◽  
Author(s):  
Hidehiro Yoshida ◽  
Papiya Biswas ◽  
Roy Johnson ◽  
Mantravadi Krishna Mohan
Keyword(s):  
Magnesium Aluminate ◽  
Magnesium Aluminate Spinel ◽  
Flash Sintering ◽  
Spinel Mgal2o4

Sintering behavior and ionic conductivity of Li1.5Al0.5Ti1.5(PO4)3 synthesized with different precursors

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Bambar Davaasuren ◽  
Qianli Ma ◽  
Alexandra von der Heiden ◽  
Frank Tietz
Keyword(s):  
Grain Size ◽  
Solid State ◽  
Ionic Conductivity ◽  
Solid State Reaction ◽  
Sintering Temperature ◽  
Sintering Behavior ◽  
Homogeneous Microstructure ◽  
Micro Cracks ◽  
Primary Particles ◽  
Total Ionic Conductivity

Abstract Li1.5Al0.5Ti1.5(PO4)3 (LATP) powders were prepared from different NO x -free precursors using an aqueous-based solution-assisted solid-state reaction (SA-SSR). The sintering behavior, phase formation, microstructure and ionic conductivity of the powders were explored as a function of sintering temperature. The powders showed a relatively narrow temperature windows in which shrinkage occurred. Relative densities of 95% were reached upon heating between 900 and 960 °C. Depending on the morphological features of the primary particles, either homogeneous and intact microstructures with fine grains of about <2 µm in size or a broad grain size distribution, micro-cracks and grain cleavages were obtained, indicating the instability of the microstructure. Consequently, the ceramics with a homogeneous microstructure possessed a maximum total ionic conductivity of 0.67 mS cm−1, whereas other ceramics reached only 0.58 mS cm−1 and 0.21 mS cm−1.

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