Microstructure Changes of Beta Alumina Sintering at Lower Temperature

2013 ◽  
Vol 456 ◽  
pp. 517-520
Author(s):  
Hua Li ◽  
Jia Chun Lu ◽  
Guang Yu Cheng ◽  
Yang Ni Zhu ◽  
Xin Biao Jiang
Keyword(s):  
Sintering Temperature ◽  
Precursor Powder ◽  
Phase Content ◽  
Microstructure Changes ◽  
Powder Particles ◽  
Lower Temperature ◽  
Beta Alumina

Changes in the microstructure and phase content of beta alumina near the lowest possible β-Al2O3 to β-Al2O3 transform temperature were investigated through varying sintering temperature. Obvious microstructure varieties were observed in stabilized β/β alumina specimens following extended sintering treatments. The results show that there is a slightly lower temperature of 1150°C for nanometer precursor powder particles to transform into grains and for β-Al2O3 to convert into β-Al2O3.

The Phase Evolution in the Si3N4-AlN System after High-Energy Mechanical Treatment of the Precursor Powder

2008 ◽  
Vol 403 ◽  
pp. 7-10 ◽  
Author(s):  
Malgorzata Sopicka-Lizer ◽  
Tomasz Pawlik ◽  
Tomasz Włodek ◽  
Marta Tańcula
Keyword(s):  
Structural Changes ◽  
Mechanical Energy ◽  
Phase Evolution ◽  
High Energy ◽  
Precursor Powder ◽  
Standard Mixture ◽  
High Energy Milling ◽  
Significant Damage ◽  
Powder Particles ◽  
Lower Temperature

The high-energy milling uses the mechanical energy to activate chemical reactions by developing structural changes in the powder particles. High-energy milling with an acceleration of 28g was applied for the mechanical activation of the aluminium and silicon nitrides mixture with yttria additive. The activated powders showed the significant damage of the crystal structure and limited formation of a solid solution. Sintering of the activated precursor demonstrated higher ability for densification and started at 300 °C lower temperature in comparison to the standard mixture. The phase evolution during sintering was dependent on the starting composition and degree of powder activation.

Spark plasma sintering of Nd–Fe–B magnetic alloy

1999 ◽  
Vol 14 (6) ◽  
pp. 2540-2547 ◽  
Author(s):  
Z. G. Liu ◽  
M. Umemoto ◽  
S. Hirosawa ◽  
H. Kanekiyo
Keyword(s):  
Magnetic Properties ◽  
Grain Growth ◽  
Spark Plasma Sintering ◽  
Sintering Temperature ◽  
Magnetic Alloy ◽  
Plasma Sintering ◽  
Spark Plasma ◽  
Powder Particles ◽  
Lower Temperature

Spark plasma sintering was used to consolidate the crystallized Nd–Fe–B alloy powders. It was found that a higher sintering temperature can improve the consolidation significantly, whereas it deteriorates the magnetic properties drastically due to the appearance of a large amount of α–Fe phase and the grain growth. Sintering at lower temperature can preserve the magnetic properties better, while the powders cannot be consolidated into a fully dense compact, even under the higher pressure of 75 MPa. Finer starting powder particles show similar behavior.

scholarly journals Transport and Dielectric Properties of Mechanosynthesized La2/3Cu3Ti4O12 Ceramics

Crystals ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 313
Author(s):  
Mohamad M. Ahmad ◽  
Hicham Mahfoz Kotb ◽  
Celin Joseph ◽  
Shalendra Kumar ◽  
Adil Alshoaibi
Keyword(s):  
Dielectric Constant ◽  
Sintering Temperature ◽  
Cubic Phase ◽  
X Ray Diffraction ◽  
Boundary Conductivity ◽  
X Ray ◽  
Giant Dielectric ◽  
Mechanochemical Milling ◽  
Giant Dielectric Constant ◽  
Lower Temperature

La2/3Cu3Ti4O12 (LCTO) powder has been synthesized by the mechanochemical milling technique. The pelletized powder was conventionally sintered for 10 h at a temperature range of 975–1025 °C, which is a lower temperature process compared to the standard solid-state reaction. X-ray diffraction analysis revealed a cubic phase for the current LCTO ceramics. The grain size of the sintered ceramics was found to increase from 1.5 ± 0.5 to 2.3 ± 0.5 μm with an increase in sintering temperature from 975 to 1025 °C. The impedance results show that the grain conductivity is more than three orders of magnitude larger than the grain boundary conductivity for LCTO ceramics. All the samples showed a giant dielectric constant (1.7 × 103–3.4 × 103) and dielectric loss (0.09–0.17) at 300 K and 10 kHz. The giant dielectric constant of the current samples was attributed to the effect of internal barrier layer capacitances due to their electrically inhomogeneous structure.

scholarly journals Effect of Sintering Temperature on Microstructure and Mechanical Properties of Hot-Pressed Fe/FeAl2O4 Composite

Crystals ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 422
Author(s):  
Kuai Zhang ◽  
Yungang Li ◽  
Hongyan Yan ◽  
Chuang Wang ◽  
Hui Li ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Bending Strength ◽  
Sintering Temperature ◽  
Raw Materials ◽  
Hot Press ◽  
Microstructure And Mechanical Properties ◽  
Powder Particles ◽  
Hot Press Sintering ◽  
Sintering Method

An Fe/FeAl2O4 composite was prepared with Fe-Fe2O3-Al2O3 powder by a hot press sintering method. The mass ratio was 6:1:2, sintering pressure was 30 MPa, and holding time was 120 min. The raw materials for the powder particles were respectively 1 µm (Fe), 0.5 µm (Fe2O3), and 1 µm (Al2O3) in diameter. The effect of sintering temperature on the microstructure and mechanical properties of Fe/FeAl2O4 composite was studied. The results showed that Fe/FeAl2O4 composite was formed by in situ reaction at 1300 °C–1500 °C. With the increased sintering temperature, the microstructure and mechanical properties of the Fe/FeAl2O4 composite showed a change law that initially became better and then became worse. The best microstructure and optimal mechanical properties were obtained at 1400 °C. At this temperature, the grain size of Fe and FeAl2O4 phases in Fe/FeAl2O4 composite was uniform, the relative density was 96.7%, and the Vickers hardness and bending strength were 1.88 GPa and 280.0 MPa, respectively. The wettability between Fe and FeAl2O4 was enhanced with increased sintering temperature. And then the densification process was accelerated. Finally, the microstructure and mechanical properties of the Fe/FeAl2O4 composite were improved.

A Dramatic Reduction in the Sintering Temperature of the Refractory Sodium β’’-Alumina Solid Electrolyte via Cold Sintering

2021 ◽  
Author(s):  
Zane A. Grady ◽  
Arnaud Ndayishimiye ◽  
Clive A Randall
Keyword(s):  
Solid State ◽  
Solid Electrolyte ◽  
Sintering Temperature ◽  
Sodium Ion ◽  
Dramatic Reduction ◽  
Sintering Process ◽  
Sodium Beta Alumina ◽  
Beta Alumina

The cold sintering process is successfully applied to one of the most refractory solid-state sodium-ion electrolytes, namely sodium beta alumina (SBA). By using a hydroxide-based transient solvent, SBA is densified...

Aspects about Sintering Behaviour of a Titanium Hydride Powder Based Alloy Used for Automotive Components

2016 ◽  
Vol 823 ◽  
pp. 467-472
Author(s):  
Cristina Ileana Pascu ◽  
Stefan Gheorghe ◽  
Ilie Dumitru ◽  
Claudiu Nicolicescu
Keyword(s):  
Automotive Industry ◽  
Sintering Temperature ◽  
Low Cost ◽  
Test Results ◽  
Automotive Components ◽  
Titanium Hydride Powder ◽  
Powder Particles ◽  
Sintering Behaviour ◽  
High Originality ◽  
Hydride Powder

For this study with high originality, some aspects about the sintering behaviour of Titanium based alloy used for automotive components are presented. This paper presents the experimental results concerning the processing of Ti based alloy by Powder Metallurgy (PM) technology. The initial powder mixture consists in TiH2 micrometric powder particles that have been combined with some metallic powders for improving the final mechanic-chemicals and functional properties for using in the automotive industry. The classical PM route have been applied for obtaining a low-cost Ti- alloy.As a result it was compulsory to study the parameters that influence the densification process and the sintered properties, depending on the sintering temperature. The experimental test results were processed using the STATISTICA program. Therefore the influence of these sintering temperatures on the height and diameter shrinkages, density and hardness for the alloys based on Ti micrometric powders has been studied.

Cu/GDC Cermet Anodes by Sintering via Surface Modification with MgO Sol

2007 ◽  
Vol 544-545 ◽  
pp. 953-956
Author(s):  
Kyoung Ran Han ◽  
Youn Ji Jeong ◽  
Chang Sam Kim ◽  
Hai Won Lee
Keyword(s):  
Surface Modification ◽  
Copper Oxide ◽  
Composite Powder ◽  
Sintering Temperature ◽  
Electronic Conductivity ◽  
Molten Copper ◽  
Uniform Microstructure ◽  
Fabrication Procedure ◽  
Lower Temperature ◽  
Oxide Melts

CuO/GDC composite powder with 50 wt% of CuO was prepared by surface modification of ~60 nm GDC powder with Cu precursors. Since copper oxide melts at lower temperature than GDC sintering temperature, fabrication procedure was modified by inducing infiltration of molten copper oxide via capillary force and then followed by heat treatment at ~1000. Surface modification was carried out with a MgO sol to suppress agglomeration of GDC. Such prepared Cu/GDC cermets showed uniform microstructure and excellent electronic conductivity of ~8500 S/cm for the Cu/GDC cermet and ~10200 S/cm for the modified one at 800.

Explorative Synthesis of Magnetic Ca-Fe-O Compounds by Mixing Precipitated CaCO3 from Limestone and Iron Sand Extracted – Fe2O3.H2O

2015 ◽  
Vol 827 ◽  
pp. 203-207 ◽  
Author(s):  
Mastuki ◽  
Malik Anjelh Baqiya ◽  
Darminto
Keyword(s):  
Calcium Carbonate ◽  
Sintering Temperature ◽  
Raw Material ◽  
Phase Content ◽  
Precipitated Calcium Carbonate ◽  
Mixing Method

Synthesis of Ca-Fe-O using solution mixing method employing CaCO3 and Fe2O3•H2O has been conducted. Extraction of limestone as the raw material of precipitated calcium carbonate (PCC) and iron sands as that of Fe2O3•H2O was prepared to explore various compound of C-Fe-O, where the CaFe4O7 phase is mainly expected. The PCC and Fe2O3•H2O each are dissolved in 1 M HNO3 and mixed to be most homogeneous. The results of the synthesis are characterized by DTA/GTA and then sintered at temperatures of 800°C, 900°C and 1000°C.The sintered samples were characterized by XRD, FTIR, and VSM. The sintering temperature at 800°C, 900°C and 1000°C gave result the phase content of CaFe4O7 being respectively 55.42%, 44.55% and 36.39%. Other major phases in the Ca-Fe-O samples consist of Ca2Fe9O13 and Ca4Fe14O25. The remanence value of the corresponding samples is 2.11, 1.28, and 1.74 emu/g respectively.

Densification of Sr-Mg Doped SiAlONs with GPS and SPS

2007 ◽  
Vol 554 ◽  
pp. 95-100 ◽  
Author(s):  
S. Kurama ◽  
Mathias Herrmann
Keyword(s):  
Mechanical Properties ◽  
Sintering Temperature ◽  
Phase 1 ◽  
Densification Process ◽  
Plasma Sintering ◽  
Spark Plasma ◽  
Lower Temperature ◽  
The Stability ◽  
Thermal Stability Of ◽  
Mg Doped

At temperature above 1200°C, the thermal stability of α-SiAlON phases has been debated since 1992; however, it has been discussed if any α-SiAlON phase can be formed in Ce, La, Eu and Sr-doped SiAlON systems. In our previous studies it was shown that the use of Mg-Ce and Mg-Sr elements as dopants SiAlON compositions, in which all elements just have very low or no stability in the α-SiAlON structure, would promote the stability of Mg-Ce elements in the α- SiAlON phase [1, 2]. However, in Mg-Sr systems, it was obtained that Mg2+ is predominantly incorporated in α-SiAlON structure whereas Sr2+ mainly remains in the grain boundaries [2]. In this study, by applying spark plasma sintering (SPS) (at 1400-1700°C) and post-sintering thermal heat treatment (at 1500°C for 5 hrs and 1700°C for 2hrs) Mg or Mg-Sr doped SiAlON (50:50 mole ratios) ceramics were prepared. The results were compared with GPS sintered samples data. The effect of sintering temperature on densification process, phase transformation, microstructure and mechanical properties of samples were investigated. The results showed that by using SPS, Sr-Mg doped samples can be sintered at lower temperature (at 1600°C) than at GPS (at 1800°C) and it has no Sr-doped grain boundary phases.

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