Synthesis of a Metallic Ceramic -Ti3SiC2 by PDS Process and its Properties

2002 ◽  
Vol 755 ◽  
Author(s):  
ZhengMing Sun ◽  
Hitoshi Hashimoto ◽  
ZheFeng Zhang ◽  
SongLang Yang ◽  
Toshihiko Abe
Keyword(s):  
Thermal Conductivity ◽  
Plastic Deformation ◽  
Room Temperature ◽  
Single Phase ◽  
Sintering Temperature ◽  
Pulse Discharge ◽  
Mechanical Tests ◽  
The Other ◽  
Powder Mixtures ◽  
Comparable Performance

ABSTRACTPowder mixtures of Ti/Si/C, Ti/SiC/C, Ti/Si/TiC, Ti/SiC/TiC and Ti/TiSi2/TiC were used for the synthesis of Ti3SiC2 by using a pulse discharge sintering (PDS) process. The Ti/Si/TiC powder was found to be the best among the five powder mixtures for the Ti3SiC2 synthesis. The highest content of Ti3SiC2 can be improved to about 99wt% at the sintering temperature of 1300°C for 15 minutes. The relative density of all the synthesized samples is higher than 98–99% at the sintering temperature above 1275°C. The nearly single phase Ti3SiC2 was found to show plastic deformation at room temperature and a good machinability. Both electrical and thermal conductivity were found to be more than two times of the value of a control pure Ti sample. The high-temperature mechanical tests confirmed that the Ti3SiC2 samples synthesized by the PDS process displayed a comparable performance with those fabricated by the other techniques.

Effect of Al Additions on the Synthesis of Single-Phase Ti3SiC2

2004 ◽  
Vol 848 ◽  
Author(s):  
ZhengMing Sun ◽  
Songlan Yang ◽  
Hitoshi Hashimoto ◽  
Michel W. Barsoum
Keyword(s):  
Single Phase ◽  
Sintering Temperature ◽  
Pulse Discharge ◽  
Optimal Temperature ◽  
Powder Mixtures ◽  
Temperature Range ◽  
Optimal Temperature Range ◽  
Al Addition ◽  
Al Additions

ABSTRACTPowder mixtures of 3Ti/SiC/C/xAl with different Al contents (x=0∼0.2) were reactively sintered by pulse discharge sintering (PDS) process, to reveal the effect of Al addition on the single-phase bulk Ti3SiC2 synthesis. It was found that the optimal sintering temperature for the Ti3SiC2 synthesis is greatly decreased by the Al addition. Almost single-phase bulk Ti3SiC2 material can be synthesized from 3Ti/SiC/C/0.15Al and 3Ti/SiC/C/0.20Al powder mixtures at temperature as low as 1200°C for 15 min by PDS. And the optimal temperature range for the Ti3SiC2 formation is enlarged obviously by the Al addition.

Electron microscope studies of the plastic deformation of ternary alloys based on GaAs

1990 ◽  
Vol 48 (4) ◽  
pp. 1120-1120
Author(s):  
R. Haswell ◽  
U. Bangert ◽  
P. Charsley
Keyword(s):  
Plastic Deformation ◽  
Electron Microscope ◽  
Room Temperature ◽  
Stacking Faults ◽  
The Other ◽  
Ternary Alloys ◽  
Dislocation Mobility ◽  
Semiconducting Materials ◽  
Micro Indentation

A knowledge of the behaviour of dislocations in semiconducting materials is essential to the understanding of devices which use them . This work is concerned with dislocations in alloys related to the semiconductor GaAs . Previous work on GaAs has shown that microtwinning occurs on one of the <110> rosette arms after indentation in preference to the other . We have shown that the effect of replacing some of the Ga atoms by Al results in microtwinning in both of the rosette arms.In the work to be reported dislocations in specimens of different compositions of Gax Al(1-x) As and Gax In(1-x) As have been studied by using micro indentation on a (001) face at room temperature . A range of electron microscope techniques have been used to investigate the type of dislocations and stacking faults/microtwins in the rosette arms , which are parallel to the [110] and [10] , as a function of composition for both alloys . Under certain conditions microtwinning occurs in both directions . This will be discussed in terms of the dislocation mobility.

The Observations on Faulted Dipoles in Deformed Tial—Based Alloys

1994 ◽  
Vol 364 ◽  
Author(s):  
Y. Gao ◽  
J. Zhu ◽  
Q. G. Cai
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Plastic Deformation ◽  
Low Temperature ◽  
Deformation Temperature ◽  
Room Temperature ◽  
Single Phase ◽  
Deformation Structure ◽  
Partial Dislocations ◽  
Transmission Electron

AbstractThe deformation structure of polycrystalline TiAl-based alloys after uniaxial compression at temperature range from 77K to 1073K has been examined using transmission electron microscopy. It was observed that a large number of faulted dipoles are commonly present in deformation structure of the alloys compressed at low temperature 77K and room temperature. The nature of the faulted dipoles has been determined to be intrinsic stacking fault lying on {111} plane, bounded by 1/6<112] partial dislocations. A possible mechanism for the formation of the faulted dipoles was suggested. The results of the statistic observation shows that faulted dipoles in deformed Ti-48A1 and Ti-(47–48) Al-X (X = V,Cr,Mn) alloys are less than those in single phase Ti-52A1 alloy, and the number of the faulted dipoles decreases with increasing deformation temperature. The effect of the faulted dipoles on plastic deformation of the alloy was discussed.

Thermoelectric Properties of Bi2Te3-Sb2Te3 Compounds Prepared by Ma-Pulse Discharge Sintering Process

1999 ◽  
Vol 581 ◽  
Author(s):  
R.E. Park ◽  
Y.H. Park ◽  
T. Abe
Keyword(s):  
Thermal Conductivity ◽  
Electrical Resistivity ◽  
Mechanical Alloying ◽  
Figure Of Merit ◽  
Room Temperature ◽  
Pulse Discharge ◽  
Sintering Process ◽  
Mechanically Alloyed ◽  
Fine Grain ◽  
Process Effects

ABSTRACTThe Bi2Te3-Sb2Te3 compounds with the composition of useful thermoelectric cooling materials were prepared by mechanical alloying-pulse discharge sintering process. Effects of the process on the Seebeck coefficient, electrical resistivity and thermal conductivity were investigated. Temperature dependence of the Hall coefficient was also observed in the temperature range 80 - 325 K.The figure of merit, Z, was found to be about 4.0 × 10−1K−1 at room temperature in the 25%Bi2Te3-75%Sb2Te3 composition sintered at 618K using grain refined mechanically alloyed powders which had the size of under 32 μm. The value of Z was remarkably improved with a decrease of the thermal conductivity shown in the fine grain compacts fabricated by mechanical alloying-pulse discharge sintering process.

Thermophysical Properties of Germanium for Thermal Analysis of Growth from the Melt

1981 ◽  
Vol 9 ◽  
Author(s):  
Roger K. Crouch ◽  
A. L. Fripp ◽  
W. J. Debnam ◽  
R. E. Taylor ◽  
H. Groot
Keyword(s):  
Thermal Conductivity ◽  
Thermal Analysis ◽  
Thermal Diffusivity ◽  
Specific Heat ◽  
Thermophysical Properties ◽  
Room Temperature ◽  
Bridgman Method ◽  
The Other ◽  
Temperature Range ◽  
Diffusivity Measurements

ABSTRACTThe thermal diffusivity of Ge has been measured over a temperature range from 300° C to 1010° C which includes values for the melt. Specific heat has been measured from room temperature to 727° C. Thermal conductivity has been calculated over the same temperature range as the diffusivity measurements. These data are reported along with the best values from the literature for the other parameters which are required to calculate the temperature and convective fields for the growth of germanium by the Bridgman method. These parameters include the specific heat, the viscosity, the emissivity, and the density as a function of temperature.

Effects of 0.03MF2 – 0.12LiF (M = Ca, Sr, Ba) on the Sintering and Dielectric Properties of SrTiO3 Ceramics

2013 ◽  
Vol 9 ◽  
pp. 1-12
Author(s):  
Laldja Taïbi-Benziada ◽  
Hassiba Kermoun ◽  
Yasmina Belaroussi
Keyword(s):  
Room Temperature ◽  
Single Phase ◽  
Sintering Temperature ◽  
Cubic Phase ◽  
Frequency Range ◽  
X Ray Diffraction ◽  
X Ray ◽  
Frequency Independent ◽  
Cold Pressed ◽  
Piezoelectric Devices

Cold-pressed pellets were prepared from the mixtures SrTiO3- 0.03MF2- 0.12LiF, M = Ca, Sr or Ba, then air-fired at 950 °C for 2 hours. The obtained samples were investigated by X-ray diffraction and scanning electron microscopy. Each ceramic is a perovskite single phase and the relative density reaches 95% for all ceramics. The addition of 3 mol. % of the eutectic composition 1MF2- 4LiF (Tm~ 760 °C) to SrTiO3lowers the sintering temperature of pure strontium titanate from 1400 °C to 950 °C and induces a strong modification in the SrTiO3cubic phase: superlattice reflections are detected and the unit cell symmetry becomes orthorhombic. Dielectric measurements were performed between - 150 °C and 200 °C in the frequency range 20 Hz - 109Hz. The dielectric permittivity εrshowed no maximum in the temperature range investigated and is almost frequency independent. At room temperature, the dielectric losses tanδ are less than 0.1 %. Moreover, the frequency dependence of the complex permittivity exhibits a resonance in the microwave region. These fluorinated ceramics could be of interest in piezoelectric devices and are promising dielectrics for class I capacitors manufactured at low temperature.

Lead Free CaTiO3-Based Ceramics: Sintering, Phase Transitions and Dielectric Properties

2010 ◽  
Vol 636-637 ◽  
pp. 111-118 ◽  
Author(s):  
Laldja Taïbi-Benziada ◽  
Samira Nemouchi
Keyword(s):  
Phase Transitions ◽  
Room Temperature ◽  
Composition Range ◽  
Sintering Temperature ◽  
Nominal Composition ◽  
Chemical Compositions ◽  
Dielectric Measurements ◽  
Powder Mixtures ◽  
Frequency Peak ◽  
Quantum Paraelectric

Various chemical compositions (1-x)CaTiO3+xMgF2+xLiF were prepared and dry-ground. The powder mixtures were pressed to pellets and co-fired at 900°C for 2h. The obtained ceramics were investigated by XRD, SEM, DSC and dielectric measurements. A new solid solution with nominal composition Ca1-xMgx(Ti1-xLix)O3-3xF3x occurred in the initial composition range 0 ≤ x ≤ 0.25. The fluoride additive MgF2+LiF lowered significantly the sintering temperature of pure CaTiO3. Above room temperature, one or two second order phase transitions were detected by DSC and confirmed by dielectric measurements. Moreover, below room temperature, a frequency peak dependent on the permittivity and losses was observed and the quantum paraelectric behaviour of CaTiO3 disappeared with increasing x. These oxifluorides could be of interest for electronic applications.

Fabrication and Properties of AlN/CNT Composite Ceramics

2012 ◽  
Vol 512-515 ◽  
pp. 898-901 ◽  
Author(s):  
Hai Long Liang ◽  
Yong Li Li ◽  
Jie Tang ◽  
Hai Lin Liu ◽  
Yan Li Huo ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Composite Material ◽  
Structural Damage ◽  
Single Phase ◽  
Sintering Temperature ◽  
Sintering Process ◽  
Densification Process ◽  
Composite Ceramics ◽  
Volume Fractions ◽  
Spark Plasma

High thermal conductivity and dense AlN/CNT composite ceramics with additive Y2O3 were fabricated by spark plasma sintered (SPS) in this paper. The results indicated that CNT blocked the densification process in a certain extent, but in the sintering temperature of 1700°C, the relative density of composite ceramics were more than 97% with 1-10% volume fractions of CNT. The content of additive Y2O3 affected the thermal conductivity of AlN/CNT obviously. The thermal conductivity of composite material linearly decreased when the content of CNT increased and the tubular structure of CNT had been destructed during once sintering. The effects of the CNT structural damage to the thermal conductivity of composite ceramics were improved by adjusting the sintering process. The thermal conductivity of the composite ceramics with 3% volume fractions of CNT sintering in 1550°C/3min×3 was up to 145W/m•K, which higher than the single-phase AlN ceramics.

Dielectric Properties of Y2NiMnO6 Ceramics at Various Sintering Times and Temperatures

2015 ◽  
Vol 804 ◽  
pp. 16-20 ◽  
Author(s):  
Panakamon Deeyai ◽  
Thanapong Sareein ◽  
Bundit Putasaeng ◽  
Naphat Chathirat
Keyword(s):  
Dielectric Properties ◽  
Dielectric Loss ◽  
Dielectric Permittivity ◽  
Room Temperature ◽  
Sintering Temperature ◽  
Dielectric Constants ◽  
The Other ◽  
Other Hand ◽  
Low Sintering Temperature ◽  
Sintering Conditions

Dielectric properties of hydrothermally decomposed Y2NiMnO6 ceramics prepared under several sintering conditions were investigated at room temperature. As the results, dielectric constants at 200 Hz were found about 928 and 23x103 for samples sintered at 1000 and 1400 oC, respectively. The dielectric permittivity for samples sintered at 1400 oC for different sintering times from 6 to 24 hours have yielded the best dielectric permittivity value of 104. On the other hand, low sintering temperature had resulted in smaller dielectric loss in comparison to larger dielectric loss generally found in the ceramics with high sintering temperature.

High-Temperature Thermoelectric Properties of Silicon Boride Ceramics as a Smart Material

1999 ◽  
Vol 604 ◽  
Author(s):  
Noriyuki Takashima ◽  
Yasuo Azuma ◽  
Jun-Ichi Matsushita
Keyword(s):  
Thermal Conductivity ◽  
Electrical Conductivity ◽  
High Temperature ◽  
Seebeck Coefficient ◽  
Relative Density ◽  
Thermoelectric Properties ◽  
Room Temperature ◽  
Sintering Temperature ◽  
Smart Material ◽  
Increasing Temperature

AbstractSeveral silicon boride phases such as SiB4, SiB6, SiB6-x, SiB6+x, and Si11B31, were previously reported. Among them, SiB6has proved to be a potentially useful material because of its excellent electrical conductivity, high degree of hardness, moderate melting point, and low specific gravity. The sintering conditions and thermoelectric properties of silicon boride (SiB6) ceramics produced by hot pressing were investigated in order to determine the suitability of this material for high-temperature thermoelectric applications as a smart material. The relative density increased with increasing sintering temperature. With a sintering temperature of 1923 K, a sintered body having a relative density of more than 99% was obtained. X-ray diffraction analysis showed no crystalline phase other than SiB6 in the sintered body. The specimens were prepared for measurement of the electrical conductivity and Seebeck coefficient by the D.C. four-terminal method. The thermal conductivity of SiB6 was obtained by calculation from the thermal diffusivity and specific heat capacity of the specimen. The electrical conductivity of SiB6 increased with increasing temperature. The electrical conductivity of the polycrystalline SiB6 (99% dense) was 0.5 to 1.1 × 103 S/m at 298 to 1273 K. The thermal conductivity decreased with increasing temperature in the range of room temperature to 1273 K. The thermal conductivity was 9.1 to 2.5 W/mK in the range of room temperature to 1273 K. The Seebeck coefficient of SiB6 increased with increasing temperature. The Seebeck coefficient of SiB6 was 140 × 10−6 V/K at 1273 K. The figure of merit Z of SiB6 increased with increasing temperature. The Z of SiB6 reached 8.1 × 10−6/K at 1273 K. The ZT value is useful to evaluate the ability of thermoelectric materials. The ZT value reached 0.01 at 1273 K. Based on the results, SiB6 showed very good thermoelectric material characteristics at high temperature.

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