Thermoelectric properties of bulk MoSi2 synthesized by solid state microwave heating

2016 ◽  
Vol 30 (19) ◽  
pp. 1650234 ◽  
Author(s):  
Yu Lan ◽  
Mianyu Xie ◽  
Ting Ouyang ◽  
Song Yue
Keyword(s):  
Solid State ◽  
Microwave Heating ◽  
Single Phase ◽  
Sintering Temperature ◽  
Seebeck Coefficients ◽  
Long Duration ◽  
Powder Factor ◽  
High Efficient ◽  
Different Temperatures ◽  
Precursor Powders

In this research, single phase [Formula: see text]-MoSi2 was prepared by solid state hybrid microwave heating within 90 min at relatively low temperature 1273 K. Such precursor powders were then ball milled and sintered by microwave heating at different temperatures. The thermoelectric (TE) properties of MoSi2 bulks were investigated in the temperature range of 300–673 K. When the sintering temperature increases from 973 K to 1273 K, the electrical resistivity decreases significantly and the Seebeck coefficients increase obviously, leading to the maximum TE powder factor of [Formula: see text] at 673 K. These results demonstrate the feasibility of high efficient and economical synthesis of MoSi2 by microwave heating technique, with the final products having comparable TE performance in comparison to those from typical methods with long duration and energy-extensive consumption.

Preparation and Thermoelectric Properties of LaCoO3 Ceramics

2010 ◽  
Vol 434-435 ◽  
pp. 404-408 ◽  
Author(s):  
Li Fu ◽  
Jing Feng Li
Keyword(s):  
Electrical Conductivity ◽  
Solid State ◽  
Thermoelectric Properties ◽  
Sintering Temperature ◽  
Conventional Solid State Reaction ◽  
Seebeck Coefficients ◽  
Different Temperatures ◽  
Higher Temperature ◽  
Increasing Temperature ◽  
Semiconducting Behavior

LaCoO3 ceramics were prepared by conventional solid state reaction and normal sintering at the temperatures ranging from 1373 to 1523 K. The sintered densities increased with increasing sintering temperature and exceeded 90 % of the theoretical values when sintered above 1473 K. The thermoelectric properties of the samples sintered at different temperatures were investigated from 323 to 673 K. The LaCoO3 samples showed a negative Seebeck coefficient, whose absolute values decreased dramatically with increasing temperature in the range of 323 to 460 K, then changed to a positive value and lightly decreased above 460 K. The electrical conductivity increased with increasing temperature, indicating a semiconducting behavior. The Seebeck coefficients showed little difference between the samples sintered at different temperatures, but the power factor of the sample sintered at a higher temperature was larger because of the higher electrical conductivity.

Preparation of Ultra–Fine La3NbO7 Powder by Solid State Reaction

2012 ◽  
Vol 512-515 ◽  
pp. 158-161 ◽  
Author(s):  
Ling Dai ◽  
Qiang Xu ◽  
Shi Zhen Zhu ◽  
Ling Liu
Keyword(s):  
Solid State ◽  
Solid State Reaction ◽  
Single Phase ◽  
Thermal Barrier ◽  
X Ray Diffraction ◽  
X Ray ◽  
Granular Particle ◽  
Fine Particle Size ◽  
Ultra Fine Particle ◽  
Different Temperatures

As a new candidate material for the ceramic layer in thermal barrier coatings (TBCs) system, La3NbO7 was synthesized with La2O3 powder and Nb2O5 powder by solid state reaction. The stating powders with a mole ratio of La to Nb of 3:1 were mixed and then the mixture was calcined under the different temperatures(800°C, 1000°C, 1200°C) and dwell times(2h, 6h, 10h). The phase structure of the powder was observed by X–ray diffraction(XRD), and the microstructure of the sample was observed by scanning electron microscope(SEM). The effect of calcination temperature and dwell Time on the phase formation were examined. The results indicate that the La3NbO7 powder with single phase can be synthesized successfully at 1200°C for 10h in air, and the La3NbOsub>7 powders synthesized have an ultra-fine particle size of 0.5˜1µm with a granular particle shape. With the temperature increasing, LaNbO4/sub> was synthesized firstly and then La3NbO7 was synthesized with a mole ratio of La2O3 to LaNbO4 of 1:1.

Characterization of NiTi Shape Memory Alloy Sintered at Different Temperatures in Reducing Environment

2020 ◽  
Vol 1010 ◽  
pp. 632-637
Author(s):  
Hafizah Hanim Mohd Zaki ◽  
Nur Azemuzahir Mohd Sobri ◽  
Jamaluddin Abdullah ◽  
Norshahida Sariffudin ◽  
Farah Diana Mohd Daud
Keyword(s):  
Solid State ◽  
Shape Memory ◽  
Phase Formation ◽  
Single Phase ◽  
Reducing Agent ◽  
Niti Shape Memory Alloy ◽  
Transformation Behavior ◽  
Formidable Challenge ◽  
Different Temperatures ◽  
Reducing Environment

NiTi has received significant interest as medical implant materials due to its shape memory effect behavior apart from its good biocompatibility and mechanical properties. The formidable challenge of obtaining single phase NiTi from elemental powders via solid state is due to oxidation problem of elemental powders and the oxygen atoms dissolve in NiTi matrix as interstitial impurities forming stable oxygen-rich TiNiOx. This may deterioriate the shape memory behavior of NiTi. This research investigates the use of MgH2 in combination with CaH2 as in-situ reducing agent to eliminate oxidation of the specimen during sintering both at lower and higher sintering temperatures. Here, the effect of sintering temperature on phase formation and transformation behavior of NiTi in reducing environment was studied. The phase formation was characterized by using x-ray diffraction (XRD) where the morphology and elemental analysis were characterized by using the scanning electron microscope (SEM) equipped with EDS. The martensitic transformation behavior was analyzed using differential scanning calorimeter (DSC). The use of MgH2 and CaH2 as reducing agent has a significant influence on the phase formation of NiTi synthesized via solid state especially at 930 °C, where almost single phase NiTi was formed with good transformation behavior. This reducing agent creates a conducive environment for the production of single phase NiTi.

Charactering and Sintering of BaZrO3 Doped with TiO2

2011 ◽  
Vol 492 ◽  
pp. 312-315
Author(s):  
Cheng Zhang ◽  
Na Zhang ◽  
Dan Yu Jiang ◽  
Ling Cong Fan
Keyword(s):  
Solid State ◽  
Single Phase ◽  
Sintering Temperature ◽  
Full Density ◽  
Solid State Chemistry ◽  
Sintered Ceramic ◽  
Sintering Aid ◽  
Ceramic Block ◽  
Pure Phase ◽  
Low Levels

The high sintering temperatures required for solid-state derived powders is a significant obstacle inhibiting more widespread use of single pure phase BaZrO3with high density. The aim of this research was to reduce the sintering temperature whilst maintaining pure single phase BaZrO3. By using of sintering aid, such as TiO2additive, the pure perovskite BaZrO3powder have been fabricated with the solid state chemistry at 1250°C. Low levels of TiO2(3%) produced the pure BaZrO3particles with the smallest size, and the corresponding sintered ceramic has the density of 95% theoretical using sintering temperature as low as 1550°C. The microstructure of the particular ceramic with full density confirmed that the particle grain in ceramic block have shaped with the less pore and connected thickly.

The Effect of Stoichiometry to the Phase Formation of Barium Titanate

2012 ◽  
Vol 620 ◽  
pp. 198-202 ◽  
Author(s):  
Meor Ahmad Faris ◽  
Cheow Keat Yeoh ◽  
W.M. Arif ◽  
Pei Leng Teh ◽  
Nadia Abdullah
Keyword(s):  
Titanium Dioxide ◽  
Solid State ◽  
Barium Titanate ◽  
High Purity ◽  
Single Phase ◽  
Sintering Temperature ◽  
Barium Carbonate ◽  
Secondary Phase ◽  
X Ray Diffraction ◽  
X Ray

This paper focus on the effect of different ratio between barium (Ba) and titanium (Ti) to the production of high purity of barium titanate (BT). On this research, the sample was prepared by solid-state reaction between barium carbonate (BaCO3) and titanium dioxide (TiO2) powder at constant sintering temperature of 1350 °C. The sample was prepared at different ratio of Ba:Ti which are 1:0.9, 1:0.95, 1:1, 1:1.05, 1:1.1. All sintered BT was characterized by X-ray diffraction (XRD). All existed phase on these samples was determined and analyzed. Sample from ratio 1:1 produced almost a single phase of BT. While; samples from other ratio produce secondary phase which is barium orthotitanate (Ba2TiO4).

Effect of Sintering Temperature on Properties of Multiferroic BaFe12O19/MgFe2O4/BaTiO3 Composites

2016 ◽  
Vol 846 ◽  
pp. 410-415
Author(s):  
M.F.A. Zolkepli ◽  
Rozidawati Awang ◽  
Zalita Zainuddin
Keyword(s):  
Grain Size ◽  
Solid State ◽  
Electrical Properties ◽  
Sintering Temperature ◽  
Xrd Analysis ◽  
Sem Analysis ◽  
Solid State Reaction Technique ◽  
Conventional Solid State Reaction ◽  
Different Temperatures ◽  
Tetragonal Batio

In this paper, the structural, magnetic and electrical properties of multiferroic BaFe12O19/MgFe2O4/BaTiO3 composites have been studied. BaFe12O19/MgFe2O4/BaTiO3 composites were synthesized by using the conventional solid state reaction technique and sintered at different temperatures. XRD analysis confirmed the existence of hexagonal BaFe12O19, cubic spinel MgFe2O4 and tetragonal BaTiO3 for ferrites and ferroelectric phases, respectively. The suitable sintering temperature for preparing BaFe12O19/MgFe2O4/BaTiO3 composites is between 1000 °C and 1050 °C. SEM analysis showed that as a whole the grain size increases and the pores is reduced with sintering temperature; thus the sample became denser. The coercive field and saturation magnetization decreases when sintering temperature is increased. Resistance of the samples decrease from 103 kW to 19 kW while the capacitance increases from 0.8 nF to 4.0 nF with sintering temperature.

scholarly journals Phase Analysis of Bio-Based Derived Tricalcium Disilicate From 2CaO:1SiO2 By X-ray Diffraction

2021 ◽  
Vol 2129 (1) ◽  
pp. 012054
Author(s):  
Siti Nur Hazwani Yunus ◽  
Khor Shing Fhan ◽  
Banjuraizah Johar ◽  
Nur Maizatul Shima Adzali ◽  
Nur Hazlinda Jakfar ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Rice Husk ◽  
Single Phase ◽  
Sintering Temperature ◽  
Rietveld Analysis ◽  
Dicalcium Silicate ◽  
X Ray Diffraction ◽  
X Ray ◽  
Different Temperatures ◽  
Complete Formation

Abstract In this paper, tricalcium disilicate was formed from dicalcium silicate compound powder, synthesised via a mechanochemical technique using a stoichiometric 2CaO:1SiO2. Compound CaO and SiO2 were derived from the bio-waste of eggshell and rice husk at the calcination temperature of 900°C and 800°C, respectively. The dicalcium disilicate powder was sintered for 2 hours at different temperatures ranging from 1150°C to 1350°C. Using X-ray diffraction with Rietveld analysis, it was found that the amount of tricalcium disilicate with monoclinic (beta) crystal structure increases on sintering temperature at the expense of dicalcium silicate. The complete formation of single-phase tricalcium disilicate began at a sintering temperature of 1300°C. The effect of sintering temperatures on the crystallisation and phase transition of dicalcium silicate is reported. The size of crystallites depends on the sintering temperature. The finding of this study rebound to the benefit of society by reducing the risk-off pollution cause by accessive redundant bio-waste eggshell and rice husk and also reduced the amount of CaO and SiO2 used in the fabrication of Ca3Si2O7.

Influence of Sintering Temperature on the Electrochemical Performance of Sm0.5-XGdxSr0.5Co 3-δ/Gd0.1Ce0.9O1.95 Composite Cathode

2011 ◽  
Vol 239-242 ◽  
pp. 1613-1616
Author(s):  
Ji Min Zhai ◽  
Xi Wen Song ◽  
Fen Zhou ◽  
Sheng Li An
Keyword(s):  
Solid State ◽  
Impedance Spectroscopy ◽  
Sintering Temperature ◽  
Perovskite Phase ◽  
Solid State Reaction Method ◽  
Composite Cathode ◽  
Reaction Method ◽  
Composite Cathodes ◽  
Different Temperatures ◽  
Alternative Current

In this paper, Sm0.5-xGdxSr0.5CoO3-δ(SGSC, x=0 and 0.2) powders were prepared using the solid-state reaction method. Their structure was identified by XRD. All powders formed the perovskite phase when calcined at 1100°C for 5 h. Sm0.3Gd0.2Sr0.5CoO3-δ/Gd0.1Ce0.9O1.95slurrieswere screen printed onto both surfaces of Gd0.1Ce0.9O1.95electrolyte and fired at different temperatures to fabricate the composite cathodes. The electrochemical property of the composite cathodes was characterized by the alternative current impedance spectroscopy. The impedance resistance of the composite cathodes increased with the increase of sintering temperature. For instance, the impedance resistance of the composite cathode fired at 1000 °C was 0.0875 Ω·cm2at 700 °C, while it was 0.175 Ω·cm2when fired at 1100 °C.

Characterization of Co-Cr-Mo (F-75) Alloy Produced by Solid State Sintering

2010 ◽  
Vol 173 ◽  
pp. 106-110
Author(s):  
Che Daud Zuraidawani ◽  
Shamsul Baharin Jamaludin ◽  
Md. Fazlul Bari
Keyword(s):  
Solid State ◽  
Bulk Density ◽  
Sintering Temperature ◽  
Linear Shrinkage ◽  
Optical Microscope ◽  
Grain Structure ◽  
Solid State Sintering ◽  
Different Temperatures ◽  
The Difference

This research was carried out to fabricate and characterize Co-Cr-Mo (F-75) alloy. The samples have been prepared via solid state sintering. The lab work comprises the mixing of F-75 alloy powder with 2 wt. % of binder. The mixture was cold compacted using uniaxially press at 500 MPa. The samples were sintered at three different temperatures (1250 °C, 1300 °C and 1350 °C) in inert environment for 90 minutes of sintering time. The sintered samples were characterized by using Scanning Electron Microscope (SEM), Energy Dispersive X-ray Spectroscopy (EDS) and optical microscope (OM) Olympus BX41M. Bulk density, apparent porosity, percentage of linear shrinkage, and microhardness of the samples were also characterized. The average of the grain sizes were measured by line intercepts method. The optical micrographs showed the difference grain size in all sintered samples after etching with Marble reagent. The result shows the percentage of linear shrinkage, bulk density value and porosity increase with increasing the sintering temperature. Beside that, higher sintering temperature yields coarser grain structure.

Preparation of PMZN Piezoceramic Using Sol-Autocombustion Synthesized PZT Powder as a Base

2007 ◽  
Vol 280-283 ◽  
pp. 219-222
Author(s):  
Hua Jun Sun ◽  
Wen Chen ◽  
Qing Xu ◽  
Jing Zhou ◽  
Xiao Fang Liu
Keyword(s):  
Solid State ◽  
Electrical Properties ◽  
Perovskite Structure ◽  
Piezoelectric Ceramic ◽  
Single Phase ◽  
Piezoelectric Properties ◽  
Sintering Temperature ◽  
Solid State Reaction Method ◽  
Reaction Method ◽  
Dielectric And Piezoelectric Properties

Using Zr(NO3)4.5H2O as Zr source, PZT powder with a single-phase perovskite structure was synthesized by a sol-autocombustion method at a calcining temperature of 700°C. Compared with a solid-state reaction method, the calcining temperature of PZT can be lowered by 200°C when using the sol-autocombustion method. PMZN ceramic was prepared at a sintering temperature of 1050°C with the resulting PZT powder as a base, which can lower the sintering temperature by 150°C. The microstructure of the PMZN ceramic was investigated by XRD and SEM, and the dielectric and piezoelectric properties were measured. The results showed that the PMZN piezoelectric ceramic has a tetragonal perovskite structure, showing the main electrical properties as follows: Kp = 0.54, Qm = 1073, tgd £ 0.001, e33 T/ e0 = 1236, d33 = 454pC/N, and fs =136.1KHz.

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