Properties of Si3N4 Based Nanocomposites Prepared by Pressureless Sintering Method

2012 ◽  
Vol 532-533 ◽  
pp. 53-56
Author(s):  
Ming Li Li ◽  
Qiong Yu ◽  
Ying Xu ◽  
Qing Guo Lu ◽  
Chun Jiang Zhou
Keyword(s):  
Dielectric Properties ◽  
Xrd Analysis ◽  
Pressureless Sintering ◽  
Low Density ◽  
Sintering Process ◽  
X Ray Diffraction ◽  
X Ray ◽  
Main Crystalline Phase ◽  
Amorphous Si ◽  
Sintering Method

Si3N4 based nanocomposites were prepared with nano-sized amorphous SiO2 and Si3N4 powders by pressureless sintering method. The microstructures, phase composition, mechanical and dielectric properties of the nanocomposites were investigated. The scanning electrical microscope (SEM) photographs reveal that the grains are big and elongated. The X-ray diffraction (XRD) analysis shows that the main crystalline phase in the composites is Si2N2O formed during the sintering process. More β-Si3N4 phases were retained in the nanocomposites with the increase amount of the amorphous Si3N4 powders and no phase of SiO2 were observed. The densities and the strength of the nanocomposites decreased with the increase of amorphous SiO2 content. Despite low density, the flexural strengths of the composites reaches 220MPa and the ceramic has excellent dielectric properties with dielectric constant as low as 3.2-4.7 and dielectric loss in the range 2.6-3.9×10-3.

Li2ZnTi3O8 Microwave Dielectric Ceramics Prepared by the Reaction-Sintering Process

2015 ◽  
Vol 655 ◽  
pp. 164-167 ◽  
Author(s):  
Xu Sheng Hu ◽  
Guo Guang Yao ◽  
Xiu Lao Tian
Keyword(s):  
Dielectric Properties ◽  
Microwave Dielectric Properties ◽  
Reaction Sintering ◽  
Sintering Process ◽  
X Ray Diffraction ◽  
X Ray ◽  
Microwave Dielectric ◽  
Pure Phase ◽  
Dielectric Ceramics ◽  
Sintering Method

Li2ZnTi3O8ceramics were prepared by reaction-sintering process (calcination free). The crystal phase and microstructure were investigated using X-ray diffraction (XRD) and scanning electron microscopy (SEM). A pure phase of Li2ZnTi3O8ceramics sintered at 1075 °C-1150 °C with cubic spinel structure was confirmed by XRD. The microwave dielectric properties (εr,Qxf) of Li2ZnTi3O8ceramics were strongly dependent on the densification and grain size. The τfof Li2ZnTi3O8ceramics was almost independent with the sintering temperatures. In particular, Li2ZnTi3O8ceramics by reaction-sintering method sintered at 1125 °C for 5 h exhibited good combination microwave dielectric properties of εr=21.7, Q×f=70 500 GHz (at 7.5 GHz) and τf=-13 ppm/°C.

Preparation and Microstructure of Pressureless Sintered Si2ON2-SiC Ceramic

2011 ◽  
Vol 335-336 ◽  
pp. 699-703
Author(s):  
Hui Hui Tan ◽  
Zhu Xing Tang ◽  
Xia Zhao ◽  
He Zhang
Keyword(s):  
Bulk Density ◽  
Sintering Temperature ◽  
Pressureless Sintering ◽  
Nitriding Temperature ◽  
X Ray Diffraction ◽  
X Ray ◽  
Effect Of Additives ◽  
Sic Ceramic ◽  
Sintering Method ◽  
Scanning Electron

This paper introduces Si2ON2-SiC ceramic fabricated by pressureless sintering method and studies the effect of additives, nitriding temperatures on bulk density, porosity, phase composition and microstructure. It is discovered that additives MgO, CeO2 can increase the densities of Si2ON2-SiC ceramic apparently, and MgO additive has a better effect than CeO2. Nitriding temperature also is an important factor. The bulk density of the specimen with MgO additive reaches maximum at 1.91 g/cm3 when sintered at 1450 °C, and the bulk density of specimen with CeO2 additive is 1.86 g/cm3 at the same condition while the bulk density of the specimen without additive is only 1.75 g/cSuperscript textm3. The X-ray diffraction and scanning electron microscopy of the specimens show that the amount of Si2ON2 increase with the sintering temperature increase. But when the temperature is higher than 1500 °C the Si2ON2 grains will decompose into Si3N4, and Si2ON2 will vanish at 1550 °C

scholarly journals Effect of Sintering Temperature on Property of Low-Density Ceramic Proppant Adding Coal Gangue

2019 ◽  
Vol 26 (1) ◽  
pp. 94-98
Author(s):  
Jianying HAO ◽  
Huilan HAO ◽  
Yunfeng GAO ◽  
Xianjun LI ◽  
Mei QIN ◽  
...  
Keyword(s):  
Solid Waste ◽  
Bulk Density ◽  
Apparent Density ◽  
Sintering Temperature ◽  
Coal Gangue ◽  
Low Density ◽  
X Ray Diffraction ◽  
X Ray ◽  
Sintering Method ◽  
Waste Coal

Calcined flint clay (45.6 wt.% Al2O3) and solid waste coal gangue were used to prepare low-density ceramic proppant by solid state sintering method. The density and breakage ratio of the ceramic proppant were systematically investigated as a function of sintering temperature. The morphology and phase composition of the ceramic proppant were examined by scanning electron microscopy (SEM) and X-ray diffraction (XRD). The results show that the ceramic proppant is composed of rod-like mullite and granular cristobalite. Bulk density and apparent density of the proppant first rise and then slightly decrease with increasing the sintering temperature, while breakage ratios under 35 MPa and 52 MPa pressure gradually decrease and then increase. As the sintering temperature increases up to 1400 °C, the ceramic proppant shows denser microstructure. The proppant sintered at 1400 °C have the best performance with 1.27 g/cm3 of bulk density, 2.79 g/cm3 of apparent density, 3.27 % of breakage ratio under 35 MPa closed pressure and 8.36 % of breakage ratio under 52 MPa closed pressure, which conform to the requirement of low-density ceramic proppant. The addition of solid waste can greatly reduce the preparation cost of the ceramic proppant.

Dielectric Properties and Raman Spectroscopy in Ca-Substituted Na0.5Bi0.5TiO3 Ferroelectric Ceramics

2011 ◽  
Vol 324 ◽  
pp. 298-301 ◽  
Author(s):  
Roy Jean Roukos ◽  
Olivier Bidault ◽  
Julien Pansiot ◽  
Ludivine Minier ◽  
Lucien Saviot
Keyword(s):  
Raman Spectroscopy ◽  
Dielectric Properties ◽  
Room Temperature ◽  
Rhombohedral Phase ◽  
Xrd Analysis ◽  
Solid State Reaction Method ◽  
Ferroelectric Ceramics ◽  
Dielectric Measurements ◽  
X Ray Diffraction ◽  
X Ray

Lead free Na0.5Bi0.5TiO3 (NBT) and (Na0.5Bi0.5TiO3)1-x(CaTiO3)x (NBT-CT) piezoelectric ceramics with the perovskite structure were studied. The NBT and NBT-CT samples were synthesized using a solid-state reaction method and characterized with X-ray diffraction (XRD), Raman spectroscopy and dielectric measurements for several compositions (x = 0, 0.07, 0.15) at room temperature. The XRD analysis showed a stabilization of a rhombohedral phase at a low concentration of Ca (0 < x <0.15), whereas Raman spectra reveal a strong modification for the sample with x = 0.15. The dielectric properties of these ceramics were studied by measuring impedance in the 79-451K temperature range for unpoled and field cooling with an electric field (FC) conditions.

Effect of Process on the Dielectric Properties of BaTiO3-Based X9R Ceramics

2014 ◽  
Vol 906 ◽  
pp. 18-24 ◽  
Author(s):  
Bao Lin Zhang ◽  
Bin Bin Zhang ◽  
Ning Ning Wang ◽  
Jing Ming Fei
Keyword(s):  
Particle Size ◽  
Dielectric Properties ◽  
Milling Time ◽  
Sintering Temperature ◽  
Sintering Process ◽  
X Ray Diffraction ◽  
Sintered Ceramic ◽  
X Ray ◽  
Particle Size Analyzer

The effect of milling time and sintering process on the dielectric properties of BaTiO3-based X9R ceramics was investigated. The characterization of the raw powders and the sintered ceramic was carried out by X-ray diffraction and scanning electron microscopy. The particle size distribution of the mixed powders was examined by Laser Particle Size Analyzer. The results shown that with the milling time extended, the Cruie Peak was depressed, or even disappeared. Moreover, with the rise of sintering temperature, the dielectric constant of the ceramics increased and the dielectric loss decreased gradually. Eventually, by milling for 11h and sintering at 1090°Cfor 2h, good dielectric properties were obtained, which were ε25°C≥ 2526, εr/εr25°C≤± 12% (–55~200°C), tanδ≤1.12% (25°C).

Preparation and Microstructure of Bauxite Ceramic Microsphere

2007 ◽  
Vol 336-338 ◽  
pp. 1124-1126
Author(s):  
Xiao Su Cheng ◽  
Ling Ke Zeng ◽  
Xiu Yan Li ◽  
Wen Yan Sheng ◽  
An Ze Shui ◽  
...  
Keyword(s):  
Raw Materials ◽  
Xrd Analysis ◽  
Al2o3 Content ◽  
Molar Ratio ◽  
X Ray Diffraction ◽  
X Ray ◽  
Main Crystalline Phase ◽  
Ceramic Microsphere ◽  
Α Al2o3 ◽  
Chinese Bauxite

In this paper, microspheres were prepared by using Chinese bauxite as raw materials through centrifugal spray drying method. The microstructure and composition of ceramic microsphere were investigated by X-ray diffraction, scanning electron microscope and X-ray energy spectrum. The particle size was 10~100#m. The XRD analysis reveals that the main crystalline phase of the ceramic microsphere were α-Al2O3 and mullite (3Al2O3•2SiO2). The Al2O3 content (chemical composition) of the microspheres was little more than 70%, and the molar ratio of Al2O3/SiO2 was near to the molar ratio of alumina and silica of mullite.

scholarly journals Preparation and properties of CaO-Al2O3-SiO2 glass-ceramics by sintered frits particle from mining wastes

2014 ◽  
Vol 46 (3) ◽  
pp. 353-363 ◽  
Author(s):  
F. He ◽  
Y. Zheng ◽  
J. Xie
Keyword(s):  
Chemical Resistance ◽  
Glass Ceramics ◽  
Xrd Analysis ◽  
Mining Wastes ◽  
X Ray Diffraction ◽  
X Ray ◽  
Main Crystalline Phase ◽  
Fine Microstructure ◽  
Produce Glass ◽  
Gold Tailings

The paper reports on some experimental results obtained from the production of glass-ceramics containing gold tailings powder (GTP). Frits particle sintered technology was used to prepare glass ceramic products. SiO2, CaO, ZnO, BaO and B2O3 were selected to adjust the composition of the glass. Based on the results of differential thermal analysis (DTA), the nucleation and crystallization temperature of parent glass samples with different schedule were identified, respectively. X-ray diffraction (XRD) analysis of the produced glass-ceramics materials revealed that the main crystalline phase was ?-wollastonite. With the increasing of CaO content, the intensity of crystal diffractive peaks also increases. The formation of ?-wollastonite crystal could be accelerated by the increasing of CaO. The glass-ceramics with fine microstructure showed better physical, mechanical properties and chemical resistance. Overall results indicated that it was a feasible attempt to produce glass-ceramics for building and decorative materials from waste materials. The amount of GTP used in the glass batches was more than 65 wt% of the whole raw.

Synthesis of CuIn0.7Ga0.3Se2 Nanoparticles and its Quarternary Sputtering Target

2013 ◽  
Vol 483 ◽  
pp. 65-70 ◽  
Author(s):  
Jun Zhou ◽  
Fu Qing Zhang ◽  
Li Hong Xia
Keyword(s):  
Hot Pressing ◽  
Rotation Speed ◽  
Mixing Time ◽  
Pressureless Sintering ◽  
Sintering Process ◽  
X Ray Diffraction ◽  
Sputtering Deposition ◽  
X Ray ◽  
Cigs Nanoparticles ◽  
Scanning Electron

The chalcopyrite-type of CuIn0.7Ga0.3Se2 nanoparticle was successfully prepared by mechanical alloying method (MA). The phase of the obtained powder was analyzed by x-ray diffraction (XRD), and its microstructure was analyzed by scanning electron microscope (SEM) and transmission election microscope (TEM). Subsequently, the sintering process of CIGS quarternary target was investigated. The result suggests that only CuIn0.7Ga0.3Se2 phase exist in the powder with the rotation speed of 350 r/min and 2 hours mixing time by planetary ball milling. The particles were seriously agglomerated and the size of agglomerates was about 100 nm. Finally the as-made CIGS nanoparticles were used to fabricate CIGS target through both pressureless sintering and hot pressing methods. The hot pressing was fairly effective to increase the density of CIGS target. This fabricated target can be used for magnetron-sputtering deposition of CIGS absorbers.

Researched on Dielectric Properties of Alumina Substrate Material

2012 ◽  
Vol 502 ◽  
pp. 87-90
Author(s):  
Chen Jie Guo ◽  
Chang Song Zhang
Keyword(s):  
Dielectric Properties ◽  
Phase Distribution ◽  
Sintering Temperature ◽  
Matrix Material ◽  
Fracture Morphology ◽  
Substrate Material ◽  
X Ray Diffraction ◽  
X Ray ◽  
Main Crystalline Phase ◽  
Ceramic Sintering

In this paper, Al2O3-Bi2O3was choosed as chip fuse matrix material. Composition of Al2O3-Bi2O3ceramics samples in different sintering temperature was studied by X-ray diffraction, and dielectric properties of samples under different frequency was measured. The results show that the mixture of Bi2O3in Al2O3ceramics can improve the sintering activity of Al2O3ceramics, and thus greatly reduced the ceramic sintering temperature. It is concluded that the main crystalline phase is pure α-Al2O3without miscellaneous phase distribution. The distribution of fracture morphology is uniform without the existence of apparent stomatal, the dielectric constant and dielectric loss was studied.

scholarly journals Effect of Transition Metal on Structural and Dielectric Properties of Mg0.5Tm0.5Fe2O4 (Tm = Zn and Cu) System

2021 ◽  
Author(s):  
Pallavi Saxena ◽  
Anand Yadav
Keyword(s):  
Dielectric Constant ◽  
Dielectric Properties ◽  
Interfacial Polarization ◽  
Xrd Analysis ◽  
X Ray Diffraction ◽  
High Frequencies ◽  
X Ray ◽  
Cubic Structure ◽  
High Dielectric

This study explored the structural and dielectric features of Mg0.5Tm0.5Fe2O4 (Tm = Zn and Cu) that were synthesized by the Solid-state reaction (SSR) method. The X-ray powder diffraction (XRD) analysis reveals that the prepared samples are single-phase cubic structure without any impurity. Rietveld-refined X-ray diffraction results reveal the formation of cubic structure and all the peaks of Mg0.5Zn0.5Fe2O4 and Mg0.5Cu0.5Fe2O4 are perfectly indexed in the cubic (Fd-3 m) structure. Dielectric constant and dielectric loss variation with frequency were also explored. Both decrease when the relevant alternating field is increasing and become constant at high frequencies which reflects the important role of interfacial polarization. Furthermore, the Mg0.5Cu0.5Fe2O4 having the smallest crystallite size (~ 44.73 nm) has a high dielectric constant (~ 4.41 × 104) value as compare to Mg0.5Zn0.5Fe2O4.

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