Microwave Sintered Porous Mullite Composite

2012 ◽  
Vol 512-515 ◽  
pp. 382-385
Author(s):  
Xu Qin Li ◽  
Xin Zhang ◽  
Rui Zhang ◽  
Bing Bing Fan
Keyword(s):  
Grain Growth ◽  
Microwave Plasma ◽  
Microwave Sintering ◽  
Xrd Analysis ◽  
High Energy ◽  
Volume Density ◽  
X Ray Diffraction ◽  
Porous Mullite ◽  
Lower Temperature ◽  
Porosity Detection

In order to aviod much high energy and CO2 generation. Microwave sintering (MS) is always carried out to prepare refractory. In this work，MS was proposed to sinter mullite composite. An insulation structure based on hybrid heating mode was well designed with the wall of high-aluminum refractory and the aided heaters of SiC. The sintered samples under different sintering processing were characterized by appearent porosity detection and volume density. Phase composition was investigated by X-ray Diffraction (XRD) analysis. Surface and fracture Flied Emission Scanning Electron Microscopy (FESEM) was applied to observe pore distribution and grain growth. Sintering profile was provided in this work. It was found that mullite composite could be prepared within 1h at relative lower temperature around 1300°C. Compared with samples prepared by convitional sintering (CS), MS samples presented better densification and more uniform grain growth. Microwave plasma phenomena was explored inside MS samples, however, not found in CS ones.

Microstructure Evolution of a Fine Grain Al-50wt%Si Alloy Fabricated by High Energy Milling

2011 ◽  
Vol 479 ◽  
pp. 54-61 ◽  
Author(s):  
Fei Wang ◽  
Ya Ping Wang
Keyword(s):  
Grain Growth ◽  
Microstructure Evolution ◽  
Room Temperature ◽  
Milling Time ◽  
High Energy ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Laser Method ◽  
X Ray ◽  
Fine Grain

Microstructure evolution of high energy milled Al-50wt%Si alloy during heat treatment at different temperature was studied. Scanning electron microscope (SEM) and X-ray diffraction (XRD) results show that the size of the alloy powders decreased with increasing milling time. The observable coarsening of Si particles was not seen below 730°C in the high energy milled alloy, whereas, for the alloy prepared by mixed Al and Si powders, the grain growth occurred at 660°C. The activation energy for the grain growth of Si particles in the high energy milled alloy was determined as about 244 kJ/mol by the differential scanning calorimetry (DSC) data analysis. The size of Si particles in the hot pressed Al-50wt%Si alloy prepared by high energy milled powders was 5-30 m at 700°C, which was significantly reduced compared to that of the original Si powders. Thermal diffusivity of the hot pressed Al-50wt%Si alloy was 55 mm2/s at room temperature which was obtained by laser method.

Bone Formation in Non-Osseous Tissues of Biphasic HA/β-TCP Bioceramics Sintered by Different Ways

2007 ◽  
Vol 336-338 ◽  
pp. 1666-1669 ◽  
Author(s):  
Jun Guo Ran ◽  
Li Gou ◽  
Bao Hui Su ◽  
Fang Hu Wang ◽  
Lu Wei Sun ◽  
...  
Keyword(s):  
Bone Formation ◽  
Body Fluid ◽  
Microwave Plasma ◽  
Microwave Sintering ◽  
Apatite Formation ◽  
Conventional Furnace ◽  
Plasma Sintering ◽  
Higher Temperature ◽  
Healthy Dogs ◽  
Lower Temperature

In order to improve the bioactivity of calcium phosphate bioceramics, biphasic HA/β-TCP (BCP) bioceramics were prepared by the microwave sintering and the microwave plasma sintering. Bone-like apatite formation of the resulting samples was investigated in simulated body fluid (SBF). The samples were also implanted in dorsal muscles of healthy dogs for 1.5and 3 months. All samples after taking out were examined by histological observation. Bone formation in different sintering ways and temperatures was investigated in details. Better osteoinductivity was found in samples sintered by the microwave and microwave plasma instead of the conventional furnace, as well as by lower temperature (1050 oC) instead of higher temperature (1150 oC). It accounts for that the increase in degradability of materials sintered by microwave and microwave plasma or lower temperature leads to the better of bone-like apatite formation and bone formation due to fine grains and lower crystallinity.

Bi-Based Superconducting Multilayers Obtained by Molecular Beam Epitaxy

1999 ◽  
Vol 13 (09n10) ◽  
pp. 991-996
Author(s):  
M. Salvato ◽  
C. Attanasio ◽  
G. Carbone ◽  
T. Di Luccio ◽  
S. L. Prischepa ◽  
...  
Keyword(s):  
Molecular Beam Epitaxy ◽  
Molecular Beam ◽  
Xrd Analysis ◽  
High Energy ◽  
X Ray Diffraction ◽  
One Dimensional ◽  
X Ray ◽  
Diffraction Model ◽  
Different Thickness

High temperature superconducting multilayers have been obtained depositing Bi2Sr2CuO6+δ(2201) and ACuO2 layers, where A is Ca or Sr, by Molecular Beam Epitaxy (MBE) on MgO and SrTiO3 substrates. The samples, formed by a sequence of 2201/ACuO2 bilayers, have different thickness of ACuO2 layers while the thickness of the 2201 layers is kept constant. The surface structure of each layer has been monitored by in situ Reflection High Energy Electron Diffraction (RHEED) analysis which has confirmed a 2D nucleation growth. X-ray diffraction (XRD) analysis has been used to confirm that the layered structure has been obtained. Moreover, one-dimensional X-ray kinematic diffraction model has been developed to interpret the experimental data and to estimate the period of the multilayers. Resistive measurements have shown that the electrical properties of the samples strongly depend on the thickness of the ACuO2 layers.

Variation of Tungsten Oxide Reduction Mode Using Different High Energy Milling Conditions

2012 ◽  
Vol 727-728 ◽  
pp. 206-209
Author(s):  
Osvaldo Mitsuyuki Cintho ◽  
H.I. Tsai ◽  
M. Bär ◽  
M. de Castro ◽  
E.F. Monlevade ◽  
...  
Keyword(s):  
Tungsten Oxide ◽  
Milling Time ◽  
Xrd Analysis ◽  
High Energy ◽  
Oxide Reduction ◽  
X Ray Diffraction ◽  
X Ray ◽  
Energy Ball ◽  
Fast Increase ◽  
Stoichiometric Proportion

High energy ball milling has been used like alternative route for processing of materials. In the present paper, the reduction of tungsten oxide by aluminum in order to obtain metallic tungsten was studied using a SPEX type high energy mill. A powdered mixture of WO3and metallic aluminum, weighed according to the stoichiometric proportion with an excess 10% Al, was processed with hardened steel utensils using a 1:6 powder-to-ball ratio. The processing was carried out with milling jar temperature measurement in order to detect the reaction type. The temperature evaluation indicated the self-propagating reaction occurrence by fast increase of the jar temperature after a short milling time. The tungsten oxide reduction was verified by X-Ray Diffraction (XRD) analysis and the milling products were characterized by Scanning Electron Microscopy (SEM). The results were slightly different from the literature due to the mill type and milling parameters used in the work.

Synthesis of Ultrafine MgAl2O4 Powders by Nitrate-Citrate Sol-Gel Combustion Process

2008 ◽  
Vol 368-372 ◽  
pp. 407-408
Author(s):  
Long Chen ◽  
Qi Zhang ◽  
Wen Ping Chen ◽  
Yao Gang Li ◽  
Yan Mo Chen ◽  
...  
Keyword(s):  
Sol Gel ◽  
Combustion Process ◽  
Xrd Analysis ◽  
Transmission Electron Microscopy Image ◽  
Solid State Reactions ◽  
X Ray Diffraction ◽  
Transmission Electron ◽  
Microscopy Image ◽  
Gel Combustion ◽  
Lower Temperature

Ultrafine MgAl2O4 powders were synthesized by a nitrate-citrate sol-gel combustion process using Al(NO3)3·9H2O, Mg(NO3)2·6H2O and C6H8O7·H2O as initial materials. The result of X-ray diffraction (XRD) analysis indicated that single-phase MgAl2O4 powder could be obtained at 850 oC, which is much lower than that needed in solid-state reactions. Transmission electron microscopy image showed that the as-prepared powder was in the nano scale and little agglomerate exited. It is concluded that this process need shorter time, lower temperature, and simple equipments.

Aluminothermic Reduction of Niobium Pentoxide in a Hydrogen Plasma Furnace

2006 ◽  
Vol 514-516 ◽  
pp. 599-603
Author(s):  
Marcio W.D. Mendes ◽  
António Carlos P. Santos ◽  
Francisca de Fatima P. Medeiros ◽  
Clodomiro Alves Jr. ◽  
A.G.P. Silva ◽  
...  
Keyword(s):  
Hydrogen Plasma ◽  
Xrd Analysis ◽  
High Energy ◽  
Steel Tube ◽  
Aluminothermic Reduction ◽  
Powder Layer ◽  
Stainless Steel Tube ◽  
Reaction Products ◽  
X Ray Diffraction ◽  
New Process

The aluminothermic reduction is a highly exothermal reaction between a metal oxide and aluminium. Conventionally this reaction is ignited by an electric resistance and the reaction products after cooling are in the form of a rigid block of mixed metal and aluminium oxide. In this work a new process of aluminothermic reduction is presented, in which the reaction is ignited by a hydrogen plasma. The niobium oxide and aluminium powders are high energy milled for six hours to form particles constituted of oxide and aluminum. Stoichiometric, substoichiometric and superstoichiometric mixtures were prepared. The mixture was placed in a stainless steel tube (the hollow cathode) inside the reactor chamber. The chamber was firstly evacuated. Then hydrogen at low pressure was introduced. In the following an electric discharge between the cathode and the anode localized just above the cathode ignites the plasma. The plasma heats the particles on the surface of the powder layer and starts the reaction that proceeds in each particle since the reactants are intimately mixed. The heat generated by the reaction propagates deeper in the layer until the whole mixture reacts. Substoichiometric mixtures can be used because hydrogen takes part of the reduction. The Nb2O5 – Al starting powder mixture and the products of the reaction are characterized by laser grain size measurement and X-Ray diffraction (XRD). The products are in form of powder or agglomerates of particles. Phases of reaction products was determined by XRD analysis and the particle size trough SEM.

Reaction Process of Al-TiO2-C-Ti-Fe Multiphase System during Combustion Synthesis

2007 ◽  
Vol 336-338 ◽  
pp. 2340-2343 ◽  
Author(s):  
Song He Meng ◽  
Xing Hong Zhang ◽  
Wei Feng Zhang
Keyword(s):  
Intermetallic Compounds ◽  
Xrd Analysis ◽  
Reaction Process ◽  
Multiphase System ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Reaction Characteristics ◽  
Lower Temperature ◽  
Kinetics Of

The reaction process and kinetics of Al-TiO2-C-Ti-Fe system were investigated by differential scanning calorimetry (DSC) analysis, X-ray diffraction (XRD) analysis and scanning electron microscope (SEM). In order to obtain the information of reaction process for complicated system, the reaction characteristics of Al-TiO2, Al-TiO2-C and Al-TiO2-C-Ti systems are explored firstly. The results show that the reaction process varies with temperature in Al-TiO2-C-Ti-Fe system. At the lower temperature, the dominating reaction in Al-TiO2-C-Ti-Fe system is that between Al and Ti, Al and Fe, and so TiAlx, FeAlx, and Ti2Fe intermetallic compounds form. With the temperature increasing, the intermetallic compounds are decomposed. Then the decomposed Ti and Al react with C and TiO2 respectively and the stable TiC, Al2O3 and Fe three phases form in the final product.

scholarly journals Phase Transformation and Microstructure Characterization of Ceramic Porcelain with Different Ratio of Treated Fgd Sludge/Feldspar

2021 ◽  
Vol 2129 (1) ◽  
pp. 012092
Author(s):  
Suffi Irni Alias ◽  
Banjuraizah Johar ◽  
Syed Nuzul Fadzli Adam ◽  
Mustaffa Ali Azhar Taib ◽  
Fatin Fatini Othman ◽  
...  
Keyword(s):  
Differential Scanning Calorimetry ◽  
Xrd Analysis ◽  
High Energy ◽  
Hydraulic Press ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Sludge Waste ◽  
Main Component

Abstract The porcelain formulation containing percentages of treated FGD sludge waste from 5% up to 15% in replacement of feldspar were prepared. The porcelain mixture formulation were mixed by high energy planatery mill at speed 300 rpm for 1 hours. The powder were compacted by using hydraulic press and sintered at temperature 1200 °C for 3 hours. The sintered samples were characterized using X-ray fluorescene (XRF), X-ray diffraction (XRD), Fourier Transform Infrared (FTIR) and Thermogravimetry/Differential scanning calorimetry (TGA/DCS). The primary effect concerning the addition of treated FGD sludge was the change of intensity composition (gypsum and anhydrate) in porcelain formulation. The XRD analysis has shown that the main component in sludge waste were gypsum and anhydrate.

Synthesis and Characterization of Fe-Based Nanocomposites

2019 ◽  
Vol 22 ◽  
pp. 39-47 ◽  
Author(s):  
Fadhéla Otmane ◽  
Salim Triaa ◽  
A. Maali ◽  
B. Rekioua
Keyword(s):  
Epoxy Resin ◽  
Loss Factor ◽  
Morphological Changes ◽  
Structural Parameters ◽  
Xrd Analysis ◽  
High Energy ◽  
Scattering Parameters ◽  
X Ray Diffraction ◽  
Average Grain Size

This study reports on the elaboration and characterization of bulk nanocomposites samples obtained by dispersion of metallic powders at the nanoscale as reinforcements in a polymer matrix. Elemental Fe powders were successfully nanostructured via high-energy ball milling. Structural characterization of the produced powders was conducted using X-Ray Diffraction (XRD) analysis and Scanning Electron Microscopy (SEM). The Halder-Wagner approach was adopted to determine the powder’s average grain size, internal strain, lattice parameters and the mixing factors. Structural parameters evolution and morphological changes according to milling progression are discussed. Bulk nanocomposites samples were shaped in a home moulder by dispersion of coarse Fe and nanostructured Fe powders in a continuous matrix of commercial epoxy resin. The obtained bulk samples match the metallic X-band wave-guide WR-90 dimensions used for electromagnetic characterization. The two-port Sij scattering parameters were measured via an Agilent 8791 ES network analyzer. The measured scattering parameters served to calculate the loss factor of samples and to extract the dielectric permittivity via the Nicholson-Ross-Weir conversion. Spectra evolution of the scattering parameters, the loss factor and the dielectric constant for epoxy resin with coarse Fe and nanostructured Fe reinforcements are commented.

scholarly journals Mg2+ Doping Effects on the Structural and Dielectric Properties of CaCu3Ti4O12 Ceramics Obtained by Mechanochemical Synthesis

Materials ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1187
Author(s):  
Piotr Dulian ◽  
Wojciech Bąk ◽  
Mateusz Piz ◽  
Barbara Garbarz-Glos ◽  
Olena V. Sachuk ◽  
...  
Keyword(s):  
Dielectric Properties ◽  
Solid Solutions ◽  
Xrd Analysis ◽  
High Energy ◽  
Ion Concentration ◽  
Dielectric Study ◽  
X Ray Diffraction ◽  
Sintering Time ◽  
Doping Effects ◽  
Ball Milling Technique

In this study, ceramic CaCu3Ti4O12 (CCTO) and CaCu3−xMgxTi4O12 solid solutions in which 0.1 ≤ x ≤ 0.5 were prepared by the mechanochemical method, realized by a high-energy ball milling technique. The effects of the Mg2+ ion concentration and sintering time on the dielectric response in the prepared ceramics were investigated and discussed. It was demonstrated that, by the use of a sufficiently high energy of mechanochemical treatment, it is possible to produce a crystalline product after only 2 h of milling the mixture of the oxide substrates. Both the addition of magnesium ions and the longer sintering time of the mechanochemically-produced ceramics cause excessive grain growth and significantly affect the dielectric properties of the materials. The X-ray diffraction (XRD) analysis showed that all of the as-prepared solid solutions, CaCu3−xMgxTi4O12 (0.0 ≤ x ≤ 0.5), regardless of the sintering time, exhibit a cubic perovskite single phase. The dielectric study showed two major contributions associated with the grains and the grain boundaries. The analysis of the electric modules of these ceramics confirmed the occurrence of Maxwell–Wagner type relaxation, which is dependent on the temperature.

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