Preparation of TiB2 Ultrafine Powders by Carbothermal Reduction

2016 ◽  
Vol 697 ◽  
pp. 58-61
Author(s):  
Jin Cheng Yu ◽  
Li Ma ◽  
Yu Jun Zhang ◽  
Hong Yu Gong ◽  
Li Wei Zhou
Keyword(s):  
Carbon Black ◽  
Carbothermal Reduction ◽  
Reduction Method ◽  
Raw Materials ◽  
Structural Evolution ◽  
Holding Time ◽  
X Ray Diffraction ◽  
X Ray ◽  
Boron Source ◽  
Different Content

TiO2, B2O3, H3BO3, B4C and carbon black were used as the raw materials to prepare TiB2 powders by carbothermal reduction method. The influence of different content of carbon black (13.6~14.8 wt%) on products was discussed. The effects of different boron sources and holding time (10~50 min) on the microstructure of TiB2 powders were also investigated. X-ray diffraction (XRD) and scanning electron microscope (SEM) were used to study the phase composition and structural evolution of the powder. The final results showed that hexagonal TiB2 crystal grain could be successfully synthesized without impurities when heated at 1700°C for 30 min in Ar atmosphere with the addition of 14.1 wt% carbon black. Submicrometric TiB2 powders range from 0.5 to 1.0 μm could be obtained when B4C was used as the boron source. The increase in holding time contributed to the grain growth and completion of chemical reactions, but could also result in oversintering.

Reaction Mechanism of LiFePO4/C Cathode Materials Synthesized by Carbothermal Reduction Method

2010 ◽  
Vol 178 ◽  
pp. 248-253 ◽  
Author(s):  
Li Min Gao ◽  
Guang Chuan Liang ◽  
Li Wang ◽  
Xiao Ke Zhi ◽  
Xiao Fei Jie
Keyword(s):  
Carbothermal Reduction ◽  
Reduction Method ◽  
Intermediate Phase ◽  
Raw Materials ◽  
X Ray Diffraction ◽  
Thermo Gravimetric ◽  
X Ray ◽  
Reducing Atmosphere ◽  
Carbothermal Reduction Method ◽  
Lower Temperature

LiFePO4/C powders were synthesized by carbothermal reduction method using Li2CO3 (A.R), FePO4 (A.R) and glucose as raw materials. In this paper, the carbothermal reaction courses were characterized by Thermo-gravimetric (TG)/Differential Thermal Analysis (DTA), X-ray diffraction (XRD) and Fourier transform infrared (FTIR). It was found that the different synthesis temperatures and the different reducing atmosphere in systems could lead to different reactions, resulting in different final products and a direct impact on material performance. At around 350 °C LiFePO4 is directly formed without intermediate phase. In lower temperature of 400-500 °C, the sample included a certain amount of Li3PO4 and Fe2O3 impurity phases. When calcination temperature rose to 550 °C, the sample could be pure LiFePO4 phase.

Preparation of A14SiC4 by Solid-State Reaction

2011 ◽  
Vol 399-401 ◽  
pp. 817-821
Author(s):  
Xiao Hong Liu ◽  
Hui Wang ◽  
Ling Ke Zeng ◽  
Cheng Ji Deng
Keyword(s):  
Carbon Black ◽  
Raw Materials ◽  
Heating Temperature ◽  
Argon Atmosphere ◽  
Mass Ratio ◽  
X Ray Diffraction ◽  
X Ray ◽  
Higher Temperature ◽  
Flake Structure ◽  
Scanning Electron

In this paper, A14SiC4 was synthesized by using flint, aluminum and carbon black as raw materials，and they mass ratio was 28:50:22. The samples were fired at 1500°C、1600°C and 1700°C in an argon atmosphere. The phase compositions were determined by X-ray diffraction (XRD), the microstructures were examined by scanning electron microscope (SEM) and the elemental and quantitative compositions were determined by the energy dispersive X-ray spectroscopy (EDX). The results showed that the flint reacted with the carbon black, and produced Al2O3 and SiC firstly; meanwhile Al4C3 as intermediate product formed by the reaction between Al and C. Then a certain Al4C3 reacted with SiC, and produced A14SiC4; most Al4C3 reacted with the Al2O3, and produced Al4O4C at higher temperature. Subsequently, the Al4O4C and the SiC reacted with carbon black, and produced A14SiC4. The formed quantity of A14SiC4 increased as the heating temperature was raised, and crystal structure was the flake structure of 1-2μm thickness and about 10μm length. The formation mechanism of A14SiC4 was also discussed.

Growth and Morphology of β-Si3N4 Nano-Belts by Carbothermal Reduction Nitridation of Used Silica Refractory Brick

2012 ◽  
Vol 624 ◽  
pp. 1-4 ◽  
Author(s):  
Wen Juan Li ◽  
Zi He Pan ◽  
Zhao Hui Huang ◽  
Yan Gai Liu ◽  
Ming Hao Fang
Keyword(s):  
Cross Section ◽  
Carbothermal Reduction ◽  
Raw Materials ◽  
Carbon Powder ◽  
X Ray Diffraction ◽  
Refractory Brick ◽  
X Ray ◽  
Vs Mechanism ◽  
Energy Disperse Spectrum ◽  
Silica Refractory

Silicon nitride (β-Si3N4) nano-belts had been synthesized by used silica bricks and carbon powder as raw materials through carbothermal reduction nitridation. The morphology and microstructure of β-Si3N4 nano-belts were characterized by scanning electron microscopy (SEM/HRSEM), energy disperse spectrum (EDS) and X-ray diffraction (XRD). Results showed that the well-crystallized β-Si3N4 nano-beltes were grown with thinness of 50-150nm and width of 3-5μm. The relatively purer β-Si3N4 were prone to be thin films with thinness of 150nm, while the as-grown SiCN (impurityβ-Si3N4with C elements) were presented as nanorods with cross section length of 150*150nm. Orientation growth mechanism by grain dislocation and vapor-solid (VS) mechanism were both involved in the growth of nanostructures of β-Si3N4 nano-beltes and SiCN nanorods.

Formation of TiC-Reinforced Iron Based Composite through Carbothermal Reduction of Hematite and Anatase

2010 ◽  
Vol 173 ◽  
pp. 116-121
Author(s):  
Mohd Salihin Hassin ◽  
Zuhailawati Hussain ◽  
Palaniandy Samayamutthirian
Keyword(s):  
Carbothermal Reduction ◽  
Milling Time ◽  
Constant Pressure ◽  
Raw Materials ◽  
Anatase Tio2 ◽  
Vacuum Furnace ◽  
X Ray Diffraction ◽  
X Ray ◽  
Heat Treated ◽  
Hematite Fe2o3

In this research carbothermal reduction of mechanical activated hematite (Fe2O3), anatase (TiO2) and graphite (C) mixture was investigated. Mixture of raw materials with composition of Fe-20vol%TiC was mechanically activated in a planetary ball mill with different milling time (0h-60h) in argon atmosphere. X-ray diffraction (XRD) results showed the intensity of Fe2O3 reduced with milling time. The activated powders were pressed using cold pressing under a constant pressure (100MPa) and heat treated at 1100°C for sintering in a vacuum furnace. The increase in milling time resulted in the formation of iron (Fe) and titanium carbide (TiC) phase as confirmed by XRD result.

Synthesis of Al2OC Ceramic Powder by a Carbothermal Reduction Process

2014 ◽  
Vol 881-883 ◽  
pp. 1017-1020
Author(s):  
Shuang Shuang Ding ◽  
Peng Cui ◽  
Hong Xi Zhu ◽  
Cheng Ji Deng ◽  
Chao Yu
Keyword(s):  
Carbothermal Reduction ◽  
Raw Materials ◽  
Heating Temperature ◽  
Ceramic Powder ◽  
Reduction Process ◽  
Synthesis Temperature ◽  
X Ray Diffraction ◽  
X Ray ◽  
Argon Flow ◽  
Micro Morphology

A12OC ceramic powder was successfully synthesized via a carbothermal reduction method using Al2O3, B2O3 and activated carbon powders as raw materials. The effects of synthesis temperature on the phase transformation and micro-morphology of A12OC were investigated by means of X-ray diffraction (XRD) and scanning electron microscopy (SEM). The results indicated that the content of A12OC in the products was increased with the increasing heating temperature. The optimized process for preparing A12OC was heating the mixtures at 1700 °C for 2 h in argon flow. A12OC particles synthesized at 1700 °C were hexagon plate-like with thickness of 5 μm and size of about 50 μm. Keywords: A12OC, synthesis, microstructure

scholarly journals Preparation and Characterization of Hydroxyapatite by the precipitation method and heat treatment

2020 ◽  
Vol 9 (6) ◽  
pp. e172963549
Author(s):  
Fellype Diorgennes Cordeiro Gomes ◽  
Julia Didier Pedrosa de Amorim ◽  
Girlaine Santos da Silva ◽  
Karina Carvalho de Souza ◽  
Aline Ferreira Pinto ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Tooth Enamel ◽  
Raw Materials ◽  
Calcium Nitrate ◽  
Structural Evolution ◽  
Precipitation Method ◽  
X Ray Diffraction ◽  
X Ray ◽  
Human Bones

Hydroxyapatite is a synthetic substance in the form of microspheres composed of calcium and phosphate, present in human bones and tooth enamel. The objective of the work was to synthesize hydroxyapatite, from the solution of calcium nitrate and diamonic phosphate by the method of precipitation and heat treatment, obtaining the hydroxyapatite in powder form. To study its structural evolution, Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and Raman spectroscopy were used. The results show that the hydroxyapatite nanocrystalline can be successfully produced by the precipitation technique from raw materials.

Phase Behavior of Silica Brick Used in Carbothermal Reduction

2011 ◽  
Vol 492 ◽  
pp. 472-475 ◽  
Author(s):  
Zi He Pan ◽  
Zhao Hui Huang ◽  
Wen Juan Li ◽  
Yan Gai Liu ◽  
Ming Hao Fang
Keyword(s):  
Phase Composition ◽  
Carbon Content ◽  
Phase Behavior ◽  
Carbothermal Reduction ◽  
Reduction Method ◽  
Raw Materials ◽  
Holding Time ◽  
Silica Brick ◽  
Many Particles ◽  
Sem Analyses

In this study we observed the phase behavior of silica brick used in the process of carbothermal reduction. At 1550°C, there are liner β-SiC in clumps huddled together; At 1550°C, short line clumps changed into filamentous, mixed together. There are many particles and some β-SiC lines and few filamentous β-SiC at 1600°C . Different ratio of carbon coke also effect the phase behavior. From the results we obtained SiC powders. SiC refractory powders were prepared via carbothermal reduction method using used silica bricks as raw materials. The effects of carbon content, temperature and holding time on the phase composition and microstructure were analyzed. XRD and SEM analyses show that: β-SiC refractory powders were synthesized at 1600°C for 6 h with100 wt% excessive of carbon content. With the increase of carbon content, the reaction temperature and holding time, content of β-SiC gradually increased while that of cristobalite decreased.

The Synthesis of TiC Powders by Carbothermal Reduction Method in Vacuum

2014 ◽  
Vol 1064 ◽  
pp. 62-65
Author(s):  
Xue Tan Ren ◽  
Yan Chun Liu ◽  
Shui Hui Chen ◽  
Lai Guang Hou ◽  
Guo Long Wang ◽  
...  
Keyword(s):  
Carbon Black ◽  
Crystalline Phase ◽  
Carbothermal Reduction ◽  
Single Phase ◽  
Reduction Method ◽  
Raw Materials ◽  
Molar Ratio ◽  
Carbothermal Reduction Method ◽  
System Pressure

The TiC powders were synthesized by carbothermal reduction of TiO2in vacuum using the titania and carbon black as raw materials. The molar ratio of C to TiO2was 3:1. The crystalline phase, microstructure and morphology of the obtained samples were investigated by XRD and SEM. The results show that single-phase and well-crystallized TiC powders were obtained at 1300°C for 1h when the system pressure was 20 Pa. The particle morphologies are composed of fine grains about 200 nm.

Microstructures and Thermophysical Properties of Polymer Derived SiC/C Composites

2012 ◽  
Vol 152-154 ◽  
pp. 86-90
Author(s):  
Xiao Yi Han ◽  
Hai Feng Cheng ◽  
Xin Xing ◽  
Jun Wang
Keyword(s):  
Thermal Conductivity ◽  
Raw Materials ◽  
Holding Time ◽  
X Ray Diffraction ◽  
X Ray ◽  
Low Thermal Conductivity ◽  
Sic Ceramics ◽  
Transmission Electron ◽  
Thermal Diffusivities ◽  
Hot Press Sintering

Polymer derived SiC ceramics usually present a relatively low thermal conductivity for the large porosity and complex phases. In order to obtain condensed SiC ceramic with low thermal conductivity, a preceramic precursor polycarbosilane (PCS) was selected as the raw materials. And hot press sintering processes were performed at 1600 °C under Ar atmosphere with the holding time in the range of 20 to 40 min for consolidation. The microstructures and phases were analyzed by scanning electron microscopy (SEM) with energy disperse X-ray spectroscopy (EDS), X-ray diffraction (XRD) and high-resolution transmission electron microscope (HRTEM). The specific heat, thermal diffusivities and thermal conductivities were measured and investigated from room temperature to 650 °C. A minimum thermal conductivity of 4.13 W•m-1•K-1 was obtained at 650 °C with a holding time of 30 min.

EFFECTS OF DIFFERENT CARBON SOURCES ON PROPERTIES OF LiFePO4/C BY A CARBOTHERMAL REDUCTION METHOD

2010 ◽  
Vol 03 (03) ◽  
pp. 155-160 ◽  
Author(s):  
NING HUA ◽  
LIUMING SUO ◽  
CHENYUN WANG ◽  
YING HAN ◽  
XUEYA KANG
Keyword(s):  
Electron Microscopy ◽  
Carbothermal Reduction ◽  
Reduction Method ◽  
Carbon Sources ◽  
X Ray Diffraction ◽  
X Ray ◽  
Carbothermal Reduction Method ◽  
Excellent Electrochemical Performance ◽  
Rate Capacity ◽  
Mean Molecular Weight

The LiFePO 4/ C composite was prepared by carbothermal reduction method (CTR) with FePO 4 ⋅ 2 H 2 O , Li 2 CO 3 as starting materials, and acetylene black or polyethylene glycol (PEG; mean molecular weight of 10,000) as carbon sources. The structural and electrochemical properties were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmittance electron microscopy (TEM), and charge–discharge tests. The results showed that LiFePO 4/ C is olivine-type phase, and the addition of carbon reduced the LiFePO 4 grain size with uniform distribution. The carbon is dispersed between the grains, forming a good electronic contact. The synthesized LiFePO 4 composites showed excellent electrochemical performance with initial discharge capacity of 161, 142 and 96 mAh ⋅ g-1 at 0.1 C, 1 C and 5 C, respectively and displays a robust rate capacity and stable cycling life.

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