Comparative Study of Biomorphic Silicon/Silicon Carbide Ceramic from Birch and Compressed Birch

2010 ◽  
Vol 434-435 ◽  
pp. 609-612 ◽  
Author(s):  
Zi Li Yan ◽  
Jie Liu ◽  
Jian Chun Zhang ◽  
Tian Ma ◽  
Zheng Cao Li
Keyword(s):  
Silicon Carbide ◽  
Treatment Method ◽  
Compression Process ◽  
Silicon Carbide Ceramic ◽  
Sic Ceramics ◽  
Carbon Template ◽  
Wood Compression ◽  
Sic Ceramic ◽  
Pre Treatment ◽  
Silicon Silicon

Wood compression process was innovatively introduced as a pre-treatment method to birch into the fabrication of biomorphic silicon/silicon carbide (Si/SiC) ceramic with high density. Firstly, birch blocks were compressed to the density in the range of 0.85-1.00g/cm3. Secondly, both birch blocks and compressed birch blocks were carbonized at 1200°C to get carbon templates. Lastly, carbon templates were infiltrated with liquid silicon to obtain biomorphic Si/SiC ceramics. The effect of compression process on the density and microstructure of both carbon template and ceramic was investigated. The results show that the maxium density of biomorphic Si/SiC ceramic from compressed birch is 3.01g/cm3, whereas the density of the ceramic from birch is only 2.80-2.89g/cm3. So the compression process was an effective method to increase the density of biomorphic Si/SiC ceramic.

Fabrication of Foam-Type Porous Silicon Carbide without Cracks and Hollow Struts

2016 ◽  
Vol 369 ◽  
pp. 48-52
Author(s):  
Jeong Won Bang ◽  
Soo Ryong Kim ◽  
Young Hee Kim ◽  
Dong Geun Shin ◽  
Yoon Joo Lee ◽  
...  
Keyword(s):  
Silicon Carbide ◽  
Porous Silicon ◽  
Silicon Oxycarbide ◽  
X Ray Diffraction ◽  
Porous Silicon Carbide ◽  
Air Atmosphere ◽  
Sic Ceramics ◽  
Sic Ceramic ◽  
Curing Condition ◽  
Porous Sic

Foam-type porous silicon carbide (SiC) ceramics without cracks and hollow struts were fabricated using the polymer replica method with polycarbosilane (PCS) and polyurethane (PU) foam as the starting materials. The synthesized porous SiC was analyzed using X-ray diffraction and scanning electron microscopy. The results revealed that a porous SiC ceramic structure was formed with a dense framework at a low temperature of 1200°C. During the heat-treatment process, the PCS experienced an organic–inorganic transformation and then converted to the SiC ceramics. It was determined that the organic–inorganic transformation of PCS, which was the stage of silicon oxycarbide formation, is affected by the curing condition. In this study, the optimum curing condition was determined to be an air atmosphere at 200°C for 7 h.

Investigation of High-Speed Nanogrinding Mechanism Based on Molecular Dynamics

2018 ◽  
Author(s):  
Yao Liu ◽  
Beizhi Li ◽  
Yihao Zheng
Keyword(s):  
Molecular Dynamics ◽  
Silicon Carbide ◽  
Brittle Material ◽  
High Speed ◽  
Ground Surface ◽  
Wheel Speed ◽  
Depth Of Cut ◽  
Silicon Carbide Ceramic ◽  
Ductile Grinding ◽  
Sic Ceramic

The SiC ceramic ductile grinding, which can obtain crack-free ground surface, is a challenge in brittle material machining. To understand the brittle material ductile grinding mechanism in the nanoscale, a molecular dynamics (MD) model is built to study the single diamond grit grinding silicon carbide ceramic. Through analyzing the MD simulation process, the grit forces the SiC to deform and form the chip through the plastic deformation and flow. The ground surface has no crack on the surface and damage layer thickness is less than one atom layer under the nanoscale depth of cut, which indicates the nanogrinding can achieve the pure ductile grinding for the SiC ceramic and obtain a crack-free and high-quality ground surface. Grinding force, stress, temperature, and specific energy increase with the wheel speed and depth of cut due to the higher grinding speed and a smaller depth of cut can generate a higher density of defects (vacancies, interstitial atoms, and dislocations) on the workpiece, which can make the silicon carbide ceramic more ductile. The high wheel speed is favorable for the ductile grinding.

A STUDY ON THE ROLE OF SINTERING ADDITIVES FOR FABRICATION OF SIC CERAMIC

2010 ◽  
Vol 24 (15n16) ◽  
pp. 2928-2933 ◽  
Author(s):  
HAN KI YOON ◽  
YOUNG JU LEE ◽  
HO JUN CHO ◽  
TAE GYU KIM
Keyword(s):  
Silicon Carbide ◽  
Energy System ◽  
Eutectic Phase ◽  
Sintering Process ◽  
Sintering Additives ◽  
Sic Ceramics ◽  
Sic Ceramic ◽  
High Temperature Components ◽  
Phase Process

Silicon carbide ( SiC ) materials have been extensively studied for high temperature components in advanced energy system and advanced gas turbine. The SiC ceramics have been fabricated by a NITE (Nano Infiltration Transient Eutectic Phase) Process, using Nano- SiC powder. The sintering additives used for forming liquid phase under sintering process, used the sintering additives ratios were an Al 2 O 3- Y 2 O 3 system or add SiO 2 contents. A major R&D focus for the SiC ceramics is the production to obtain high purity SiC ceramics. In this study, we investigated roles of the sintering additives( Al 2 O 3: Y 2 O 3) to fabrication of the SiC ceramics. The effects of SiO 2 contents and density properties of the SiC ceramics were also investigated. To investigate the effects of SiO 2, Al 2 O 3/ Y 2 O 3 composition were fixed and then SiO 2 ratios were changed as several kinds, and to confirm the effects of sintering additives ratios ( Al 2 O 3: Y 2 O 3) they were changed between 4:6 and 6:4 in x wt.%.

Influence of Features of Silicon Carbide Ceramic Matrix Composite (Cp/SiC) on Carbon Content

2012 ◽  
Vol 512-515 ◽  
pp. 1639-1642 ◽  
Author(s):  
You Jun Lu ◽  
Yan Min Wang
Keyword(s):  
Silicon Carbide ◽  
Carbon Particle ◽  
Ceramic Matrix Composite ◽  
Mechanochemical Method ◽  
Resistant Material ◽  
Silicon Carbide Ceramic ◽  
Sic Ceramic ◽  
Sic Composites ◽  
Fire Resistant Material ◽  
Better Than

In this article, the properties of carbon particle modified silicon carbide (Cp/SiC) composites was studied. The mixture powder of nano carbon black and submicro-SiC was prepared through soft mechanochemical method. Then Cp/SiC composites was pressureless sintered.The result shows that appropriate content of carbon is 25 percent in this condition the machinability of Cp/SiC is better than that of SiC ceramic. At the same time, the oxidation resistence, wear resistence, and flexure strength of Cp/SiC meet the challenge for special fire resistant material.

The Effect of SiC Content on Pressureless Sintered Si2ON2-SiC Ceramic

2012 ◽  
Vol 562-564 ◽  
pp. 27-30
Author(s):  
Zhu Xing Tang ◽  
Hui Hui Tan ◽  
He Zhang ◽  
Ke Zhou Xu ◽  
Ying Zhang
Keyword(s):  
Silicon Carbide ◽  
Phase Composition ◽  
Silicon Oxynitride ◽  
Pressureless Sintering ◽  
Silicon Carbide Ceramic ◽  
Ceramic Samples ◽  
Sic Ceramic ◽  
Carbide Ceramics ◽  
Silicon Carbide Ceramics ◽  
Sintering Method

The Si¬2ON2-SiC ceramic was fabricated by pressureless sintering method. In this paper we researched the effect of SiC content (50%, 70% and 90%) on the performance of silicon oxynitride bonded silicon carbide ceramics. Through testing and analyzing the SEM, XRD, density and porosity of the final silicon oxynitride bonded silicon carbide ceramic samples, the results show that: changes in SiC content not only affect the bulk density of the composites but also affect the phase composition and the microstructure of fracture surface. The most compactness experimental product is sintered at1500°C containing 50wt% SiC.

Effect of Microstructure on Removal Mechanism of Solid State Sintered Silicon Carbide in Polishing Procedure

2010 ◽  
Vol 434-435 ◽  
pp. 21-23
Author(s):  
Jian Qin Gao ◽  
Zheng Ren Huang ◽  
Jian Chen ◽  
Gui Lin Liu ◽  
Xue Jian Liu
Keyword(s):  
Silicon Carbide ◽  
Solid State ◽  
Optical Materials ◽  
High Hardness ◽  
Pull Out ◽  
Sic Ceramics ◽  
Sic Ceramic ◽  
Mechanical Procedure ◽  
High Space ◽  
Sintered Silicon

Solid state sintered silicon carbide (S-SiC) ceramic is one of the top optical materials for high space reliability and other excellent properties. Two microstructures were produced by sintering under different conditions. The effects of microstructure on removal rates of SiC ceramics during polishing processes were studied. The material removal mechanisms during polishing were analysed and modeled. With the increase of the aspect ratio and grain diameter size during polishing, grain pull-out is more difficult in elongated grains than in exquiaxed grains. The SiC ceramic with high hardness has high removal resistance leading to get bad surface quality under the same mechanical procedure. The samples with elongated microstructure have low hardness and surface toughness.

EELS characterization of “Smut” layer films on steel surface prepared for chrome plating by anodic etching

1995 ◽  
Vol 53 ◽  
pp. 538-539
Author(s):  
E Y. Wang ◽  
J. T. Cherian ◽  
A. Madsen ◽  
R. M. Fisher
Keyword(s):  
Steel Surface ◽  
Surface Preparation ◽  
Treatment Method ◽  
Chrome Plating ◽  
Transmission Electron ◽  
Alloy Steels ◽  
Pre Treatment ◽  
Hard Chrome ◽  
Electron Energy Loss

Many steel parts are electro-plated with chromium to protect them against corrosion and to improve their wear-resistance. Good adhesion of the chrome plate to the steel surface, which is essential for long term durability of the part, is extremely dependent on surface preparation prior to plating. Recently, McDonnell Douglas developed a new pre-treatment method for chrome plating in which the steel is anodically etched in a sulfuric acid and hydrofluoric acid solution. On carbon steel surfaces, this anodic pre-treatment produces a dark, loosely adhering material that is commonly called the “smut” layer. On stainless steels and nickel alloys, the surface is only darkened by the anodic pre-treatment and little residue is produced. Anodic pre-treatment prior to hard chrome plating results in much better adherence to both carbon and alloy steels.We have characterized the anodic pre-treated steel surface and the resulting “smut” layer using various techniques including electron spectroscopy for chemical analysis (ESCA) on bulk samples and transmission electron microscopy (TEM) and electron energy-loss spectroscopy (EELS) on stripped films.

High thermal conductivity of pure dense SiC ceramics prepared via HTPVT

2019 ◽  
Vol 12 (03) ◽  
pp. 1950032 ◽  
Author(s):  
Yuchen Deng ◽  
Yaming Zhang ◽  
Nanlong Zhang ◽  
Qiang Zhi ◽  
Bo Wang ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Silicon Carbide ◽  
Grain Size ◽  
Phase Composition ◽  
Room Temperature ◽  
Vapor Transport ◽  
Physical Vapor Transport ◽  
Growth Substrate ◽  
Sic Ceramics ◽  
Evolution Of Microstructure

Pure dense silicon carbide (SiC) ceramics were obtained via the high-temperature physical vapor transport (HTPVT) method using graphite paper as the growth substrate. The phase composition, the evolution of microstructure, the thermal diffusivity and thermal conductivity at RT to 200∘C were investigated. The obtained samples had a relative density of higher than 98.7% and a large grain size of 1[Formula: see text]mm, the samples also had a room-temperature thermal conductivity of [Formula: see text] and with the temperature increased to 200∘C, the thermal conductivity still maintained at [Formula: see text].

Sign in / Sign up

Export Citation Format

Share Document