The effect of carbon on surface quality of solid-state-sintered silicon carbide as optical materials

2014 ◽  
Vol 89 ◽  
pp. 7-12 ◽  
Author(s):  
Jian Chen ◽  
Zhengren Huang ◽  
Zhongming Chen ◽  
Ming Yuan ◽  
Yan Liu ◽  
...  
Keyword(s):  
Silicon Carbide ◽  
Solid State ◽  
Surface Quality ◽  
Optical Materials ◽  
Sintered Silicon

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.

Influence of Carbon Content on Surface Quality of Solid-State Sintered SiC Ceramics

2012 ◽  
Vol 9 (4) ◽  
pp. 847-852 ◽  
Author(s):  
Jianqin Gao ◽  
Jian Chen ◽  
Guiling Liu ◽  
Yongjie Yan ◽  
Zhengren Huang
Keyword(s):  
Solid State ◽  
Carbon Content ◽  
Surface Quality ◽  
Sic Ceramics

Effects of Electricity Parameters on Surface Quality of Reaction Bonded Silicon Carbide Ceramic with Electrical Discharge Diamond Grinding

2016 ◽  
Vol 874 ◽  
pp. 15-21 ◽  
Author(s):  
Xiao Shuang Rao ◽  
Fei Hu Zhang ◽  
Chen Li
Keyword(s):  
Surface Roughness ◽  
Silicon Carbide ◽  
Surface Quality ◽  
Electrical Discharge ◽  
Machining Process ◽  
Hybrid Machining ◽  
Micro Cracks ◽  
Sic Ceramic ◽  
Hybrid Machining Process

With some conductivity and low grinding affectivity, a hybrid machining process termed electrical discharge diamond grinding (EDDG) is applied to the precision machining of reaction bonded silicon carbide (RB-SiC) ceramic. As there is electrical spark in the hybrid machining process, the electrical parameters are varied to explore their effects on the surface quality of RB-SiC ceramic with EDDG. In this paper, the experiments of different polarity and gap voltage with EEDG were investigated, and the microstructure and surface roughness on the machined surface of RB-SiC ceramic were analyzed. The surface morphology and micro-cracks were examined with a scanning electron microscope, and the surface roughness was measured with a confocal scanning laser microscope. It is found that surface roughness initially increases and then decreases with increase of the gap voltages and is higher with negative polarity than that with positive polarity. The micromorphology Micro-cracks were observed on the surface machined and are outstanding in re-solidified zone with EDDG.

A Study of the Solid-State Reaction for Polishing Sapphires

2012 ◽  
Vol 497 ◽  
pp. 195-199 ◽  
Author(s):  
Qian Fa Deng ◽  
Zhi Xiong Zhou ◽  
Zhao Zhong Zhou ◽  
Ju Long Yuan ◽  
Ji Cui Wang
Keyword(s):  
Solid State ◽  
Surface Quality ◽  
Material Removal Rate ◽  
Surface Finish ◽  
Solid State Reaction ◽  
Material Removal ◽  
Removal Rate ◽  
Substrate Material ◽  
Quality Requirements

As sapphire is an important substrate material, stringent surface quality requirements (i.e., surface finish and flatness) are required. In order to acquire the higher material removal rate and the better surface quality of sapphire, the solid state-reaction were introduced in this paper; abrasive of SiO2 and SiO2 with mixing the MgF2 power were compared to polish sapphire. The result showed that abrasive of SiO2 with mixing the MgF2 can obtain higher material removal rate and better surface quality. The result of the pr

Improving the Surface Roughness of a CVD Coated Silicon Carbide Disk by Performing Ductile Regime Single Point Diamond Turning

2008 ◽  
Author(s):  
Deepak Ravindra ◽  
John Patten
Keyword(s):  
Surface Roughness ◽  
Silicon Carbide ◽  
Surface Quality ◽  
Removal Rate ◽  
Single Point ◽  
Extreme Environments ◽  
High Hardness ◽  
Diamond Turning ◽  
Ductile Regime Machining

Silicon carbide (SiC) is one of the advanced engineered ceramics materials designed to operate in extreme environments. One of the main reasons for the choice of this material is due to its excellent electrical, mechanical and optical properties that benefit the semiconductor, MEMS and optoelectronic industry respectively. Manufacture of this material is extremely challenging due to its high hardness, brittle characteristics and poor machinability. Severe fracture can result when trying to machine SiC due to its low fracture toughness. However, from past experience it has been proven that ductile regime machining of silicon carbide is possible. The main goal of the subject research is to improve the surface quality of a chemically vapor deposited (CVD) polycrystalline SiC material to be used in an optics device such as a mirror. Besides improving the surface roughness of the material, the research also emphasized increasing the material removal rate (MRR) and minimizing the diamond tool wear. The surface quality was improved using a Single Point Diamond Turning (SPDT) machining operation from 1158nm to 88nm (Ra) and from 8.49μm to 0.53μm (Rz; peak-to-valley).

Investigating the Effects of Powder Mixed Electrical Discharge Machining on the Surface Quality of γ–TiAl Intermetallic

2012 ◽  
Vol 488-489 ◽  
pp. 396-401 ◽  
Author(s):  
B. Jabbaripour ◽  
M.H. Sadeghi ◽  
Mohammad Reza Shabgard ◽  
S. Shajari ◽  
H. Hassanpour
Keyword(s):  
Silicon Carbide ◽  
Surface Quality ◽  
Aluminum Powder ◽  
Automotive Industry ◽  
Electrical Discharge ◽  
Electrical Discharge Machining ◽  
Machining Parameters ◽  
Working Temperature ◽  
Corrosion Creep

Due to outstanding properties of γ–TiAl intermetallic such as high resistance against fatigue, oxidation, corrosion, creep, dynamic vibration, high working temperature and also its application in aerospace, automotive industry and turbojet engines; in this paper, powder mixed electrical discharge machining (PMEDM) of γ–TiAl intermetallic by means of different additive powders including aluminum (Al), graphite (Gr), silicon carbide (SiC), chrome (Cr) and iron (Fe) is investigated to compare the output characteristic of surface quality and roughness. The results indicate that aluminum powder produces the best surface finish, followed by silicon carbide, graphite, chrome and iron respectively. The experimental results show that in the determined settings of input machining parameters, aluminum powder can improve the surface roughness of TiAl sample about 32%.

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