• Title/Summary/Keyword: SiC particle size

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The Effect of SiC Powder Size at Reaction Bonded SiC Composite Fabricated by a Molten Si Infiltration Method (용융 Si 침윤법에 의해 제조된 반응소결 탄화규소 복합체에서 SiC 입자 크기의 영향)

  • Yun, Sung-Ho;Cho, Kyung-Sun;Tan, Phang Nhun;Cheong, Hun;Kim, Young-Do;Park, Sang-Whang
    • Journal of the Korean Ceramic Society
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    • v.45 no.8
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    • pp.486-492
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    • 2008
  • Reaction bonded silicon carbide(RBSC) composite for heat-exchanger was fabricated by molten Si infiltration method. The raw materials with variable particle sizes were used in this experience. The finer the particle size in sintered silicon carbide was the more increasing 3-point bending strength and fracture toughness. As the adaptable particle sizes had been occupied interstice arising from packing sample, the mechanical properties were increased. In the PCS1-1 sample, the 3-point bending strength and fracture toughness were 323MPa and $4.9\;MPa{\cdot}m^{1/2}$, respectively.

Material Removal Rate Modeling of SiO2/TiO2 Mixed-Abrasive Slurry CMP for SiC (SiO2/TiO2 혼합입자 슬러리 SiC CMP의 재료제거율 모델링)

  • Hyunseop Lee
    • Tribology and Lubricants
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    • v.39 no.2
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    • pp.72-75
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    • 2023
  • Silicon carbide (SiC) is used as a substrate material for power semiconductors; however, SiC chemical mechanical polishing (CMP) requires considerable time owing to its chemical stability and high hardness. Therefore, researchers are attempting to increase the material removal rate (MRR) of SiC CMP using various methods. Mixed-abrasive CMP (MAS CMP) is one method of increasing the material removal efficiency of CMP by mixing two or more particles. The aim of this research is to study the mathematical modeling of the MRR of MAS CMP of SiC with SiO2 and TiO2 particles. With a total particle concentration of 32 wt, using 80-nm SiO2 particles and 25-nm TiO2 particles maximizes the MRR at 8 wt of the TiO2 particle concentration. In the case of 5 nm TiO2 particles, the MRR tends to increase with an increase in TiO2 concentration. In the case of particle size 10-25 nm TiO2, as the particle concentration increases, the MRR increases to a certain level and then decreases again. TiO2 particles of 25 nm or more continuously decreased MRR as the particle concentration increased. In the model proposed in this study, the MRR of MAS CMP of SiC increases linearly with changes in pressure and relative speed, which shows the same result as the Preston's equation. These results can contribute to the future design of MAS; however, the model needs to be verified and improved in future experiments.

Effects of Processing Parameters on the Mechanical Properties of Aluminium Matrix Composites (알루미늄 기지 금속복합재료의 기계적 성질에 미치는 제조변수의 영향)

  • Kim, J.D.;Koh, S.W.;Kim, H.J.
    • Journal of Power System Engineering
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    • v.9 no.4
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    • pp.130-136
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    • 2005
  • The effects of additional Mg content, the size and volume fraction of reinforcement phase on the mechanical properties of ceramic particle reinforced aluminium matrix composites fabricated by pressureless metal infiltration process were investigated. The hardness of $SiC_p/AC8A$ composites increased gradually with an increase in the additive Mg content, while the bending strength of $SiC_p/AC8A$ composites increased with an increase in additive Mg content up to 5%. However, this decreased when the level of additive Mg content was greater than 5% due to the formation of coarse precipitates by excessive Mg reaction and an increase in the porosity level. The hardness and strength of the composites increased with decreasing the size of SiC particle. It was found that the composites with smaller particles enhanced the interfacial bonding than those with bigger particles from fractography of the composites. The hardness of $Al_2O_{3p}/AC8A$ composites increased gradually with an increase in the volume fraction, however, the bending strength of $Al_2O_{3p}/AC8A$ composites decreased when the volume fraction of alumina particle was greater than 40% owing to the high porosity level.

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Formation of Silicon Particles Using $SiH_4$ pyrolysis at atmospheric pressure (상압에서 열분해법을 이용한 실리콘 입자 제조)

  • Woo, Dae-Kwang;Nam, Kyung-Tag;Kim, Young-Gil;Kim, Kwang-Su;Kang, Yun-Ho;Kim, Tae-Sung
    • Proceedings of the KSME Conference
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    • 2007.05a
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    • pp.126-129
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    • 2007
  • The particle formation using pyrolysis has many advantages over other particle manufacturing techniques. The particles by pyrolysis have relatively uniform size and chemical composition. Also, we can easily produce high purity particles. Thus, we studied the formation of silicon particles by pyrolysis of 50% $SiH_4$ gas diluted in Ar gas. A pyrolysis furnace was used for the thermal decomposition of $SiH_4$ gas at $800^{\circ}C$ and atmospheric pressure. The aerosol flow from furnace is separated into two ways. The one is to the Scanning Mobility Particle Sizer (SMPS) for particle size distribution measurement and the other is to the particle deposition system. The produced silicon particles are deposited on the wafer in the deposition chamber. SEM measurement was used to compare the particle size distribution results from the SMPS. Depending on the experimental conditions, particles of high concentration in the $30\sim80$ nm size range were generated.

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Age-Hardening Behavior of SiCp Reinforced 6061 Aluminum Alloy Composites (SiCp/6061Al합금복합재료의 시효거동)

  • An, Haeng-Geun;Yu, Jeong-Hui;Kim, Seok-Won;U, Gi-Do
    • Korean Journal of Materials Research
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    • v.10 no.12
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    • pp.793-798
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    • 2000
  • The age-hardening behavior of unreinforced 6061 Al alloy and SiCp/6061 Al alloy composites reinforced with different size of SiC particle (average diameter ; 0.7$\mu\textrm{m}$ and 7.0$\mu\textrm{m}$) was investigated by hardness measurement, calorimetric technique and transmission electron microscopy. At 17$0^{\circ}C$ isothermal aging treatment, the peak aging time of 0.7$\mu\textrm{m}$SiCp/6061Al alloy composite and 7.0$\mu\textrm{m}$SiCp/6061Al alloy composite is shorter than that of unreinforced 6061Al alloy, and the aging of 7.0$\mu\textrm{m}$SiCp/6061Al alloy composite is accelerated more than that of 0.7$\mu\textrm{m}$SiCp/6061Al alloy composite. This acceleration is due to the increase of dislocation density by the compositeness with SiCp and the SiC particle size. In the peak aged condition, the major strengthening phase of these materials is intermediate $\beta$ phase(Mg$_2$Si), and the activation energy for the formation of $\beta$ phase is considerably decreased by the compositeness with SiCp and the increasing of SiC Particle site.

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The Effect of Extrusion Temperatures on Microstructures and Mechanical Properties of Ultra-Fine Structured and Extruded Al81Si19 Alloys (초 미세조직 Al81Si19 합금분말 압출재의 미세조직과 기계적 성질에 미치는 압출온도의 영향)

  • 이태행;홍순직
    • Journal of Powder Materials
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    • v.10 no.5
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    • pp.325-332
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    • 2003
  • The effect of extrusion temperature on the microstructure and mechanical properties was studied in gas atomized TEX>$Al_{81}Si_{19}$ alloy powders and their extruded bars using SEM, tensile testing and wear testing. The Si particle size of He-gas atomized powder was about 200-800 nm. Each microstructure of the extruded bars with extrusion temperature (400, 450 and 50$0^{\circ}C$) showed a homogeneous distribution of primary Si and eutectic Si particles embedded in the Al matrix and the particle size varied from 0.1 to 5.5 ${\mu}m$. With increasing extrusion temperature from 40$0^{\circ}C$ to 50$0^{\circ}C$, the ultimate tensile strength (UTS) decreased from 282 to 236 ㎫ at 300 K and the specific wear increased at all sliding speeds due to the coarse microstructure. The fracture behavior of failure in tension testing and wear testing was also studied. The UTS of extrudate at 40$0^{\circ}C$ higher than that of 50$0^{\circ}C$ because more fine Si particles in Al matrix of extrudate at 40$0^{\circ}C$ prevented crack to propagate.

Method and mechanism of dispersing agent free dispersion of short carbon fibers in silicon carbide powder

  • Raunija, Thakur Sudesh Kumar;Mathew, Mariamma;Sharma, Sharad Chandra
    • Carbon letters
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    • v.15 no.3
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    • pp.180-186
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    • 2014
  • This study highlights a novel method and mechanism for the rapid and effective milling of carbon fibers (CFs) in silicon carbide (SiC) powder, and also the dispersion of CFs in SiC powder. The composite powders were prepared by chopping and exfoliation of CFs, and ball milling of CFs and SiC powder in isopropyl alcohol. A wide range of CFs loading, from 10 to 50 vol%, was studied. The milling of CFs and SiC powder was checked by measuring the average particle size of the composite powders. The dispersivity of CFs in SiC powder was checked through scanning electron microscope. The results show that the usage of exfoliated CF tows resulted in a rapid and effective milling of CFs and SiC powder. The results further show an excellent dispersion of CFs in SiC powder for all CFs loading without any dispersing agent.

Electrochemical Properties of SiOx Anode for Lithium-Ion Batteries According to Particle Size and Carbon Coating (입자 크기 및 탄소 코팅에 따른 리튬이온배터리용 SiOx 음극활물질의 전기화학적 특성)

  • Anna Park;Byung-Ki Na
    • Korean Chemical Engineering Research
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    • v.62 no.1
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    • pp.19-26
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    • 2024
  • In this study, the electrochemical properties of SiOx@C composite materials were prepared to alleviate volume expansion and cycle stability of silicon and to increase the capacity of anode material for LIBs. SiO2 particles of 100, 200, and 500 nm were synthesized by the Stӧber method, and reduced to SiOx (0≤x≤2) through the magnesiothermic reduction method. Then, SiOx@C anode materials were synthesized by carbonization of PVC on SiOx. The physical properties of prepared SiOx and SiOx@C anode materials were analyzed by XRD, SEM, TGA, Raman spectroscopy, XPS and BET. The electrochemical properties were investigated by cycling performance, rate performance, CV and EIS test. As a result, the SiOx@C-7030 manufactured by coating carbon at SiOx : C = 70 : 30 on a 100 nm SiOx with the smallest particle size showed the best electrochemical properties with a discharge capacity of 1055 mAh/g and a capacity retention rate of 81.9% at 100 cycles. It was confirmed that cycle stability was impoved by reducing particle size and carbon coating.

Effects of Glass Particle Size on Sintering Behaviors of the Glass-Alumina Composites for Low Firing Temperature (저온 소성용 유리-알루미나 복합체에서 유리 입자크기에 따른 소결거동)

  • 박덕훈;김봉철;김정주;박이순
    • Journal of the Korean Ceramic Society
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    • v.37 no.6
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    • pp.545-551
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    • 2000
  • Sintering behaviors of the glass-alumina composites for low firing temperature were investigated as a function of the particle size of glass frit. The system of glass frit was Pb-B-Si-Al-O. The median particle sizes of the glass frits were 2.72$\mu\textrm{m}$, 2.67$\mu\textrm{m}$ and 1.33$\mu\textrm{m}$, which were prepared with changing ball-milling times as 24 h, 48 h and 96 h. The glass-alumina composites showed maximum density at certain temperature, and further heating led to dedensification behaviors, so called over-firing. The sintering temperature, which showed maximum density, raised from 425$^{\circ}C$ to 475$^{\circ}C$ with increase of particle size of glass frit from 1.33$\mu\textrm{m}$ to 2.72$\mu\textrm{m}$. Especially, the over firing behaviors, which were occurred at high sintering temperatures, were greatly increased with decrease of particle size of glass frit.

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Effect of agitation on hydrothermal preparation of $\alpha$-$SiO_2$ powder (수열합성법에 의한 $\alpha$-$SiO_2$분말 제조시 교반의 영향)

  • 임진홍;서경원;목영일;이강인;유효신;이철경
    • Journal of the Korean Crystal Growth and Crystal Technology
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    • v.9 no.2
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    • pp.191-196
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    • 1999
  • Effects of agitation and heating rate on crystallinity, size distribution and mean size of $\alpha$-$SiO_2$powder prepared hydrothermally were investigated. $\alpha$-$SiO_2$crystalline powder, in mean particle size of 1~3.2 $\mu\textrm{m}$, was obtained at $350^{\circ}C$ using KOH as a mineralized for a 3 h reaction. Experimental results showed that particle size became smaller as the rate of agitation increased if it was introduced from the beginning of reaction, however, crystallinity was reduced at the low rate of agitation and it was became enhanced at above 150 r/min. Particle size became larger if agitation was introduced at any time during the reaction rather than introduced from the beginning of reaction. It was also found that particle size became smaller if heating rate was reduced, while the rate of agitation kept constant.

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