• 한국세라믹학회지
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• 제36권1호
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• pp.36-42
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• 1999

2단계 열탄소환원법으로 탄화규소 휘스커를 기상-고상, 2단계, 기상-액상-고상 성장기구로 각각 합성하였다. 그리고 휘스커에 있는 적층결합을 X-ray와 투과전자현미경을 이용하여 분석하였다. 탄화규소 휘스커에 있는 적층결함은 휘스커의 지름과 상관관계가 있는 것으로 나타났다. 즉, 기상-고상, 2단계 성장, 기상-액상-고상 성장기구에 상관없이 지름이 1$\mu\textrm{m}$이하로 작아지는 경우 적층결합이 많아지고, 기상-액상-고상 기구로 성장한 지름이 2$\mu\textrm{m}$보다 큰 경우 적층결함이 거의 없는 것으로 나타났다. 이같은 현상은 휘스커 지름이 작아짐에 따라 휘스커의 비표면적이 증가하는 때문인 것으로 판단되었다.

• 한국세라믹학회지
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• 제43권4호
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• pp.199-202
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• 2006

In this study, SiC whiskers were grown on a porous SiC diesel particulate filter for nanoparticle filtering. To grow the whiskers at the inner pore without closing the pores, we used chemical vapor infiltration with a solution source and a dilute. As the deposition time increased, the whiskers grew and formed a network structure. After 180 min of deposition, the mean diameter of the whiskers was 174 nm and the compressive strength was 58.4 MPa. The pores shrank from $10{\mu}m\;to\;0.4{\mu}m$ and, because the whiskers filed the inner pores, the gradient of permeability decreased as the deposition time increased. However, by using the network structure of whiskers deposited for 120 min and 180 min, we obtained a diesel particulate filter with pores of $0.98{\mu}m\;and\;0.4{\mu}m$, respectively. Furthermore, the filter shows better permeability than a porous body with pores of $1{\mu}m$. In short, by filtering the nanoparticulate materials, the network structure of whiskers improves the strength, reduces the pore size and minimizes the permeability drop.

• 한국세라믹학회지
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• 제33권12호
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• pp.1380-1386
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• 1996

The effects of urea addition and reaction conditions were examined in the prepareation of zirconia coated SiC whiskers through surface precipitation taking place during high-temperature aging of Zr(SO4)2 solutions containing the whiskers. More dense zirconia-hydrate was precipitated on the surfaces of the whiskers in the presence of urea. The ratio of the concentration of Zr(SO4)2 to the amount of added whiskers was the most important factor to confine the precipitation of zirconia-hydrate only at the surfaces of the whiskers The from of the coating layers was unchanged after heat-treatment leading to the dehydration and crystallization of the layers.

• 한국세라믹학회지
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• 제35권12호
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• pp.1249-1256
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• 1998

${\beta}$-Silicon carbide(${\beta}$-SiC) whiskers could be synthesized by the carbothermal reduction of kaolin at tem-peratures between 1400 and 1500$^{\circ}C$. The whiskers were grown up to about 1150 of aspect ratio by VS mechanism (showing tapering tips) and to about 45 of that by VLS mechanism (showing round droplet tips) respectively. Hydrocarbon like methane in the reaction atmosphere promoted the formation of gaseous il-icon monoxide(SiO) from silicon dioxide(SiO2) and subsequently reacted with it to form whiskers. The for-mation of ${\beta}$-SiC whiskers increased with increasing carbon content(to 30 wt%) and reaction temperatures. The max. yield of ${\beta}$-SiC whiskers was 15% at 1500$^{\circ}C$ under 20%CH4/80%H2.

• 한국윤활학회:학술대회논문집
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• 한국윤활학회 1998년도 제28회 추계학술대회
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• pp.25-29
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• 1998

Sliding wear test and surface characterization techniques such as micro-Raman spectroscopy were employed to determine the effect of whisker content and orientation on the friction and wear behavior of SiC whisker reinforced alumina. Composites containing unidirectionally oriented whiskers were fabricated by novel technique Addition of SiC whiskers up to 20 vol.% lowered the friction and improved wear resistance. The results of this study indicated that highly disordered graphite and size of the layer behind the whiskers were responsible for variation of wear rate and friction coefficient.

• 한국세라믹학회지
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• 제36권10호
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• pp.1007-1015
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• 1999

The Si3N4 composites reinforced with carbon-coated SiC whiskers were fabricated by hot-pressing at 180$0^{\circ}C$ for 2 hours to examine the effects of carbon-coated whiskers on the mechanical properties of SiC whisker reinforced Si3N4 composites. The flexural strength of the Si3N4 composites and Si3N4 monolith respectively. The weak interfacial bond between carbon-coated SiC whiskers and Si3N4 matrix which enhances the crack deflection and whisker pull-out could contribute to the improvement of mechanical properties of the composites.

• 자원리싸이클링
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• 제2권4호
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• pp.17-22
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• 1993

왕겨와 활성탄을 출발물질로 하여 탄소열 환원법으로 SiC 휘스커를 합성하였다. 그리고, 이에 있어서 가수와 첨가제의 영향을 조사하였다. 실험온도는 $1450^{\circ}C$ 이었고 합성도니 SiC 휘스커는 후처리 후 SEM, XRD 분석을 행하였다. 반응관내에 수소의 농도가 높을수록, 총유량이 클수록 휘스커의 생성율이 증가하였으며 가스의 유속이 Ar : $H_2$=300:45(cc/min)이고 NaF : $CaF_2$= 1:1가 되도록 혼합하여, 첨가하고, Ni를 flake ($1{\times}1$mm)로 첨가한 경우에 가장 양호한 형태의 휘스커를 얻을 수 있었다.

• 전자공학회논문지SC
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• 제47권4호
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• pp.55-60
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• 2010

설치류는 수염을 통해서 물체를 인식하는 능력을 갖추고 있다. 단연 설치류뿐만 아니라 많은 수의 포유류가 사물을 인식하는데 수염을 이용하지만 특히 설치류는 수염을 통해서 마이크로미터 단위의 표면의 거칠기 차이도 구별 할 수 있다. 설치류는 수염을 앞, 뒤로 능동적으로 움직이며 물체의 모양이나 표면의 거칠기, 패턴 따위를 판별한다. 실제 쥐 수염에는 수염뿌리 가까운 모낭 안에 수많은 신경이 모여 있어서 수염이 떨리거나 구부러질 때의 신호를 받아들인다. 쥐의 이러한 능력을 모방하여, 본 논문에서는 마이크로폰을 이용하여 쥐 수염 센서를 제작하고 제작한 수염 센서를 통해 물체 표면의 거칠기에 대한 정보를 얻고자 한다.

• 한국환경과학회지
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• 제17권11호
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• pp.1235-1241
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• 2008

Membrane separation is extensively used for water/wastewater treatment because of its efficiency separation processes. However, particles in the feed water can deposit and accumulate on the membrane surface to created cake layer. As a consequence, the selectivity of the membrane and flux through the membrane are decreased, which is called fouling/blocking phenomenon. In order to solve fouling problem, we developed a novel membrane named Carbon Whisker Membrane (CWM) which contains vapor-grown carbon fibers/whiskers on the surface of the membrane and a layer of carbon film coated on the ceramic substrate. We firstly employed polymethyl methacrylate (PMMA) as a testing material to investigate the fouling mechanism. The results suggested that Carbon Whiskers on the surface of the membrane can prevent the directly contact between the membrane body and particles so that the fouling/blocking could not occurred easily compared to the membrane without carbon whiskers. We also researched the relationship with the diameter, density of carbon whisker on the membrane surface and total flux of solutions. Finally, we will be able to control the diameter and density of carbon whiskers on the membrane and existence of carbon whiskers on the membrane, it is important factor, might be prevent fouling/blocking in the water treatment.

• Corrosion Science and Technology
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• 제6권1호
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• pp.24-28
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• 2007

Alumina coated SiC whiskers were prepared by homogeneous precipitation of aluminum sulfate. The Si3N4 composites reinforced with coated SiC whiskers were fabricated by hot-pressing at $1800^{\circ}C$ for 2 h under an $N_{2}$ atmosphere of 0.1 MPa to examine the effects of coated whiskers on the mechanical properties of SiC whisker reinforced $Si_{3}N_{4}$ composite. By the addition of alumina coated SiC whiskers instead of as received ones, the fracture toughness of composite was about 6.7 $MPam^{1/2}$ which was slightly lower than as received SiC whisker reinforced composite. This result seems to be caused by the fact that the crack deflection and whisker pull-out were decreased. Thus, alumina coated SiC whiskers were considered to form relatively strong interface bond with $Si_{3}N_{4}$ matrix.