• 제목/요약/키워드: Si(111)

검색결과 818건 처리시간 0.046초

Thermal Properties of 0.9CaMgSi2O6-0.1MgSiO3 Glass-Ceramics

  • Jeon, Chang-Jun;Sun, Gui-Nam;Lee, Jong-Kyu;Ju, Han-Sae;Kim, Eung-Soo
    • 한국세라믹학회지
    • /
    • 제49권1호
    • /
    • pp.111-117
    • /
    • 2012
  • Dependencies of thermal properties on the crystallization behavior of $0.9CaMgSi_2O_6-0.1MgSiO_3$ glass-ceramics were investigated as a function of heat-treatment temperature from $750^{\circ}C$ to $950^{\circ}C$. The crystallization behavior of the specimens depended on the heat-treatment temperature, which could be evaluated by differential thermal analysis (DTA), Fourier transform infrared spectroscopy (FT-IR), and X-ray diffraction (XRD) analysis by the Rietveld-reference intensity ratio (RIR) combined procedure. With an increase of the heat-treatment temperature, the thermal conductivity and thermal diffusivity of the heat-treated specimens increased. These results could be attributed to the increase of crystallization with heat-treatment temperature. However, the specific heat capacity of the heat-treated specimens was not affected by the heat-treatment temperature. The thermal conductivities measured from $25^{\circ}C$ to $100^{\circ}C$ were also discussed for application to lighting-emitting diode (LED) packages and substrate materials.

울릉도 조면암질 유리의 변절에 의한 할로이사이트의 생성 (Halloysite Formation by the Alteration of Trachytic Glass in Ulleung Island)

  • 정기영
    • 한국광물학회지
    • /
    • 제24권2호
    • /
    • pp.111-118
    • /
    • 2011
  • 울릉도의 조면암질 응회암의 저온변질작용으로 할로이사이트가 생성되었다. 할로이사이트는 자연 상태에서 수화된 상태로 발견되었으며, 양파구조의 구상 또는 가장자리가 휘어진 판상 입자로 산출된다. 할로이사이트는 Si의 함량이 고령토 광물의 이상값보다 높아서 약간의 비정질이 혼재한 것으로 해석되었다. 또한 할로이사이트의 높은 Fe 함량은 판상 할로이사이트 생성의 원인이다. 조면암질 유리가 변질되면서 용탈된 원소들이 주로 화산유리의 입간 공극에 할로이사이트로 침전되었으며, 유리를 교대한 Si가 풍부한 반구상 비정질 집합체도 부분적으로 구상할로이사이트로 변질된 것으로 보인다. 할로이사이트는 조면암질 화산활동이 활발했던 울릉도에서 화산재의 주요 변질물 중의 하나이다.

기판과 부도체층을 개선한 $FM/Al_2O_3/FM$ (FM=Ferromagnet) 자기터널링 접합제작 및 자기수송에 관한 연구 (Improvement of Substrate and Insulationg Layer of FM Magnetic Tunneling Jundtion and the Study of Magnetic Transport)

  • 변상진;박병기;장인우;염민수;이재형;이긍원
    • 한국자기학회지
    • /
    • 제9권5호
    • /
    • pp.245-250
    • /
    • 1999
  • 기판/Py/Al2O3/Co(Py=Ni81Fe19) 터널접합의 TMR(Tunneling Magnetoresistance)에 미치는 기판과 부도체층의 효과를 보기위해 산화시간을 변화시키고 기판의 종류를 변화시켜며 전기적 특성을 측정하였다. 시료는 진공중에서 in-situ로 새도우마스크를 교환하며 제작하였다. 산화시간의 증가에 따라 터널접합의 저항은 증가하였으며 측정된 MR 값은 감소하였다. 터널 비저항이 0.17 M$\Omega$($\mu\textrm{m}$)2이하인 경우 MR이 관측되었다. 기판의 종류에 따른 MR 값은 열산화시킨 Si(111), Si(100), Cornng Glass 2948, Corning Glass 7059 순으로 감소하였다. MR 값의 부호와 변화를 불균일 전류의 흐름으로 설명하였다.

  • PDF

고주파 때려내기법에 의한 질화알루미늄 박막의 제작과 특성 (Preparation and characterization of AiN Thin Films by RF sputtering method)

  • 정성훈;김영호;문동찬;김선태
    • E2M - 전기 전자와 첨단 소재
    • /
    • 제10권7호
    • /
    • pp.706-712
    • /
    • 1997
  • AlN(Aluminium Nitride) thin films were prepared using by RF sputtering method on the Si(100) and Si(111) substrates as the parameters of the substrate temperature, RF power, sputtering duration and the $N_2$/Ar ratio and investigated by X-ray diffraction, IR spectrometry, n&k analyzer. For the Si(100) substrate, the AlN thin films of (101) orientation were obtained under the conditions of room temperature and the nitrogen of 60 vol.%. For the Si(111) substrate, the (002) AlN thin films were obtained under the nitrogen of 100 vol.%. In case of the thin film prepared in the condition of above 60 vol.% of the nitrogen, the average value of the surface roughness of the film was 151$\AA$. From the changes of the half widths of E$_1$[TO] phonon bands at the wavenumber of 680$cm^{-1}$ /, it were compared of the crystallinities of the films which were grown under the different conditions. The thicknesses of AlN films were decreased dramatically in the region of the nitrogen of 40~60 vol.%. Its due to the nitridation of the Al target surface and getting low of the sputtering yield by the $N_2$/Ar ratio being increased.

  • PDF

Coating Performance of SiO2 / Epoxy Composites as a Corrosion Protector

  • Rzaij, Dina R.;Ahmed, Nagham Y.;Alhaboubi, Naseer
    • Corrosion Science and Technology
    • /
    • 제21권2호
    • /
    • pp.111-120
    • /
    • 2022
  • To solve the corrosion problem of industrial equipment and other constructions containing metals, corrosion protection can be performed by using coating which provides a barrier between the metal and its environment. Coatings play a significant role in protecting irons and steels in harsh marine and acid environments. This study was conducted to identify an anti-corrosive epoxy coating for carbon steel composite with 0.1, 0.3, and 0.5 wt% concentrations of nanoparticles of SiO2 using the dip-coating method. The electrochemical behavior was analyzed with open circuit potential (OCP) technics and polarization curves (Tafle) in 3.5 wt% NaCl and 5 vol% H2SO4 media. The structure, composition, and morphology were characterized using different analytical techniques such as X-ray Diffraction (XRD), Fourier Transform Infrared spectrum (FT-IR), and Scanning Electron Microscopy (SEM). Results revealed that epoxynano SiO2 coating demonstrated a lower corrosion rate of 2.51 × 10-4 mm/year and the efficiency of corrosion protection was as high as 99.77%. The electrochemical measurement showed that the nano-SiO2 / epoxy coating enhanced the anti-corrosive performance in both NaCl and H2SO4 media.