• Journal of the Korean Ceramic Society
• /
• v.29 no.4
• /
• pp.319-327
• /
• 1992

Sb-doped SnO2 films were formed on Corning glass 7059 substrate by chemical vapor deposition using simulataneous hydrolysis of SnCl4 and SbCl5. Fairly good transparent conducting film with a low resistivity of ~6$\times$10-4{{{{ OMEGA }}cm and high average optical transparency above ~85% in the range of visible light was obtained at the deposition condition of 50$0^{\circ}C$ and input-gas ratio, [Psbcl5/Psncl4] of 0.05. Film conductivity was improved without loosing optical transparency at light doping of Sb and found to be due to the increase of electron concentration. However, high doping of Sb into SnO2 film largely deteriorated conductivity, optical transparency and crystallinity of the film.

• Journal of the Korean Ceramic Society
• /
• v.38 no.7
• /
• pp.621-627
• /
• 2001

알루미나 졸에 평균 25nm의 TiO$_2$(Degussa P25) 광 촉매 분말을 분산하여 광촉매 코팅제를 제조하였다. 점도 약 24 cps를 가지 4.4 wt%의 알루미나 졸로부터 약 300nm 두께의 코팅막이 제조되었으며, 졸 점도의 증가에 비례하여 코팅막의 두께도 증가하였다. TiO$_2$광 촉매의 코팅용 바인더로 이용한 알루미나 졸의 결정형은 25~30$0^{\circ}C$에서 pseudo boehmite (AlOOH)이었으며, 50$0^{\circ}C$ 이상에서는 ${\gamma}$-Al$_2$O$_3$으로 전환되었다. AlOOH/TiO$_2$코팅막은 oleic acid와 humic acid에 대한 기상 및 수상 조건에서의 광 촉매 실험에서 우수한 유기물의 광분해 효능을 나타내었다. 아울러 EGI(Electro-Galvanized Iron)에 코팅된 AlOOH/TiO$_2$코팅막은 내식성 및 내지문성의 효과도 부수적으로 나타내었다.

• Journal of the Korean Ceramic Society
• /
• v.13 no.3
• /
• pp.21-27
• /
• 1976

Foam formation of Slag-Quartz-$\textrm{Na}_2\textrm{CO}_3$ system was investigated. The foaming agent used was sulphide and sulphate compounds which are present in the slag. The microstructures and x-ray analysis of foam slag, the effect of composition and particle size of slag on the formation temperature, and foam size and distribution of slag foam were studied. The Increment of $\textrm{Na}_2\textrm{O}$ in the slag batch composition decrease the initial foam formation temperature and enhance the foam growth. The formation of temperature and soaking time had pronounced effect on the foam growth and increasing the glass phase in the slag foam.

• Journal of the Korean Ceramic Society
• /
• v.16 no.4
• /
• pp.237-242
• /
• 1979

In order to improve hydration reactivity of blast furnace slag, it's composition was changed by adding of CaO. The slags were quenched in water at 1,400℃. Hydration reactivityof modified slags was studied by x-ray diffractometer, conduction calorimeter and so on. Experimental results were summarized as follows. 1. Glass content and hydration reactivity of slag depend significantly on quenching temperature of the slag melt. To enhance the reactivity, slag melts which belongs to Frenkel-type liquid, must be quenched above 1,300℃. 2. Vitrification of slag melts was confirmed as CaO/SiO2 ratio increased up to 1.57 with flux, 1.51 without flux, also their hydration reactivity was improved.

• Journal of the Korean Ceramic Society
• /
• v.47 no.3
• /
• pp.205-209
• /
• 2010

In the last (fourth) section, the discussion will entail a silicon-nitride/silicon-carbide nanocomposite, produced by pyrolysis of liquid polymer precursors, demonstrating one of the lowest creep rates reported so far in ceramics at the comparable temperature of $1400^{\circ}C$. This was first achieved by avoiding the oxynitride glass phase at the intergrain boundaries. One important factor in the processing of these nanocomposites was the use of the electrical field assisted sintering method.

• Journal of the Korean Ceramic Society
• /
• v.13 no.2
• /
• pp.8-16
• /
• 1976

The conductive transparent film is prepared by spraying thin salt solution. In stannic chloride solution as a base solution, various dopants such as Al, Co, Cu and Ni were dissolved respectively as a chloride state and then the films were made by spraying solutions on hot glass plates. The properties of them were compared with those of the stannic salt single component film. The films doped with copper oxide and nickle oxide were improved by decreasing their sheet resistivity and temperature coefficient of resistivity. In comparison with the sheet resistivity and temperature coefficient of resistivity of stannic oxide single component film, being 2.5 K ohm/$\textrm{cm}^2$ and -1650ppm/$^{\circ}C$ respectively, its values of the film containing 15 mol % of copper oxide and formed at 40$0^{\circ}C$ were 2.5K ohm/$\textrm{cm}^2$ and -920ppm/$^{\circ}C$ respectively. The film containing 15 mol % of nickel oxide and formed at 50$0^{\circ}C$ has shown its sheet resistivity and temperature coefficient 0.7 K ohm/$\textrm{cm}^2$ and -940ppm/$^{\circ}C$ respectively.

• Journal of the Korean Ceramic Society
• /
• v.30 no.5
• /
• pp.373-380
• /
• 1993

Li2O-B2O3-P2O5 glasses with high lithium content were analysed by electrical characterization. The electrical conductivity increase with Li content and exhibits a maximum value of 1.2$\times$10-4S/cm near B2O3/P2O5=1 at 15$0^{\circ}C$. Glass transitiion temperature increased with conductivity. Concentration of charge carrier and distribution of relaxation time were independent of temperature. In this system the variation of conductivity with the composition was depend on mobility of lithium ion. Basically, it is attribute to primitive activation energy. Enhancement of conductivities was related to be formation of (B-O-P)-, di-, and metaborate group, which give additional available sites for Li+ diffusion.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 1995.10a
• /
• pp.1028-1032
• /
• 1995

This paper describes the manufacture of spherical and aspherical surface on glass, superalloy and ceramic components. The rotationally symmetricallenses, and the ceramic or superalloy molds with spherical shapes are mainly generated by cutting processes on CNC lathe machine or 4,5 axis CNC machining centers. Recently, spherical shape parts require more precise and efficent machining technologies for wide material range such as optical lens of the lithography device in semiconductor manufacturing processes or the high precision mold machining of anti-chemical, anti-wear materials. In this paper, we introduce a newly developed infeed grinding machine with metal with metal bonded cup type wheel and its effects on spherical surface grinding.

• Journal of Powder Materials
• /
• v.6 no.4
• /
• pp.320-324
• /
• 1999

The formation, microstructure and properties of novel ceramic composite materials manufactured by active-filler-controlled polymer pyrolysis were investigated. In the presence of active filler particles such as transition metals, bulk components of various geometry could be fabricated from siliconorganic polymer. Molybdenum- and tungsten-filled polymer suspensions were prepared and their conversion to ceramic composites by annealing in $CH_4$ atmosphere were studied. Dimensional change. porosity and phase distribution (filler network) were analyzed and correlated to the resulting hardness values. Molybdenum and tungsten as active filler were carburized completely to $Mo_2C$, $W_2C$ and WC in $CH_4$ atmosphere. Consequently, microcrystalline composites with the filler reaction products embedded in a silicon oxycarbide glass matrix were formed. Hardness was increased with increasing carburization and reached 8.6-9.5 GPa in the specimen pyrolyzed in $CH_4$ atmosphere.

• Journal of the Korean Ceramic Society
• /
• v.43 no.1 s.284
• /
• pp.28-32
• /
• 2006

Diarylethene in photochromic materials was doped in organic-inorganic hybrid low-melting glasses were synthesized through a nonaqueous acid-base reaction process, which consists of network units including a small number of bridging oxides. The organic phase is a dichlorodimethylsilane while the inorganic phase is a tin(II) chloride. Diarylethene was incorporated into the glasses without any degradation of its functionality. The open form of diarylenthene, which is converted from the opening one upon UV-irradiation, is change to the closed form visible light-irradiation. The rate constant of the photochemical reaction is $31.78\times10^{-3}s^{-1}$ with 400 W UV lamp irradiation.