• Title/Summary/Keyword: Ceramic-glass

Search Result 1,315, Processing Time 0.025 seconds

The effect of heat treatment on catalytic crystallization in Li$_2$O-Al$_2$O$_3$-SiO$_2$ glass system (LI$_2$O-Al$_2$O$_3$-SiO$_2$계 유리의 catalytic crystallization에 미치는 열처리 효과)

  • 박원규;이채현
    • Journal of the Korean Crystal Growth and Crystal Technology
    • /
    • v.6 no.2
    • /
    • pp.275-285
    • /
    • 1996
  • The effect of heat-treatment on catalytic crystallization in $LI_2O-Al_2O_3-SiO_2$ glass system over its glass transition temperature was investigated. Glass composition $4Li_2O{cdot}22AL_2O_3{cdot}66SiO_2{cdot}2TiO_2{cdot}2.5ZrO_2{cdot}1.5P_2O_5{cdot}1.0Na_2O{cdot}1.0As_2O_3$ (wt%) was selected and heat-treated at different heating conditions to obtain transparent glass-ceramic. Nucleation and crystallization behaviour of this composition were estimated by differential thermal analysis (DTA) and X-ray diffractometer (XRD) and its thermal expansion coefficients were measured by Dilatometer. As a result, glass transition temperature was $730^{\circ}C$ and two maximum nucleation temperatures were estimated at $730^{\circ}C$ and 82$0^{\circ}C$ using JMA(Johson-Mehl-Avrami) equation by DTA. $ZrTiO_4$ $\beta$-Quartz solid solution and $\beta$-Spodumene crystals were identified by XRD. The optimum crystallization temperature was 92$0^{\circ}C$ and three step heating schedule was expected to be useful to obtain transparent glass-ceramic.

  • PDF

Dissolution Properties of K2O-CaO-MgO-SiO2-P2O5 Glasses (K2O-CaO-MgO-SiO2-P2O5계 유리의 제조 및 용출특성)

  • 이용수;윤태민;강원호
    • Journal of the Korean Ceramic Society
    • /
    • v.40 no.11
    • /
    • pp.1132-1137
    • /
    • 2003
  • For the application of environment conscious glass-fertilizer, dissolution characteristics of phosphate glass was investigated. In 0.1K₂O-0.1SiO₂-0.6P₂O/sub 5/ glass system, the compositions were designed according to variation of CaO & MgO contents, and glass formation region was confirmed. From the glass composition, the confirmed glasses were investigated to figure out thermal and dissolution properties. It was detected that glass transition & softening temperature of the glasses increased with increasing MgO contents. The dissolution properties of the glasses was affected by CaO and MgO content ratio.

Development of Thin and Lightweight Bulletproof Windows Using Strengthened SLS Glass by Ion Exchange

  • Shim, Gyu-In;Kim, Seong-Hwan;Ahn, Deok-Lae;Park, Jong-Kyoo;Choi, Se-Young
    • Journal of the Korean Ceramic Society
    • /
    • v.52 no.2
    • /
    • pp.123-127
    • /
    • 2015
  • Soda-lime silicate (SLS) glass was strengthened by ion exchange for application of thin and lightweight bulletproof windows. The optimal conditions for ion exchanged SLS glass (thickness of 3 and 10 mm) at $480^{\circ}C$ were 10 and 17 min, respectively. The Vickers hardness values of the strengthened SLS glass samples with thicknesses of 3 and 10 mm were $5.9{\pm}0.22$ and $6.7{\pm}0.17GPa$, respectively, which values were about 22% higher than those of parent SLS glass. By laminating a multilayer defense film and polycarbonate sheet with ion exchanged SLS glass, we were able to make a thin and lightweight bulletproof window (24.25 mm, 4.57 kg, $50.06kg/m^2$, $V_{50}$ 901.8 m/s). As a result, the thickness of the bulletproof window was decreased by about 39% from 40 to 24.25 mm. The light transmittance in the visible range satisfied the standard (over 76%) for bulletproof windows.

Synthesis of P2O5-V2O5-ZnO Glass Frit for Laser Sealing of OLED by the Addition of Filler (필러 첨가에 의한 OLED의 레이저 실링용 P2O5-V2O5-ZnO 유리프릿의 제조)

  • Bang, Jae-Chul
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
    • /
    • v.28 no.9
    • /
    • pp.571-576
    • /
    • 2015
  • In this study, we developed a lead-free $P_2O_5-V_2O_5-ZnO$ glass frit for sealing OLED using laser irradiation. The frit satisfied the characteristics required for laser sealing such as low glass transition temperature, low coefficient of thermal expansion (CTE), high water-resistance, and high absorption at the wavelength of the laser beam. Ceramic fillers were added to the glass frit in order to further reduce and match its CTE with that of the commercial glass substrate. The addition of Zirconium Tungsten Phosphate (ZWP) to the frit yielded the most desirable results, reducing the CTE to $45.4{\times}10^{-7}/^{\circ}C$, which is very close to that of the glass substrate ($44.0{\times}10^{-7}/^{\circ}C$). Successful formation of a solid sealing layer was observed by optical and scanning electron microscopy.

Anti-bacterial effects of the Na2O-TiO2-P2O5 glass-ceramics added Ag+ ion (은이온을 함유한 Na2O-TiO2-P2O5 glass-ceramic의 항균 특성)

  • Park, No-Hyung;Yoo, Eun-Sung
    • Journal of the Korean Crystal Growth and Crystal Technology
    • /
    • v.21 no.5
    • /
    • pp.210-213
    • /
    • 2011
  • Glass-ceramics composed of $5Na_2O-36CaO-10TiO_2-xP_2O_5$ could be obtained with $P_2O_5$ content as following procedure: 1) leaching out $Ca_3(PO_4)_2$ crystals between $Ca_3(PO_4)_2$ and $NaTi_2(PO_4)_3$ selectively in 1 N HCl solution for 2 days, and 2) exchanging $Na^+$ ion to $Ag^+$ ion in Ag($NO_3$) solution for 1 day. Scanning electron microscope (SEM) and X-rat diffractometer (XRD) were measured to verify the proper synthesis of glass-ceramics. And anti-bacteria test was accomplished using Staphylococus aureus bacteria. In the results of anti-bacteria test, the bacteria were died perfectly after 3 hours.

The Decision on the Thermal Expansion Coefficient of the Glass Infiltrated in All Ceramic Crown (전부도재관 제작용 침투유리의 열팽창계수의 결정)

  • 김병수;이득용;김학관;장주웅
    • Journal of the Korean Ceramic Society
    • /
    • v.40 no.1
    • /
    • pp.93-97
    • /
    • 2003
  • Using alumina-glass infiltrated material which has been in the spotlight of biomaterials including dental material, appropriate composition of glass infiltrated material mainly depends on the thermal expansion coefficient. To obtain proper compositional glass of suitable thermal expansion coefficient effiiently. a Taguchi analysis was conducted. The influence of alkali oxide and alkali earths oxide, which affect mostly the thermal expansion coefficient of glass infiltrated material, was infiltrated material, the effect having influenced on the thermal expansion coefficient of glass was presented in this order (Na$_2$O≫K$_2$O ≫MgO≒CaO). The effect of Na$_2$O was about eight times as great as the effects of MgO, CaO and $K_2$O was about four times. Among the interaction affects of each variables the interaction affects of $K_2$O-CaO showed most significantly and thermal expansion property of specified composition was predicted by calculating contribution rate on each level of variables and interaction affects.

Preparation and Characteristics of Bioactive Silica-free Calcium Phosphate Glass-ceramics (실리카를 함유하지 않는 생체활성 칼슘인산염 글라스-세라믹스의 합성 및 특성)

  • Song, Chang-Weon;Lee, Joo-Hyeok;Yang, Tae-Young;Yoon, Seog-Young;Park, Hong-Chae
    • Journal of the Korean Ceramic Society
    • /
    • v.48 no.3
    • /
    • pp.217-221
    • /
    • 2011
  • Glass-ceramic materials, which consist of glass matrix phase containing crystalline ${\beta}-Ca_3(PO_4)_2$ and ${\beta}-Ca_2P_2O_7$, have been prepared by heating at $750-900^{\circ}C$ of calcium phosphate invert glasses in the silica-free $CaO-P_2O_5-TiO_2-Na_2O$, system. With increasing heating temperature from 750 to $900^{\circ}C$, the crystallite size of precipitated ${\beta}-Ca_3(PO_4)_2$ in glass with $55CaO{\cdot}35P_2O_5{\cdot}3TiO_2{\cdot}7Na_2O$ (mol%) composition increased from 48 to 91 nm. With the extension of the immersion time in dilute acetic acid solution (pH = 5) to ${\geq}$200 min, the degree of dissolution of $Ca^{2+}$ and $P^{5+}$ ions in the glass-ceramics was linearly increased and the solution was constantly maintained at pH = ~7. Biomimetic nanostructured (62-88 nm in average dia.), sphere-shaped hydroxyapatite was homogeneously formed on the surface of the glass-ceramics when socked for 7-14 days in a Hanks' solution, indicating bioactivity of the prepared glass-ceramics.

Effect of Glass Composition on the Properties of Glass-infiltrated Alumina(I) : Effect of Al2O3 (유리가 침투된 알루미나 복합체의 물성에 미치는 유리조성의 영향(I): Al2O3의 영향)

  • 이재희;김철영
    • Journal of the Korean Ceramic Society
    • /
    • v.40 no.3
    • /
    • pp.301-308
    • /
    • 2003
  • Glass-infiltrated alumina, which can be used as an all-ceramic dental crown, was prepared. The glasses in the system of SiO$_2$-B$_2$O$_3$-Al$_2$O$_3$-CaO-La$_2$O$_3$with various amount of $Al_2$O$_3$infiltrated into a porous sintered alumina. The effect of $Al_2$O$_3$on the infiltration characteristics and its mechanical strength were studied. The corrosion of the sintered alumina by infiltrated glasses was prevented by increasing the amount of $Al_2$O$_3$in the glass batches, this increased the bending strength of the glass infiltrated alumina composite. The crack like voids in the sintered alumina was a cause of the deteriorating the mechanical strength of the composite, and this can be eliminated by sintering the alumina at 130$0^{\circ}C$. Glass infiltration under the vacuum atmosphere enhanced the hording strength of the composite up to 453$\pm$31 MPa.

Relationship between Surface Roughness and Crystal size of Li2O-Al2O3-SiO2(LAS) Glass-Ceramic System (Li2O-Al2O3-SiO2(LAS)계 결정화유리에서 결정크기와 표면조도 관계)

  • Kim Yu Jin;Hwang Seong Jin;Kim Hyung Sun
    • Korean Journal of Materials Research
    • /
    • v.14 no.7
    • /
    • pp.505-510
    • /
    • 2004
  • The glass-ceramic based on LAS($Li_{2}O-Al_{2}O_3-SiO_{2}$) system was observed using SEM(Scanning Electric Microscopy) and AFM(Atomic Force Microscopy) and it was expected to get a correlation between the crystal size and the surface roughness through the result. At heat treatment conditions (the nucleation: $740\~800^{\circ}C$, the crystal growth: $900\~1150^{\circ}C$), the crystal size was increased from 72 to 450 nm so that the mean of surface roughness was also risen from 0.8 to 6.3 nm. Based on the results, the surface roughness of glass-ceramic is controlled by the factors, crystal size, crystallines, and the condition of heat treatment.

Fracture Behavior of Plate Shape Ceramic using Compressive Shock Wave (압축 충격파를 이용한 평판형상 세라믹의 파괴거동)

  • Hwang, Kwon-Tae;Kim, Jae-Hoon;Lee, Young-Shin;Park, Jong-Ho;Song, Kee-Hyuck;Yoon, Soo-Jin
    • Proceedings of the Korean Society of Propulsion Engineers Conference
    • /
    • 2009.05a
    • /
    • pp.103-106
    • /
    • 2009
  • Fracture characteristics of plate shape using shock tube for glass filled ceramics was carried out. Glass filled ceramics have been considered as a promising candidate material for the dome port cover of air breathing engine. This part of the air breathing engine has an important role separating solid and liquid fuel, and needs the frangible characteristics that the fracture of a part should not affect the internal components of combustion. The objectives of this study are to evaluate the fracture pressures for various thicknesses and diameters of shock impact area. Also fracture phenomena of separated membrane using a shock tube are observed. The experimental apparatus of shock tube consists of a driver, a driven section and a dump tank. The used material is glass filled ceramic made from Corning company. Specimens are used 3, 4.5 and 6mm thickness. Also diameters of shock wave area are chosen 70, 60 and 50 mm. It is expected that the results obtained from this study can be used in the basic data for the dome port cover design of an air breathing engine.

  • PDF