• Electrical & Electronic Materials
• /
• v.8 no.1
• /
• pp.95-101
• /
• 1995

Crystallizable glasses with precipitation of celsian, anorthite, wollastonite and gahnite were prepared for the purpose of insulating dielectric layers in devices such as integrated circuit substrates. The starting glasses were prepared by melting the batches for 1 hour at 1450.deg. C and then Quenching to a distilled water. And crystallization behavior of these glasses were studied by DTA, TMA, XRD analysis and by the measurement of dielectric properties. The overall composition of the glass-ceramic consists in weight percent of 30-35% A1$_{2}$O$_{3}$, 13-26% BaO, 5-21% CaO, 10-24% ZnO, 4.5-9.0% TiO$_{2}$ and 4-8% B$_{2}$O$_{3}$. As a result, in barium-rich glasses only celsian phase was developed in the range of 850-900.deg. C. Also, the thermal expansion coefficient, dielectric constant and quality factor of these glass-ceramics were 68*10$^{-7}$ /.deg. C, about 9 and more than 1000, respectively.

• Journal of the Korean Ceramic Society
• /
• v.41 no.8
• /
• pp.599-604
• /
• 2004

The LTCCs (Low-Temperature Co-fired Ceramics) are very important for electronic industry to build smaller RF modules and to fulfill the necessity for miniaturization of devices in wireless communication industry. The dielectric materials with sintering temperature $T_{sint}$＜90$0^{\circ}C$ are required. In this study, BaO-N $d_2$ $O_3$-Ti $O_2$ (BNT ： 20∼40 wt％) for ceramic materials and L $a_2$ $O_3$- $B_2$ $O_3$-Ti $O_2$ (LBT ： 80∼60 wt％) for crystallizable glasses were used. The glass/ceramic composites were investigated for sintering behavior, phase evaluation, densities, interface reaction and microwave dielectric properties. It was found that the addition LBT glass frist significantly lowered the sintering temperature to below 90$0^{\circ}C$ and the densification with increasing addition LBT glass frist developed rapidly which was meant to be namely 90％ of relative density. The sintered bodies ekhibited applicable dielectric properties, namely 15 for $\varepsilon$$_{r}$,, 10000 GHz for Q＊ $f_{0}$. The results suggest that the composites have good potential as a new candidate for LTCC materials.

• Proceedings of the Korean Ceranic Society Conference
• /
• 2000.10a
• /
• pp.167.2-167
• /
• 2000

• Proceedings of the Korea Institute of Fire Science and Engineering Conference
• /
• 2009.04a
• /
• pp.188-193
• /
• 2009

유리벌브는 다양한 자동 소화장치 또는 시설에 신뢰성이 높은 감열체로서 각광받고 있다. 당사는 최근 작동온도가 매우 균일하고 하중강도가 우수한 유리벌브를 개발하였고 양산화에도 성공하였다. 본 논문에서는 당사가 개발한 유리벌브의 품질특성을 소개하고자 한다. 특히 본 연구에서는 화재 감지용 감열체로서 유리벌브의 주요 특성치인 반응시간지수 (RTI)에 대해 비중 있는 연구를 진행하여 유리벌브의 RTI를 결정하는 주요 변수들을 도출하고, 이를 설계에 응용하여 유리벌브의 RTI를 조절할 수 있는 툴로서 개발하였다.

• Korean Journal of Materials Research
• /
• v.7 no.1
• /
• pp.81-88
• /
• 1997

Vanadate glasses using $B_2O_3$ as a network former and with CuO additive were mainly investigated in relation to electrical properties. Crystalline phases formed by heat-treatment in each composition were examined and dc electrical conductivity changes of the glasses were analyzed. Crystalline phases were identified as $V_3O_5,\;a-CuV_2O_6\;and\;{\beta}-CuV_2O_6$ by XRD analysis. Crystallization degrees of $V_2O_5$ and ${\beta}-CuV_2O_6$ were little changed with heat-treatment time, but those of ${\alpha}u-CuV_2O_6$ were changed sharply with heat-treatment time. The more crystallization of ${\alpha}u-CuV_2O_6$ occurred, the higher electrical conductivity was observed. Electrical conductivities with $10^{-2}~10^{-4}/{\Omega}/cm$ at room temperature(303K) could be obtained by controlling the glass compositions. The electrical conductivities were increased with increasing of $V_20_5$ content and decreasing of alkality($CuO/B_2O_3$). In this study, electron was proved to be charge carrier by seebeck coefficient measurement. Accordingly, the glasses are believed to be n-type semiconductor. Calculated activation energies for the conduction were in the range 0.098-0.124 eV. Electrical conduction mechanism was small polaron hopping without showing variable range hopping in the temperature range $30~200^{\circ}C$.

• Composites Research
• /
• v.35 no.2
• /
• pp.75-79
• /
• 2022

In this study, the effect of mechanical and chemical properties of glass fiber reinforced thermoplastic (GFRTPs) according to the number of recycling was confirmed. The composite materials were manufactured through a hot press compression molding process using an E-glass chopped strand mat and a polypropylene film. Four specimens were named according to the number of recycled test repeat: First manufacture, 1st Recycle, 2nd Recycle, and 3rd Recycle. To investigate the mechanical properties of the prepared specimen, tensile test, flexural test, drop-weight impact test, differential scanning calorimetry (DSC), and field emission electron gun-scanning electron microscope (FE-SEM) was performed. As a result, as the number of recycling steps repeat, the degree of crystallization, tensile strength, elastic modulus, and flexural strength were increased, but the impact properties were greatly reduced.

• Proceedings of the Materials Research Society of Korea Conference
• /
• 1996.11a
• /
• pp.132-132
• /
• 1996

• Proceedings of the Korean Institute of Surface Engineering Conference
• /
• 1999.10a
• /
• pp.57-58
• /
• 1999

• Proceedings of the Materials Research Society of Korea Conference
• /
• 1994.05a
• /
• pp.81-81
• /
• 1994

• Proceedings of the KAIS Fall Conference
• /
• 2000.04a
• /
• pp.21.1-21
• /
• 2000