• Journal of the Korean Ceramic Society
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• v.36 no.12
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• pp.1350-1355
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• 1999

Sintering characteristics and dielectric properties of low temperature sinterable Glass/Ceramic dielectric materials were investigated. The dielectric materials which were developed for microwave frequency applications consist of SiO2-TiO2-Bi2O3-RO system(RO:BaO-CaO-SrO) crystallizable glass and Al2O3 as a ceramic filler. Sintering experiments showed that no more densification occurred above 80$0^{\circ}C$ and bulk density and shrinkage depended on Al2O3 content only. Results of dielectric measurements showed that $\varepsilon$r Q$\times$f and $\tau$f of the material containing 30wt% Al2O3 were 17.3, 600 and +23 ppm respectively. Those values for 45 and 60wt% Al2O3 samples were 11.6, 1400, +0.7 ppm and 7.2, 2000, -8.5 ppm, repectively. The results clearly showed that the Glas/Ceramic materials of present experiment decreased in $\varepsilon$r and increased in $\times$f value and changed from positive to negative value in $\tau$f value with the increasement of Al2O3 content.

• Journal of the Korean Ceramic Society
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• v.46 no.3
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• pp.323-329
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• 2009

Influences of ceramic filler types and dose on the sintering, phase evolution, and dielectric properties of ceramic/CaO-$Al_2O_3-SiO_2$ glass composites were investigated. All of the specimens were sintered at $900^{\circ}C$ for 2 h, which conditions are required by the lowtemperature co-firing ceramic (LTCC) technology. Ceramic fillers of $Al_2O_3,\;SiO_2$, kaolin, and wollastonite were used. The addition of $Al_2O_3$ filler yielded the crystalline phases of alumina and wollastonite, and the densification over 95% of the relative density was achieved up to 50 wt% addition of the filler. For the cases of the fillers of $SiO_2$, kaolin, and wollastonite, crystalline phases of quartz, mullite, and wollastonite formed, while the densification decreased monotonically with the filler addition. In overall, all the investigated fillers with 10 wt% addition resulted in a reasonable sintering (over 95 %) and low dielectric constants (less than 6), demonstrating the feasibility of the investigated composites for application to a LTCC substrate material with a low dielectric constant.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.11a
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• pp.81-81
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• 2009

Non-sintered Alumina films were fabricated via inkjet printing processes without a high temperature sintering process. The packing density of these inkjet-printed alumina films measured around 60%. Polymer resin was infiltrated thru these non-sintered films in order to fill out the 40% of voids constituting the rest of the inkjet-printed films. The concept of inkjet-printed Alumina-Resin hybrid materials was designed in order to be applicable to the ceramic package substrates for 3D-system module integration which may possibly substitute LTCC-based 3D module integration. So, the dielectric properties of these inkjet-printed $Al_2O_3$ hybridmaterialsareofourgreatinterest. We have measured dielectric constant and dissipation factor of the inkjet-printed $Al_2O_3$-resinhybridfilmsbyvaryingtheamountofresininfiltratedthruthe$Al_2O_3$films.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.22 no.5
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• pp.397-404
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• 2009

Effects of ceramic filler types and dose on the low temperature sintering and dielectric properties of ceramic/$CaO-Al_2O_3-SiO_2$ (CAS) glass composites were investigated. All of the specimens were sintered at $850{\sim}900^{\circ}C$ for 2 h, which conditions are required by the low-temperature co-firing ceramic (LTCC) technology. Ceramic fillers of $CaCO_3$, $Al_2O_3$, $CaCO_3-Al_2O_3$ mixture, and $CaCO_3-Al_2O_3$ compound ($CaAl_2O_4$), respectively, were used. The addition of $Al_2O_3$ yielded the crystalline phase of alumina, which was associated with the inhibition of sintering, while, $CaCO_3$ resulted in no apparent crystalline phase but the swelling was significant. The additions of $CaCO_3-Al_2O_3$ mixture and $CaAl_2O_4$, respectively, yielded the crystalline phases of alumina and anorthite, and the sintering properties of both composites increased with the increase of filler addition and the sintering temperature. In addition, the $CaAl_2O_4$/CAS glass composite, sintered at $900^{\circ}C$, demonstrated good microwave dielectric properties. In overall, all the investigated fillers of 10 wt% addition, except $CaCO_3$, yielded reasonable sintering (relative density, over 93 %) and low dielectric constant (less than 5.5), demonstrating the feasibility of the investigated composites for the application of the LTCC substrate materials.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.28 no.5
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• pp.76-81
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• 2014

The ozone generation is commonly made with silent discharge method using quartz glass dielectric. In this paper, using $Al_2O_3$ dielectric to instead of the traditional quartz glass dielectric to improve the system efficiency is presented. The dielectric was manufactured as tube shape (Internal diameter${\times}$ Outside diameter: $11{\times}15mm$) using 99% $Al_2O_3$ ceramic. The characteristics of dielectric discharge and ozone generation were studied of experiments with variation of discharge power, discharge electrode space and rate of flow for supplied gas ($O_2$/Air). As the experimental results, in the same discharge space, the ozone concentration continuously increased with input power increasing, and ozone yield increased until saturation happened. Also, the expended power increased with discharge space extended due to discharge power increased. In additional, the ozone concentration of oxygen ozone was higher than air that was observed when using oxygen ozone in proposed experiments.

• Journal of Powder Materials
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• v.25 no.6
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• pp.494-500
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• 2018

In this study, the effect of the content of $MgO-CaO-Al_2O_3-SiO_2$ (MCAS) glass additives on the properties of AlN ceramics is investigated. Dilatometric analysis and isothermal sintering for AlN compacts with MCAS contents varying between 5 and 20 wt% are carried out at temperatures ranging up to $1600^{\circ}C$. The results showed that the shrinkage of the AlN specimens increases with increasing MCAS content, and that full densification can be obtained irrespective of the MCAS content. Moreover, properties of the AlN-MCAS specimens such as microhardness, thermal conductivity, dielectric constant, and dielectric loss are analyzed. Microhardness and thermal conductivity decrease with increasing MCAS content. An acceptable candidate for AlN application is obtained: an AlN-MCAS composite with a thermal conductivity over $70W/m{\cdot}K$ and a dielectric loss tangent (tan ${\delta}$) below $0.6{\times}10^{-3}$, with up to 10 wt% MCAS content.

• Journal of the Korean Ceramic Society
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• v.30 no.1
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• pp.1-6
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• 1993

Dielectric and piezoelectric porperties of pseudoternary xPb(Al2/3W1/3)O3-(1-x)Pb(Zr0.52Ti0.48)O3 (x=1~10mol%) ceramic system have been investigated as a function of the amount of PAW[Pb(Al2/3W1/3)O3] and sintered from 110$0^{\circ}C$ to 120$0^{\circ}C$ for 1hr. As the amount of PAW increases, the c/a of tetragonal structure decreases. The grain size was reduced with increasing the amount of PAW addition. However, the density, dielectric constant and electromechanical coupling factor(kp) exhibited a maximum value at the amount of 5mol% PAW addition.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.07b
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• pp.611-615
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• 2003

The crystalline and dielectric properties on $Al_2O_3$ filled glass frit ($CaO-Al_2O_3-SiO_2-MgO-B_2O_3$) with admixtures of $TiO_2$ have been investigated. The dielectric constant value of $7.5{\sim}7.8$, quality factor value of 700 were obtained for glass frit : $Al_2O_3$ (50 : 50 wt%) ceramics. As the amount of $TiO_2$ increased, temperature coefficient of dielectric constant were decreased.

• Journal of the Korean Ceramic Society
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• v.39 no.5
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• pp.438-445
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• 2002

In this study, the glass frit of $PbO-TiO-2-SiO_2-BaO-ZnO-Al_2O-3-CaO-B_2O_3-Bi_2O_3-MgO$ system was manufactured. The glass was melted at $1,400{\circ}C$, quenched and attrition-milled. The glass frit powder was pressed and fired for 2h at the range of $750~1,000{\circ}C$. The crystallization of glass frit began at about $750{\circ}$ and at low temperature, the main crystal phases were hexagonal celsian($BaAl_2Si_2O_8$) and alumina. As the firing temperature increased, the crystal phases of monoclinic celsian, zinc aluminate, zinc silicate, calcium titanium silicate and titania appeared. And the increase of firing temperature led to transformation of hexagonal celsian to monoclinic. The only glass frit containing 15wt% PbO had the crystal phase of solid solution of $PbTiO_3-CaTiO_3$. At the frequency of 1 MHz, the dielectric constant of glass frit crystallized was in the range of 11~16 and the dielectric loss less than 0.020. But the glass frit containing 15wt% PbO had the dielectric constant of 17~26 and loss of 0.010~0.015 because of crystal phase of solid solution of $PbTiO_3-CaTiO_3$.

• Journal of the Korean Ceramic Society
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• v.43 no.6 s.289
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• pp.338-343
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• 2006

The effects of lead-borosilicate glass frits on the sintering behavior and microwave dielectric properties of ceramic-glass composites were investigated as functions of glass composition of glass addition ($10{\sim}50vol%$), softening point (Ts) of the glass, and sintering temperature of the composites ($500{\sim}900^{\circ}C$ for 2 h). The addition of 50 vol% glass ensured successful sintering below $900^{\circ}C$. Sintering characteristics of the composites were well described in terms of Ts. PbO addition in to the glass enhanced the reaction with $Al_{2}O_3$ to form liquid phase and $PbAl_{2}Si_{2}O_8$, which was responsible to lower Ts. Dielectric constant(${\epsilon}_r$), $Q{\times}f_0$ and temperature coefficient of resonant frequency (${\tau}_f$) of the composite with 50 vol% glass contents ($B_{2}O_{3}:PbO:SiO_{2}:CaO:Al_{2}O_3$ = 5:40:45:5:5) demonstrated 8.5, 6,000 GHz, $-70\;ppm/^{\circ}C$, respectively, which is applicable to substrate requiring a low dielectric constant. When the same glass composition was applied sinter $MgTiO_3\;and\;TiO_2,\;at\;900^{\circ}C$ (50 vol% glass in total), the properties were 23.8, 4,000 GHz, $-65ppm/^{\circ}C$ and 31.1, 2,500 GHz, $+80ppm/^{\circ}C$ respectively, which is applicable to filter requiring an intermidiate dielectric constant.