• 한국세라믹학회지
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• 제36권12호
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• pp.1342-1349
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• 1999

In order to improve the density and the mechanical strength without change in chemical composition the hardened pastes of hydroxyapatite cement were reinforced with powders and/or whiskers of hydroxyapatite. The powders behaved as a seed of hydroxyapatite formation rather than a filler while the whiskers were mrerly dispersed in matrix and capillary pores of the hardened bodies leading to increase in mechanical strength. But the increase in strength But the increase in strength was nnt enough owing to the lack of homogeneous dispersion of the fibers. The highest diametral tensile strength of 18.5 MPa was measured at the hardened hydroxyapatite body in which well-dispersed whisker phase formed uniformly during hydro-thermal curing of power-added and dry-formed hydroxyapatite cement.

• 반도체디스플레이기술학회지
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• 제5권3호
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• pp.33-36
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• 2006

To produce a fine structure with uniform surface of barrier ribs in PDP, acid etching process has been used in manufacture process. It is necessary to understand the mechanism of etching, particularly on the interface of ceramic fillers and matrix glass. We investigated the effect of ceramic fillers (ZnO, $Al_2O_3$) on the microstructure of borate glass system to find an etching mechanism of barrier ribs. The barrier ribs was etched with several steps, dissolving a small amount of residual glass, taking out alumina fillers, and removing a cluster type of ZnO fillers and glass matrix.

• 한국분말야금학회:학술대회논문집
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• 한국분말야금학회 2006년도 Extended Abstracts of 2006 POWDER METALLURGY World Congress Part 1
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• pp.101-102
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• 2006

Processing techniques for producing microcellular silicon carbide, mullite, and cordierite ceramics have been developed by a reaction method that incorporates a polysiloxane and reactive fillers. The techniques developed in this study offer substantial flexibility for producing microcellular ceramics whereby cell size, cell density, degree of interconnectivity, composition, and porosity can all be effectively controlled. It is demonstrated that the adjustment of filler composition enables the possibility of tailoring the composition and properties of the microcellular ceramics. The present results suggest that the proposed novel processing techniques are suitable for the manufacture of microcellular ceramics with high morphological uniformity.

• 마이크로전자및패키징학회지
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• 제6권1호
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• pp.51-58
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• 1999

지르코니아에 접합과 반응성이 정합되며 고온에서 물리화학적으로 안정성을 갖는 접합재를 제조하기 위하여 silicate계 유리의 조성에 따른 적심특성, 결정화 및 반응성등 제반 특성을 고찰하였다. 지르코니아와의 열팽창계수가 정합 될 수 있는 유리계에 대한 조성 실험하였다. Alkaline earth silicate 유리는 적심성이 우수하였으며 적심각이 낮으며 $B_2O_3$의 첨가함로써 유리의 점도를 조절 및 결정화를 억제할 수가 있었다. $900^{\circ}C$ 이하에서 적심공정에 일어났으며 $800^{\circ}C$에서 10시간동안 유지한 후에 결정화와 계면 반응을 조사한 결과 기공이 많이 발생하였으며 $B_2O_3$를 15mo1% 첨가한 경우 흐름성이 증가하였으며 기판과의 반응성이 높아졌다. 기공을 없애기 위해서는 공정변수를 조절하여 유리의 소결을 촉진할 필요가 있으며 유리점도와 반응성에 관한 최적화가 요구된다. 본 연구에서는 유리-세라믹필러 복합체의 고온적심성에 대하여 조사하였다. Filler로서 $ZrO_2$분말을 여러 조건으로 열처리하여 분말종류와 첨가량에 따라 기공, $ZrO_2$ filler의 형상 및 계면반응 등을 고찰하였다.

• 대한치과보철학회지
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• 제31권3호
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• pp.317-349
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• 1993

This study investigated the effect of filler particle size and weight% on mechanical properties of dental core porcelain. In alumina, variation in particle size and weight% and in zirconia, variation in weight%, all specimens were tested three-point bending strength, transmittance, thermal expansion coefficient, porosity and shrinkage and observed with SEM and analysed with X-ray diffractometer. In order to develop shrink-free porcelain, after firing alumina only, glass wasinfiltrated. And aluminum was added to alumina with the expanding character of aluminum oxidize into alumina, and was followed by second firing of glass infiltration procedure. Then mechanical properties were observed. The results of this study were obtained as follows. 1. The bending strength of zirconia was higher than that of alumina, and $5{\mu}m$ alumina had highest strength in variation of particle size of alumina. Except for $5{\mu}m$ alumina, increased with weight%, bending strength increased up to 80% and decreased at 90%. In case of glass infiltration, bending strength was slight higher than 80% and 90% of $5{\mu}m$ alumina. 2. Transmittance increased with increase of shrinkage, decrease of porosity, and with increase of filler size and had no direct correlation with weight%. 3. Thermal expansion coefficient of alumina group was $7.42\sim8.64\times10^{-6}/^{\circ}C$ and that of zirconia group was $9.83\sim12.11\times10^{-6}/^{\circ}C$ and the latter was higher than the former. 4. In x-ray diffraction analysis, alumina group and zirconia group increased $Al_2O_3$ peak and $t-ZrO_2$ peak with increase of weight%. The second phase(cristobalite peak) was observed in zirconia 40% group. 5. Porosity of zirconia was lower than that of alumina and $5{\mu}m$ alumina group had many pores with SEM. In case of low filler content, fracture occurred in glass and high filler content, in glass and filler. In case of aluminum addition to alumina, small oxidised aluminum was observed. 6. Zirconia group had high shrinkage than alumina group, and mixed group of alumina group had high shrinkage. In case of glass infiltration, shrinkage decreased and aluminum addition to alumina group was almost shrink-free.

• 자원리싸이클링
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• 제16권1호
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• pp.44-53
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• 2007

전주일 광산 광미는 $SiO_2$의 함유량이 높고, 유해 중금속 성분의 함유량이 적은 특성을 갖고 있다. 본 연구에서는 이러한 광미를 각종 산업원료로 재활용할 수 있는 가능성을 알아보았다. 광미는 세라믹스 소결체의 원료로 사용한 결과, 색도 및 색상, 소성수축률, 흡수율 등에서 우수한 물성을 보였다. 보통포틀랜드시멘트 원료 중 실리카 성분으로 조합 원료의 2.59%까지 사용이 가능하였다. 광미를 조립물과 미립물로 분리하여 조립산물은 건조 시멘트 모르타르 원료로, 미립산물은 역청 포장용 채움재로 사용한 결과, 두 시료 모두 환경 위해성이 없고 KS 규격에 적합한 물성을 나타내었다.

• 한국세라믹학회지
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• 제31권10호
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• pp.1218-1230
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• 1994

In manufacturing process of porous glass-ceramics by the filler method, the sintering behaviour of crystallizable glass powder mixed with various salts was studied and also the effects of precipitated crystal phases on the properties of porous glass-ceramics were investigated. Fine-grained crystallizable glass powder was homogeneously mixed with various slat having grain size 100~200 ${\mu}{\textrm}{m}$ and sintered for densification. After washing out the inorganic salt with distilled water, the porous sintered body was heat treated additionly for crystallization. The MgO-Al2O3-SiO2 base glass was used as crystallizable glass powder and the water soluble salts such as K2SO4 and MgSO4 were used as filler. When K2SO4 was used, leucite crystal phase was formed as a result of the ion exchange and porous glass-ceramics which exhibit high temperature resistance and high thermal expansion coefficient of 17$\times$10-6/$^{\circ}C$ could be obtained. On the contrary, when MgSO4 was used, only slight ion exchange is observed and $\mu$-cordierite and $\alpha$-cordierite crystal phases were formed and porous glass-ceramics which exhibit low thermal expansion coefficient schedule were determined with the results of DTA curves, thermal shrinkage curves and XRD patterns analysis. From DTA curves and thermal shrinkage curves, it was found that the sintering densification have been completed at the temperature range of exothermic peak for crystallization. The pore size distributions and pore diameters were measured by mercury porosimeter. The pore diameter of porous glass-ceramics was 10~15 ${\mu}{\textrm}{m}$ when 100~200${\mu}{\textrm}{m}$ grain size of K2SO4 was used and it was 25~30 ${\mu}{\textrm}{m}$ when the same grain size of MgSO4 was used. The porous glass-ceramics K2SO4 used shows bimodal pore size distribution and its porous skeleton structure was ascertained by SEM observation.

• 한국세라믹학회지
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• 제54권4호
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• pp.340-348
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• 2017

$SiC_f/SiC$ composites were joined using a $60{\mu}m-thick$ $Ti_3AlC_2$ or $Ti_3SiC_2$ MAX phase tape. The filler tape was inserted between the $SiC_f/SiC$ composites containing a 12 wt.% $Al_2O_3-Y_2O_3$ sintering additive. The joining was performed to a butt-joint configuration at $1600^{\circ}C$ or $1750^{\circ}C$ in an Ar atmosphere by applying 3.5 MPa using a hot press. Microstructural and phase analyses at the joining interface confirmed the decomposition of $Ti_3AlC_2$ and $Ti_3SiC_2$, indicating the joining by solid-state diffusion. The results showed sound joining interface without the presence of cracks. Joining strengths higher than 150 MPa could be obtained for the joints using $Ti_3AlC_2$ or $Ti_3SiC_2$ at $1750^{\circ}C$, while those for joined at $1600^{\circ}C$ decreased to 100 MPa approximately without the deformation of the joining bodies. The thickness of initial filler tape was reduced significantly after joining because of the decomposition and migration of MAX phase owing to the plasticity at high temperatures.

• Journal of Welding and Joining
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• 제13권3호
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• pp.134-146
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• 1995

Aluminium nitride(AlN) is currently under investigation as potential candidate for replacing alumium oxide(Al$_{2}$ $O_{3}$) as a substrate material for for electronic circuit packaging. Brazing of aluminium nitride(AlN) to Cu with Ag base active alloy containing Ti has been investigated in vacuum. Binary Ag$_{98}$ $Ti_{2}$(AT) and ternary At-1wt.%Al(ATA), AT-1wt.%Ni(ATN), AT-1wt.% Mn(ATM) alloys showed good wettability to AlN and led to the development of strong bond between brate alloy and AlN ceramic. The reaction between AlN and the melted brazing alloys resulted in the formation of continuous TiN layers at the AlN side iterface. This reaction layer was found to increase by increase by increasing brazing time and temperature for all filler metals. The bond strength, measured by 4-point bend test, was increased with bonding temperature and showed maximum value and then decreased with temperature. It might be concluded that optimum thickness of the reaction layer was existed for maximum bond strength. The joint brazed at 900.deg.C for 1800sec using binary AT alloy fractured at the maximum load of 35kgf which is the highest value measured in this work. The failure of this joint was initiated at the interface between AlN and TiN layer and then proceeded alternately through the interior of the reaction layer and AlN ceramic itself.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2006년도 하계학술대회 논문집 Vol.7
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• pp.272-273
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• 2006

LTCC(low temperature co-fired ceramics)용 glass/ceramic 복합체를 제조하기 위해 4 종류의 borosilicate계 glass를 선정하고 filler로 $Al_2O_3$ ceramics를 filler 사용하여 30~50 vol% glass frit에 따른 소결 및 유전 특성에 대하여 조사하였다. Glass frit은 $SiO_2$와 $B_2O_3$ 함량비를 고정한 후 R(CaO, BaO, ZnO, $Bi_2O_3$)에 따라 유리 연화온도(Ts)와 함량이 소결에 미치는 영향 및 유전 특성 변화를 고찰한 결과, CaO-$B_2O_3-SiO_2$ glass의 경우 다량의 2 차상이 형성되었고, 이에 $900^{\circ}C$ 이하에서 완전 소결이 이루어지지 않았으며, BaO-$B_2O_3-SiO_2$ glass는 celsian($BaAl_2Si_2O_8$) 결정이 형성되면서 소결성의 저하를 갖고 왔으며, ZnO-$B_2O_3-SiO_2$ glass는 소결이 진행됨에 따라 주상이 $Al_2O_3$에서 gahnite($ZnAl_2O_4$) 결정이 형성되면서 품질계수가 크게 증가하였으며, $Bi_2O_3-B_2O_3-SiO_2$ glass는 45 vol%일 때 $900^{\circ}C$에서부터 일정한 선수축율 특성을 나타내었지만, 다량의 액상으로 인하여 유전 특성의 저하를 나타내었다.