• 한국세라믹학회지
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• 제38권11호
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• pp.1055-1059
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• 2001

인산염계 Li$_2$O.CaO.Ti $O_2$.P$_2$ $O_{5}$ 조성을 기본으로 하여 다공성 글래스 세라믹스를 제조하였으며, 제조된 모유리는 최적 핵 형성을 위해 61$0^{\circ}C$, 최고 결정성장을 위해 78$0^{\circ}C$에서 열처리하였다. 연속적으로 1N-HCl에 3일간 담지함으로써 $\beta$-Ca$_3$(PO)$_4$결정상만을 선택적으로 용출하였으며 Li $Ti_2$(P $O_4$)$_3$골격구조를 갖는 다공성 glass ceramics를 제조하였다. 1M-농도의 AgN $O_3$수용액에 2일간 담지함으로써 Li$^{+}$ 이온을 Ag$^{+}$ 이온으로 이온교환 하였으며, 그에 따른 항균효과 및 특성을 평가하였다. 항균 특성평가를 위해서는 staphylococus aureus와 salmonella typhi균을 사용하였으며, 시편 첨가 후 staphylococcus aureus 균주에 대해서는 6시간 이후에 salmonella typhi 균주에 대해서는 3시간 이후에 모든 균이 소멸되는 것으로 관찰되었다.

• E2M - 전기 전자와 첨단 소재
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• 제9권2호
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• pp.146-151
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• 1996

PZT powders were prepared by the molten salt synthesis method. The porous PZT ceramics were made from a mixture of PZT and polyvinylalcohol(PVA) by BURPS(Bumout Plastic Sphere) technique. The 3-3 type composites were fabricated by impregnating an sintered porous PZT ceramics with various polymer matrices. The relative permittivity of 3-3 type composite specimens was shown 860-1,100 smaller than that of solid PZT ceramics(2,100), and the dissipation factors of composite specimens were about 0.02 to 0.03. The piezoelectric coefficient d$_{33}$ of composite specimens(285-328*10$^{12}$ C/N) was comparable with that of single phase PZT specimens(364*10$^{-12}$ C/N). The thickness mode coupling factor k$_{t}$(O.5-0.6) of composite specimens was comparable with that of single phase PZT specimens(k$_{t}$-0.7), and the mechanical quality factor of composite specimens was smaller than 10, and thus these 3-3 type composite specimens would be believed as a good candidates for broad band transducer applications.ons.

• 한국세라믹학회지
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• 제46권6호
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• pp.609-614
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• 2009

The low-temperature preparation of porous ceramics was carried out using mixtures of alumina-zinc borosilicate (ZBS) glass. The compositions of alumina-ZBS glass mixture with PMMA pore-former were unfortunately densified. Because PMMA was evaporated below the softening point of ZBS glass ($588{^{\circ}C}$), the densification through the pore-filling caused by the capillary force might occur. Howerver, those with carbon possessed pores where carbon was evaporated above the softening point. The porous ceramic having 35% porosity was successively fabricated by the low-temperature sintering process below $900{^{\circ}C}$ using 45 vol% of alumina, 45 vol% ZBS of glass, and 10 vol% of carbon as starting materials.

• 한국세라믹학회지
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• 제44권6호
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• pp.338-342
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• 2007

Porous silicon nitride ceramics were prepared by SHS (Self-Propagating High Temperature Synthesis) from silicon powder, silicon nitride powder and pore-forming precursor. The microstructure, porosity and the flexural strength of the porous silicon nitride ceramics were varied according to the Si/Si3N4 ratio, size and amount of the pore-forming precursors. Some sample exhibited as high flexural strength as $162{\pm}24\;MPa$. The high strength is considered to result from the fine pore size and the strong bonding amoung the silicon nitride particles.

• 한국세라믹학회지
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• 제39권10호
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• pp.948-954
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• 2002

차세대 발전 시스템에서 사용되는 고온 가스 필터용 지지층 소재를 제조하기 위하여 용융 Si 침윤 방법으로 기공율이 32∼36%, 주기공 크기가 37∼90 ${\mu}m$ 범위를 갖는 고강도 다공질 반응소결 탄화규소(RBSC)를 개발하였다. 반응소결 탄화규소 다공체의, 최대 파괴강도는 120MPa이었으며, 용융 Si 침윤 방법으로 제조된 반응소결 탄화규소 다공체에서는 SiC 입자 사이에 SiC/Si로 이루어진 기지상이 형성되어 있기 때문에 파괴 강도 및 열충격 특성이 점토 결합 탄화규소 다공체 보다 우수하였다. 반응소결 탄화규소 다공체의 기공율 및 기공 크기는 잔류 Si의 양 및 성형체에 사용한 SiC 입자 크기에 따라 다르게 나타났다.

• Korean Chemical Engineering Research
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• 제53권4호
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• pp.425-430
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• 2015

고분자 복제방법을 이용하여 제조한 폼 형태의 다공성 탄화규소 표면에 수열 합성 방법을 적용하여 ZSM-5를 합성하였다. 다공성 탄화규소 표면으로부터 ZSM-5가 합성될 수 있도록 유도하기 위하여 합성단계에 앞서 탄화규소 표면에 산화 층을 형성하였다. 수열합성 반응은 산화처리 된 다공성 탄화규소와 TEOS, $Al(NO_3){\cdot}9H_2O$ 및 TPAOH를 원료로 사용하여 $150^{\circ}C$에서 7시간 진행하였다. XRD 및 SEM 분석을 통하여 $1{\sim}3{\mu}m$ 크기의 ZSM-5가 다공성 탄화규소 표면에 코팅되어 성장하였음을 확인하였다. BET 분석결과 ZSM-5 합성 후에 $10{\AA}$이하의 미세기공이 급격히 증가하였으며, 비표면적이 $0.83m^2/g$에서 $30.75m^2/g$으로 급격히 증가되었음을 알 수 있었다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1995년도 하계학술대회 논문집 C
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• pp.1199-1201
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• 1995

PZT powders were prepared by the molten salt synthesis method. The porous PZT was preapred from the mixture of PZT and PVA powders by BURPS(BURnout plastic Sphere) technique. The acoustic properties with various plastic sphere wt.% were studied. The acoustic impedance of porous PZT was smaller than that of single phase PZT ceramics. And the pulse-reponse of porous PZT maded transducer was significantly advanced to that of solid PZT maded transducer.

• 한국세라믹학회지
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• 제31권11호
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• pp.1323-1329
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• 1994

Tape casting and lamination were used to produce heterogeneous laminates with alternating layers of different porosity and homogeneous laminates with component layers of the same porosity. The pore structure was investigated for heterogeneous laminates, and bend strength was measured for comparison with that of homogeneous laminates. For a reference, strength measurement was made for the porous body fabricated by sintering samples dry-pressed at low pressure with spray-dried granules. Strength increase, in the range 50~120 MPa, was achieved in the presence of the surface dense layer, while extensive delamination, presumably responsible for enhanced fracture toughness, took place through the internal porous layer.

• 한국세라믹학회지
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• 제36권6호
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• pp.662-670
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• 1999

Porous alumina was fabricated from pressureless powder packing forming method using powders granulated by spray drying. It was investigated the pore size distribution of fabricated porous alumina. The results of microstructural observation showed that intraganular pore size and intragranular pore size. At 1700$^{\circ}C$ there were no intragranular pores but it showed homogeneous distribution of intergranular pore size. The bending strength and shrinkage increased as porosity decreased. In case of thermal shock resistance sudden decrease of bending strength to $\Delta$T was not shown because intergranular large pore prevented sudden crack propagation.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1994년도 하계학술대회 논문집 C
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• pp.1475-1477
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• 1994

Porous piezoelectric ceramics of PZT have been newly developed to apply for ultrasonic transducers. The porous PZT was prepared from a mixture of PZT and polyvinylalcohol (PVA) powders by BURPS(Burnout Plastic Sphere) technique. Porous PZT bodies were shown a homogeneous microstructure consisting of 30 - 80 (${\mu}m$) pore size in sintered PZT bodies. The dielectric and piezoelectric properties on various PVA wt.% have investigated.