• 한국세라믹학회지
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• 제36권1호
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• pp.61-68
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• 1999

층상구조를 이루는 재료의 소결시 형성되는 다양한 결함 및 잔류응력을 고찰하기 위해 TZP-SUS계 및 ZT/SUS계다층재료와 porcelain/alumina 및 porcelain/Y-TZP 이층재료를 소결법으로 제조하였다. 상압소결로 제조한 다층재료에서는 층간의 소결수축율 차이에 의해 warping, splitting, 균열 등의 소결결함이 관찰되었으며, 중간층수 및 두께의 조절과 출발물질의 제어를 통해 이러한 소결결함이 완화됨을 알 수 있었다. Tape casting법으로 제조한 다층재료에서는 소결시 가한 압력에 의해 소결결함, 특히 warping이 제어됨을 확인할 수 있었다. 이층재료에서 형성되는 잔류응력은 vickers 압입법으로 관찰하였다. Porcelain/alumina에서는 porcelain 측의 계면에 작은 인장응력이, porcelain/Y-TZP에서는 압축응력이 형성됨을 확인할 수 있었으며, 이러한 잔류응력은 이층재료의 강도에도 영향을 미침을 알수 있었다. 결국 다층재료의 소결결함 및 잔류응력은 재료설계와 출발물질 상수에 영향을 받는다는 것을 알 수 있었다.

• 한국재료학회지
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• 제16권3호
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• pp.157-162
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• 2006

Pressable ceramics have many applications in the field of dental industry because of their excellent esthetic, compressive strength, chemical durability. Despite these attractive characteristics, they have not been widely used since they are very brittle and extremly sensitive to porcelain. In this study, the fabrication of pressable dental porcelain ($SiO_2-Al_2O_3-K_2O-Na_2O$) as a function of contents of $Al_2O_3,\;BaO\;and\;ZrO_2$ were investigated. And then compressive strength, Vickers hardness, density and thermal expansion coefficient (TEC) tests have been carried out to evaluate properties of pressable dental porcelain fabricated. The property of pressable dental porcelain fabricated by adding of 15%$Al_2O_3$ and 2%BaO contents was closely approximated to that of natural tooth.

• 한국전기전자재료학회논문지
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• 제17권8호
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• pp.882-887
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• 2004

The new magnetic porcelain materials have been studied by mixing magnetic St-ferrite powders with traditional porcelain materials before forming process. For the maintenance of magnetic characteristics after glaze firing process, the Sr-ferrite grains with the size of 1∼2 ${\mu}{\textrm}{m}$ were agglomerated as the isotropic granules with the size of 0.5∼2 mm. The high characteristics of magnetic porcelain materials were achieved at the following conditions; isotropic Sr-ferrite granules of 30 wt%, granule size of 1.4∼2 mm, and glaze firing temperature of $1250^{\circ}C$ in air The magnetic porcelain materials indicated the high magnetic properties, such as the remanent flux density of 240 G, the intrinsic coercivity of 3910 Oe, and the surface flux density of 178 G. The extraction properties of the magnetic tea cups were high compared to that of the traditional tea cups.

• 구강회복응용과학지
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• 제18권3호
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• pp.179-184
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• 2002

To compare surface roughness in various porcelains and know effects of condensation, We used Ceramco dentin porcelain, Creation dentin porcelain, Creation margin porcelain, Vintage margin porcelain, Vintage dentin porcelain, and Vita dentin porcelain, and built up the powders with condensation or not, and then fired according to the instructions with porcelain furnace( Dekema, Germany ). We polished the samples step by step using the porcelain adjustment kit( Shofu Inc., Japan ), and then measured, compared and analysed Ra, Rz, and Rmax with Surftest SV-400( Mitutoyo Co., Japan ). 1. With condensation, roughness is significantly increased in Ceramco dentin porcelain (p<0.05) and decreased in Vita dentin porcelain(p<0.05). 2. In Ra, Vita dentin porcelain is significantly the roughest and Creation margin porcelain is rougher than others in no condensation, (p<0.05), and there is no difference under condensation. 3. In Rz, Vita dentin porcelain is significantly the roughest and Creation margin porcelain is rougher than others in no condensation, and Creation margin porcelain is significantly the roughest and Creation dentin porcelain is rougher than others under condensation(p<0.05). 4. In Rmax, Vintage dentin porcelain is significantly the roughest and Creation margin porcelain is rougher than others in no condensation, and Creation margin porcelain is significantly the roughest than others under condensation(p<0.05).

• 한국재료학회지
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• 제31권11호
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• pp.608-613
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• 2021

This study investigated the reaction between clay and Mn. Mn was coated using a manganese sulfate on porcelain plate and sintered from 1,100 ℃ to 1,250 ℃. The body begin to shrink around 950 ℃ with the increase in temperature and rapidly progressed after 1,100 ℃. Shrinkage of celadon body was performed at a lower temperature than for other substrates. Quartz, kaolin, and feldspar were the main crystalline phases of the starting materials, but they became mullite and crystobalite during the firing process, and some formed amorphous glass. When manganese sulfate was applied and fired, manganese oxide was fused, and some manganese oxide reacted with the substrate to show a dense microstructure different from that of the substrate; the substrate had pores. The manganese coated porcelain fired at 1,200 ℃ had L^* values of 55.25, 36.87, and 37.13 for the white ware, celadon body, and white mixed ware, respectively; with a^* values of 4.63, 3.07, and 2.15, and b^* values of 7.93 and 3.98, it was found to be 3.42. This result indicated that the color of the surface was affected during firing by the chemical reaction between the substrate and manganese.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2003년도 춘계학술대회 논문집 초전도 자성체 연구회
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• pp.88-91
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• 2003

The magnetic porcelain materials were studied by using the porcelain materials added Sr-ferrite powders before forming and firing process. For the high magnetic property, the Sr-ferrite magnetic powders with the grain size of 1 ${\mu}m$ were agglomerated the powder size of about 1 mm. The magnetic porcelain with 30 wt% of Sr-ferrite powders indicated the magnetic characteristics such as the remanent flux density of 240 G and the intrinsic coercivity of 3910 Oe, at the firing conditions of $1250^{\circ}C$/1hr in air.

• 대한치과보철학회지
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• 제43권2호
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• pp.149-157
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• 2005

Statement of problem. Dental ceramics exhibit excellent esthetic property, compressive strength, chemical durability biocompatibility and translucency. However, it suffers from inherent brittle fractures. Various techniques and materials for intraoral porcelain repair has been suggested. Purpose. This study is to compare the tensile bond strength of four commonly used porcelain repair systems (Vivadent, Bisco, Ulttadent, Voco) and to insure the best system for the clinical application to the fractured porcelain. Materials and methods. A total of fifty specimens were fabricated. Specimens were stored in $37^{\circ}C$ distilled water for 7 days and thermocycling was performed(1000 cycles), and subjected to a tensile force parallel to the repair resin and porcelain interface by use of an Universal Testing Machine. Result. 1. Voco showed the highest tensile bond strength. In decreasing order, the tensile bond strength of the other materials was as follows : Ultradent, Bisco, Vivadent. 2. There was a statistically significant difference between the porcelain repair systems(Voco, Ultradent > Bisco, Yivadent) (p<0.05). 3. SEM examination of prepared porcelain surfaces revealed that the surface treated with Voco showed brittle fracture. However, Ultradent, Bisco and Vivadent showed ductile fracture. 4. All specimens treated with four porcelain repair systems showed adhesive failure between porcelain and composite resin.

• 한국전기전자재료학회논문지
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• 제29권11호
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• pp.690-695
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• 2016

Induction cooktop has a great attention due to its safety, quick heating and cleanness compared to gas oven. However, the materials for induction cookware is limited to steel or stainless-steel which has the magnetic property. Recently, it has been tried to apply various porcelain to induction cookware after printing the silver layer on the bottom of cookware plates and co-firing at high temperature. Glass frits are added in the silver paste to improve an adhesion force between porcelain materials containers and transferred silver layer. The hybrid silver pastes for induction cookware requires the proper electrical resistance and the thermal conductivity with base plates. After sintering process at $800^{\circ}C$, a part of melted glass migrated to the porcelain and the rest of the glass frit was exposed to the surface. It was confirmed that most of the glass frit formed an adhesion layer between the porcelain and transferred silver layer that enhances the adhesion force.

• 대한치과보철학회지
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• 제32권1호
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• pp.9-22
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• 1994

Porcelain and resin are widely used in esthetic dentistry. In the field of esthetic dentistry, the color and color stability of prosthetic materials are very important in esthetics. In this study, porcelain and resin with the same color were used to veneer on the 3 different metal alloys. Color was evaluated by the CIE $L^*a^*b^*$ system. The purpose of this study was evaluated the cole, difference and cole, stability of the specimens, according to the veneered materials and types of metal alloys. Specimens were divided into 6 groups as follows ; Group 1; Porcelain on the precious metal alloy Group 2; Porcelain on the semiprecious metal alloy Group 3; Porcelain on the nonprecious metal alloy Group 4; Resin on the precious metal alloy Group 5; Resin on the semiprecious metal alloy Group 6; Resin on the nonprecious metal alloy The results obtained were as follows; 1. In porcelain specimens, $L^*$ values showed no significant difference and $a^*$ value of group 2 was lower than that of groups 1, 3 and $b^*$ value of group 2 was higher than that of groups 1, 3. The ${\Delta}E^*ab$ values between group 1-2, group 2-3 were higher than 1.5. 2. In resin specimens. $L^*$ value of group 6 was lower than that of groups 4, 5, $a^*$ value of group 4 was higher than that of group 6, $b^*$ value of group 4 was higher than that of groups 5, 6. The ${\Delta}E^*ab$ values between group 4-5, group 5-6 were higher than 1.5, and between group 4-6 was higher than 3.0. 3. Comparing with veneered materials, $L^*$ flues of porcelain were higher than that of resin. 3. Comparing with veneered materials, $L^*$ values of porcelain were higher than that of resin. In semiprecious metal alloy, $a^*$ values of porcelain were lower than that of resin. In semiprecious and nonprecious metal alloy, $b^*$ values of porcelain were higher than that of resin. The ${\Delta}E^*ab values were higher than 6.0. 4. The color stability of resin specimen was relatively inferior to porcelain specimen.

• 한국전기전자재료학회논문지
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• 제30권9호
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• pp.558-565
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• 2017

Hybrid insulators that have the advantages of both porcelain (high mechanical strength and chemical stability) as well as polymer (light weight and high resistance to pollution) insulators, can be used in place of individual porcelain and polymer insulators that are used for both mechanical support as well as electrical insulation of overhead power transmission lines. The most significant feature of hybrid insulators is the presence of porcelain/polymer interfaces where the porcelain and polymer are physically bonded. Individual porcelain and polymer insulators do not have such porcelain/polymer interfaces. Although the interface is expected to affect the mechanical/electrical properties of the hybrid insulator, systematic studies of the adhesion properties at the porcelain/polymer interface and the effect of the interface on the insulation characteristics and electric field distribution of the hybrid insulator have not been reported. In this study, we fabricated small hybrid insulator specimens with various types of interfaces and investigated the effect of the porcelain/polymer interface on the microstructure, insulating characteristics, and electric field distribution of the hybrid insulators. It was observed that the porcelain/polymer interface of the hybrid insulator does not have a significant effect on the insulating characteristics and electric field distribution, and the hybrid insulator can exhibit electrical insulating properties that are similar or superior to those of individual porcelain and polymer insulators.