• 한국세라믹학회지
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• 제38권9호
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• pp.860-865
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• 2001

본 논문은 출발물로서 2mol% CdO가 치환된 $0.05Pb(Mn_{1/3}Sb_{2/3})O_3-0.95Pb(Zr_{0.52}Ti_{0.48})O_3$ 분말을 제조 후, 닥터 블레이드 방법으로 green sheet를 제조하기 위한 slurry의 최적 공정첨가제 조성에 관한 연구를 수행하였다. 또한, 제조된 green sheet에 대하여 소결 특성과 두께 변환에 따른 유전 및 압전 특성을 관찰하였다. 공정첨가제의 첨가에 따른 점도거동을 통하여 slurry를 최적화하였고, TGA 분석으로 소결조건을 정하였으며, sheet의 특성에 미세구조와 XRD 등으로 측정하였다. 최적의 slurry는 고형분량 30vol%에 대해 분산제 3.0wt%에서 가장 안정화되었고, 이후 바인더/가소제(0.75/0.25) 3.0wt% 첨가시 점도는 7.55Pa${\cdot}$s이었다. Green sheet의 유전 및 압전 특성들은 각각 900$^{\circ}$C, 950$^{\circ}$C, 1000$^{\circ}$C로 소결온도를 증가함에 따라 다소 증가하였지만, 두께에 따른 특성들은 큰 변화가 관찰되지 않음을 확인하였다.

• 한국세라믹학회지
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• 제36권7호
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• pp.705-710
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• 1999

Stability and chemical durability for aqueous casting of BaTiO3 slurry with polycarylic acid(PAA) were studied. PAA was well chemisorbed on surface of BaTiO3 powder at neutral pH but did not chemically adsorbed at low pH. The amount of Ba dissolution in aqueous BaTiO3 slurry was abruptly increased at strong acid pH2 and also at high amount of PAA. Protection of Ba dissolution and stability of slurry could be obtained through the optimization of slurry conditions such as pH amount of surfactant and solid content.

• 한국전기전자재료학회논문지
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• 제32권6호
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• pp.483-489
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• 2019

For machine learning techniques, a large amount of high-quality material property data should be accumulated. In this study, several data for an alumina tape casting process were produced with the variables of slurry viscosity, gap size, and coating speed. The alumina tapes were manufactured in the range of 1,000~6,000 cps for slurry viscosity, $300{\sim}1,000{\mu}m$ for gap size, and 0.5~2.0 m/min for coating speed. As a result, the lower the viscosity, coating speed, and gap size, the more pore-free tapes could be manufactured. The viscosity of the slurry limited the minimum thickness of the tape. Green sheets with high packing density were manufactured from the slurry of 100~6,000 cps slurry viscosity, coating speed of 0.5 m/min, and a $300{\sim}500{\mu}m$ gap size.

• 한국세라믹학회:학술대회논문집
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• 한국세라믹학회 2002년도 추계총회 및 연구발표회 초록집
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• pp.96.1-96
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• 2002

• 한국세라믹학회지
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• 제48권1호
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• pp.74-79
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• 2011

The pore generation technology using GHM (Glass Hollow Microsphere) was studied in order to reduce the weights of porcelain. In this study, we verify the property of modified slurry by adding GHM. The modified slurry was prepared by adding 1.0~2.5 wt%(K1), 1.0~6.0 wt%(K37) of GHM to the slurry for porcelain. The slurry viscosity were stable inside a content range of 1.0~2.5 wt%(K1), 1.0~6.0 wt%(K37). However, the viscosity of modified slurry increased more than 3.0 wt%(K1) and 6.5 wt%(K37). The formed specimen by slip casting was fired at $1229^{\circ}C$, $1254^{\circ}C$. As the amount of GHM content increased, the weight decreased and the addition of 1.0~2.5 wt%(K1), 1.0~6.0 wt%(K37) of GHM resulted in a weight drop of 30%(K1) and 25(K37). However, when the GHM content increased, the strength decreases over 70%. This is caused by the presence of a large volume of surface defects (pores) and defects from the agglomeration of GHM.

• 한국정밀공학회지
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• 제16권6호
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• pp.36-44
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• 1999

The rapid Tooling technique is classified into two methods: one to directly utilize the model which was made by rapid prototyping technologies for dies, and the other to make a transferred type using the model as a master model and create dies and molds using it. In this study, the Al powder filled resin was made several mixed ratios and meshes sizes, and applied to slurry casting. And, variation of mechanical characteristics such as the shrinkage rate, the tensile strength, the elongation, the hardness, and surface roughness, are measured to compare. Consequently, as higher is the powder mixed ration and as smaller is the grain size of the power, the mechanical characteristics of the final mold are improved. Finally, the metal short fiber which can be fabricated easily and cheaply, if the self-excited vibration of an elastic tool, was also applied to slurry casting. It has been found tat the hardness gets higher, while the shrinkage rate lower, if mixed with short fiber.

• 한국주조공학회지
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• 제28권5호
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• pp.231-236
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• 2008

H-NCM(Hong-Nanocast Method)has several benefits such as a lower porosity defect and high quality casting comparing to conventional die casting. Influence of casting parameters of hybrid-lower arm in rheocasting process on the slurry flow and the amount of porosity defect was investigated using experimental and simulation methods. In the present study, the Carreau model was adopted to simulate the pattern of rheological flow. Optimal casting paremeters such as injection speed and stroke variations were established. Sound products with integral microstructure and sound shape of joinning different materials of Al and steel pipe without deforming the steel pipe were obtained by the H-NCM slurry and X-ray analysis also showed integral condition throughout the entire parts.

• 한국세라믹학회지
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• 제34권11호
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• pp.1173-1181
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• 1997

Effects of particle size distribution of alumina ceramics on behaviors of tape casting were investigated with emphases on the rheological characteristic of slurry, green density, green sheet strength, and sintering density. For the control of particle size distribution of alumina, the commercial grade low soda alumina, which had different mean particle size of 3.58 ${\mu}{\textrm}{m}$ and 0.42 ${\mu}{\textrm}{m}$, were chosen and blended together. As results, the mixing of 80 wt% fine powder and 20 wt% coarse powder(designated to FC20) led to the increase of packing density and strength of green sheet, and made it easy to handle during processing without lowering of sintering density. Besides, the pseudoplastic behavior of slurry decreased with increase of the fraction of coarse alumina powder.

• 한국세라믹학회지
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• 제34권4호
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• pp.394-398
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• 1997

Mn-Zn ferrite powders were prepared by alcoholic dehydration, using coprecipitation method. Then the effects of organic dispersant and polymeric binder concentration on stability and casting of slurry were discussed. Citric acid, the organic dispersant and polyvinylacohol(PVA), the non-ionic binder, were selected as additives of slurry. With variation of concentration of water, citric acid and polyvinylalcohol(PVA), optimum forming conditions were determined from viscosity and density. To compare with dry process, density and microstructure of sintered body formed by uniaxial die pressing were observed.

• 한국주조공학회지
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• 제27권4호
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• pp.173-178
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• 2007

The bearing bracket, which has produced by the squeeze casting for the high strength in lightweight part of automobile, was developed by the rheocasting process using the H-NCM slurry. Compared with the squeeze casting, the rheocasting process has some merits such as shortening cycle-time, reducing total weight, and increasing productivity. In this study, partial feeding test was carried out by controlling plunger stroke length and compared with semisolid simulation. Optimal casting parameters such as injection speed and stroke variations were established. Sound products with integral microstructure were obtained by the H-NCM slurry and X-ray analysis also showed the integral condition throughout the entire parts.