• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 1988년도 추계학술대회 논문집
• /
• pp.105-107
• /
• 1988

The dielectric properties of complex perovskite compound Sr$(Mg_{1/3}Mb_{2/3})$$O_3$-Ba$(Mg_{{1/3}Nb_{2/3})$$O_3$(BMN) system were investigated as a function of composition and sintering time. In the case of the specimens sintered at $1650^{\circ}C$ for same time, dielectric constant and dielectric loss were increased with increasing the mole ratio of BMN. The maximum temperature coefficient of resonant frequency was found in composition Ba$(Mg_{{1/3}Nb_{2/3})$$O_3$. In the case of the specimens with same composition, dielectric constant and dielectric loss were slightly increased with increasing the sintering time. As the sintering time was increased, the temperature coefficient of resonant frequency for SMN was slightly increased, however, that of BMN and ($Sr_{1/2}Ba_{1/2}$) ($Mg_{1/3}Ta_{2/3}$)$O_3$ was largely depended on sintering time.

• 한국결정성장학회지
• /
• 제21권1호
• /
• pp.34-40
• /
• 2011

무기성 폐기물인 준설토를 원료로 인공골재를 제조함에 있어, 직화소성법을 이용하여 소성온도(1100 및 $1200^{\circ}C$)와 시간(10~60 min)을 변수로 하여 인공골재의 부피비중, 흡수율 그리고 미세구조를 제어하였다. 또한 직화소성과 기존에 발표된 승온소성의 방법 차이에 따른 인공골재의 물성을 비교 분석하였다. 직화소성 시, 소성온도가 $1100^{\circ}C$에서 $1200^{\circ}C$로 증가하면, 껍질의 두께가 증가함과 동시에 블랙 코어 부분의 기공크기가 증가하면서 골재의 부피비중이 1.0 이하를 나타내었다. 또한 같은 소성온도에서 소성시간이 증가할수록 블랙코어의 단면적이 감소하고, 껍질의 두께가 증가하면서 흡수율이 감소하였다. 부피비중 1.0 이하의 인공골재는 직화소성이나 승온소성으로 제조된 경우 모두 블랙 코어부분의 미세구조가 서로 비슷한 경향을 나타내었다. 반면, 껍질(shell)의 미세구조는 승온소성된 경우에 더 치밀한 구조를 나타냈으며, 따라서 직화소성된 골재의 흡수율이 상대적으로 높았다. 이로서 직화소성법은 세라믹 담체 또는 흡착제등에 적용될 인공골재 제조에 적합한 방법임을 알 수 있었다.

• 한국정밀공학회:학술대회논문집
• /
• 한국정밀공학회 2002년도 춘계학술대회 논문집
• /
• pp.1026-1029
• /
• 2002

Outlet of gas has been a big problem in deforming rubber or plastic in pressing mold. Air vent has been used to solve the problem, but it has weak points such as the increased cost, the increased number of process, and vent marks on the surface of a produce. In this study, the sintering method is used for making porous metal mold. Porous metal mold has many open pores, which are very small. When Porous metal mold is used for pressing mold, all process would be made short, produce cost would be down, and it would not leave vent marks on the surface of a produce. Porosity varies from sintering and pressing conditions, which are the pressure of compacting powder, the length of sintering time, sintering temperature and sintering atmosphere etc. This study will find optimized sintering temperature condition for the Porous metal mold.

• 한국정밀공학회지
• /
• 제20권1호
• /
• pp.91-98
• /
• 2003

Removal of gas in a mold has been a big problem in pressing mold or in injection mold. Air vent has been used to solve the problem, but it has weak points such as the increased cost, the increased number of process, and vent marks on the surface of a product. In this study, the sintering method and rapid tooling method are used for making porous metal mold. Porous metal mold has many open pores, which are very small. When porous metal mold is used for pressing mold or injection mold, all process would be made short, produce cost would be down, and vent marks would be not leaved on the surface of a product. Characteristic of porous material varies from sintering conditions, which are the length of sintering time, sintering temperature and sintering atmosphere etc. This study will find optimized sintering condition for the porous metal mold.

• 한국정밀공학회:학술대회논문집
• /
• 한국정밀공학회 2002년도 추계학술대회 논문집
• /
• pp.308-311
• /
• 2002

Removal of gas in a mold has been a big problem in pressing mold or in injection mold. Air vent has been used to solve the problem, but it has weak points such as the Increased cost, the increased number of process. and vent marks on the surface of a product. In this study, the sintering method and rapid tooling method are used for making porous metal mold. Porous metal mold has many open pores, which are very small. When porous metal mold is used for pressing mold or injection mold, all process would be made short, produce cost would be down, and vent marks would be not leaved on the surface of a product. Characteristic of Porous material varies from sintering conditions, which are the length of sintering time, sintering temperature and sintering atmosphere etc. This study will find optimized sintering condition for the porous metal mold.

• 한국분말재료학회지
• /
• 제19권1호
• /
• pp.19-24
• /
• 2012

The consolidation results of fine tungsten powders, W-Cu composite and W/Cu FGM by using a novel method combining resistance sintering with ultra high pressure have been reviewed. The densification effects of the consolidation parameters, including pressure, input power and sintering time, have been investigated. The sintering mechanism of this method was quite different from other sintering methods. Particle rearrangement, sliding, distortion and crushing due to the ultra high pressure are the dominant mehanisms at the initial stage, then the dominant sintering mechanisms are transient arc-fused processes controlled by the input power.

• 한국표면공학회지
• /
• 제41권5호
• /
• pp.245-253
• /
• 2008

The porous metal material is used for injection metal mold with a great deal of gas production because it makes plenty of gas exhausted through pores formed in the metal mold. A canning HIP method was conventionally used for manufacturing of porous metals, but because of difficulty of process control and high cost of production its application was limited. In this experiment, porous metal mold material was produced by an enhanced vacuum sintering method with simply controlled and economical process and porosities/mechanical properties with variation of sintering temperature and duration time during vacuum sintering were studied. As a result, quality goods were obtained at optimized conditions as follows: sintering temperature of $1230^{\circ}C$, duration time of 2 hr and showed superior properties in wear loss and thermal conductivity and the same properties in hardness, TRS (Transverse Rupture Strength), and thermal expansion coefficient in comparison with those under canning HIP.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 1987년도 정기총회 및 창립40주년기념 학술대회 학회본부
• /
• pp.248-250
• /
• 1987

Transparent CdS films with low electrical restivity on glass substrates were prepared by coating a CdS slurry which contained 10 wt.% $CdCl_2$, and sintering in a nitrogen atmosphere at $600^{\circ}C$ for 2hr. All-polycrystalline CdS/CdTe solar cells were fabricated by coating CdTe slurries, which contained 1.0 or 4.5 wt.% $CdCl_2$, on the sintered CdS films and sintering at $700^{\circ}C$ for various periods of sintering. The spectral responses of the sintered CdS/CdTe solar cells were measured and compared with theoretically calculated quantum efficiency. The spectral responses of the sintered CdS/CdTe solar cells in the short-wavelength region decreases with-increasing sintering time. The poor response in this region is attributed to the existence of the Cd-S-Te solid solution in the compositional junction. The decrease in the maximum response in the long-wavelength region as the sintering exceeds certain time appears to be caused by the increase in the depth of the buried homo junction and by the increase in the series resistance. The $CdCl_2$ in the CdTe layer during sintering enchances the interdiffusion of S, Te or donor impurities across the metallurgical Junction causing the formation of deeper n-p junction in the CdTe layer.

• 한국세라믹학회지
• /
• 제54권4호
• /
• pp.285-291
• /
• 2017

This study investigated the effects of grain size and phase constitution on the mechanical properties of $3Y-ZrO_2$ by varying the sintering conditions. The raw powder prepared by a low-cost wet milling using the coarse solid oxide powders was sintered by both pressureless sintering and hot-pressing, respectively. As increasing holding time at $1450^{\circ}C$ for pressureless sintering, it promoted the microstructural coarsening of matrix grains and the phase transformation to tetragonal phase, whereas the bimodal microstructure embedded with abnormal $cubic-ZrO_2$ grains was observed regardless of sintering time. On the other hand, the specimens hot-pressed at $1300^{\circ}C$ for 2 h reached ~ 97% of relative density with homogeneous fine microstructure and mixed phase constitution. It was found that the proportion of untransformed monoclinic zirconia had the most adverse effect on the biaxial strength compared to the impacts of grain size and density. The pressureless sintering of the low-cost powder for prolonged sintering time to 8 h led to a decent combination of mechanical properties ($H_V=13.2GPa$, $K_{IC}=8.16MPa{\cdot}m^{1/2}$, ${\sigma}=981MPa$).

• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 2007년도 하계학술대회 논문집 Vol.8
• /
• pp.274-275
• /
• 2007

In this study, in order to develop low temperature sintering ceramics for multilayer piezoelectric actuator application. At the PMN-PZN-PZT ceramics, the influence of the ball-mill time on piezoelectric characteristics was investigated. All the specimens improved according to the increase of the ball-mill time increase. The specimen showed the optimum value when ball-mill time is 60 hour. Their optimum values were density=$7.93g/m^3$, ${\varepsilon}_r=1371$, kp=0.551, Qm=1609, $d_{33}=321pC/N$, respectively.