• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2002년도 하계학술대회 논문집 Vol.3 No.2
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• pp.657-661
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• 2002

PZT powder was prepared by partial oxalate method using $(Zr_{0.53}Ti_{0.47})O_2$, $Pb(NO_3)_2$ and $(COOH)_2{\cdot}2H_2O$ as a precipitant. $Nb_2O_5$ additive effect on microstructure and piezoelectric properties of PZT ceramics were investigated. The coexistence of rhombohedral and tetragonal phases of PZT ceramics at the sintering temperature of $1100^{\circ}C$ was revealed from the X-ray diffraction patterns. The grain size PZT ceramics was decreased with the increase $Nb^{5+}$. and the sinterbility of PZT ceramics was decreased with the increase $Nb^{5+}$ addition. The electromechanical coupling factors $K_p$ show above 0.60 at $1100^{\circ}C$ sintering temperature by $Nb_2O_5$ addition above 0.6mol%.

• 한국세라믹학회지
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• 제20권3호
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• pp.193-198
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• 1983

This experiment has been carried out for the purpose of investigating the effect of $V_2O_5$ and $H_3BO_3$ additives on sintering of magnesium oxide over the temperature range of 1300-150$0^{\circ}C$ MgO powder has been obtained by calcin-ing extra reagent grade magnesium carbonate(basic) at 90$0^{\circ}C$ for 30 minutes. The specimens were prepared by compression with pressure of 700Kg/cm2 then fired at 1300-150$0^{\circ}C$ for 0-5hrs. Sintering behaviour and microstructure of fired specimens were examined. Densification rates obeyed the equation D=K 1n t+C. The ratio of density in case of addition of $V_2O_5$ to theoretical density of pure periclase was 95-99% Activation energy of densification in case of $V_2O_5$ addition was 30.15 Kcal/mole. The range of average grain size in case of addition of $V_2O_5$ was 40-50$\mu\textrm{m}$. $H_3BO_3$ addtivie had not an effect on densification of MgO.

• 한국재료학회지
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• 제26권4호
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• pp.216-221
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• 2016

A sintering process for copper based films using a rapid thermal process with infrared lamps is proposed to improve the electrical properties. Compared with films produced by conventional thermal sintering, the microstructure of the copper based films contained fewer internal and interfacial pores and larger grains after the rapid thermal process. This high-density microstructure is due to the high heating rate, which causes the abrupt decomposition of the organic shell at higher temperatures than is the case for the low heating rate; the high heating rate also induces densification of the copper based films. In order to confirm the effect of the rapid thermal process on copper nanoink, copper based films were prepared under varying of conditions such as the sintering temperature, time, and heating rate. As a result, the resistivity of the copper based films showed no significant changes at high temperature ($300^{\circ}C$) according to the sintering conditions. On the other hand, at low temperatures, the resistivity of the copper based films depended on the heating rate of the rapid thermal process.

• 한국분말재료학회지
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• 제21권2호
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• pp.137-141
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• 2014

In this study, we report the sintering behavior and properties of a $Ge_2Sb_2Te_5$ alloy powders for use as a sputtering target by spark plasma sintering. The effect of various sintering parameters, such as pressure, temperature and time, on the density and hardness of the target has been investigated in detail. Structural characterization was performed by scanning electron microscopy and X-ray diffraction. Hardness and thermal properties were measured by differential scanning calorimetry and micro-vickers hardness tester. The density and hardness of the sintered $Ge_2Sb_2Te_5$ materials were 5.8976~6.3687 $g/cm^3$ and 32~75 Hv, respectively.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2006년도 추계학술대회 논문집 Vol.19
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• pp.214-216
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• 2006

In this study, in order to develop the composition ceramics for low loss and low temperature sintering multilayer piezoelectric actuator, PMN-PZN-PZT ceramics were fabricated using two stage calcination method and $Li_2CO_3$, $Bi_2O_3$ and CuO as sintering aids and their piezoelectric characteristics were investigated according to the 2nd calcination and sintering temperature. At the calcination temperature of $750^{\circ}C$ and sintering temperature of $930^{\circ}C$, density, electromechanical coupling factor ($k_p$), mechanical quality factor ($Q_m$), Dielectric constant (${\varepsilon}_r$) and piezoelectric constant ($d_{33}$) of specimen showed the optimum value of $7.94g/cm^2$ 0.581, 1554, 1555 and 356pC/N, respectively for multilayer piezoelectric actuator application.

• 한국전기전자재료학회논문지
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• 제18권7호
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• pp.615-621
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• 2005

The electrical stability against surge stress of varistors, which are composed of Zn-Pr-Co-Cr-Y oxide system, were investigated at different sintering times. As sintering time increases, the varistor voltage and nonlinear exponent decreased in the range of $279.6\~179.1$ and $52.5\~24.9$, respectively. On the contrary, the leakage current and dielectric dissipation factor increased in the range of $1.2\~9.8\;{\mu}A$ and 0.0461\~0.0651 with increase of sintering time. For all varistors, the variation rates of V-I characteristic parameters against surge stress were more strongly affected in order of varistor voltage ${\rightarrow}nonlnear$ $exponent{\rightarrow}leakage$ current. On the whole, the electrical stability against surge stress increased with increasing sintering time. Conclusively, it is assumed that the varistors sintered for 2 h exhibited comparatively good characteristics, in view of overall characteristics.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2001년도 하계학술대회 논문집 C
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• pp.1436-1438
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• 2001

The $\beta$-SiC + $ZrB_2$ ceramic electroconductive composites were pressureless-sintered and annealed by adding 12wt% $Al_2O_3$ + $Y_2O_3$ (6 : 4wt%) powder as a function of sintering temperature. The relative density showed the highest value of 81.1% at 1900$^{\circ}C$ sintering temperature. The phase analysis of the composites by XRD revealed of $\alpha$-SiC(6H), $TiB_2$, $Al_5Y_2O_{12}$ and $\beta$-SiC(15R). Flexural strength showed the highest value of 230 MPa for composites sintered at 1900$^{\circ}C$. The vicker's hardness and the fracture toughness showed the highest value of increased with increasing sintering temperature and showed the highest of 9.88 GPa and 6.05 $MPa{\cdot}m^{1/2}$ at 1900$^{\circ}C$. The electrical resistivity was measured by the Pauw method from 25$^{\circ}C$ to 700$^{\circ}C$. The electrical resistivity of the composites showed the PTCR (Positive Temperature Coefficient Resistivity).

• 대한치과기공학회지
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• 제42권2호
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• pp.121-128
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• 2020

Purpose: This study aimed to investigate the effects of the sintering conditions of zirconia core on the adaptability. Methods: Ten specimens of each of commercial brand of zirconia(Razor 1100, U&C international, Seoul, Korea) were made and sintered under three different conditions. Specimens were divided into three subgroup(n=10) and sintered with various total time(1hr, 3hr, 9hr) at the maximum temperature(1500℃). The digitized data was superimposed with 3D inspection software to quantitatively obtain the adaptation of a zirconia core, and visual differences were confirmed with a color map. The root mean square(RMS) values of group were statistically analyzed with one-way ANOVA(α=0.05). Results: The overall adaptation of the zirconia cores were as follows; ss-1hr: 36.18±5.2㎛, ss-3hr: 39.55±3.9㎛, cs-9hr: 46.62±4.3㎛. They were statistically significant differences between groups for adaptation(p<0.05). Conclusion: Based on the results of this study, it could be considered that sintering condition of 1500℃ and 1~3 hour is recommended for the better marginal and internal fit. Speed sintering can be widely utilized to fabricate zirconia prothesis as the properties of those almost are to dentistry uses.

• 센서학회지
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• 제27권4호
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• pp.249-253
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• 2018

Infrared transparent ZnS ceramics were synthesized through hydrothermal synthesis ($180^{\circ}C$, 70 h) and sintered using a hot press process at $750^{\circ}C-1000^{\circ}C$. We carried out x-ray diffraction, scanning electron microscopy, and Fourier transform-infrared spectroscopy to confirm the optical properties of the ZnS ceramics after sintering at various temperatures. The phase of ZnS nanopowders was a single phase (cubic) without the hexagonal phase. However, as sintering temperature increased, the formation and increment of hexagonal structures was confirmed. The ZnS ceramic sintered at a temperature of $750^{\circ}C$ showed poor transmittance because it was not completely sintered and because of the pore effect. The ZnS ceramic with the highest transmittance (approximately 69%) was sintered at $800^{\circ}C$. As sintering temperature increased, transmittance gradually decreased owing to the increase in the formation of the hexagonal phase.

• 한국전기전자재료학회논문지
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• 제27권1호
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• pp.22-26
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• 2014

$(Ba_{0.85}Ca_{0.15})(Ti_{0.9}Zr_{0.1})O_3$ + 0.04 wt% $CeO_2$ lead-free ceramics were prepared by conventional oxide-mixed method and the effect of sintering temperature on microstructure, dielectric and piezoelectric properties were investigated. Improved piezoelectric properties have been observed at $1,400^{\circ}C$ sintering temperature which show the optimal electrical properties, $k_p{\sim}0.412$, $d_{33}{\sim}316pC/N$, $Q_m{\sim}144$, ${\varepsilon}_r{\sim}3,345$ and $T_c{\sim}85^{\circ}C$. These results show that the sintering temperature plays an important role in piezoelectric properties.