• Journal of the Korean Ceramic Society
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• v.20 no.2
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• pp.93-98
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• 1983

The sensitivity characteristics of $SnO_2$-based gas sensor prepared by sintering method have been studied at the presence of CO and Propane gas. Samples mixed with 1wt% $La_2O_3$ and 1wt% $PdCl_2$ showed highest sensitivity to CO and propane gas at 250$^{\circ}$C but the addition of $CeO_2$ did not enhance the sensitivity. For slectivity for gas a $SnO_2-La_2O_3$ (1wt%) sample without $PdCl_2$ showed better results. A sample sintered sintered at 115$0^{\circ}C$ has shown the optimum condition in sensitivity and electroding

• Journal of the Korean Ceramic Society
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• v.26 no.3
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• pp.297-304
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• 1989

The dielectric properties of SrTiO3 GBL Capacitor have been investigaetd as a function of the second heat treatment time and the amount of Ta. The grain size of semiconductive SrTiO3 after sintering at 1,46$0^{\circ}C$ for 4 hours in N2/H2 atmosphere increased as the amount of Ta increased, and then decreased as the amount of Ta exceed 0.01 mole. Also, the dielectric constant after the second heat treatment showed the same tendency. When the semiconductive SrTiO2 was second heat treated at 1,10$0^{\circ}C$ in air with varying time, the dielectric constant increased as the second heat treatment time increased up to 60 minutes, and then decreased as the time became longer than 60 minutes.

• Journal of the Korean Ceramic Society
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• v.48 no.5
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• pp.390-395
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• 2011

The objective of our study was to produce an imitation bone material consisting of hydroxyapatite with a compact and spongy structure. This study shows the ideal content of $SiO_2$ and the sintering temperature to produce imitation bone that has the mechanical properties of natural bone. On the basis of our determination of the ideal conditions, a compact part was produced and its mechanical properties were tested. A compact part made of 0.5 wt% $SiO_2$ and sintered at $1350^{\circ}C$ showed excellent mechanical properties. The bioactivity of the compact part under this condition was tested, and it was found to be bioactive. The porous part was produced by controlling the powder size, and the dual structure was manufactured by combining the compact and porous parts. A water permeability test confirmed that the dual structure had an interconnected pore structure. Therefore, this dual-body structure is feasible for use in the creation of implants.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.43 no.5
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• pp.789-794
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• 1994

In this study, the structural and microwave dilelectric properties of 0.15BaO-0.15SmS12TOSI3T-0.7TiOS12T ceramics with sintering and annealing conditions were investigated. In the specimen sintered at 1350 [$^{\circ}C$], dielectric constant and quality factor were good values of 80.19,2006 (fS10T=4.6851[GHz]). To improve the $\tau$S1fT of specimen which was manufactured by the optimumsintering condition (1350[$^{\circ}C$],2[Hr.]), annealed from 2[hr.] to 16[hr.] at the annealing temperature of 1200 [$^{\circ}C$]. Increasing the annealing time, dielectric constant was almost constant and quality factor was increased. In the specimen of 4[hr.] annealed, the temperature coefficient of resonant frequency was minimum value, and increased with increasing the annealing time.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.11a
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• pp.292-295
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• 2001

The NdBaCuO superconducting samples were prepared by the Zone melting under low oxygen partial pressure. After the zone-melting the oxygenation process of the NdBaCuO samples in a oxygen flow furnace was studied. In order to compare the oxygenation condition the sintering NdBaCuO samples were studied also. In the study it is found that the optimum temperature for the oxygenation is $350{\circ}C$, and the oxygen flow speed, the sample volume and the surface area of the sample would if1uence the oxygenation and the oxygen content.

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2006.09a
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• pp.566-567
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• 2006

The characteristics of residual stresses occurring in PM steel based nickel (FLN2-4405) was investigated. The measurements of residual stresses were carried out by electrochemical layer removal technique. The values and distributions of residual stresses occurring in PM steel processed under various densities and heat treatment conditions were determined. In most of the experiments, tensile residual stresses were recorded in surface of samples. The residual stress distribution on the surface of the PM steels is affected by the heat treatment conditions and density. Maximum values of residual stresses on the surface were observed sinter hardened condition and $7.4\;g/cm^3$ density. Minimum level of recorded tensile residual stresses are150 MPa and its maximum level is 370 MPa.

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2006.09a
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• pp.303-304
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• 2006

The mechanical properties of ferrous powder metallurgy (P/M) materials are directly related to their microstructure. Ferrous P/M materials with sufficient hardenability will develop microstructures containing significant percentages of martensite in the as-sintered condition. Recently, sinter-hardening has developed into a highly cost effective production method through hardened P/M parts without the need for additional heat-treatments. This paper reviews the advances of sinter-hardening as well as some key processing parameters such as sintering temperature, cooling rate, tempering required to produce high quality sinter-hardened components. Specific topics including effect of alloying elements, alloying methods, and the Characterization and observation of microstructure are discussed.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.07a
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• pp.142-145
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• 2004

[ $Pb(Zr_{0.8}Ti_{0.2})TiO_3$ ] powder were prepared by the sol-gel method using a solution of Pb-acetate, Zr n-propoxide and Ti iso-propoxide. PZT thick film were fabricated by the screen printing method. and then the structural properties as a function of the sintering temperature were studied. PZT film thickness, obtained by four screen printing, was approximately $70{\sim}90{\mu}m$. The PZT thick film, sintered at $1050^{\circ}C$, showed deuse and uniform grain stractures and percent porosity of the thick film was 25.43%.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2005.07a
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• pp.544-545
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• 2005

This paper describes the long duration withstand current characteristics of ZnO varistors. Two ZnO varistors were manufactured with general ceramic production methods and three abroad varistors were also prepared to be compared. During long duration withstand test, sample 1 was destroyed at 4th impulse current but the rest passed test. Before and After the test, the residual voltage variation of varistors passed was below 5%. According to the test results, it is thought that the manufacturing process such as insulating coating, sintering condition and soldering method should be improved.

• Journal of the Korean Magnetics Society
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• v.5 no.5
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• pp.610-613
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• 1995

The effect of processing parameters such as milling, additives and sintering atmoshpere on the magnetic properties of Mn-Zn ferrite was investigated. The experiment was followed by general ceramic fabrication process and added additives were $CaCO_{3}$, $SiO_{2}$, $V_{2}O_{5}$, $ZrO_{2}$, and $Nb_{2}O_{5}$. The effects of additives could be divided into three categories which were formation ofliquid phase, substitution in lattice and inducing stress. Core loss smong the magnetic properties was dependent mainly on the additives and also correlated with processing parameters. As a result, an optimum condition of preparing process for a high quality Mn-Zn ferrite was suggested by controlling the correlation of each processing parameters.