• 한국세라믹학회지
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• 제40권1호
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• pp.69-76
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• 2003

리튬이차 박막전지로서, 실리콘 첨가(0, 2, 6, 10, 20㏖%)에 따른 주석 산화물 박막을 기판온도 30$0^{\circ}C$, Ar:O$_2$=7:3으로 R.F. magnetron sputtering법으로 제조하였다. 실리콘의 함량이 증가함에 따라, Si-O 결합량이 증가하고 Sn-O 결합량은 감소하였다. 적정량의 실리콘 첨가는 주석의 산화상태를 감소시켜 비가역성을 줄이고 충방전 동안 주석의 부피변화를 막아 사이클 특성이 향상되는 결과를 보여주었다. 6㏖% Si를 첨가한 주석 산화물 박막은 100사이클동안 700mAh/g의 용량을 가지는 가장 좋은 사이클 특성을 나타내었다.

• 한국주조공학회지
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• 제15권4호
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• pp.368-376
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• 1995

An Al-composite material was fabricated with using the rheocompocasting process and the microstructure of the Al-Cu/SiCp composite material was investigated depending on the stirring times and the amount of Ti additions. The distribution of SiC dispersion shows the good result at the stirring time of 30 min. The degree of microdistribution of the $Al_2Cu$ and SiCp is improved when the amount of Ti addition is increased. At the compositon of 0.3%Ti, the primary solid is the compound of $Al_3Ti$ and no exist of the SiCp and $Al_2Cu$ phase around the primary $Al_3Ti$. In the process of compositization, SiCp is found at the primary and final solid parts and is found at the final solid part after remelting. $Al_2Cu$ and SiCp are distributed around and outside of dendrite or independently after remelting, which is different from the process of compositization.

• 한국재료학회지
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• 제33권9호
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• pp.353-359
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• 2023

This study investigated the growth behavior and characteristics of compounds formed at the interface between a liquid Al-Si-Cu alloy and solid cast iron. Through microstructural analyses, it was observed that various AlFe and AlFeSi phases are formed at the interface, and the relative proportion of each phase changes when small amounts of strontium are added to the Al alloy. The results of the microstructural analysis indicate that the primary phases of the interfacial compounds in the Al-Si-Cu base alloy are Al₈Fe₂Si and Al_4.5FeSi. However, in the Sr-added alloys, significant amounts of binary AlFe intermetallic compounds such as Al₅Fe₂ and Al₁₃Fe₄ formed, in addition to the AlFeSi phases. The inclusion of Sr has a slight diminishing effect on the rate at which the interfacial compounds layer thickens during the time the liquid Al alloy is in contact with the cast iron. The study also discusses the nano-indentation hardness and micro-hardness of the interfacial phases.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1997년도 추계학술대회 논문집 학회본부
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• pp.311-313
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• 1997

The effects of porosity on the pressureless sintered $\beta$-SiC-$ZrB_2$ composites with $Al_2O_3$ additions(4, 8, 12wt.%) under argon atmosphere were investigated. Relative density of $\beta$-SiC-$ZrB_2$ composites were decreased with the $Al_2O_3$ content. The relative density and fracture toughness of $\beta$-SiC-$ZrB_2$ with 4wt% $Al_2O_3$ are 93.2%, $1.323MPa{\cdot}m^{1/2}$ respectively. The Vicker's hardness and flexural strength of $\beta$-SiC-$ZrB_2$ with 12wt.% $Al_2O_3$ are 0.492GPa, 261MPa respectively. Fracture toughness of $\beta$-SiC-$ZrB_2$ composites are directly proportional to relative density.

• 한국주조공학회지
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• 제18권4호
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• pp.364-372
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• 1998

Effects of Si and Ca additions on the mechanical properties of AM60 based Mg alloys have been investigated. Hardness of the AM60 based Mg alloys reached a maximum value after aging for approximately 33 hours but the amount of hardness increase was negligible. The poor age hardening response of the alloys was due to low Al content, which implies that Al content must be >6 wt.% to observe age hardening effect. The tensile and yield strength increased with increasing Al, Si, and Ca content but elongation decreased with increasing Al and Si content. The best mechanical properties obtained in AM 40-2.5Si-0.2Ca alloy after T4 heat treatment were as follows; tensile strength 193.4 MPa, yield strength 79.2 MPa, and elongation 11.2%. High temperature property obtained from creep test was also improved by introducing $Mg_2Si$ which has high hardness, high melting temperature and low thermal expansion coefficient.

• 한국표면공학회지
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• 제33권1호
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• pp.3-9
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• 2000

Arc-melted alloys of TiAl-(o.25, 0.5, 1.0at%) Si were isothermally oxidized at 800, 900 and $1000^{\circ}C$ in air for 60hr. It was found that the oxidation resistance of the prepared TiAl-Si alloys was much better than that of pure TiAl, being progressively increasing with an increase in the Si content. This was attributed to the formation of $SiO_2$in addition to ($TiO_2$+$Al_2$$O_3$) oxides which formed in TiAl alloys with and without silicon additions. However, the silica formation within the oxide layer unfortunately accelerated the oxide scale spallations. During oxidation, all the elements in the base alloy diffused outward, whereas oxygen from the atmosphere diffused inward. The oxides were primarily composed of an outer thick $TiO_2$layer, an intermediate diffuse $Al_2$$O_3$layer and an inner $TiO_2$layer. A small amount of $SiO_2$was present all over the oxide scale and some voids were found around the intermediate layer.

• 한국자동차공학회논문집
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• 제12권3호
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• pp.1-9
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• 2004

During the SI engine starting up, starting conditions directly contribute to the unburned hydrocarbon emissions in spark ignition engines. The effects of catalyst temperatures and fuel injection skip methods on HC emissions were investigated. The test was conducted on a 1.5 L, 4-cylinder, 16 valve, multipoint-port-fuel-injection gasoline engine. To understand the formation of HC emissions, HC concentration was measured in an exhaust port using a Fast Response Flame ionization Detector (FRFID). The result showed that HC emissions, which were emitted at the cold coolant and catalyst temperature, were generated much higher than those of hot coolant and catalyst temperatures. In additions, fuel injection skips reduced highly HC emissions. It is convinced that optimized fuel injection skip method according to coolant and catalyst temperatures could be applied to reduce HC emissions during the SI engine starts.

• 한국세라믹학회지
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• 제34권11호
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• pp.1151-1158
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• 1997

Fracture of uni-directional carbon fiber reinforced carbon matrix composite is strongly dependent on the orientation of basal plane in graphite matrix when it is limited within matrix. The orientation of basal planes are vertically stacked to carbon fiber which results in the weakness for applied tensile or shear force in thermosetting resin derived-carbon matrix composite. Microtextural control of the matrix was tried through chemical interaction between metal carbides and furan resin derived-carbon matrix. SiC and TiO2 addition made the orientation disordered. However, porosity increased due to decomposition of SiC. Interfacial bonding could be controlled by TiO2 addition, but carbon fiber was considerably reacted with TiC during thermal treatment higher than 2$600^{\circ}C$. Therefore, it is desirable to control the thermal treatment temperature at which decomposition of SiC was not serious and TiC/C was not formed eutectoid.

• 한국연소학회:학술대회논문집
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• 대한연소학회 2003년도 제27회 KOSCO SYMPOSIUM 논문집
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• pp.257-262
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• 2003

Engine-out HC emissions were investigated during engine start. The tests were conducted on a 1.5L, 4-cylinder, 16 valve, multipoint-port-fuel-injection gasoline engine at different coolant temperatures and fuel injection-skip methods; no skip, 1 cycle-skip and 3 cycle-skip. To understand the characteristics of engine-out HC emissions, HC concentration was measured at a exhaust port using a Fast Response Flame Ionization Detector (FRFID). The result show that HC emissions were emitted at the cold coolant temperature much higher than those of the hot coolant. In additions, the fuel injection skip highly reduced engine-out HC emissions. It is convinced that optimized fuel injection skips according to coolant temperatures could be applied to reduce HC emissions during SI engine start.

• 한국세라믹학회지
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• 제20권3호
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• pp.243-249
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• 1983

This study has examined on the effect for the fitting in porcelain body of MgO-SiO system. The mixture was made of correponding in the theoretical composition of enstatite with Kyul Sung Talc and sea water magnesia cake. Hyup Jin Kaolin as clay minerals to give the mixture plasticity was added 10% by weight of the mixture. Feldspar was added inv various kinds of 1%-20% by weight of the above mixture. After the physical properties and microstructures were carefully examined the following results were obtained. 1. The addition amount of feldspar should generally be from 5% to 10% by weight of the mixture to be good for the properties of the strength and the range of the firing temperature. 2. The 5% addition amount of feldspar was good for the apparent bulk density. 3. 5% and 10% additions showed up stably excellant with respect to the various properties Therefore when we considered the apparent bulk density and the thermal shock resistance 5% addition amount of feldspar showed the most excellant properties between $1350^{\circ}C$ and $1400^{\circ}C$.