• 한국분말야금학회:학술대회논문집
• /
• 한국분말야금학회 2003년도 international symposium on advanced powder metallurgy
• /
• pp.120-120
• /
• 2003

• 한국세라믹학회:학술대회논문집
• /
• 한국세라믹학회 2003년도 추계총회 및 연구발표회 초록집
• /
• pp.99.2-99
• /
• 2003

• 한국문화재보존과학회:학술대회논문집
• /
• 한국문화재보존과학회 2002년도 제16회 추계학술대회 및 국제학술강연회
• /
• pp.85-89
• /
• 2002

• Tribology and Lubricants
• /
• 제12권4호
• /
• pp.18-27
• /
• 1996

An interlaboratory wear testing was performed in order to understand the friction behaviors and the wear mechanisms of the sintered composites. The specimens were the sintered bronze matrix composites having various contents of friction additives, friction control agents and reinforcements. The variation of the wear characteristics according to the constituents of the composites as well as the wear conditions was investigated by SEM, EPMA, OM, the hardness testing and the measurement of friction. The specimen having glass fiber as the matrix reinforcement showed a remarkable increase in wear resistance as increasing the content of glass fiber. Graphite particles in the composites exhibited the lubricating effect and also resulted in the lowering strength of the matrix. Addition of Mo powder to the composites led to the deterioration of wear properties at the room temperature, however, an enhanced wear properties were obtained in the containing Mo at an elevated temperature.

• 조명전기설비학회논문지
• /
• 제25권9호
• /
• pp.75-79
• /
• 2011

The MOV(Metal Oxide Varistor), a voltage limiting element, has been installed in the SPD(Surge Protective Device) or inside the internal circuit of an electronic appliance for protection of the electric power system and electronic device against electrical surge. Such an MOV is exposed, however, to the risk of the thermal runaway resulting from excessive voltage and deterioration. In this paper, a reciprocal action has been tested and analyzed using a phosphorus bronze switching module and the low-temperature solder. And a short current break characteristic test linked with the circuit breaker has been performed to limit the inrush current when the MOV breaks down. It has been proven that the phosphorus bronze switching module installed inside the internal circuit can improve the safety of the power line system and the electronic device.

• Environmental Engineering Research
• /
• 제23권2호
• /
• pp.164-174
• /
• 2018

Corrosion of copper alloys (copper, bronze and brass) in soil was evaluated at ambient temperature using various methods such as electrochemical impedance spectroscopy (EIS), polarization curves and Scanning Electron Microscopy (SEM) coupled with Energy Dispersive Spectroscopy microanalysis measurements. Three equivalent circuits were separately used to interpret the obtained impedance spectra. The EIS measurements indicated that the polarization resistance of all electrodes increases with increasing the immersion time. SEM showed a presence of three layers of corrosion products with various composition and morphology covering each electrode. In addition, it was found that at 20% of moisture content the $R_p$ values and the current density of all electrodes in the studied soil give the following order: copper > bronze > brass. Good consistency between the data obtained from EIS and PP measurements was observed.

• 보존과학회지
• /
• 제16권
• /
• pp.5-14
• /
• 2004

루미네선스 연대측정법은 자연계에 일반적으로 존재하는 석영과 장석 같은 무기결정 내에 축적된 루미네선스가 주위 환경방사능과 상관관계에 있어 축적된 루미네선스를 자연선량계로 이용할 수 있음을 전제로 한다. 이 연구에서는 청동기시대 전기 유적인 충남 아산 명암리 유적과 충북 진천 사양리 유적에서 발굴된 토기와 화덕자리 시료를 광 여기 루미네선스 연대측정법으로 연대를 계산하였고 그 결과들을 고고학적인 견해와 비교하였다. 산출된 연대는 고고학적 연대와 잘 일치하였다. 그러므로 광 여기 루미네선스 연대측정법은 앞으로 고고학 유물의 연대측정에 크게 기여할 것으로 판단된다.

• 한국주조공학회지
• /
• 제8권3호
• /
• pp.271-281
• /
• 1988

Al-bronze has a good mechanical property, corrosion resistance and castability, so being highlighted for the new copper alloy. So, effects of alloy composition and cooling rate in the mechaincal properties and solidification behavior have been investigated. The results obtained are as follows; 1) Change in volume on solidification is larger in metal mold casting than in sand mold casting. And it decreases by the addition of Al. 2) The mechanical property in metal mold casting is superior to the one in sand mold casting, and the inclination is obvious up to 9% Al, after heat-treatment ($885^{\circ}C$, $1.5hrs\;{\rightarrow}\;W\;{\cdot}\;Q\;{\rightarrow}\;540^{\circ}C$, 3hrs) 3) By adding Al, the mechanical property is slightly increased up to 9% Al, Above 9% Al, it is increased rapidly, and is accelerated by adding Fe. 4) Cooling rate and hardness, and grain size and cooling rate are related as follows in the range of $1100^{\circ}C$ to $1200^{\circ}C$ pouring temperature. Grain size(${\mu}m$)=$929.6422{\times}cooling\;rate(^{\circ}C\;/\;sec)^{-0.51537}$ Hardness(BHN)=$765.45713{\times}grain\;size({\mu}m)^{-0.31058}$.

• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 2003년도 하계학술대회 논문집 Vol.4 No.2
• /
• pp.739-743
• /
• 2003

[ $Ba_2NaNb_5O_{15}$ ], hereafter BNN, thin films are attractive candidates for nonvolatile memory and electro-optic devices. In the present work, thin films that have different contents of Ba, Nb and Na have been prepared by H-MOD technique on silicon and Pt substrates. XRD and SEM were used to investigate the phase evolution behavior and the microstructure of the films. It was found that the films of about 500nm thick were crack-free and uniform in microstructure. Nb content strongly influenced the phase formation of the films, where unwanted phases were always formed at the stoichiometric BNN composition. However, the unwanted phases decreased with the increase of excess Nb content, and the single phase (tetragonal tungsten bronze structure) BNN thin film was obtained when the niobium content reached some point. From this study, the sub-solidus phase diagram below $850^{\circ}C$ for $BaO-Na_2O-Nb_2O_5$ ternary system is proposed.

• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 2004년도 추계학술대회 논문집 Vol.17
• /
• pp.489-493
• /
• 2004

[ $Ba_2NaNb_5O_{15}$ ]은 orthorhombic tungsten bronze 결정구조를 갖는 강유전체로서, 단결정의 경우 $LiNbO_3$에 비해 우수한 비선형 전광계수 값을 나타내는 것으로 알려져 있으며, 또한 주목할만한 초전, 압전, 강유전특성을 나타내고 있다. 본 연구에서는 다른 강유전체박막에 비하여 상대적으로 연구가 덜 이루어진 BNN 박막을 세라믹 타겟을 사용하여 이온빔 보조 증착법을 사용하여 제조하였으며, $Ar/O_2$ 분위기에서 증착된 BNN 박막에 대한 결정화 및 배향 특성을 고찰하였고, 이에 따른 전기적 특성의 변화를 살펴보았다. 연구에 사용된 기판은 $Pt(100)/TiO_2/SiO_2/Si(100)$이었으며, 이온빔 보조 증착법에서 보조 이온빔의 에너지를 $0{\sim}400eV$로 변화 시키며 BNN 박막을 증착한 후, 열처리하였다. BNN 박막의 전기적 특성은 MFM 박막 커패시터의 형태로 제조하여 강유전 특성에 대해 살펴보았다.