• Journal of Korea Foundry Society
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• v.43 no.5
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• pp.230-240
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• 2023

The pitting corrosion behavior of 329LD cast lean duplex stainless steel and CF3M cast austenitic stainless steel was investigated in chloride environments. The pitting corrosion resistance of the 329LD alloy was superior to that of the CF3M alloy because the pitting potential, passive region, and critical pitting temperature of the low Ni-low Mo 329LD alloy were higher than those of the high Ni-medium Mo commercial CF3M alloy. There are two main reasons for the enhancement of the pitting corrosion resistance of high Cr-low Momedium N 329LD alloy compared to the low Cr-medium Mo CF3M alloy: First, the pitting resistance equivalent number (PREN_δ+γ) value of the 329LD alloy is higher than that of the CF3M alloy. Second, the passive region of the 329LD alloy is larger than that of the CF3M alloy. It indicates that the synergistic effect of the three elements by adding high Cr and low Mo-medium N to the 329LD alloy enhances the passivity of the passive film, thereby increasing the pitting corrosion resistance. It was verified that based on the PREN_γ of austenite (γ) and PREN_δ of ferrite (δ) values calculated using an N-factor of 16, the pitting corrosion of the 329LD alloy was selectively initiated at the γ-phases because PREN_γ value of austenite (γ) was smaller than that of ferrite (δ), and finally propagated from the γ-phase to the δ-phase.

• Journal of the Korean Society for Heat Treatment
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• v.11 no.2
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• pp.82-91
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• 1998

The elastic modulus and wear resistance in austempered ductile cast iron(ADI) are two important mechanical properties for automobile parts. Therefore, the effect of Cu, Ni, Mo and special austempering treatment such as preheated, prequenched, and step austempering treatments on elastic modulus and wear resistance has been investigated systomatically. As a result, elastic modulus and wear resistance were increased by the addition of Mo-Cu and preheated austempering treatment.

• Journal of the Korean Society for Heat Treatment
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• v.11 no.2
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• pp.121-130
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• 1998

The effects of alloying elements(Mo, Cu, Ni) and austempering temperature conditions on the microstructural morphologies and mechanical properties in austempered ductile cast iron has been investigated. The austempering at $350^{\circ}C$ for 2hrs after austenitizing at $900^{\circ}C$ for 2hrs in all specimens with various alloying elements was optimum because the good combination of tensile and yield strength, hardness and impact value was obtained. The microstructures of these ADIs treated by a forementioned austempering condition are nearly a mixture type of needle and feathery bainite. Among those alloys, Mo-Cu alloyed DCI had the best optimum mechanical properties of hardness and toughness for automobile parts by austempering treatment for 2hrs at $900^{\circ}C$ followed by $350^{\circ}C$ for 2hrs.

• Journal of the KSME
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• v.26 no.4
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• pp.284-289
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• 1986

이들 기기, 장치는 대부분 철강재가 그 근간을 이루고 있지만, 특히 고온부를 형성하는 부재는 내열용 철강과 합금이다. 강을 모재로 하고 고온에서의 강도유지를 위하여 유용한 소랴의 Cr, Mo 등을 합금시킨 저합금내열강이 1차적으로 사용되어 왔으나 사용조건이 고도화 되면서 이들 합금성분 량이 늘어나 주로 Cr 성분을 증가시킨 고 Cr 페라이트계, 그리고 Ni 성분을 다량으로 첨가한 오스테나이트계 내열강이 제 2차, 제 3차대상이 되어 연구 발전되어 왔다. 그 사용한계는 사용 가스등 환경의 영향과 고온의 크리이프나 피로, 파괴에 대한 저항성등에 크게 좌우되지만, 대개 2.25Cr-1Mo 강의 저합금강에서 $550^{\circ}C$, 9~12% Cr인 페라이트계 내열강에서 $^650{\circ}C$ 까지가 한도이며 그 이상온도에서는 오스테나이트계 내열강이 고려의 대상이 되고 있는 것 같다. 이들 고온부에 사용되는 철강 재료를 중심으로 최근의 동향을 주로 금속학적 입장에서 살펴보기로 한다.

• 한국정보디스플레이학회:학술대회논문집
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• 2008.10a
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• pp.270-271
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• 2008

The contact resistance between organic semiconductor and source-drain electrode in Bottom Contact Organic Thin-Film Transistors (BCOTFTs) can be effectively reduced by metal oxide/molybdenum double layer structure; metal oxide layers including nickel oxide (NiOx/Mo) and moly oxide(MoOx) under molybdenum work as a high performance carrier injection layer. Step profiles of source-drain electrode can be easily achieved by simultaneous etching of the double layers using the difference etching rate between metal oxides and metal layers.

• Proceedings of the Korean Nuclear Society Conference
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• 2005.05a
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• pp.309-310
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• 2005

Some minor elements(Al, B, Ba, Ca, Cd, Co, Cr, Cu, Gd, Mg, Mn, Mo, Nd, Ni, P, Pb, Si, Sn, Sr, Ti, V, Yb, Zn and Zr) in iron compounds such as the S/G sludge of a power plant were separated from iron by anionic and cationic exchange methods. If a ICP-AES or AAS determination follows this method, minor elements of more than 2 or 20 ppm of Fe can be determined with an error less than 20% except Sn and Mo. Alkaline elements were excluded from this study since they can be easily recovered from an anionic exchange. Application to real sludge samples is ongoing.

• Journal of Ocean Engineering and Technology
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• v.2 no.1
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• pp.150-162
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• 1988

The dynamic fracture toughness, $K_{Id}$,is measured in the heat-treated and ion-nitrided Cr-Mo, Ni-Cr-Mo steel using standard and Precracked Charpy specimens an imstrumented impact machine. The value of $K_{Id}$and both the energy of initiate fracture, and the total energy of fracture. Since the $K_{Id}$values of the precraked impact specimens are in accord with their theoretical ones, this testing method is sufficently practical. The effect of ion-nitriding are found to be larger than the heat-treaded specimen.

• Bulletin of the Korean Chemical Society
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• v.12 no.2
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• pp.138-143
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• 1991

Laser Raman spectroscopy has been used to study the interaction of $MoO_3$ with $TiO_2$. The bulk molybdenum oxide appeared to spread on the surface of titania under the submonolayer coverage. The surface polymolybdate was observed to be very stable with respect to the repeated treatment of reduction and subsequent calcination. Owing to the interaction of molybdate and titania, the phase transformation of $TiO_2$ seemed to be strongly retarded. The additives such as Co and Ni reacted readily with $MoO_3$ to form the corresponding molybdate salts. Nevertheless, the polymolybdate species appeared to be more stable on the titania surface than the molybdate salts.

• 대한공업교육학회지
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• v.31 no.1
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• pp.200-210
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• 2006

This C-ring test, normally employed for evaluating susceptibility to stress-corrosion cracking, was determined to be a suitable small scale test to evaluate PWHT(Post-Weld Heat Treatment) cracking susceptibility. This test is possible to incorporate an actual weld, to introduce a notch into the coarse grained HAZ(Heat Affected Zone), to load the coarse grained HAZ any level of stress ad, most importantly, since the C-ring is an approximately constant strain type test, the stress decreases with time at temperature in a manner similar to that of an actual steel weldment. The procedure employed in making the C-ring was presented in the experimental procedure section, however, several points deserve further discussion. The walls of the weld groove are made along radial lines form the center of th var in order to obtain an HAZ which is oriented perpendicular to the walls of the machined C-ring. Therefore, the plane of maximum stress will be aligned through the HAZ and, therefore, crack propagation will not be forced to deviate form the plane of maximum stress in order to remain in the coarse grained HAZ as is the case with the Y groove test.

• 한국신재생에너지학회:학술대회논문집
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• 2006.11a
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• pp.451-454
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• 2006

WGS reaction over Mo2C and ceria based catalysts was investigated to develop an alternative commercial Cu-Zn/Al2O3 catalyst for fuel processor and hydrogen station. The Mo2C catalysts were prepared by a temperature programmed method and the various metal supported cerium oxide catalysts were prepared by an Impregnation method. The catalysts were characterized by the N2 physisorption, Co chemisorption, XRD, TEM and TPR. It was found that Mo2C and 0.2wt% Pt-40wt%, Ni/CeO2 catalysts had higher activity and stability than the Cu-Zn/Al203 above $260^{\circ}C$. Moreover, CO conversion of more than 85% was observed at $280{\sim}300^{\circ}C$. But all catalysts were deactivated during the thermal cycling runs. The results suggest that these catalysts are an attractive candidate for the alternative Cu-Zn/Al2O3 catalyst for fuel processor and hydrogen station applications.