• Corrosion Science and Technology
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• 제9권6호
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• pp.259-264
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• 2010

In continuous hot dip galvanizing process, oxide formation on steel surface has an influence on Zn wetting. High strength automotive steel contains high amount of Si and Mn, where Si-Mn composite oxides such as $Mn_2SiO_4$ or $MnSiO_3$ covers the surface after annealing. Zn wetting depends on how the aluminothermia reaction can reduce the Mn-Si composite oxides and then form inhibition layer such as $Fe_2Al_5$ on the steel surface. The outward diffusion of metallic ions such as $Mn^{2+}$, $Si^{2+}$ in the steel matrix is very important factor for the formation of the surface oxides on the steel surface. The surface state and grain boundaries provide an important role for the diffusion and the surface oxide reactions. Some elements such as P, Sb, and B have a strong affinity for the interface precipitation, and it influence the diffusivity of metallic ions on grain boundaries. B oxide forms very rapildly on the steel surface during the annealing, and this promote complex oxides with $SiO_2$ or MnO. P has inter-reacted with other elements on the grain boundaries and influence the diffusion through on them. Small addition of Sb could suppress the decarburization from steel surface and retards the formation of internal and external selective oxides on the steel surface. Interface control by the trace elements such as Sb could be available to improve the Zn wettability during the hot dip galvanizing.

• 대한치과보철학회지
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• 제25권1호
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• pp.317-325
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• 1987

A study on the shear bonding strength between dental alloy and porcelain according to various kidns of sputtered metallic thin films was established by Ingtron universal testing machine, and the change of the elemental weight % at the surface of dental alloy was studied by E.D.S. The kind of metallic thin films were Al, Ni, In, Cr. Ti and Sn with $0.3{\mu}m$ thickness. The dental alloys were Verabond made by Aalba Dent. Co. and Degudent H manufactured by Degussa Co. The control groups were Verabond and Degudent H. The obtained results were as follows; 1. The shear bonding strength of Al plated sample was the strongest of all. 2. The shear bonding strength of Ni plated sample was stronger than that of Degudent H, Sn plated samples. 3. The shear bonding strength of Verabond was weaker than that of Al, Ni, In, Cr, plated samples. 4. After degassing, it is more weight % of Ni at the alloy surface of the Ni sputtered specimen than the Sn sputtered sample.

• 한국세라믹학회지
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• 제20권3호
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• pp.236-242
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• 1983

The purpose of present study is to find the structures physical properties and their inter-relations in the system of (60-x) PbO.xMO.$40B_2O_3$ glasses where MO represents for ZnO and CdO. The experiments such as differential thermal analysis infrared spectral analysis X-ray diffraction analysis density and thermal expansion measurements have been done. From infrared spectral analysis the structural units of glasses and the corresponding crystallized glasses were com-posed of $BO_3$ triangles and $BO_4$ tetrahedra. These basic units found in $PbO-B_2O_3$ binary glass system did not charge even though the divalent metallic oxides were substituted for PbO. The structures of these ternary glasses were more coalescenced than $PbO-B_2O_3$ binary glass system. This fact was supported bydecrease in thermal expansion coeffici-ent and molar volume with substitution of divalent metallic oxide for PbO. Crystalline phases obtained from the heat treatment of the $PbO-ZnO-B_2O_3$ glasses were 4PbO.2ZnO.$5B_2O_3$ PbO.2ZnO.$B_2O_3$ and unknown phases.

• Corrosion Science and Technology
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• 제21권4호
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• pp.300-313
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• 2022

Interest in polymer electrolyte fuel cell is growing to replace fossil fuels. In particular, in order to reduce the cost and volume of the fuel cell, research on a metallic bipolar plate is being actively conducted. In this research, investigated the effects of temperature and chloride concentration on the electrochemical characteristics and damage behavior of 316L stainless steel in an accelerated solution simulating the cathodic operating condition of PEMFC(Polymer electrolyte membrane fuel cell). As a result of the experiments, the corrosion current density, damage size, and surface roughness increased as the temperature and chloride concentration increased. In particular, the temperature had a significant effect on the stability of the oxide film of 316L stainless steel. In addition, it was described that the growth of the pit was affected by the chloride concentration rather than the temperature. As a result of calculating the corrosion tendency to compare the pitting corrosion rate and the uniform corrosion rate, the uniform corrosion tendency became larger as the temperature increased. And the effects of chloride concentration on corrosion tendency was different according to temperature.

• 한국진공학회지
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• 제6권1호
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• pp.1-8
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• 1997

SUS 316 합금의 노출 조건에 따른 오염 과정과 구조를 x-ray photoelectron spectroscopy실험을 통해 보았다. SUS표면에 부착된 오염 물질은 주로 metal-oxide, metal-H-oxide, CO, COH, 그리고 CxHy임을 보았다. 오염 물질의 층별 형성 구조는 $C_xH_y$/CO(COH)/metal-H-oxide/metal-oxide가 SUS합금 위에 있는 형태이다. 오염 과정은 주로 금속 구성물의 산화와 $C_xH_y$의 흡착과정 두 가지에 의해서 이루어지는 것을 볼 수 있 었다. 초고진공 환경에서는, 오염은 주로 산화층 형성에 의한 것으로 노출 시간이 증가함에 따라 산화층의 두께가 계속 증가하였다. 고진공 또는 높은 압력 환경에서는 노출 초기에 대 부분의 산화층이 형성되고, 노출 시간의 증가에 대해서는 주로 $C_xH_y$에 의한 오염이 계속 증 가하였다. 스테인레스 표면 안에 깊이 분포하고 있는 metal-oxide의 농도는 지수형으로 감 소하는 형태의 분포를 가지며 그 두께는 대기 노출된 시료의 경우 광전자의 평균자유행로 규모로 형성되는 것을 보았고, 특히 Fe-oside가 Cr-oxide를 덮고 있는 표면 편석 현상이 보 였다.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2010년도 추계학술대회 초록집
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• pp.82.2-82.2
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• 2010

The development of bipolar plate having high efficiency and chemical properties has a major impact on fuel cell applications commercialization. Even though graphite bipolar plate has high electric conductivity and chemical resistance, it has demerits about mass production and brittle property for commercialization. Hence, metallic bipolar plate can be substitute for fuel cell bipolar plate. Although its inadequate corrosion behavior under PEMFC environment lead to a deterioration of membrane by dissolved metal ions, metallic bipolar plate for PEMFC is more suitable for automotive and residential power generation system because of its high mechanical strength, low gas permeability and applicability to mass production. Therefore, several types of coating has been applied to prevent corrosion and oxide film growth and to achieve more high durability. This work presents durability of coated metal bipolar plate for low temperature PEMFC which made for fuel cell vehicle. This results showed surface treatment increase long-term durability, even electric conductivity and corrosion resistance.

• 대한기계학회논문집
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• 제6권2호
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• pp.113-120
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• 1982

In the previously reported Part I, the experimental results in frictional machining that finished medium carbon steel SM 50 C under 6 kinds of liquid atmospheres by using ceramic tip as a frictional tool was described. The present study reports the experimental results that all the machining conditions are same in the Part I except tool material changed ceramics into tungsten carbide. The ceramic tool material is a stable oxide and a non-metallic material, but the tungsten carbide has the metallic characteristics that adhere to carbon steel at about 750.deg.C. The present study shows th comparison of the experimental results for the above 2 kinds of frictional tool material.

• 한국분말야금학회:학술대회논문집
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• 한국분말야금학회 2000년도 추계학술대회 및 발표대회 강연 및 발표논문 초록집
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• pp.10-10
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• 2000

Mechanical alloying (MA) is a powder metallurgy processing technique involving cold welding, fracturing, and rewelding of powder particles in a high-energy ball mill. This has now become an established commercial technique in producing oxide dispersion strengthened (ODS) nickel- and iron-based materials. The technique of MA is also capable of synthesizing non-equilibrium phases such as supersaturated solid solutions, metastable crystalline and quasicrystalline intermetallic phases, nanostructures, and amorphous alloys. In this respect, the capabilities of MA are similar to those of another important non-equilibrium processing technique, viz, rapid quenching of metallic melts. however, the science of MA is being investigated only during the past ten years or so. The technique of mechanochemistry, on the other hand, has had a long history and the materials produced this way have found a number of technological applications, e.g., in areas such as hydrogen storage materials, heaters, gas absorber, fertilizers. catalysts, cosmetics, and waste management. The present talk will concentrate on the basic mechanisms of formation of non-equilibrium phases by the technique of MA and these aspects will be compared with those of rapid quenching of metallic melts. Additionally, the variety of technological applications of mechanically alloyed products will be highlighted.

• Transactions on Electrical and Electronic Materials
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• 제3권2호
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• pp.6-9
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• 2002

Indium tin oxide (ITO) films were deposited on unheated PET substrates by DC reactive magnetron sputtering of In-Sn (90-10 wt%) metallic alloy target. Electrical and optical properties of as-deposited films were systematically studied by control of the deposition parameters such as working pressure, DC power, and oxygen partial pressure. The figures of merit are important factors that summarize briefly the relationship between electrical and optical properties of transparent conducting films. The formulae of T/R$\_$sh/ and T$\^$10// R$\_$sh/ are expressed as a function of transmittance and sheet resistance. The best values of those figures of merit were approximately 38.6 and 8.95 ($\times$10$\^$-3/Ω$\^$-1/), respectively.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2001년도 추계학술대회 논문집 Vol.14 No.1
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• pp.398-401
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• 2001

Indium tin oxide films were deposited on unheated PET substrates by DC reactive magnetron sputtering of In-Sn (90-10 wt%) metallic alloy target. Electrical and optical properties of as-deposited films were systematically studied by control of the deposition parameters such as working pressure, DC power, and oxygen partial pressure. The figures of merit are important factors that summarize briefly the relationship between electrical and optical properties of transparent conducting films. The formulae of $T/R_{sh}$ and $T^{10}/R_{sh}$ are expressed as a function of transmittance and sheet resistance. The best values of those figures of merit were approximately 38.6 and $8.95({\times}10^{-3}\Omega^{-1})$ respectively.