• 한국주조공학회지
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• 제38권3호
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• pp.55-59
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• 2018

To optimize the conductivity and to reduce the weight by as much as possible, Al-Cu composites were prepared through a suction-casting procedure. Pure copper metal foam was infiltrated by melted aluminum with the use of the vacuum, after which warm rolling was conducted to remove several remaining pores at the interface between the Cu foam and the aluminum matrix. Despite the short casting time, significant dissolution of Cu into the melt was observed. Moreover, it was found that various Al-Cu intermetallic compounds arose at the interface during the isothermal heating process after the casting and rolling steps. The average thickness of the Al-Cu intermetallic compound tended to increase in proportion to the heating time. The electrical and thermal conductivity levels of the cast composites were found to be comparatively low, mainly due to the dissolution of the Cu foam and the formation of intermetallics at the interface.

• 마이크로전자및패키징학회지
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• 제23권4호
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• pp.19-24
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• 2016

Along the few nano sizing dimensions of integrated circuit (IC) devices, acceptable interlayer material for design is inevitable. The interlayer which include dielectric, interconnect, barrier etc. needs to achieve not only electrical properties, but also mechanical properties for endure post manufacture process and prolonging life time. For developing intermetallic dielectric (IMD) the mechanical issues with post manufacturing processes were need to be solved. For analyzing specific structural problem and material properties Raman spectroscopy was performed for various researches in Si semiconductor based materials. As improve of the laser and charge-coupled device (CCD) technology the total effectiveness and reliability was enhanced. For thin film as IMD developed material could be analyzed by Raman spectroscopy, and diverse researches of developing method to analyze thin layer were comprehended. Also In-situ analysis of Raman spectroscopy is introduced for material forming research.

• Tribology and Lubricants
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• 제34권2호
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• pp.67-73
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• 2018

Ni-Al intermetallic coating technology is an available method for the strengthening of aluminum substrate. In this study, Ni-Al intermetallics were coated on an aluminum substrate through a reaction synthesis process at a temperature lower than melting point of aluminum. And the sliding wear properties of the coatings have been investigated to verify their usability and compared the wear properties with those of a cast Al-12.5%Si alloy and an anodizing layer on aluminum. Results show that the wear rate of the coating layer greatly increased at 1 m/s and 1.5 m/s when compared with that of the cast Al-12.5%Si alloy. Much pitting damages were observed on the worn surfaces at these sliding speeds, unlike at other sliding speeds. The wear of the intermetallic coating layer at these sliding speeds seems to be increased by pitting as a consequence of adhesion. In contrast, wear of the coating layer at other speeds hardly occurs, regardless of wear periods. Nevertheless, the wear properties of the intermetallic coating layer on the aluminum substrate through the reaction synthesis process are more stable than those of anodized aluminum and are superior to those of the cast Al-12.5%Si alloy in a steady-state wear period.

• 한국주조공학회지
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• 제36권1호
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• pp.24-31
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• 2016

CD4MCU duplex stainless steel with gadolinium was fabricated as a neutron absorbing material by the air induction melting method. The gadolinium formed intermetallic compounds of Cu-Gd-Fe. There were no significant differences in hardness or ultimate tensile strength between experimental alloys. With the addition of gadolinium the yield strength of the cast alloy significantly increased, from $478.8{\pm}11.6$ to $514.2{\pm}29.9MPa$, whereas elongation of the cast alloy decreased with the addition of gadolinium, from $26.0{\pm}7.1$ to $7.0{\pm}2.5%$ due to the formation of gadolinium based intermetallic compounds.

• 열처리공학회지
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• 제28권4호
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• pp.190-199
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• 2015

The study is intended to investigate the effect of solution treatment on microstructure and corrosion behavior of AZ91(Mg-9%Al-1%Zn-0.3%Mn)-2%Ca casting alloy. In as-cast state, the AZ91-2%Ca alloy consisted of intermetallic ${\beta}(Mg_{17}Al_{12})$, $Al_8Mn_5$ and $Al_2Ca$ phases in ${\alpha}-(Mg)$ matrix. After the solution treatment, Al within the ${\alpha}-(Mg)$ matrix was distributed more homogeneously, along with the slight decrease in the total amount of intermetallic compounds. The corrosion resistance of the AZ91-2%Ca alloy was improved after the solution treatment. The microstructural examinations for the solution-treated samples revealed that the better corrosion resistance may well be related to the incorporation of more oxides and hydroxides such as $Al_2O_3$, $Al(OH)_3$, CaO and $Ca(OH)_2$ into the surface corrosion product without dissolution of the intermetallic phases along the grain boundaries.

• Journal of Welding and Joining
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• 제25권3호
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• pp.51-56
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• 2007

A $CO_2$ laser overlay was conducted by using a Fe-based powder on the AC2B aluminum substrate. Cracks and intermetallic compounds (IMC) were observed inconsistently along the interface between the overlay and post-molten layer. A scanning electron microscopy (SEM) with energy dispersive spectroscopy (EDS) detected some Fe-rich IMC ($Fe_3Al$, FeAl) as well as the brittle Al-rich IMC ($Fe_2Al_5,\;FeAl_3$). Micro vickers hardness proved the formation of Al-rich IMC ($FeAl_3$) along the interface by showing HV0.1 $800{\sim}900$. Furthermore, nano indentation was successfully applied to investigate the behavior of IMC more precisely than the micro vickers hardness.

• 한국분말재료학회지
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• 제6권1호
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• pp.42-48
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• 1999

Three mixtures of elemental powders of Al-25at.%Ti, 48at.%Ti and 70at.%Ti were offered to ball milling process for the formation of intermetallic compounds of $Al_3Ti$, AlTi and $Ti_3Al$. Ballmilling or attrition process were carried out at the condition of rotaing speed of 110 or 350 rpm at $10^{-3}$ torr vacuum or argon atmospheres. $Al_3Ti$phases were fully obtained by heat treatment for 1 hors at $600^{\circ}C$ with Al-25at.%Ti composition mixtures milled by 100 hours. The amorphous phase was completely formed at the composition of Al-48at.%Ti mixed powders by milling 100hours at the 50 to 1 weight ratio of ball to powder, and AlTi compounds were obtained by heat treament. In the case of Al-70at%Ti mixed powders milled for 100 hours, $Ti_3Al$ and $Al_3Ti$intermetallic compounds were formed by heat treatment for 1 hour at $600^{\circ}C$. By attrition milling of 350rpm for 10 hours, $Ti_3Al$ phase was formed completley after heat treatment for 1 hour at $600^{\circ}C$.

• 한국분말재료학회지
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• 제11권2호
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• pp.105-110
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• 2004

In this study the possibility to obtain a homogeneous mixture and to produce solid solutions and intermetallic compounds of Fe and Al nano particles by simultaneous pulsed wire evaporation (S-PWE) have been investigated. The Fe and Al wires with 0.45 mm in diameter and 35 mm in length were continuously co-fed by a special mechanism to the explosion chamber and simultaneously exploded. The characteristics, e.g., phase composition, particle shape, and specific surface area of Fe-Al nano powders have been analyzed. The synthesized powders, beside for Al and $\alpha$-Fe, contain significant amount of a high-temperature phase of $\gamma$-Fe, Fe Al and traces of other intermetallics. The phase composition of powders could be changed over broad limits by varying initial explosion conditions, e.g. wire distance, input energy, for parallel wires of different metals. The yield of the nano powder is as large as 40 wt ％ and the powder may include up to 46 wt % FeAl as an intermetallic compound.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1999년도 춘계학술대회 논문집
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• pp.708-711
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• 1999

The Cu/Ni/Au lamellar structure is extensively used as an under bump metallization on silicon file, and on printed circuit board(PCB) pads. Ni is plated Cu by either electroless Ni plating, or electrolytic Ni plating. Unlike the electrolytic Ni plating, the electroless Ni plating does not deposit pure Ni, but a mixture of Ni and phosphorous, because hypophosphite Is used in the chemical reaction for reducing Ni ions. The fracture crack extended at the interface between solder balls of plastic ball grid (PBGA) package and conducting pads of PCB. The fracture is duets to segregation at the interface between Ni$_3$Sn$_4$intermetallic and Ni-P layer. The XPS diffraction results of Cu/Ni/Au results of CU/Ni/AU finishs showed that the Ni was amorphous with supersaturated P. The XPS and EDXA results of the fracture surface indicated that both of the fracture occurred on the transition lesion where Sn, P and Ni concentrations changed.

• Journal of Welding and Joining
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• 제25권4호
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• pp.72-78
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• 2007

Aluminized steel sheet is a material with excellent heat resistance, thermal reflection and corrosion resistance. It has wide applications, owing to its low cost and excellent performance, in the petrochemical industry, electric power and other energy conversion systems, etc and has attracted the attention of many investigators. But the welding of aluminized steel sheet has a problem of decreasing tensile-shear strength, caused by mixed Al in the weld. This study investigated behavior of Al and its structural properties to resolve this problem. Several analysis equipment(SEM, EDX, EPMA) were used to investigate Al element in the weld. Also microhardness tester and TEM equipment were used to find the intermetallic compound. As a result of this study, Al-rich zones existed in the weld and Fe-Al intermetallic compounds were found in these zones. At the same time, the weldability of aluminized stainless steel sheet was investigated and compared with that of aluminized steel sheet. Although there is a difference between the base metal of the low carbon steel and stainless steel, it is interpreted that a behavior of Al element in the weld is similar.