• Journal of the Korean Ceramic Society
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• v.40 no.5
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• pp.460-467
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• 2003

Al-SiC$_{p}$ composite layer was prepared by plasma thermal spray on aluminum substrate using composite powder prepared by mechanical alloying. Mechanically alloyed powder was achieved after 24 h milling, which was used for thermal spray coating. The correlations between process conditions and thickness/porosity were analyzed, and increase of hardness was confirmed. The presence of Al-Si-C-O compound was detected by TEM analysis.

• Journal of Powder Materials
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• v.4 no.1
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• pp.26-41
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• 1997

The powder metallurgy (P/M) processed 2009 and 2124 Al composites reinforced with SiC particulates were studied by focusing on the effect of consolidation temperature on the microstructural and mechanical Properties. The mechanical properties such as tensile properties and microhardness of the second phases were analysed in relation to the microstructures observed by a SEM and an optical microscope. The in situ fracture process study using SEM showed that the grain refinement and the removal of manganese-containing particles often observed in the 2124 Al-${SiC}_{p}$ composites were important for the improvement of the mechanical properties. This study offers an optimum consolidation temperature for the control of the manganese-containing particles in the 2124 Al-${SiC}_{p}$ composites that yields mechanical properties higher than those of the 2009 Al-${SiC}_{p}$ composites.

• Journal of Power System Engineering
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• v.15 no.5
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• pp.77-82
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• 2011

SiC particulate reinforced Al matrix composites with different SiC volume fractions were fabricated by thermal spray process. And the dry sliding wear test were performed on these composites using the applied load of 10 N, rotational speed of 30 rpm, radius of rotation 15 mm. Wear tracks on the Al/SiC composites were investigated using scanning electron microscope(SEM) and energy dispersive spectroscopy (EDS). It was observed that wear behavior of Al/SiC composites and formation of MML was changed dramatically according to reinforcement volume fraction.

• Transactions of the Korean Society of Mechanical Engineers
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• v.18 no.9
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• pp.2374-2385
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• 1994

SiCw/Al composite material is especially attractive because of their superior specific strength, specific stiffness, corrosion fatigue resistance, creep resistance, and wear resistance compared with the corresponding wrought Al alloy. In this study, Fatigue crack growth behavior and fatigue crack path morphology(FCPM) of SiC whisker reinforced Al 6061 alloy with 25% SiC volume fraction and Al 6061 allay were performed. Result of the fatigue crack growth test sgiwed that fatigue crack growth rate of SiCw/Al 6061 composite was slower than that of Al 6061 matrix therefore it was confirmed that Sic whisker have a excellent fatigue resistance. And Al 6061 matrix had only FCPM perpendicular to loading direction. On the other hand SiCw/Al 6061 composite had three types in fatigue crack path morphology. First type is that both sides FCPM of artificial notch are perpendicular to loading direction. Second type is that a FCPM in artifical notch has slant angle to loading direction and the other side FCPM is perpendicular to loading direction. Third type is that both sides FCPM of notch have slant angle to loading direction. It was considered that this kinds of phenomena were due to non-uniform distribution of SiC whisker and confirmed by SEM observation for fracture mechanism study.

• Journal of the Korean Vacuum Society
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• v.1 no.3
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• pp.382-388
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• 1992

Electromigration은 인가된 전계하에서 발생하는 전자풍력에 의한 금속 이온의 현 상이며, 반도체 디바이스의 주요 결함 원인으로 보고되어 왔다. 선폭 1$mu extrm{m}$의 Al-1%Si 금속 박막전도체에 대한 electromigration 수명 실험을 위해 인가된 d.c. 전류밀도는 10MA/cm2 이었고, electromigration에 대한 활성화 에너지 측정을 위한 분위기 온도는 $80^{\circ}C$, 10$0^{\circ}C$ 그리고 $120^{\circ}C$이었다. 평균수명 및 신뢰성에 대한 보호 절연막 효과를 위해 두께 3000 $\AA$의 SiO2 산화막을 sputtering 진공증착기를 사용하여 Al-1%Si 금속 박막 전도체 위에 증착하였 다. 주요 연구 결과는 다음과 같다. Al-1%Si 금속 박막 전도체의 electromigration에 대한 활성화 에너지값은 0.75eV이었고 온도가 증가함에 따라 Al-1%Si의 수명은 감소하였고 신 뢰성은 향상되었다. SiO2 보호막은 electromigration에 대한 저항성을 크게 함으로써 평균수 명을 향상시켰으며, electromigration failure는 lognormal failure distribution은 갖는 것으로 나타났다.

• Journal of the Korean Ceramic Society
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• v.26 no.1
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• pp.31-36
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• 1989

In order to synthesize AlN-polytypes from AlN-SiO2-Al2O3 system, composition A (AlN/SiO2/Al2O3=1/0.3/0.05, mole ratio) and composition B(AlN-SiO2-Al2O3=1/0.2/0.05, mole ratio) were used. AlN-polytypes were produced by nitriding the mixture at 175$0^{\circ}C$~190$0^{\circ}C$ under N2 atmosphere. For lower reaction temperature, 15R phase was produced and in the case of higher reaction temperature, AlN phase was only produced. As each composition was heated at 185$0^{\circ}C$ in N2 atmosphere, produced main phases were 15R phase for composition A and 21R phase for composition B respectively. The fracture surfaces of produced reactants showed porous skeleton structure.

• Journal of the Korean Society for Heat Treatment
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• v.13 no.2
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• pp.108-114
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• 2000

The effects of heat treatments in Al-Si-Mg alloys on the microstructure and hardness have been investigated by the optical microscope, scanning electron microscope(SEM), and Rockwell hardness tester. The materials of various compositions are melted in a vacuum induction furnace under argon atmosphere. Five different Al alloys are prepared from commercial purity aluminium, magnesium and Al-25Si alloy. Two types of aging treatments are performed: i) Isothermal aging of the specimens at $150^{\circ}C$, $170^{\circ}C$ and $190^{\circ}C$. ii) Pre-aging of the specimens at $60^{\circ}C$, $80^{\circ}C$ and $100^{\circ}C$, and followed by final-aging at $170^{\circ}C$ and $190^{\circ}C$. After the heat treatments, Rockwell hardness are measured with all the specimens.

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2006.09b
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• pp.1301-1302
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• 2006

Sintered composites of Al-8wt%Cu-10vol%SiCp were deformed by repressing or equal channel angular pressing(ECAP) at room temperature, $500^{\circ}C$ and $600^{\circ}C$. Repressing produced more densification than ECAP but resulted in much lower transverse rupture strengths. In both cases, deformation at room temperature and $500^{\circ}C$, resulted in much lower strengths than deformation at $600^{\circ}C$, and also caused the fracturing of some SiC particles. The higher bend strengths and less SiC fracturing at $600^{\circ}C$ are attributable to the presence of an Al-Cu liquid phase during deformation. The employment of copper coated SiC instead of bare SiC particles for preparing the composites was found not improving the properties.

• Journal of the Korean Ceramic Society
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• v.27 no.8
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• pp.965-970
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• 1990

A nitrogenation of coal ash in the presence of carbon was carried out to examine the effects of reaction temperature, reaction time and carbon composition on the formation of AlN, SiC and Si3N4. Decreasing the particle size increased the formation of AlN and its maximum composition in the product was obtaiend under 1450~150$0^{\circ}C$, 2 hours of reaction time and about 30% of carbon addition(on the basis of sample weight). Compositions of SiC and Si3N4 were distributed to the opposite so that SiC showed a higher composition compared with Si3N4 at a lower temperature, a shorter reaction time and a greater carbon addition.

• Journal of the Korean Vacuum Society
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• v.10 no.1
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• pp.22-26
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• 2001

Microstructures of AlN thin films on Si substrates grown by plasma assisted molecular beam epitaxy were analyzed with various growth temperatures and substrate orientations. Reflection high energy electron diffraction (RHEED) patterns were checked for the in-situ monitoring of the growth condition. X-ray diffraction(XRD), double crystal X-ray diffraction (DCXD), and transmission electron microscopy/diffraction (TEM/TED) techniques were employed to characterize the microstructure of the films after growth. On Si(100) sub-strates, AlN thin films were grown mostly along the hexagonal c-axis orientation at temperature higher than $850^{\circ}C$. On the other hand the AlN films on Si(111) were epitaxially grown with directional coherencies in AlN(0001)/Si(111), AlN(1100)/Si(110), and AlN(1120)/Si(112). The microstructure of AlN thin films on Si(111) substrates, with a full width at half maximum of almost 3000 arcsec at 2$\theta$=$36.2^{\circ}$, showed that the single crystal films were grown, even if they includ a lot of crystal defects such as dislocations and stacking faults.