• 한국분말재료학회지
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• 제28권6호
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• pp.502-508
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• 2021

SiAlON-based ceramics are a type of oxynitride ceramics, which can be used as cutting tools for heat-resistant super alloys (HRSAs). These ceramics are derived from Si3N4 ceramics. SiAlON can be densified using gas-pressure reactive sintering from mixtures of oxides and nitrides. In this study, we prepare an α-/β-SiAlON ceramic composite with a composition of Yb_0.03Y_0.10Si_10.6Al_1.4O_1.0N_15.0. The structure and mechanical/thermal properties of the densified SiAlON specimen are characterized and compared with those of a commercial SiAlON cutting tool. By observing the crystallographic structures and microstructures, the constituent phases of each SiAlON ceramic, such as α-SiAlON, β-SiAlON, and intergranular phases, are identified. By evaluating the mechanical and thermal properties, the contribution of the constituent phases to these properties is discussed as well.

• 열처리공학회지
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• 제35권3호
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• pp.150-158
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• 2022

The effects of scandium addition on the Al-6Si-2Cu Alloy were investigated. The Al-6Si-2Cu-Sc alloy was prepared by gravity die casting process. In this study, scandium was added at 0.2 wt%, 0.4 wt%, 0.8 wt%, and 1.0 wt%. The microstructure of Al-6Si-2Cu-Sc alloy was investigated using Optical Microscope, Field Emission Scanning Electron Microscope, Electron Back Scatter Diffraction, and Transmission Electron microscope. The microstructure of Al-6Si-2Cu alloy with scandium added changed from dendrite structure to equiaxed crystal structure in specimens of 0.4 wt% Sc or more, and coarse needle-shape eutectic Si and β-Al₅FeSi phases were segmented and refined. The nanosized Al₃Sc intermetallic compound was observed to be uniformly distributed in the modified Al matrix.

• 한국표면공학회지
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• 제37권3호
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• pp.152-157
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• 2004

Ti-Al-N ($Ti_{75}$ $Al_{25}$ N) and Ti-Al-Si-N ($Ti_{69}$ $Al_{23}$ $Si_{8}$N) coatings synthesized by a DC magnetron sputtering technique were studied comparatively with respect to phase characterization and high-temperature oxidation behavior. $Ti_{69}$ $Al_{23}$ $Si_{ 8}$N coating had a nanocomposite microstructure consisting of nanosized(Ti,Al,Si)N crystallites and amorphous $Si_3$$N_4$, with smooth surface morphology. Ti-Al-N coating of which surface $Al_2$$O_3$ layer formed during oxidation suppressed further oxidation. It was sufficiently stable against oxidation up to about $700^{\circ}C$. Ti-Al-Si-N coating showed better oxidation resistance because both surface Ab03 and near-surface $SiO_2$ layers suppressed further oxidation. XRD, GDOES, XPS, and scratch tests were performed.

• 한국진공학회지
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• 제10권1호
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• pp.22-26
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• 2001

Plasma assisted molecular beam epitaxy(PAMBE)를 사용하여 Si 기판위에 성장시킨 AlN 박막에 대하여 성장온도 및 기판의 방향성에 따른 박막의 결정성 변화를 분석하였다. Reflection high energy electron diffraction(RHEED) 패턴을 이용하여 성장 중의 결정성을 관찰하였고, 성장 후에는 X-ray diffraction(XRD), double crystal X-ray diffraction(DCXD), transmission electron microscopy/diffraction(TEM/TED)분석을 하였다. $850^{\circ}C$이상의 온도에서 Si(100)위에 성장된 AlN박막은 육방정계의 c축 방향으로 우선 배향되어 있음을 확인하였으며 Si(111)위에 성장된 AlN박막의 경우 AlN(0001)/Si(111), AlN(1100)/Si(110), AlN(1120)/Si(112)의 결정방위를 가지고 성장하였음을 확인하였다. 또한 Si(111) 기판 위에서는 전위와 적층결함 등 많은 결정결함에 의해 DCD패턴의 반치폭이 2$\theta$=$36.2^{\circ}$에서 약 3000arcsec에 이르는 등 결정성은 좋지 않았으나 AlN박막이 단결정으로 성장된 것으로 나타났다.

• 한국재료학회지
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• 제22권2호
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• pp.97-102
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• 2012

The microstructure and tensile properties of Al-Mn/Al-Si hybrid aluminum alloys prepared by electromagnetic duocasting were investigated. Only the Al-Mn alloy showed the typical cast microstructure of columnar and equiaxed crystals. The primary dendrites and eutectic structure were clearly observed in the Al-Si alloy. There existed a macro-interface of Al-Mn/Al-Si alloys in the hybrid aluminum alloys. The macro-interface was well bonded, and the growth of primary dendrites in Al-Si alloy occurred from the macro-interface. The Al-Mn/Al-Si hybrid aluminum alloys with a well-bonded macro-interface showed excellent tensile strength and 0.2% proof stress, both of which are comparable to those values for binary Al-Mn alloy, indicating that the strength is preferentially dominated by the deformation of the Al-Mn alloy side. However, the degree of elongation was between that of binary Al-Mn and Al-Si alloys. The Al-Mn/Al-Si hybrid aluminum alloys were fractured on the Al-Mn alloy side. This was considered to have resulted from the limited deformation in the Al-Mn alloy side, which led to relatively low elongation compared to the binary Al-Mn alloy.

• 한국표면공학회:학술대회논문집
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• 한국표면공학회 2014년도 추계학술대회 논문집
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• pp.192-192
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• 2014

TiN, Ti(C,N), TiAlSiN, TiZrAlN, TiAlCrSiN 박막을 제조한 후, 이 들의 고온산화 특성을 SEM, EPMA, TGA, TEM, AES 등을 이용하여 조사하고, 산화기구를 제안하였다. 산화속도, 생성되는 산화물의 종류와 분포는 박막의 조성, 산화온도, 산화시간에 따라 변하였다.

• 한국표면공학회지
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• 제42권2호
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• pp.73-78
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• 2009

Quinary Ti-Al-Si-C-N films were successfully synthesized on SUS 304 substrates and Si wafers by a hybrid coating system combining an arc ion plating technique and a DC reactive magnetron sputtering technique. In this work, the effect of Si content on the microstructure and mechanical properties of Ti-Al-C-N films were systematically investigated. It was revealed that the microstructure of Ti-Al-Si-C-N coatings changed from a columnar to a nano-composite by the Si addition. Due to the nanocomposite microstructure of Ti-Al-Si-C-N coatings, the microhardness of The Ti-Al-Si-C-N coatings significantly increased up to 56 GPa. In addition the average friction coefficients of Ti-Al-Si-C-N coatings were remarkably decreased with Si addition. Therefore, Ti-Al-Si-C-N coatings can be applicable as next-generation hard-coating materials due to their improved hybrid mechanical properties.

• 한국분말재료학회지
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• 제7권1호
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• pp.35-41
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• 2000

Al2O3$.$SiC particle was prepared was prepared by the self-propagting high temperature sYthesis(SHS) process from a mixture of SiO2, Al and C powders, The fabricated Al2O3$.$SiC particle was applied to 2024Al/(Al2O3$.$SiC)pcomposite as a reinforcement. Aluminum matix composites were fabricares by the powder extrusion method using the synthesized Al2O3$.$SiC particle and commercial 2024Al powder. Theoptimum preparation conditions for Al2O3$.$SiC partticle by SHS process were described. The influence of the Al2O3$.$SiC voiume fraction on the mechanical was composite was also discussed. Despite adiabatic temperature was about 2367K, SHs reaction was completed not by itself, but by using pre-heating. Mean particle size of final particle synthesized was 0.73 ${\mu}$m and most of the particle was smaller than 2${\mu}$m. Elastic modulus and tensile strength of the composite increased with increase the volume fraction of reinforcement but, tensile strength depreciated at 30 vol% of reinforcement.

• 한국진공학회지
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• 제22권3호
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• pp.126-130
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• 2013

PSG/$SiO_2$ 보호막 처리된 Al-1%Si 박막배선 내 sodium (Na)과 수분($H_2O$) 게터링(gettering) 현상을 측정, 분석하였다. PSG/$SiO_2$ 보호막과 Al-1%Si 박막을 상압CVD (APCVD: atmosphere pressure chemical vapor deposition)법과 DC 마그네트론 스퍼터로 각각 증착하였고, 이차이온 질량분석기(SIMS: secondary ion mass spectrometry)를 이용한 깊이분포측정(depth profiling) 분석을 통해 PSG/$SiO_2$ 보호막으로부터 Al-1%Si 박막배선 층까지의 sodium과 수분 등 성분들의 분포를 확인하였다. Sodium과 수분 피크 모두 Al-1%Si 박막배선 내부보다는 막 간 계면에서 강하게 나타났다. PSG와 $SiO_2$ 보호막 계면에서는 sodium 피크는 관찰되었지만 수분 피크는 관찰되지 않았다.

• 한국주조공학회지
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• 제29권5호
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• pp.225-232
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• 2009

For comprehensive understanding of the formation behavior of $\beta-Al_5FeSi$ phase in Al-Si-Cu alloys with the existence of Fe element, microstructure characterizations were performed using combined analysis of OM, SEM-EDS, XRD. Especially, experimental and predictive works on solidification events of $\beta-Al_5FeSi$ phase as well as other phases formed together with $\beta-Al_5FeSi$ have been carried out by using DSC analysis and Java-based Materials Properties software (J. Mat. Pro.). Primary and eutectic $\beta-Al_5FeSi$ phases were able to distinguish from each other on microstructures by their morphological features. Primary $\beta-Al_5FeSi$ phase was seen to have rough surface perpendicular to growth direction, indicating free attachment of solute atoms in liquid state. On the other hand, the eutectic $\beta-Al_5FeSi$ phase was formed with plain and straight surface during eutectic reaction together with $\alpha$-Al phase. The eutectic reaction of $\beta-Al_5FeSi$ and $\alpha$-Al phases was seen to be able to separate into each formation depending on cooling rate.