http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
Cho, Seungchan,Jo, Ilguk,Lee, Yeong-Hwan,Yoo, Yeon Woo,Byon, Eungsun,Lee, Sang-Kwan,Lee, Sang-Bok Elsevier 2018 APPLIED SURFACE SCIENCE - Vol.448 No.-
<P><B>Abstract</B></P> <P>Oxidation resistance of TiC–SKD11 composite has been improved through SiC/TiB<SUB>2</SUB> based hybrid coating by a simple air spray process and subsequent transition to dense and stable phases in oxidation environment. As a result of the oxidation test at 700 °C for up to 50 h, the coated TiC–SKD11 composite exhibited excellent oxidation resistance characteristics compared with the uncoated TiC–SKD11 composite, and also compared to SUS431 and 17-4PH. The formation of a thermally stable, volume-expanded SiO<SUB>2</SUB> and TiO<SUB>2</SUB> coating layer with the aid of B<SUB>2</SUB>O<SUB>3</SUB> by phase transition of TiB<SUB>2</SUB>/SiC based hybrid coating under oxidation atmosphere is the origin of the improved anti-oxidation ability of the TiC–SKD11 composite.</P> <P><B>Highlights</B></P> <P> <UL> <LI> A SiC/TiB<SUB>2</SUB> based hybrid coating layer was successfully deposited on the surface of TiC–SKD11 composite by simple air spray process. </LI> <LI> The anti-oxidation ability was found to be much better than that of the uncoated TiC–SKD11 composite, as well as better than those of SUS431 and 17-4PH. </LI> <LI> The formation of SiO<SUB>2</SUB> and TiO<SUB>2</SUB> layer with the aid of B<SUB>2</SUB>O<SUB>3</SUB> by phase transition of SiC/TiB<SUB>2</SUB> based hybrid coating is the origin of the improved anti-oxidation ability of the TiC–SKD11 composite. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>
용융가압함침 공정으로 제조한 TiC-SKD11 복합재료의 미세조직 및 내마모 특성
조승찬 ( Seungchan Cho ),조일국 ( Ilguk Jo ),이상관 ( Sang-kwan Lee ),이상복 ( Sang-bok Lee ) 한국복합재료학회 2017 Composites research Vol.30 No.3
본 연구에서는 용융가압함침 공정을 통해 고체적율의 TiC 입자가 균일 분산된 SKD11 금속복합재료를 제조하고, 미제조직, 기계적 특성 및 내마모 특성에 대해 분석하였다. 약 60 vol%의 TiC가 균일하게 분산된 TiC-SKD11 복합재료를 제조함으로써 SKD11 대비 약 24% 경량화에 성공하였고 경도 및 압축항복강도는 증가하였다. 내마모 시험 결과 복합소재의 우수한 내마모 특성을 확인하였으며, 이는 높은 경도를 가지는 TiC 입자가 SKD11 기지와 강한 계면 결합력을 가지면서 높은 체적율로 존재함으로 인한 분산강화 효과와 TiC에 의한 SKD11의 산화 억제가 원인으로 판단된다. Titanium carbide (TiC) reinforced SKD11 matrix composites were successfully fabricated by a novel liquid pressing infiltration process. Microstructure, mechanical properties, and wear characteristics of the fabricated 60 vol% TiC-SKD11 composite are analyzed. The composite exhibits superior mechanical properties, such as hardness and compressive strength with 24% lower density as compared with SKD11. Improved wear resistance of the TiC-SKD11 composite originates from uniformly reinforced TiC having strong interfacial bonding strength between TiC/ SKD11 interface.
Park, Jongbok,Lee, Junho,Jo, Ilguk,Cho, Seungchan,Lee, Sang Kwan,Lee, Sang Bok,Ryu, Ho Jin,Hong, Soon Hyung Elsevier 2016 Surface & Coatings Technology Vol. No.
<P><B>Abstract</B></P> <P>This study investigates the effects of a surface modification of a SiC tile on the wetting behavior and interfacial bond strength of SiC tile/Al7075-SiC<SUB>p</SUB> hybrid composites fabricated by a liquid-press process. SiO<SUB>2</SUB>, Ni, and Si layers were fabricated on each SiC tile, and the microstructures at the interface between the surface-modified SiC tile and the Al7075 were analyzed. In addition, the interfacial bond strength and wettability between the SiC tile and Al7075 were measured by the push-out method and the sessile drop method, respectively. The interfacial bond strength and wettability tests demonstrate that the surface modification of a SiC tile with Al7075 can effectively improve the tendency to attain wetting between the SiC tile and Al7075, due to the suppression of the formation of brittle Al<SUB>4</SUB>C<SUB>3</SUB> at the interface between the SiC tile and Al7075.</P> <P><B>Highlights</B></P> <P> <UL> <LI> The surface of SiC tile (SiC<SUB>t</SUB>) was modified by oxidation, Ni plating, and Si coating. </LI> <LI> The tendency to attain wetting between the modified SiC<SUB>t</SUB> and Al7075 was improved. </LI> <LI> The interfacial bond strength between the modified SiC<SUB>t</SUB> and Al7075 increased. </LI> <LI> The surface modification suppressed the formation of Al<SUB>4</SUB>C<SUB>3</SUB> at the interface. </LI> </UL> </P>
Lee, Hyungsoo,Choi, Jin Hyeok,Jo, Min Chul,Lee, Donghyun,Shin, Sangmin,Jo, Ilguk,Lee, Sang-Kwan,Lee, Sunghak Elsevier 2018 Materials science & engineering. properties, micro Vol.738 No.-
<P><B>Abstract</B></P> <P>Quasi-static and dynamic compressive properties of 7075-T6 Al matrix composites reinforced with SiC<SUB>p</SUB>s (size; 10 µm, 30 µm, and bimodal (10 + 30) μm), <I>i.e</I>., 10S, 30S, and BS composites, respectively, were investigated in relation with fracture mechanisms. SiC<SUB>p</SUB>s were homogeneously distributed without SiC<SUB>p</SUB> agglomeration, pores, or cracks, and their volume fractions were 49.5 vol%, 54.1 vol%, and 56.5 vol% in the 30S, 10S, and BS specimens, respectively. Compressive properties could be explained by a rule of mixtures based on SiC<SUB>p</SUB> volume fraction and by three major fracture phenomena including deformation of Al matrix, cracking of SiC<SUB>p</SUB>s, and interfacial debonding between SiC<SUB>p</SUB> and Al. As the SiC<SUB>p</SUB> size decreased, crack initiation sites changed from SiC<SUB>p</SUB>s themselves to SiC<SUB>p</SUB>/Al interfaces, which mainly affected the compressive strength. In the BS composite, coarse SiC<SUB>p</SUB>s additionally worked for the strengthening by increasing the total reinforcement fraction, and the three fracture phenomena were well homogenized, thereby leading to the highest strain energy density as well as the best combination of strength and strain.</P>
Effects of Strain Rate on Compressive Properties in Bimodal 7075 Al-SiCp Composite
Lee, Hyungsoo,Choi, Jin Hyeok,Jo, Min Chul,Jo, Ilguk,Lee, Sang-Kwan,Lee, Sunghak Springer-Verlag 2018 METALS AND MATERIALS International Vol.24 No.4
<P>A 7075 Al alloy matrix composite reinforced with SiC particulates (SiC(p)s) whose sizes were 10 and 30 mu m, i.e., a bimodal Al-SiCp composite, was made by a liquid pressing process, and its quasi-static and dynamic compressive properties were evaluated by using a universal testing machine and a split Hopkinson pressure bar, respectively. Mg-Si-, Al-Fe-, and Cu-rich intermetallic compounds existed inside the Al matrix, but might not deteriorate compressive properties because of their low volume fraction (about 2.6%) which was much lower than that of SiCp. The dynamic compressive strength was higher than the quasi-static strength, and was higher in the specimen tested at 2800 s(-1) than in the specimen tested at 1400 s(-1) according to the strain-rate hardening. For explaining the strain data, the blocking extent of crack propagation by the Al matrix was quantitatively examined. The melting of Al matrix occurred by adiabatic heating was favorable for the improvement in compressive strain because it favorably worked for activating the shear band formation and for blocking the crack propagation, thereby leading to the excellent compressive strain (10.9-11.6%) as well as maximum compressive strength (1057-1147 MPa). Thus, the present bimodal 7075 Al-SiCp composite provides a promise for new applications to high-performance armor plates.</P>
Lee, Hyungsoo,Sohn, Seok Su,Jeon, Changwoo,Jo, Ilguk,Lee, Sang-Kwan,Lee, Sunghak Elsevier Sequoia 2017 Materials science & engineering Structural materia Vol.680 No.-
<P><B>Abstract</B></P> <P>In this study, A356 Al alloy composites reinforced with SiC particulates (SiC<SUB>p</SUB>), whose SiC<SUB>p</SUB> volume fraction was quite high (about 56vol%) for a candidate surface material of multi-layered armors, were fabricated by a liquid pressing process, and their dynamic compressive properties were investigated by using a split Hopkinson pressure bar. Defects such as misinfiltration or pores were eliminated, but about 2vol% of eutectic Si particles and about 3vol% of Fe-Al intermetallic compound particles were contained in the Al matrix. According to the dynamic compressive test results, dynamic compressive strength and strain were much higher than quasi-static ones because of strain-rate hardening effect and existence of molten Al matrix formed by adiabatic heating. The as-cast composite showed the best combination of dynamic strength and strain, together with the highest dynamic toughness, because the crack propagation was effectively blocked by the molten Al matrix and deformation band formation, while the T6-heat-treated composite showed the lowest compressive strain in spite of the highest strength. These findings suggested that the present Al-SiC<SUB>p</SUB> composites could be reliably applied to armors because the dynamic toughness or resistance to fracture was much higher under the dynamic loading than under the quasi-static loading.</P>
무전해 Ni-TiO₂ 복합도금을 이용한 광분해 특성 연구
최철영(Chul young Choi),한길수(Gilsoo Han),조일국(Ilguk Jo),김영석(Young seok Kim),김양도(Yangdo Kim) 한국표면공학회 2009 한국표면공학회지 Vol.42 No.4
Many fundamental studies have been carried out regarding waste water and hazardous gas treatments technologies using the photolysis effect of TiO₂. However, a permanent use of TiO₂ particles immobilized using organic or organic-inorganic binders is impossible. In this study, Ni-TiO₂ composite coating was produced by electroless plating to trap TiO₂ particles in the Ni coating layer. The electroless plating was performed in the bath solutions with three different concentrations of TiO₂ particles : 10 g/l, 20 g/l, and 40 g/l. The surface and photolytic characteristics of the coating layer was investigated by the use of SEM, a scratch tester, and an UV-Visible spectrophotometer. The results showed that the amounts of immobilized TiO₂ particles and the photolytic rate of the coating increased with the initial content of TiO₂ particles in the electroless bath. In addition, the photolytic rate of the Ni-TiO₂ composite coating was remarkably promoted by etching process in 10% HCl solution.