Eco-Materials Processing and Design IX

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Authors: Sung Pill Nam, Sung Gap Lee, Young Hie Lee
Abstract: The V1.9W0.1O5 thin films deposited on Pt/Ti/SiO2/Si substrates by RF sputtering method exhibited fairly good TCR and dielectric properties. It was found that film crystallinity, dielectric properties, and TCR properties were strongly dependent upon the annealing temperature. The dielectric constants of the V1.9W0.1O5 thin films annealed at 300°C were 37.7, with a dielectric loss of 2.535, respectively. Also, the TCR values of the V1.9W0.1O5 thin films annealed at 300°C were about -3.7%/K.
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Authors: Jong Min Lim, Sang Woo Kim
Abstract: Nickel coated gadolinium doped ceria (GDC) powder was synthesized by microwave radiation and combustion. For the synthesis, the precipitates of gadolinium cerium oxycarbonate hydrate (GdxCe2-xO(CO3)2·H2O) were formed by a microwave radiated reaction between cerium nitrate (Ce(NO3)3.6H2O) and gadolinium nitrate (Gd(NO3)3.6H2O) and urea (CO(NH2)2), then nickel coatings on the gadolinium cerium oxycarbonate hydrate were performed by further microwave reaction between nickel chloride and urea. The shape and size of the gadolinium cerium oxycarbonate hydrate particles were critically dependent on aging time during microwave radiation. The irregular particles were transformed to rod shape particles with well-crystallized with increasing aging time to 40 min at 70 - 80°C because of the gradual decomposition of urea during microwave radiation. Small nickel precursor particles were homogeneously coated on the gadolinium cerium oxycarbonate hydrate particles with rod shape with aid of microwave radiation at 80 °C for 40 min. As a result, the nickel coated GDC nanopowders were sucessfully produced by the microwave radiation synthesis and further microwave combusted at 450°C for 20 min.
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Authors: Jong Hae Kim, Won Chul Choi
Abstract: In this paper, we consider the analysis of grinding collagen and mathematical function from the cell toxic experiments using interpolation method in new synthetic organic compounds. The extracted collagens and functional cosmetics such as mask, whitening, and serum from collagen are measured with a SEM (Scanning Electron Microscope) and a light-microscope. Also, interpolation method is used for analysis of cell toxic experiments in new synthetic compounds from collagens. The obtained mathematical function can help to provide analytic approach on various toxic substances at different densities. The results can be used as basic data on development for synthesis of new marine functional materials and their derivatives.
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Authors: Dong Hwan Song, Jong Kook Lee, Dong Seok Seo, Gon Seung Yang
Abstract: Titanium-based nitride coatings on cutting tools, press molds and dies can prolong their life cycle because of superior corrosion and oxidation resistance of coatings. In this study, TiAlN/ZrN and TiCrN/ZrN multilayer coatings were prepared by R.F magnetron sputtering, and microstructural evolution and corrosion resistance of the coatings were investigated during heat treatment. The TiAlN/ZrN and TiCrN/ZrN multilayer coatings were degraded by heating up to 600 oC with formation of oxides particles on the surface. During the heat treatment, the TiCrN/ZrN and TiAlN/ZrN multilayer coatings showed the lowest corrosion current density and the highest polarization resistance at temperature range of 400 oC and 500 oC. Consequently, the TiAlN/ZrN and TiCrN/ZrN multilayer coatings showed good corrosion resistance at temperature range of 400°C and 500°C during heating.
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Authors: Xi Hai Jin, Lian Gao, Jing Sun
Abstract: SiC/ZTM nanocomposites were prepared, and the influence of nanosized SiC addition on the microstructure and mechanical properties were investigated. It was found that the addition of nanosized SiC significantly retarded the matrix grain growth, making the microstructure much finer and more uniform. This led to a significant improvement in the mechanical properties. And further enhancement in the mechanical property can be achieved through the addition of mullite seeds in the starting powder and improving the distribution homogeneity of SiC nanoparticles in the matrix.
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Authors: Yong Hwan Kim, S.I. Kwun
Abstract: The phases formed in the wide-gap region brazed with Ni-14Cr-10Co-3.5Al-2.5Ta-2.8B filler metal powder in IN738 superalloy were investigated by electron backscatter diffraction (EBSD). The wide-gap brazing process was carried out in a vacuum of 2×10-5 torr at 1503 K. The region brazed with filler metal powders had a microstructure consisting of two kinds of eutectic colonies, one is Ni solid solution-CrB eutectic and the other is Ni solid solution-Ni3B eutectic. EBSD pattern analysis revealed that the CrB phase had orthorhombic structure with lattice parameters of a=0.297, b=0.786 and c=0.293 nm, and the Ni3B phase had orthorhombic structure with lattice parameters of a=0.439, b=0.522 and c=0.662 nm. The cuboidal-shaped phase precipitated in the Ni solid solution was found to be the γ' (Ni3Al) phase, which had cubic structure with lattice parameter of a=0.357 nm.
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Authors: Tao Zhang, Hai Yun Jin, Yong Ian Wang, Zhi Hao Jin
Abstract: AlN/BN laminated ceramic composites were fabricated using tape-casting and hot-pressing by optimizing the designs of the structure and geometry of AlN/BN laminated ceramic composites. The results showed that the fracture toughness and bending strength for AlN/BN laminated ceramics reached 9.1MPa.m1/2 and 378MPa respectively. The fracture toughness is two times higher than that of AlN monolithic ceramics. The excellent fracture toughness of AlN/BN laminated ceramics could be mainly attributed to crack deflection, delaminating, branching, parallel propagation and crack laminate pilling out at the AlN/BN weak interface.
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Authors: Ji Hwan Yun, Sung Kyu Ahn, Kwang Ho Kim
Abstract: CrN-based multi-component coatings were deposited by a hybrid coating system combining the arc ion plating (AIP) and sputtering technique. In this work, comparative studies on microstructure and mechanical properties of microhardness and wear behavior among CrN, Cr-Mo- N, Cr-Si-N coatings were systematically conducted. Adding Mo and Si atoms into CrN coatings had important effects on microstructural change and mechanical properties of CrN coatings. The maximum hardness values of Cr-Mo-N and Cr-Si-N coatings were the same value of 34GPa, These values were much enhanced compared with 18GPa of CrN coating. The average friction coefficient of CrN-based coatings decreased to 0.37 and 0.2 with the incorporation of Mo and Si content
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Authors: Eun Young Choi, Ji Hoon Park, Kwang Ho Kim
Abstract: In this work, the Ti-Al-Si-C-N coatings were synthesized on Stainless steel and Si wafer by a hybrid coating system, where arc ion plating (AIP) technique was combined with a magnetron sputtering technique. Also, the effect of Si content on the microstructure and mechanical properties of Ti-Al-C-N coatings were systematically investigated. The Ti-Al-Si-C-N coatings characterized by a nanocomposite comprising nano-sized Ti-Al-C-N crystallites embedded in amorphous Si3N4 phase. The micro-hardness values of Ti-Al-Si-C-N coatings were largely depended on Si content and the micro-hardness value of Ti-Al-Si-C-N coatings significantly increased from 38Gpa of Ti-Al-C-N coatings to approximately 56 GPa with the addition Si content of 9.8 at.%. The enhanced hardness values of Ti-Al-Si-C-N coatings were explained with the refinement of Ti-Al-C-N crystallites and composite microstructure characteristics by the percolation of amorphous Si3N4/SiC phase. The average friction coefficient of Ti-Al-Si-C-N decreased from 0.6 of Ti-Al-C-N to 0.23 with increasing the Si content up to 15.3 at. %. The decreased friction coefficients of Ti-Al-Si-C-N coatings was elucidated by the formation of SiO2 or Si(OH)2 layer known as self-lubricant materials.
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Authors: Gui Wu Liu, Guan Jun Qiao, Hong Jie Wang, Jian Feng Yang, Tian Jian Lu
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