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        검색결과 5

        1.
        2022.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The low-temperature sinterability of TiO2-CuO systems was investigated using a solid solution of SnO2. Sample powders were prepared through conventional ball milling of mixed raw powders. With the SnO2 content, the compositions of the samples were Ti1-xSnxO2-CuO(2 wt.%) in the range of x  0.08. Compared with the samples without SnO2 addition, the densification was enhanced when the samples were sintered at 900oC. The dominant mass transport mechanism seemed to be grain-boundary diffusion during heat treatment at 900oC, where active grain-boundary diffusion was responsible for the improved densification. The rapid grain growth featured by activated sintering was also obstructed with the addition of SnO2. This suggested that both CuO as an activator and SnO2 dopant synergistically reduced the sintering temperature of TiO2.
        4,000원
        2.
        2022.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The green body of WC-Co cemented carbides containing polymeric binders such as paraffin, polyethylene glycol (PEG), and polyvinyl acetate (PVA) are prepared. The green density of the WC-Co cemented carbides increases with the addition of binders, with the exception of PVA, which is known to be a polar polymeric substance. The green strength of the WC-Co cemented carbides improves with the addition of paraffin and a mixture of PEG400 and PEG4000. In contrast, the green strength of the WC-Co does not increase when PEG400 and PEG4000 is added individually. The compressive strength of the green body increases to 14 MPa, and the machinability of the green body improves when more than 4–6 wt% paraffin and a mixture of PEG400 and PEG4000 is used. Simultaneously, the sintered density of WC-Co is as high as 99% relative density, similar to a low binder addition of 1–2 wt%.
        4,000원
        3.
        2020.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Ti0.5Al0.5N/CrN nano-multilayers, which are known to exhibit excellent wear resistances, were prepared using the unbalanced magnetron sputter for various periods of 2–7 nm. Ti0.5Al0.5N and CrN comprised a cubic structure in a single layer with different lattice parameters; however, Ti0.5Al0.5N/CrN exhibited a cubic structure with the same lattice parameters that formed the superlattice in the nano-multilayers. The Ti0.5Al0.5/CrN multilayer with a period of 5.0 nm exceeded the hardness of the Ti0.5Al0.5N/CrN single layer, attaining a value of 36 GPa. According to the low-angle X-ray diffraction, the Ti0.5Al0.5N/CrN multilayer maintained its as-coated structure up to 700oC and exhibited a hardness of 32 GPa. The thickness of the oxidation layer of the Ti0.5Al0.5N/CrN multilayered coating was less than 25% of that of the single layers. Thus, the Ti0.5Al0.5N/CrN multilayered coating was superior in terms of hardness and oxidation resistance as compared to its constituent single layers.
        4,000원
        4.
        2018.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Nanoparticles of PbTe are prepared via chemical reaction of the equimolar aqueous solutions of Pb(CH3COO)2 and Te at 120°C. The size of the obtained particles is 100 nm after calcination in a hydrogen atmosphere. Dense specimens for the thermoelectric characterization are produced by spark plasma sintering of prepared powders at 400°C to 500°C under 80 MPa for 5 min. The relative densities of the prepared specimens reach approximately 97% and are identified as cubic based on X-ray diffraction analyses. The thermoelectric properties are evaluated between 100°C and 300°C via electrical conductivity, Seebeck coefficient, and thermal conductivity. Compared with PbTe ingot, the reduction of the thermal conductivities by more than 30% is verified via phonon scattering at the grain boundaries, which thus contributes to the increase in the figure of merit.
        4,000원
        5.
        2014.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        A high temperature dilatometer attached to a graphite furnace is built and used to study the sintering behaviorof B4C. Pristine and carbon doped B4C compacts are sintered at various soaking temperatures and their shrinkage pro-files are detected simultaneously using the dilatometer. Carbon additions enhance the sinterability of B4C with sinteringto more than 97% of the theoretical density, while pristine B4C compacts could not be sintered above 91% due to par-ticle coarsening. The shrinkage profiles of B4C reveal that the effect of carbon on the sinterability of B4C can be seenmostly below 1950°C. The high temperature dilatometer delivers very useful information which is impossible to obtainwith conventional furnaces.
        4,000원