• 한국분말야금학회:학술대회논문집
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• 한국분말야금학회 2004년도 International Symposium on Powder Materials and Processing
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• pp.98-99
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• 2004

(1) Using high-frequency induction heating sintering and spark plasma sintering method, the densification of WC-Ni hard materials was accomplished using ultra fine power of Ni and WC. (2) Nearly fully dense WC-Ni could be obtained within 1 min. (3) Relative density and mechanical properties of WC-Ni obtained by HFIHS were high than those obtained by SPS. And WC grain size made by HFIHS was smaller than that made by SPS. (4) The fracture toughness and hardness values of WC-8Ni, WC-10Ni, and WC-12Ni made by HFIHS were $13MPa{\cdot}m^{1/2}\;and\;1950kg/mm^2,\;13.5Mpa{\cdot}m^{1/2}\;and\;1810kg/mm^2,\;14.4MPa{\cdot}m^{1/2}\;and\;1690kg/mm^2$, respectively for 60MPa and an induced current for 90% output of total capacity, 15KW. (5) The fracture toughness and hardness values of WC-8Ni, WC-10Ni, and WC-12Ni made by SPS were $12.2MPa{\cdot}m^{1/2}\;and\;1796kg/mm^2,\;12.9MPa{\cdot}m^{1/2}\;and\;1725kg/mm^2,\;13.6MPa{\cdot}m^{1/2}\;and\;1597kg/mm^2$, respectively for 60MPa and the electric current of 2500 A

• 대한금속재료학회지
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• 제48권7호
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• pp.639-643
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• 2010

Nanopowder of FeAl was synthesized by high energy ball milling. Using the pulsed current activated sintering method, a dense nanostuctured FeAl was consolidated within 2 minutes from mechanically synthesized powders of FeAl and horizontally milled powders of Fe+Al. The grain size and hardness of FeAl sintered from horizontally milled Fe+Al powders and high energy ball milled FeAl powder were 150 nm, 50 nm and $466\;kg/mm^2$, $574\;kg/mm^2$, respectively.

• 대한금속재료학회지
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• 제48권9호
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• pp.819-824
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• 2010

NiTi powders were synthesized during high energy ball milling for 10 h. Highly dense nanostructured NiTi with a relative density of up to 99% was obtained within 1 minute by high frequency induction heated sintering under a pressure of 80 MPa. The grain size, microstructure, and mechanical properties of NiTi were investigated. The grain size and hardness of TiNi are about 122 nm and $590kg/mm^2$, respectively.

• 한국분말재료학회지
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• 제31권1호
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• pp.23-29
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• 2024

This study investigates the effect of the microstructure of Li_1.3Al_0.3Ti_1.7(PO₄)₃ (LATP), a solid electrolyte, on its ionic conductivity. Solid electrolytes, a key component in electrochemical energy storage devices such as batteries, differ from traditional liquid electrolytes by utilizing solid-state ionic conductors. LATP, characterized by its NASICON structure, facilitates rapid lithium-ion movement and exhibits relatively high ionic conductivity, chemical stability, and good electrochemical compatibility. In this study, the microstructure and ionic conductivity of LATP specimens sintered at 850, 900, and 950℃ for various sintering times are analyzed. The results indicate that the changes in the microstructure due to sintering temperature and time significantly affect ionic conductivity. Notably, the specimens sintered at 900℃ for 30 min exhibit high ionic conductivity. This study presents a method to optimize the ionic conductivity of LATP. Additionally, it underscores the need for a deeper understanding of the Li-ion diffusion mechanism and quantitative microstructure analysis.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1995년도 추계학술대회 논문집
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• pp.61-64
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• 1995

Grinding has been adapted as a finishing process,which can carry out form and surface integrity at the same time. Recently, high efficient and precise grinding technique is required bacause the needs for functional parts such as silicon wafer,ceramic,and electric materials are increasing. Accordingly, the development of grinding wheel appropriate to that purpose is very important. So, in this paper we newly developed a diamond grinding wheel by applying the superior characteristics of spheroidal graphite of the cast iron sintered product. Especially, a electric resistance sintering method was applied in which rapid heat treatment is possible. Finally, we have achieved successful results that the grinding wheel has high hardness,durability and grinding ability,and satisfies above conditions.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2006년도 춘계학술대회 논문집
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• pp.195-196
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• 2006

Direct laser sintering (DLS) technology for the resign coated sand is one of attractive technologies to produce molds and cores for the foundry industry rapidly and cost effectively. The objective of this case study is to develop casting pilot models using computer simulation technology, DLS RP machine and industrial computed tomography. The proposed casting design was verified by the Z-Cast software in the fields of fluid flow and solidification during the casting process. Casting parts with aluminum alloy using the post-curing treated sand moulds and cores are accurate to dimension and defect free.

• 한국정밀공학회지
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• 제16권5호통권98호
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• pp.98-103
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• 1999

The application field of porous mold is more and more expended. A mixture of alumina and cast iron is used for making porous mold using slip and vacuum casting method in this study. Slip casting is a process that slurry is poured into silicon rubber mold, dried in vacuum oven, debinded and sintered in furnace, In this procedure, slurry is composed of powder, binder, dispersion agent, and water. Vacuum casting is a technique for removing air bubbles existed in the slurry under vacuum condition. Since ceramics has a tendency of over-shrinkage after sintering, cast iron is used to compensate dimensional change. The results shows that sintering temperature has a great effect on characteristics of alumina-cast iron composite sintered parts. Finally ceramic-metal composite sintered mold can be used for aluminum alloy casting of shoe mold using this process.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2009년도 춘계학술대회 논문집
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• pp.282-285
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• 2009

Selective laser sintering (SLS) is a fast growing process of rapid production fur metallic based parts. To restore damaged mold surface using SLS, single layer experiments of $20{\mu}m$ Fe-Cr powder was performed under various heat input. Process window of $20{\mu}m$ Fe-Cr powder provided feasible process parameters for the smooth regular surface. To estimate coherence between melted powder and basematal, tendency of hardness distribution has been observed. Hardness of melted zone and remelted zone was diversified from 5GPa to 6.5GPa. It is over 2 times compared of hardness of basemetal. Average surface roughness of each direction on surface of melted powder was measured. Experimental results show that the mold restoring process using SLS can be successfully applied in the mold repair industry.

• 한국분말재료학회지
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• 제13권1호
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• pp.57-61
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• 2006

The present work illustrates the use of water-soluble cupric salts as ingredients of binder for injection molding of $W-10 wt\%$ Cu. Parts produced are dense, homogeneous and have good surface finish, compared to those produced using conventional binder system. This new binder system provides also process-simplification benefit. $CuCl_2\;and\;Cu(NO_3)_2$ with the purity of $98\%$ was selected for this study. Rapid sintering process involving thermal decomposing was successful in densification for 1h. Final density that is about $93\%$ of theoretical value could be obtained, and are distinguishable from conventionally processed W-Cu composites.

• 한국분말야금학회:학술대회논문집
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• 한국분말야금학회 2006년도 Extended Abstracts of 2006 POWDER METALLURGY World Congress Part 1
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• pp.252-253
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• 2006

The fabrication of complex-shaped parts out of Co-Cr-Mo alloy and 316L stainless steel by three-dimensional printing (3DP) was studied using two grades of each alloy with average particle size of 20 and $75\;{\mu}m$, respectively. To produce sound specimens, the proper 3DP processing parameters were determined. The sintering behavior of the powders was characterized by dilatometric analysis and by batch sintering in argon atmosphere at $1280^{\circ}$ for 2h. The 3DP process has successfully produced complex-shaped biomedical parts with total porosity of 12-25% and homogenous pore structure, which could be suitable for tissue growth into the pores.