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초미립 WC-Graphene-Al<sub>2</sub>O<sub>3</sub> 복합재료 소결 및 기계적 성질
손인진 ( In-jin Shon ) 한국열처리공학회 2023 熱處理工學會誌 Vol.36 No.4
Tungsten carbide has many industrial applications due to its high electrical and thermal conductivity, high melting temperature, high hardness and good chemical stability. Because tungsten carbide is difficult to sinter, it is sintered with nickel or cobalt as a binder and is currently used in nozzles, cutting tools, and molds. Alumina is reported to be a viable binder for tungsten carbide due to its higher oxidation resistance and lower cost than nickel and cobalt. The ultrafine tungsten carbide-graphene-alumina composites were rapidly sintered in a high frequency induction heating active sintering unit. The microstructure and mechanical properties (fracture toughness and hardness) of the composites were investigated and analyzed by Vickers hardness tester and electron microscope. Since the high-frequency induction heating sintering method enables high-speed sintering, ultrafine composites can be prepared by preventing grain growth. In the tungsten carbide-graphene-alumina composites, the grain size of tungsten carbide increased with the amount of alumina participation. The hardness and fracture toughness of the tungsten carbide-5% graphene- x% alumina (x = 0, 5, 10,15) composites were 5.1, 8.6, 8.6, and 8.4 MPa-m<sup>1/2</sup> and 2384, 2168, 2165, and 2102 kg/mm<sup>2</sup>, respectively. The fracture toughness increased without a significant decrease in hardness. Sinterability was improved by adding alumina to tungsten carbidegraphene. (Received June 9, 2023; Revised June 19, 2023; Accepted July 3, 2023)
손인진 ( In Jin Shon ),조형곤 ( Hyoung Gon Jo ),김병수 ( Byung Su Kim ),윤진국 ( Jin Kook Yoon ),홍경태 ( Kyung Tae Hong ) 대한금속재료학회(구 대한금속학회) 2015 대한금속·재료학회지 Vol.53 No.7
For the formation of cemented Tic composite, Co or Ni is added as a binder. However, the high cost and low hardness of Co or Ni as binder and the low corrosion resistance of Tic-Co and Tic-Ni composite have generated interest to find alternative binder materials. It has been reported that FeAl show higher oxidation resistance and hardness as well as low cost compared to Co or Ni. Highly dense nanocrysatlline Tic and Tic-FelAl with a relative desity of up to 100% were obtained within 2 min by PCAS(pulsed current activated sintering) under the condition of 80MPa and up to 1300. The effect of FeAl addition of FeAl on the consolidation, the microstructure and the mechanical properties (hardness and fracture toughness) of TiC were investigated. The fracture toughness of TiC greatly increases without great decrease of the hardness by addition of FeAl. Not only fracture toughness but also hardness values of TiC-10vol.%FeAl were higher than those of TiC-10vol.%Fe, TiC-10vol.%Ni and TiC-10vol.%Co.
기계화학적 합성과 나노구조 CoZr-ZrO<sub>2</sub> 복합재료 소결
손인진 ( In-jin Shon ),윤진국 ( Jin-kook Yoon ),홍경태 ( Kyung-tae Hong ) 대한금속재료학회(구 대한금속학회) 2017 대한금속·재료학회지 Vol.55 No.9
Abstract: Since their development in the 1970s ZrO<sub>2</sub> ceramics have been shown to be promising alternative materials for total hip arthroplasty (THA) and total knee arthroplasty (TKA). However, ZrO<sub>2</sub> is so brittle that in vivo failure can result from fracture of the ceramic femoral head and fracture of the ceramic acetabular liner due to the low toughness of the ceramics. To improve its fracture toughness, the approach commonly utilized has been the addition of a second phase to form a composite and produce nanostructured materials. The purpose of this study was to produce a mechanical synthesis of CoZr and ZrO<sub>2</sub> nanopowders from CoO and Zr powders, and fabricate dense nanocrystalline 2CoZr-ZrO<sub>2</sub> composites within two minutes using this pulsed current activated sintering method. Their mechanical properties, biocompatibility and microstructure were then evaluated. Nanopowders of CoZr and ZrO<sub>2</sub> were synthesized mechanochemically according to the reaction (2 CoO + 3 Zr → 2CoZr + ZrO<sub>2</sub>) from CoO and Zr powders by high-energy ball milling. The synthesized powders were consolidated by the pulsed current activated sintering method within two minutes under 80Mpa pressure. CoZr and ZrO<sub>2</sub> composite was sintered by the rapid heating of the nanophase. The hardness and fracture toughness of the 2 CoZr-ZrO<sub>2</sub> composite in this study were better than the hardness of monolithic CoZr and the fracture toughness of a monolithic ZrO<sub>2</sub>. Additionally, the 2 CoZr-ZrO<sub>2</sub> composite exhibited good biocompatibility. (Received January 18, 2017; Accepted February 18, 2017)
손인진 ( In-jin Shon ) 대한금속재료학회(구 대한금속학회) 2016 대한금속·재료학회지 Vol.54 No.12
The low mechanical properties of SiC limit its wide application despite many attractive properties. To improve the mechanical properties, a second phase has been generally added to make a nanostructured composite. In this respect, graphene was evaluated as the reinforcing agent of SiC. SiC-graphene composites were sintered within 2 min by high-frequency induction heating under a pressure of 80 MPa. The rapid consolidation method allowed the retainment of the nano-scale microstructure by inhibiting the grain growth. The effect of graphene content on the microstructure and hardness of the SiC-graphene composite was investigated using FE-SEM and Vickers hardness tester. †(Received June 1, 2016; Accepted July 18, 2016)
펄스전류활성가열에의한나노구조의FeAl급속소결과기계적성질
손인진 ( In Jin Shon ),고인용 ( In Yong Ko ),윤진국 ( Jin Kook Yoon ),도정만 ( Jung Mann Doh ),조승훈 ( Seung Hoon Jo ) 대한금속재료학회 ( 구 대한금속학회 ) 2010 대한금속·재료학회지 Vol.48 No.7
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/mm2, 574 kg/mm2, respectively.
손인진 ( In-jin Shon ) 대한금속재료학회(구 대한금속학회) 2016 대한금속·재료학회지 Vol.54 No.11
CoTi and ZrO₂ nanopowders were mechanochemically synthesized from CoTiO<sub>3</sub> and Zr powders according to the reaction (2CoTiO<sub>3</sub> + 3Zr → 2CoTi + 3ZrO₂). The milled powders were then consolidated by pulsed current-activated sintering within two minutes under an applied pressure of 80MPa. The average hardness and fracture toughness of the nanostructured 2CoTi-3ZrO₂ composite sintered from high energy ball milled powder were 940 kg/mm² and 6 MPaㆍm<sup>1/2</sup>, respectively. The mechanical properties of the composite were higher than those of monolithic CoTi or ZrO₂, respectively. The microstructure and phases of the composite were investigated using FE-SEM and XRD. (Received May 4, 2016; Accepted May 23, 2016)
논문 : 기계적 활성화된 분말로부터 펄스전류활성 연소합성에 의한 나노구조 Al2O3-MgSiO3-SiO2복합재료 제조 및 기계적 특성
손인진 ( In Jin Shon ),강현수 ( Hyun Su Kang ),도정만 ( Jung Mann Doh ),윤진국 ( Jin Kook Yoon ) 대한금속재료학회(구 대한금속학회) 2011 대한금속·재료학회지 Vol.49 No.7
Nanopowders of MgO, Al2O3 and SiO2 were made by high-energy ball milling. The fast sintering of nanostructured Al2O3-MgSiO3-SiO2 composites was investigated from mechanically activated powders of MgO, Al2O3 and SiO2 by a pulsed-current activated sintering process. Nanocrystalline materials have received much attention as advanced engineering materials with improved physical and mechanical properties; in particular greater strength, hardness, excellent ductility and toughness. Highly dense nanostructured Al2O3-MgSiO3-SiO2 composites were produced with simultaneous application of 80 MPa and pulsed output current of 2800A within 2 minutes. The sintering behavior, grain size and mechanical properties of Al2O3-MgSiO3-SiO2 composites were investigated.
손인진 ( In Jin Shon ) 대한금속재료학회(구 대한금속학회) 2014 대한금속·재료학회지 Vol.52 No.8
Pulsed current activated sintering and spark plasma sintering enhance sinter-ability. The advantage of these processes is that they allow very quick densification to near theoretical density and inhibition of grain growth. Highly dense nanostructured intermetallic compounds, oxides, metal-ceramic composites, high temperature materials and hard materials were produced with a simultaneous application of pressure and a pulsed current within several minutes. The role of the current in sintering or synthesis has been the focus of several studies aimed at explaining enhanced sintering and improved properties. The role played by the current has had various interpretations, with the effect explained in terms of the fast heating rate due to Joule heating, the presence of plasma in pores separating powder particles, and the intrinsic contribution of the current to mass transport.
기계적 활성화된 분말로부터 고주파유도 가열 연소합성에 의한 나노구조 Mg2SiO4-MgAl2O4 복합재료 제조 및 기계적 특성
손인진 ( In Jin Shon ),강현수 ( Hyun Su Kang ),홍경태 ( Kyung Tae Hong ),도정만 ( Jung Mann Doh ),윤진국 ( Jin Kook Yoon ) 대한금속재료학회(구 대한금속학회) 2011 대한금속·재료학회지 Vol.49 No.8
Nanopowders of MgO, Al2O3 and SiO2 were made by high energy ball milling. The rapid sintering of nanostructured MgAl2O4-Mg2SiO4 composites was investigated by a high-frequency induction heating sintering process. The advantage of this process is that it allows very quick densification to near theoretical density and inhibition of grain growth. Nanocrystalline materials have received much attention as advanced engineering materials with improved physical and mechanical properties. As nanomaterials possess high strength, high hardness, excellent ductility and toughness, undoubtedly, more attention has been paid for the application of nanomaterials. Highly dense nanostructured MgAl2O4-Mg2SiO4 composites were produced with simultaneous application of 80MPa pressure and induced output current of total power capacity (15 kW) within 2min. The sintering behavior, gain size and mechanical properties of MgAl2O4-Mg2SiO4 composites were investigated.
기계적 합성된 분말로부터 펄스전류활성 소결에 의한 나노구조 Ti3Al-Al2O3 복합재료 제조 및 기계적 특성
손인진 ( In Jin Shon ),왕희지 ( Hee Ji Wang ),서창열 ( Chang Yul Suh ),조성욱 ( Sung Wook Cho ),김원백 ( Won Baek Kim ) 대한금속재료학회(구 대한금속학회) 2011 대한금속·재료학회지 Vol.49 No.5
Nano-powders of Ti3Al and 2(Al2O3) were synthesized from 3Ti(O2) and 5Al powders by high energy ball milling. A nanocrystalline Al2O3 reinforced composite was consolidated by pulsed current activated sintering within 2 minutes from mechanochemically synthesized powders of Al2O3 and Ti3Al. Nanocrystalline materials, have received much attention as advanced engineering materials due to their improved physical and mechanical properties. The relative density of the composite was 99.5%. The average obtained hardness and fracture toughness values were 1510 kg/mm2 and 9 MPa·m1/2, respectively.