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Vol.44, No.6, 451 ~ 456, 2006
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| Title |
| Special Edition : Symposium on Nano and Biomaterials ; Synthesis of Co-Coated Al2O3 Powders Using Electroless Deposition and Fabrication of Al2O3-Co Composites by SPS Process |
| 김기호 Ki Ho Kim , 윤형철 Hyeong Chul Yoon , 오익현 Ik Hyun Oh , 장세훈 Se Hun Chang , 이병택 Byong Taek Lee |
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| Abstract |
| Microstructure and fracture characteristic of Co-coated Al2O3 powders synthesized by electroless deposition process and their spark plasma sintered (SPS) bodies were investigated depending on the sintering temperature. In the Al2O3-12wt%Co powders, Co particles in range of 5 nm to 15 nm in diameter with spherical shapes were adhered on the Al2O3 powders. In the SPSed Al2O3-Co sintered bodies, the Co particles less than 500 nm in diameter were homogeneously dispersed in the Al2O3 matrix and their values of relative density, hardness and fracture toughness increased as increasing the sintering temperature. The maximum value of fracture toughness was about 8.1 MPa·m(1/2) which is about 2 times higher than that of monolithic Al2O3 body. In the sample sintered at 900℃, the main fracture mode was an intergranular type containing many pores. However, as increasing the sintering temperature, the fracture mode was changed into dense and semi-brittle fracture mode due to the dispersion of fine co particles. |
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| Key Words |
| Cobalt coating, Electroless deposition, Nano coating, Spark plasma sintering |
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