http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
Elizabeth Refugio-García,José G. Miranda-Hernández,José A. Rodríguez-García,Enrique Rocha-Rangel 한양대학교 세라믹연구소 2011 Journal of Ceramic Processing Research Vol.12 No.3
The production of Al2O3/Ti/TiN functional materials through the nitriding in ammonia salts of previously Al2O3/Ti fabricated composites was achieved. The matrix for the preparation of the functional materials is to create an Al2O3-based composite that presents a fine and homogeneous dispersions of very fine metallic particles of Ti. After the nitriding, microstructural observations were carried out on the transverse zone of the materials’ surface showing the presence of a very thin film of about 20 μm of a constituent that was identified with the help of EDS as TiN. In addition, measurements of micro-hardness on the surface and in the core of the functional material were realized in order to determine the effect of nitride formation on the hardness.
Production and characterization of Al2O3-Cu composite materials
Enrique Rocha-Rangel,José G. Miranda-Hernández,Socorro Moreno-Guerrero,Ana B. Soto-Guzmán 한양대학교 세라믹연구소 2006 Journal of Ceramic Processing Research Vol.7 No.4
Using an intense powder mixture of Al2O3 with different copper contents (1, 5, 10, 20 or 30 mass %) several Al2O3-Cu composite materials were fabricated. The microstructure of the composites was observed by optical and scanning electron microscopy. The observations show a microstructure formed by an Al2O3 ceramic matrix with fine Cu metallic networks. Due to the liquid sintering mechanism, the relative density reached by the samples was higher than 95%, this together with the fine and homogeneous microstructure present in the samples let us obtain composite materials with good values of toughness, hardness, elastic modulus and electrical properties. The incorporation of a ductile metal inside a hard ceramic matrix increments its toughness. The probable toughening mechanism is crack bridging due to the presence of a homogeneous ductile metal networks in the material’s microstructure. The values of density, hardness, elastic modulus and electrical resistance of the composites are directly dependent on the copper content in the matrix, because with an increase in copper content the density of the composites is larger, whereas, the hardness, elastic modulus and electrical resistance are reduced. Using an intense powder mixture of Al2O3 with different copper contents (1, 5, 10, 20 or 30 mass %) several Al2O3-Cu composite materials were fabricated. The microstructure of the composites was observed by optical and scanning electron microscopy. The observations show a microstructure formed by an Al2O3 ceramic matrix with fine Cu metallic networks. Due to the liquid sintering mechanism, the relative density reached by the samples was higher than 95%, this together with the fine and homogeneous microstructure present in the samples let us obtain composite materials with good values of toughness, hardness, elastic modulus and electrical properties. The incorporation of a ductile metal inside a hard ceramic matrix increments its toughness. The probable toughening mechanism is crack bridging due to the presence of a homogeneous ductile metal networks in the material’s microstructure. The values of density, hardness, elastic modulus and electrical resistance of the composites are directly dependent on the copper content in the matrix, because with an increase in copper content the density of the composites is larger, whereas, the hardness, elastic modulus and electrical resistance are reduced.
Fracture toughness enhancement for metal-reinforced alumina
Enrique Rocha-Rangel,Elizabeth Refugio-García,José G. Miranda-Hernández,Eduardo Terrés-Rojas 한양대학교 세라믹연구소 2009 Journal of Ceramic Processing Research Vol.10 No.6
With the idea to determine ways of tailoring alumina (Al2O3) in order that one or more toughening mechanisms are activated in service, investigations about the production of Al2O3-based composites with different reinforcement metals and intermetallics have been carried out. The synthesis of composites materials has been made by means of both; liquid and solid pressureless sintering of an intensive mechanical mixture of powders. With the use of some metals in the chemical formulations, significant improvements in ceramic toughness have been reported. From the fracture toughness measurements and microstructural observations, it can be concluded that the toughening mechanism in Al2O3/metal reinforced composites is due to crack bridging and crack deflection. With the idea to determine ways of tailoring alumina (Al2O3) in order that one or more toughening mechanisms are activated in service, investigations about the production of Al2O3-based composites with different reinforcement metals and intermetallics have been carried out. The synthesis of composites materials has been made by means of both; liquid and solid pressureless sintering of an intensive mechanical mixture of powders. With the use of some metals in the chemical formulations, significant improvements in ceramic toughness have been reported. From the fracture toughness measurements and microstructural observations, it can be concluded that the toughening mechanism in Al2O3/metal reinforced composites is due to crack bridging and crack deflection.