Papers by Keyword: Al₂O₃ Fiber

Abstract: Lightweight ceramics have a low density, which leads to a decrease in strength and toughness. In the development of lightweight ceramics, high-strengthening technology is necessary. Alumina fiber was mixed with raw materials for the purpose of producing high-strength lightweight ceramics. After adding alumina fiber at 1, 3, and 5wt% and sintering at 1300^°C, we found that strength and toughness increased in proportion to the amount. Instead of the high melting temperature of alumina fiber, it is reacted with matrix and generated mullite phase. And lots of alumina fiber remains in the matrix, thereby allowing improvements in strength and toughness. When alumina fiber was not added, we found a low density of 1.35~1.80 g/m³, along with low values for strength and toughness at 30~60MPa and 0.7~1.2 MPa m^1/2 respectively. With 1wt% addition of alumina fiber, we obtained a higher strength of 92MPa at 1300^°C, which is close to the strength of general white porcelains at 112MPa.

Abstract: In this study, Al2O3 fiber composite papers with a certain strength and flexibility were prepared by pressure filtration. Microstructure and pore size of the composite papers with different density were investigated and thermal conductivities were measured by plane table thermo-conductivity meter at 600°C to 1200°C. Then the relationship between density ρ and thermal conductivity λ was studied, and the optimum density of Al2O3 fiber composite papers at different temperature was determined.

Abstract: Al2O3/Al-4%Cu alloy composites were manufactured by squeeze casting. Segregation at the interface between fiber and matrix in the composites was researched. The results indicated that at the end of solidification of the composites, the change of the solute in the surplus liquid phase resulted in the type of matrix alloy being changed because of the selecting crystallization, and the segregation at the interface was finally formed. There might be the dual effect of the segregation on structures and property of the composites.

Abstract: The preform of Al2O3 fiber was obtained by wet method,and the result shows that the fiber distribution of preform is more uniform after the pretreatment, and the length - diameter ratio can fully meet the demand of qualified preform. The surface of preform prepared by this process is flat, and fiber is distributed evenly, with certain strength,so it can be used for pressure infiltration fabrication of alumina fiber reinforced metal matrix composites.

Abstract: The conductive composites in which nano RuO2 particles are dispersed throughout a glass matrix have been successfully fabricated by sintering at 850°C. The sensing properties of conductive composites were investigated in real time during tensile testing by measuring the electrical resistance. It is shown that the excellent sensing ability based on electrical resistance changes in the low strain range was due to deformation of conduction paths between nano RuO2 particles by brittle fracture of the glass matrix. The change of electrical resistance depends strongly on the volume percent of Al2O3 fiber reinforcement.