Alumina fibers were prepared by sol-gel method using an in-house fabricated extruder. The starting material used for the preparation of alumina sol was aluminiurn-tri-isopropoxide. A suitable binder was added to the sol and aged at room temperature for gelation to occur. When the sol became a paste appropriate for extrusion, the fibers were drawn through the extruder and dried at room temperature and subsequently sintered at 1200, 1400, and 1600 C deg in air. It was found that regardless of sintering temperature, the XRD traces indicated that the only phase present in sintered fibers was alpha-Al2O3. Thermogravimetric analysis of the extruded fibers indicated that most of the volatile compounds were burned out at 500 C deg. The DTA and FTIR studies confirmed the phase transition to alpha-Al2O3 and this was in good agreement with the XRD analysis. The SEM investigation revealed that a dense microstructure formed when fibers sintered at 1600 C deg. In addition, the SEM micrograph revealed that an intergranular fracture was the predominant fracture mode. Mechanical tests indicated that the optimum tensile strength was achieved for fibers sintered at 1600 C deg.
Sol-gel based extrusion of alumina fibers
Materials and Manufacturing Processes ; 21 , 3/4 ; 319-323
2006
5 Seiten, 13 Bilder, 1 Tabelle, 21 Quellen
Article (Journal)
English
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