Synthesis and Characterization of Al2O3-SiC Nano Composite by Sol-Gel Method and the Effect of TiO2 on Sintering
In the present article, α-Al2O3 nano powder was synthesized by a simple aqueous sol–gel method by using AlCl3 as precursor. It was shown that the gel calcined at 1000°C, 1100 °C and 1200 °C resulted in the formation of a crystalline α-Al2O3 nano powder. In continue TEOS and saccharose was used to prepare SiO2 xerogels containing carbon nano particles. The conversion of the gel to β-SiC nano powders was accomplished by carbothermal reduction at 1500°C for 1 h in argon atmosphere. In second pace alumina matrix composites with nano particles of 5 vol% SiC were prepared with the addition of TiO2 as sintering aid and densified by pressureless sintering method at 1600°C and 1630°C for 2 h in nitrogen atmosphere. Green pellets were obtained by uniaxial pressing of 137 MPa. Maximum density (97.3%) was achieved at 1630°C. Vickers hardness was 16.5 GPa after sintering at 1630°C. Scanning electron microscopy revealed that the SiC particles were well distributed throughout the composite matrix. The precursors and the resultant powders were characterized by X-ray diffraction (XRD), thermal analysis (STA) and scanning electron microscopy (SEM).
Prof. Andreas Öchsner, Prof. Irina V. Belova and Prof. Graeme E. Murch
H. R. Rezaie et al., "Synthesis and Characterization of Al2O3-SiC Nano Composite by Sol-Gel Method and the Effect of TiO2 on Sintering", Journal of Nano Research, Vol. 13, pp. 7-19, 2011