Synthesis and Characterization of Al2O3-SiC Nano Composite by Sol-Gel Method and the Effect of TiO2 on Sintering
|Periodical||Journal of Nano Research (Volume 13)|
|Main Theme||Journal of Nano Research Vol. 13|
|Citation||Hamid Reza Rezaie et al., 2011, Journal of Nano Research, 13, 7|
|Online since||February, 2011|
|Authors||Hamid Reza Rezaie, Raheleh Mohammad-Rahimi, Ali Nemati, M. Samadani|
|Keywords||Al2O3, Nanocomposite, Silicon Carbide (SiC), Sintering, Sol-Gel (SG), TiO2|
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).