Optimization of mechanical activation process for self-propagation hightemperature synthesis of ceramic-based composites
Abstract
Self-propagation high-temperature synthesis (SHS) method is one of the rapidly emerging costeffective technologies used to synthesize ceramic matrix composite (CMC) materials. For this
purpose, a powder mixture containing the starting materials should be mechanically activated before
SHS process otherwise no SHS takes place. On the other hand, intensive mechanical activation (MA)
in a ball-mill might lead to solid-state reactions before SHS, and the products would be synthesized
via mechanochemical synthesis instead of SHS. Therefore, in order to use the unique benefits of SHS
process, MA was optimized in this study by using response surface methodology (RSM) technique.
The intensity and temperature of the last exothermic peak in DSC curves of mechanically activated
powders, which correspond to occurrence of SHS process, were chosen as the responses for
optimization of the main parameters of MA process (milling time and rotation speed). Al-TiO2-H3BO3
thermite mixture was chosen in this regard for MA optimization before SHS of Al2O3-TiB2 ceramic
composite powders. The results showed that the optimized condition for mechanical activation were
340 rpm and of 17.63 hour for milling speed and milling time, respectively.
Keywords: Mechanical activation; RSM; Ball-milling; SHS; Al2O3-TiB2.