Low temperature synthesis of zircon from silicone resins and oxide nano-sized particles

In this paper we present a new route for the realization of crack-free zircon monoliths, at very low temperature (1200°C). Zircon ceramics are for the first time synthesized from a mixture of preceramic polymers, consisting of silicone resins, filled with active nano-sized fillers, being ZrO2 nano-particles. The introduction of small quantities (up to 10 mol%) of TiO2 as a sintering aid, and of zircon micro-powders, as seeds, has been also considered. The additives demonstrated to be extremely effective in increasing the zircon yield, with a synergistic effect when used together. Moreover, an appropriate mixture of different preceramic polymers as SiO2 source was found to be critical for the obtainment of crack-free monoliths. This simple methodology demonstrated kinetic features comparable to those of sol-gel processes, but coupled with the possibility of an easy shaping of the desired ceramic before heat treatment.