Novel synthesis and applications of yttrium silicates from a silicone resin containing oxide nano-particle fillers

In this paper, a novel method for the synthesis of yttrium silicates is presented. Such silicates are well known to be promising materials for protecting various substrates against high temperature oxidation, but they can typically be produced only after quite complicated processing. The use of preceramic polymers, in which a silicate article is obtained by direct thermal treatment in air of nano-composites consisting of silicone resins containing suitable oxide nano-particles, is a valid alternative, since the desired phases, i.e. Y-monosilicate (Y2O3·SiO2) and Y-disilicate (Y2O3·2SiO2) can be obtained by treatments at low temperature (1000–1400 °C). Y-disilicate could be employed for the manufacturing of dense and thick coatings on SiC foamed substrate, by simply dipping the substrates into silicone suspensions, before ceramic conversion. Y-monosilicate, that could be also useful for coatings, was found to exhibit promising characteristics, when doped with Eu2O3, making it of interest for application as red phosphor for LEDs.