Hydrothermal etectrophoretic deposition of yttrium silicate coating on SiC-C/C composites

Yttrium silicate coatings were deposited on the surfaces of SiC-C/C composites by a hydrothermal electrophoretic process using yttrium silicate nanocrystallites, isopropanol and iodine as source materials, solvent and charging agent respectively. The yttrium silicate nanocrystallites were preprepared by a sonochemical process. The influence of deposition temperatures on the microstructures and degree of crystallisation of yttrium silicate coatings were investigated. The as prepared coatings were characterised by XRD and SEM. Results show that the coatings are composed of yttrium silicate crystallites with Y2Si2O7 as the main phase and smaller amounts of Y2SiO5. The thickness and density of the coatings increase with increasing deposition temperature; but the coating process has little influence on the phase compositions of the coatings.