화학공학소재연구정보센터
Journal of the American Ceramic Society, Vol.83, No.6, 1351-1355, 2000
Yttrium silicate coatings for oxidation protection of carbon-silicon carbide composites
Yttrium silicate (Y2SiO5) coatings complement SiC coatings for protecting ceramic multilayer composite materials based on carbon-fiber-reinforced SiC composites (C-SIC). Thick (100 pm), dense Y2SiO5 coatings were prepared by dip coating, using concentrated aqueous slips. The resulting phases were studied by taking into account the simultaneous presence of oxide and non-oxide materials, which affected the chemical stability of the coatings. Thick, mechanically stable coatings were obtained by sintering in carbon crucibles and a SiC bed in an argon-flow furnace. Pure Y2SiO5 coatings completely separated from the SIC substrates. A high percentage of Y2Si2O7 was necessary to fit the thermal expansion coefficients and ensure the stability of the coatings. Oxidation resistance of the coated substrates was investigated by isothermal and stepwise oxidation tests.