Fabrication of thin oxide coatings on ceramic fibres by a sol-gel technique

Various metal oxides are potential reaction barriers in titanium/silicon carbide composites. A sol-gel process utilizing metal alkoxides was developed to coat silicon carbide fibres with relatively thick, crack-free, adherent layers of yttrium and calcium oxide. A multiple-dip technique was employed in order to avoid cracking due to large residual thermal and drying stresses produced in the film. The influence of several processing parameters and the geometry of the substrate on the coating thickness is discussed.