| abstract |
A method of preparing a composite of a metal oxide matrix with reinforcement particles distributed therein in gel form, by preparing a sol of a metal oxide of Al 2 O 3 , SiO 2 , MgO, ZrO 2 , Y 2 O 3 and mixtures thereof, bringing the sol near the point of gelation, adding reinforcement material consisting of Al 2 O 3 , SiC, SiO 2 , MgO, ZrO 2 , Y 2 O 3 and mixtures thereof in particulate form in an amount from about 5% by volume to about 90% by volume, and adding a control gelling agent in the form of an aqueous solution of a metal salt consisting of aluminum nitrate, magnesium nitrate, zirconium nitrate, chromium nitrate, silicon nitrate, neodymium nitrate and mixtures thereof in an amount corresponding to from about 1% to about 5% by weight of the metal salt based on the metal oxide in the sol to promote controlled gelation. |