Patent ID: 8734729

Claim:
A method of preparing a ceramic composition comprising the steps of: a) preparing a granular ceramic composition including at least: (i) at least 20 wt. % of a first grain mode based upon the total weight of said ceramic composition, said first grain mode comprising stabilized zirconia having a D50 grain size in the range of from 5 to 2000 μm, said stabilized zirconia including a matrix oxide stabilizer; and (ii) at least 1 wt. % of a second grain mode having a D50 grain size in the range of from 0.01 μm up to not greater than one-fourth the D50 grain size of said first grain mode based upon the total weight of said ceramic composition, (iii) at least 1 wt. % of a preservative component within the ceramic composition, based upon the total weight of said ceramic composition, said preservative component selected from at least one of an yttrium-containing compound, CaO, MgO, Y 2 O 3 , CeO 2 , and mixtures thereof; b) combining said first grain mode, said second grain mode, and said preservative component to form a dispersed composition; and c) sintering said dispersed composition at a temperature of at least 1500° C. for at least ten minutes to form a ceramic composition, wherein (i) after sintering said ceramic composition has a porosity at ambient temperature in the range of from 5 to 45 vol % and (ii) the grains of the second grain mode consist essentially of yttria.