Abstract: There is disclosed a sintered, alpha-cordierite solid solution glass-ceramic body in which the properties of coefficient of thermal expansion and modulus of rupture are stabilized and controlled by using a combination of two dopants in the glass during sintering and crystallization. There is further disclosed the method of producing such bodies, and controlling such properties, through the use of the two dopants.

Abstract: The instant invention is related to the production of porous spinel materials which exhibit exceptional durability in both acid and basic solutions, and possess high porosity with high surface area and narrow range of pore size. More specifically, the present invention is directed to the production of porous spinel materials involving the impregnation of finely-divided trivalent metal oxides, usually Al.sub.2 O.sub.3, Fe.sub.2 O.sub.3, or Cr.sub.2 O.sub.3, with a solution of a divalent metal ion-containing compound, commonly selected from the group of Mg.sup.+2, Fe.sup.+2, Mn.sup.+2, and Zn.sup.+2, and thereafter firing the mixture to effect reaction, resulting in the conversion of the trivalent metal oxide to a spinel.