Abstract: This is a voltage-dependent non-linear resistance ceramic composition wherein resistance of crystal is decreased by containing SrTiO.sub.3 as host material, and Nb.sub.2 O.sub.5 and Ta.sub.2 O.sub.5 as semiconductorization accelerating agent, and further by adding as additive one kind or more oxide of element selected from the group consisting of MnO.sub.2, Ga, Pt, Tl, Si, Ti, Li, La, Cu, Y, Cs, Au, Mo, S, Be, Al, Na, K, Ca, Cd, In, Ba, Pb, Eu, Gd, Tb, Tm, Lu, Th, Ir, Os, Hf, Ru, Mg, Zr, Sn, Sb and W, these additive is segregated at crystal granule boundaries, thereby making the crystal granule boundaries to high resistance.Accordingly, by the high resistance layer at the crystal boundaries the varistor characteristic is obtainable, and a capacitance characteristic is obtainable between the crystal granule-crystal granule boundary-crystal granule.

Abstract: The invention concerns self-supporting ceramic structures, including ceramic composite structures embedding a filler, and methods of making them. The ceramic structures comprise a polycrystalline material made by oxidation of a body of molten parent metal with an oxidant. The polycrystalline material has a first region substrate surmounted by a terminal region stratum which is integral with the first region. The terminal region stratum is harder and of denser, finer crystalline structure than the first region substrate and is formed in a reaction stage subsequent to the reaction stage in which the first region of polycrystalline material is formed. Growth of the first stage is attained by attenuating or interrupting the transport of molten parent metal to the first region under conditions which nonetheless leave or maintain therein enough oxidizable molten parent metal to form the polycrystalline material of the terminal region.

Abstract: A method is provided for reducing the abrasiveness of calcined clay, e.g. kaolin clay. The method comprises contacting the clay prior to calcination with an aliphatic diol, preferably ethylene glycol, in an amount sufficient to reduce the abrasiveness of the calcined product.