Abstract: In porous ceramic for slide member including independent pores having a pore size of 5 ?m or more, the independent pore is flattened body having minor axis in a direction perpendicular to a sliding surface, and a cross sectional area (S1) of an independent pore at a cross section perpendicular to the sliding surface is 95% or less of an area (S2) of a complete round having a diameter which is the same length as a major axis of the cross section of the independent pore, and in a cumulative distribution curve of pore sizes of independent pores in a plane parallel to the sliding surface, a ratio (P75/P25) of a pore size of cumulative 75% by volume (P75) to a pore size of cumulative 25% by volume (P25) is 1.9 or less. The porous ceramic can be suitably used as slide member such as seal ring.

Abstract: In porous ceramic for slide member including independent pores having a pore size of 5 ?m or more, the independent pore is flattened body having minor axis in a direction perpendicular to a sliding surface, and a cross sectional area (S1) of an independent pore at a cross section perpendicular to the sliding surface is 95% or less of an area (S2) of a complete round having a diameter which is the same length as a major axis of the cross section of the independent pore, and in a cumulative distribution curve of pore sizes of independent pores in a plane parallel to the sliding surface, a ratio (P75/P25) of a pore size of cumulative 75% by volume (P75) to a pore size of cumulative 25% by volume (P25) is 1.9 or less. The porous ceramic can be suitably used as slide member such as seal ring.

Abstract: A porous ceramic sintered body for slidable member, which has a mean pore diameter of 20 to 39 ?m, and a porosity over 13.0 volume % and not more than 18.0 volume %, can be obtained by: forming bubbles by removing organic matter from a ceramic green body containing ceramic powder, forming aid, and pore forming material which is resin beads selected from suspension-polymerized non-cross-linked polystyrene and suspension-polymerized non-cross-linked styrene-acryl copolymer; followed by heating and sintering. The porous ceramic sintered body is used as a slidable member such as a seal ring.

Abstract: An Al.sub.2 O.sub.3 -TiC sintered product comprising Al.sub.2 O.sub.3 as a main component and containing TiC in an amount of from 20 to 40% by weight, wherein the average particle diameter of Al.sub.2 O.sub.3 particles in the sintered product is larger by 5 to 50% than the average particle diameter of TiC particles, the average particle diameter of the sintered product as a whole is not larger than 1 .mu.m, the average particle diameter of TiC particles is not larger than 0.9 .mu.m, and the total amount of the grain boundary phases other than Al.sub.2 O.sub.3 and TiC is not larger than 1.0% by weight. The Al.sub.2 O.sub.3 -TiC sintered product can be used as a substrate 1 for a magnetic head, and has portions such as grooves 4 and stepped portions formed in the surface of the air bearing surface 2 of the slider by being irradiated with ions. The sintered product exhibits excellent surface quality after machined by being irradiated with ions and can be machined at an increased rate.