Abstract: Ceramic sliding member including (a) a ceramic substrate consisting of a dense sintered body of a ceramic material consisting essentially of metal oxide and/or silicate, (b) an intermediate film formed on a mechanically ground surface of the ceramic substrate, the intermediate film being formed from a product produced by pyrolysis of an organosilicon compound and comprising carbon and silicon, and (c) a pyrolytic carbon film formed on the intermediate film, the pyrolytic carbon film being produced by pyrolysis of hydrocarbon and having a graphite-like layered structure, the pyrolytic carbon film serving as a sliding surface of the ceramic sliding member.

Abstract: Calcined powder of coagulated spherical particles having a secondary coagulated particle size of 0.2 .mu.m to 3 .mu.m, composed of primary particles of less than 500 .ANG. in the crystalline size, and obtained by calcining ultrafine zirconia particles with or without other metal compounds is disclosed. As the ultrafine zirconia particles, coagulated spherical zirconia particles composed of ultrafine monoclinic primary particles of less than 100 .ANG. in the crystalline size, coagulated with each other into a substantially spherical shape with the size of the coagulated particles being in a range from 0.2 .mu.m to 3 .mu.m is preferably used.

Abstract: Disclosed herein is a high-dispersion sol of monoclinic zirconia supermicrocrystals which is translucent and contains monoclinic zirconia supermicrocrystals of uniform size and a rodlike shape or ellipsoidal shape having a diameter or width smaller than 100 .ANG., at a concentration higher than 0.1 mol/liter. The sol is produced by preparing a clear or sherbetlike mixture of water and zirconyl chloride or an aqueous solution of a zirconium salt of hydroxide and hydrochloric acid, subjecting the mixture or the aqueous solution to hydrothermal treatment in a sealed container at more than 130.degree. C. for more than 24 hours, to give a white pasty product, diluting the pasty product with water so that the concentration decreases below 1 mol/liter as zirconium, adjusting the pH to 3 to 7, and finally concentrating the diluted product.

Abstract: Flaky zirconia type fine crystals having a lamellar structure with a thickness of less than 500 .ANG. and a size in a direction parallel to the plane of lamellar layers of greater than five times that of the thickness, including flaky SO.sub.4 ion-containing zirconia fine crystals, flaky hydrous zirconia fine crystals, monoclinic flaky zirconia fine crystals and tetragonal or cubic flaky zirconia fine crystals. These crystals may be used in making piezoelectric ceramics.

Abstract: Coagulated particles of ultrafine monoclinic zicronia crystals oriented in fiber bundle-like form, wherein primary particles of ultrafine monoclinic zirconia are oriented to join and extended in the direction of C-axis into fine fibrous form of less than 50 .ANG. diameter and they are further gathered into a bundle-like form having from 300 to 2000 .ANG. of width and from 2000 to 10000 .ANG. of length. Such particles are prepared by hydrothermal processing which is applied at a temperature from 120.degree. to 300.degree. C. to an acidic aqueous solution containing a water-soluble zirconium compound in an amount of from 0.1 to 2.0 mol/l as Zr, SO.sub.4.sup.2- in an amount of from 0.2 to 2.0 mol/l and a water-soluble compound selected from the group consisting of water-soluble magnesium compounds, water-soluble ammonium compounds and mixtures thereof in an amount of from 0.05 to 1.5 mol/l as Mg.sup.2+ or NH.sub.4.