Abstract: A ceramic sheet has a burr height on the periphery of the sheet of ±100 ?m or less and/or a dimple height on the sheet surface of 100 ?m or less, as determined by irradiating the sheet with a laser beam to measure reflected light, and three-dimensionally analyzing the reflected light with a laser optical three-dimensional profiling instrument. This sheet is highly resistant to stacking-induced loads and thermal stresses. Further, when the ceramic sheet includes a zirconia ceramic partially stabilized with 2.8 to 4.5% by mole of yttria and containing 0.1 to 2% by mass of at least one dispersed reinforcing oxide, in which the grain size of the surface of the sheet has an average of 0.1 to 0.4 ?m, a maximum of 0.4 to 0.8 ?m, and a coefficient of variation of 30% or less, which grain size is determined by scanning electron microscopic observation, the ceramic sheet has satisfactory strength at room temperature and at high temperatures and satisfactory durability of strength at high temperatures.

Abstract: The invention provides a setter which comprises a sheet ceramic containing 40% to 90% by weight of an [NiO] unit; a process for producing a porous ceramic sheet containing nickel oxide and stabilized zirconia, by the use of the setter; and a porous ceramic sheet having a ratio X of a ratio Xa relative to a ratio Xb ranging from 0.85 to 1.18, where the ratio Xa is a ratio of an X-ray diffraction peak intensity of the (200) line of nickel oxide relative to an X-ray diffraction peak intensity of the (111) line of the stabilized zirconia on one side of the sheet, and the ratio Xb is a ratio of an X-ray diffraction peak intensity of nickel oxide in the (200) line relative to an X-ray diffraction peak intensity of the (111) line of the stabilized zirconia on the other side, where the ceramic sheet is mainly produced by the process.

Abstract: The present invention provides the first package (10) for brittle sheets, which comprises the brittle sheets (12) which are placed in a state of multiple layers and the end cushioning materials (20) (20) which are larger than the outer shape of the brittle sheets (12) and whose elasticity range from 2 to 100 mm and which are placed at both ends of the brittle sheets of lamination. The present invention also provides the second package for brittle sheets, which comprises the brittle sheets which are placed in a state of multiple layers, and the side cushioning material whose proof compressive load is not less than 1960 N in vertical direction and not less than 98 N in lateral direction and which is placed at the side of the said brittle sheets of lamination.

Abstract: A zirconia powder has an average particle diameter in a range from larger than 0.5 .mu.m to 0.8 .mu.m, and particles of 90 volume percent of the zirconia powder having a diameter of 1.5 .mu.m or smaller. Using this zirconia powder, a zirconia ceramics having uniform quality can be produced. The zirconia powder of the present invention can be efficiently produced by wet-milling a raw material powder using balls under a condition satisfying the following mathematical relation (I):1.times.10.sup.12 .ltoreq.(W.sub.1.sup.2 .div.W.sub.2).times.(.omega..sup.2 .div.d).times.T.ltoreq.1.times.10.sup.14 (I)where W.sub.1 is the weight (g) of balls, W.sub.2 is the weight (g) of the raw material powder, .omega. is the peripheral velocity (cm/min) at outer periphery of a rotor, d is the diameter (cm) of a milling chamber, and T is the milling time (min).

Abstract: Disclosed are a ceramics sheet which has an area of 400 cm.sup.2 or more, thickness of 0.4 mm or less, maximum waviness height of 100 .mu.m or less, and warp of 0.1% or less and in which frequency of generated cracking and breakage is 10% or less when a load-applying test and a deflection-loading test each described in the text are carried out in succession, and a flat and large ceramics sheet having an area of 600 cm.sup.2 or more and thickness of 1 mm or less.

Abstract: The present invention discloses a ceramic precursor composition, comprising (A) 100 parts by weight of at least one fine ceramic powder selected from the group consisting of zirconia and alumina and having an average particle diameter in the range of 0.01 to 2 microns and (B) 10 to 40 parts by weight of a copolymer produced by copolymerizing (a) 10 to 50% by weight of an alkyl or cycloalkyl acrylate having an alkyl group of 1 to 10 carbon atoms or a cycloalkyl group of 4 to 8 carbon atoms, (b) 30 to 80% by weight of an alkyl or cycloalkyl methacrylate having an alkyl group of 1 to 20 carbon atoms or a cycloalkyl group of 4 to 8 carbon atoms, (c) 1 to 5% by weight of a copolymerizable unsaturated carboxylic acid, and (d) 0 to 59% by weight of a hydroxyalkyl acrylate having a hydroxyalkyl group of 2 to 10 carbon atoms (providing that the total amount of the monomers is 100% by weight) and having a number average molecular weight in the range of 10,000 to 100,000 and a glass transition point in the range of -40.

Abstract: A method for the production of micronized zirconia by the addition of an alkali to an aqueous solution of a zirconium salt or to a mixed aqueous solution of said zirconium salt and a stabilizer such as yttrium, calcium, and magnesium compounds, which method comprises carrying out the reaction for formation of a hydroxide by the addition of the alkali continuously in a flow type reaction system while keeping the pH of said reaction system at a fixed level, separating the hydroxide produced consequently by the reaction, and drying and calcining the separated hydroxide, and a zirconia-containing micronized particle which contains such stabilizer and has an average particle diameter of not more than 0.02 .mu.m.