Abstract: An aluminum nitride sintered body in which the ratio of a peak area S2 of a diffraction peak at 2?=34° or more and 35° or less corresponding to an aluminum oxynitride phase to a peak area S1 of a diffraction peak of an aluminum nitride crystal face [100] in X-ray diffraction, i.e. S2/S1, is 0.01 or more and 0.3 or less, and the spin concentration at a magnetic field between 336 mT and 342 mT as measured by an electron spin resonance method is 1×1015 spins/cm3 or more and 1×1020 spins/cm3 or less. This is manufactured by: mixing a predetermined amount of the aluminum nitride powder and the ?-alumina powder whose ratio of average particle diameter to that of aluminum nitride powder is within the range of 0.3 or more and 0.8 or less; and sintering the mixed powder at ambient-pressure.

Abstract: An aluminum nitride joined body comprising two pieces of aluminum nitride sintered body plates joined together without using adhesive, and a metal layer formed on a portion of the junction interface thereof, wherein, as viewed on a side section passing through the center of the joined body, a plurality of voids are existing in the directly joined region where the sintered body plates are directly facing each other on the junction interface, the voids having an average length L of 0.5 to 4 ?m along the junction interface, thereby forming non-joined portions due to the voids, and a non-joined ratio Q on the side section as calculated by the following formula (1), Non-joined ratio Q=(X/Y)×100??(1) where X is a length of the non-joined portion in the direction of junction interface expressed by the sum of lengths L of the voids existing in the directly joined region, and Y is a length of the directly joined region where the voids are existing, is in a range of from 0.1 to 0.5% on average.

Abstract: An aluminum nitride junction body useful as an electrostatic chuck for holding a semiconductor wafer in an apparatus for producing a semiconductor, comprising aluminum nitride sintered plates joined together via a sintered metal layer. When used in the above application, the junction structure works to uniformly adsorb the semiconductor wafer. The aluminum nitride junction body is obtained by joining aluminum nitride sintered plates 1-a and 1-b together having a sintered metal layer 2 of tungsten or molybdenum of a thickness of 15 to 100 ?m formed on at least a portion of the junction surface thereof, the sintered metal layer having a sheet resistivity of not larger than 1 ?/? and warping by not more than 100?/100 mm.

Abstract: An aluminum nitride joined body comprising two pieces of aluminum nitride sintered body plates joined together without using adhesive, and a metal layer formed on a portion of the junction interface thereof, wherein, as viewed on a side section passing through the center of the joined body, a plurality of voids are existing in the directly joined region where the sintered body plates are directly facing each other on the junction interface, the voids having an average length L of 0.5 to 4 ?m along the junction interface, thereby forming non-joined portions due to the voids, and a non-joined ratio Q on the side section as calculated by the following formula (1), Non-joined ratio Q=(X/Y)×100??(1) where X is a length of the non-joined portion in the direction of junction interface expressed by the sum of lengths L of the voids existing in the directly joined region, and Y is a length of the directly joined region where the voids are existing, is in a range of from 0.1 to 0.5% on average.

Abstract: The present invention relates to novel fluorine-contained resin molded articles having antistatic property, and specifically, the invention relates to fluorine-contained resin molded articles which exhibit good antistatic effect while maintaining properties inherent in the fluorine-contained resin and are fouled very little, owing to the provision of an antistatic layer of a fluorine-contained resin of which the surface resistivity is adjusted to be not larger than 10.sup.13 .OMEGA. by making present the ion-exchange groups on the surface layer of a base material composed of a fluorine-contained resin which does not substantially contain ion-exchange group.