alpha-ALUMINA, SLURRY, POROUS MEMBRANE, LAMINATED SEPARATOR, AND NONAQUEOUS ELECTROLYTE SECONDARY BATTERY AND METHOD FOR PRODUCING SAME

An object of the present invention is to provide an alumina used for a slurry for reducing unevenness in a surface of a porous membrane. The present invention is an α-alumina wherein a crystallite size obtained by a Rietveld analysis is not greater than 95 nm, and a lattice strain obtained by the Rietveld analysis is not greater than 0.0020. A BET specific surface area by a nitrogen adsorption method of the α-alumina is preferably not greater than 10 m/g. A particle diameter D50 equivalent to 50% cumulative percentage by volume of the α-alumina is also preferably not greater than 2 μm.