ALUMINA FILM, ALUMINA SOL, AND METHOD FOR PRODUCING ALUMINA FILM

摘要

PROBLEM TO BE SOLVED: To provide an alumina film that has high hardness with a pencil hardness of 7H or more, to provide an alumina sol that can form the alumina film and to provide a method for producing an alumina film that can form an alumina film without deteriorating a substrate.SOLUTION: The alumina film comprises a crosslinked alumina nanofiber formed by crosslinking at least two alumina nanofibers by reacting an alumina nanofiber having an aspect ratio of 30-5,000 with at least one of Rto Rand at least one of Rto R, respectively, in a silicon compound represented by formula (1)(provided that at least one of Rto Rand Rto R, respectively, is an alkoxy group, a halogen group or a hydroxyl group and each of Rto Rmay be the same or different from each other; and A represents a 1-30C saturated hydrocarbon or unsaturated hydrocarbon group).