| abstract |
An object of the present invention is to provide an inorganic oxide having excellent heat resistance. A particulate form containing aluminum oxide, a metal oxide that does not form a composite oxide of aluminum oxide, and at least one additive element selected from the group consisting of rare earth elements and alkaline earth elements An inorganic oxide of The content ratio of the aluminum oxide is 48 to 92 at% as an element with respect to the total amount of aluminum in the aluminum oxide, the metal element in the metal oxide, and the additive element, 80% or more of the primary particles of the inorganic oxide have a particle size of 100 nm or less, At least a part of the primary particles has a surface concentrated region in which the content ratio of the additive element is locally increased in the surface layer portion, and The inorganic oxide, wherein the amount of the additive element in the surface enriched region is 0.06 to 0.98% by mass in terms of oxide with respect to the total amount of the inorganic oxide. [Selection figure] None |