| abstract |
An α-alumina powder suitably used as an additive to a magnetic recording medium and a method of producing the same are described. An α-alumina powder wherein the average primary particle diameter is 10 to 100 nm, the content of an α phase represented by the following formula: I(113)/I(113)+I(200) (1) [wherein, I(113) represents the peak intensity of a (113) plane α-alumina in an X-ray diffraction spectrum, and I(200) represents the peak intensity of a (200) plane θ-alumina in an X-ray diffraction spectrum] is 90% or more, at least one first component selected from silicon, zirconium, phosphorus and boron is contained in an amount of 0.1 to 10 wt% in terms of oxide, and at least one second component selected titanium, iron and chromium is contained in an amount of 0.1 to 30 wt% in terms of oxide. |