Patent ID: 7179550
Filing Date: 2007-02-20
Classification: G11B

Abstract:
1. A member of supporting magnetic disc substrates, comprising a ceramic sinter containing a ceramic component and at least one conductive component selected from a group consisting of iron, niobium, tin zinc, copper, nickel, cobalt and chromium, wherein the ceramic sinter has conductive aggregates on its peripheral surface, in which the ceramic component is forsterite and the conductive component is an iron oxide compound, wherein the ceramic sinter comprises a main phase of 2MgO.SiO 2 and a secondary phase of at least one of MgFe 2 O 4 , Fe 3 O 4 , and Fe 2 O 3 , wherein in X-ray diffraction analysis using Cu Kα monochromatic rays, a peak intensity of Fe 2 O 3 phase at a diffraction angle 2θ of 33° contained inside the sinter is 1 or less with respect to a peak diffraction intensity of 100 in a range of 20θ of 35° to 36° in the present of MgFe 2 O 4 , Fe 3 O 4 , and Fe 2 O 3 phases, while a peak diffraction intensity of Fe 2 O 3 phase at the diffraction angle 2θ of 33° in X-ray diffraction analysis which is contained in a peripheral surface layer of the sinter is in a range of 1 to 30 with respect to a peak diffraction intensity of 100 in a range of 2θ of 35° to 36° in the present of MgFe 2 O 4 , Fe 3 O 4 , and Fe 2 O 3 phases.