Alumina base substrate of recording head and process for the production thereof

摘要

An alumina base substrate material for recording heads, which comprises a densely sintered body consisting essentially of: per 100 parts by weight of a base component of 30 to 40% by weight of a titanium compound having TiO2 to (TiC+TiO2) percentage of 5 to 15% by weight and the balance being Al2O3, components A, B and C, provided that the A to B ratio is within a hatched KLMN area in FIG. 1, in the following given parts by weight, and oxidic impurities in amounts of no higher than 0.2% by weight based on the total composition, said sintered body having an average crystal grain size of no higher than 1.3 microns, a porosity per area of no higher than 0.5%, a bending strength of at least 70 kg/cm2 and a hardness HRA of at least 93.0: wherein component A is at least one of spinels expressed by RO-Al2O3, where R is at least one of Mg, Mn, Ni and Co, in an amount of 2.0 to 17.5 parts by weight, component B is 0.2 to 2.0 parts by weight of ZrO2, and Component C is 0.05 to 2.0 parts by weight of Y2O3.