ALUMINA CERAMIC EXCELLENT IN WEAR RESISTANCE, AND METHOD FOR PRODUCING THE SAME

摘要

PROBLEM TO BE SOLVED: To provide alumina ceramic excellent in wear resistance with high stability to wearing even by using an inexpensive alumina raw material such as one produced by the Bayer process or the like, and a method for producing a molding comprising the alumina ceramic.;SOLUTION: This alumina ceramic excellent in wear resistance comprises Al₂O₃, sintering aid thereof and an inevitable amount of impurities, where (A) the composition comprises (a) ≥99 wt.% content of Al₂O₃; (b) a sintering aid comprising three components of SiO₂, MgO and CaO with the ratios of 12-20 wt.% SiO₂, 60-84 wt.% MgO and 4-20 wt.% CaO, and the total of respective components of the sintering aid being 0.2-1 wt.% to the total amount of the alumina ceramic; (c) ≤0.2 wt.% inevitable impurities to the total amount of the alumina ceramic; and (B) the physical properties are (i) ≥3.70 g/cm³ bulk density; (ii) 1-4.5 μm average crystal grain diameter; (iii) ≤7 μm maximum crystal grain diameter; (iv) ≤2.5 ratio of the maximum crystal grain diameter to the average crystal grain diameter i.e. maximum crystal grain diameter/average crystal grain diameter. A method for producing a molding comprising the alumina ceramic is also disclosed.;COPYRIGHT: (C)2009,JPO&INPIT