A zirconia sintered body that suppresses discoloration due to porcelain. The zirconia sintered body contains at least one of a coloring agent A, which is erbium oxide and a coloring agent B, which is nickel oxide, and contains a composite oxide of zirconium and vanadium. A composition, containing zirconium oxide, yttrium oxide, and a coloring agent, where the coloring agent contains at least one of a coloring agent A, which is erbium oxide and a coloring agent B, which is nickel oxide, and contains a coloring agent C, which is a composite oxide of zirconium and vanadium.

A ferrite sintered magnet includes a composition expressed by a formula (1) of Ca.sub.1-w-xLa.sub.wA.sub.xFe.sub.zCo.sub.mO.sub.19. In the formula (1), w, x, z, and m satisfy a formula (2) of 0.30w0.50, a formula (3) of 0.08x0.20, a formula (4) of 8.55z10.00, and a formula (5) of 0.20m0.40. In the formula (1), A is at least one kind of element selected from a group consisting of Sr and Ba. Cr is further contained at 0.058 mass % to 0.132 mass % in terms of Cr.sub.2O.sub.3.

An alumina-based filling sand for sliding nozzle comprising at least 50 wt % of mixed sand including 20 to 90 vol % of alumina sand and 80 to 10 vol % of silica sand, wherein the alumina sand has surface irregularities of 1.3 or less and comprises 50 wt % or more of an Al.sub.2O.sub.3 component.

A fused grain is provided with the following chemical composition, expressed in weight percent on the basis of the oxides: MgO: 2.5% to 5.8%; Cr.sub.2O.sub.3: 0.2% to 4.5%; oxides other than MgO, Cr.sub.2O.sub.3 and Al.sub.2O.sub.3: 1.5%; Al.sub.2O.sub.3: remainder up to 100%.