Patent ID: 8557012

Claim:
A fused particle, comprising: more than 15% and less than 55% of Al 2 O 3 ; more than 25% and less than 60% of TiO 2 ; less than 20%, in total, of at least one oxide of an element M 1 selected from the group consisting of MgO and CoO; more than 0.7% and less than 20%, in total, of at least one oxide of an element M 2 , selected from the group consisting of Fe 2 O 3 , Cr 2 O 3 , MnO 2 , La 2 O 3 , Y 2 O 3 , and Ga 2 O 3 ; less than 20%, in total, of at least one oxide of an element M 3 , selected from the group consisting of ZrO 2 , Ce 2 O 3 , and HfO 2 ; and less than 30% of SiO 2 , wherein percentages are by weight, based on oxide content, a composition of the particle, in mol % on the basis of oxide in the particle, satisfies an expression a′−t+2m 1 +m 2 of a value from −15 to 15, a is a molar percentage of Al 2 O 3 , s is a molar percentage of SiO 2 , a′=a−0.37 s, t is a molar percentage of TiO 2 , m 1 is a total molar percentage of the at least one oxide of M 1 , and m 2 is a total molar percentage of the at least one oxide of M 2 , wherein the fused particle is obtained by melting the Al 2 O 3 , the TiO 2 , the at least one oxide of element M 1 , the at least one oxide of element M 2 , the at least one oxide of element M 3 , and the SiO 2 to a molten liquid, cooling the molten liquid into a solid mass, and grinding the solid mass to produce the fused particle.