Patent ID: 8586494

Claim:
A fused grain comprising, in weight percentages, more than 15% and less than 55% of Al 2 O 3 ; more than 35% and less than 80% of TiO 2 ; more than 2% and less than 20% of MgO; more than 0.7% and less than 20% of ZrO 2 ; and less than 20% of SiO 2 , said fused grain also corresponding to the following composition, in molar percentages, on the basis of the single oxides Al 2 O 3 , TiO 2 , MgO, ZrO 2 : 90<2a+3m<110 100+a<3t<210−a, a+t+m+zr=100, in which: a is the molar percentage of Al 2 O 3 ; t is the molar percentage of TiO 2 ; m is the molar percentage of MgO; and zr is the molar percentage of ZrO 2 , wherein said fused grain comprises a main pseudo-brookite phase and at least one secondary phase, said secondary phase being (1) a silicate phase; and/or (2) a phase consisting essentially of titanium oxide TiO 2 and/or zirconium oxide ZrO 2 .