Patent ID: 8545582

Claim:
A coated abrasive article comprising: a backing; fused alumina-zirconia abrasive grains attached to the backing with a binder, the fused alumina-zirconia abrasive grains including between about 35 wt % and about 45.5 wt % ZrO 2 +HfO 2 , between about 43.7 wt % and about 65 wt % Al2O3, less than about 0.8 wt % SiO 2 and less than about 10 wt % other oxides, wherein the fused alumina-zirconia abrasive grains conform to at least one of the following conditions: (1) at least about 97 wt % of the grains do not cross a 1400 μm square mesh sieve and at most about 20 wt % of the grains do not cross a 2360 μm square mesh sieve, and the loose packed density is between about 2.18 and about 2.43 g/cm 3 ; (2) at least about 96 wt % of the grains do not cross a 1000 μm square mesh sieve and at most about 3 wt % of the grains do not cross a 1700 μm square mesh sieve, and the loose packed density is between about 2.04 and about 2.26 g/cm 3 ; (3) at least about 92 wt % of the grains do not cross a 600 μm square mesh sieve and at most about 18 wt % of the grains do not cross a 850 μm square mesh sieve, and the loose packed density is between about 1.94 and about 2.17 g/cm 3 ; (4) not more than 5% of the grains contain inclusions, at least 50% of the grains containing at least about 500 nodules per mm 2 , at least about 92 wt % of the grains do not cross a 425 μm square mesh sieve and at most about 18 wt % of the grains does not cross a 600 μm square mesh sieve, and the loose packed density is between about 1.85 and about 2.05 g/cm 3 ; (5) not more than 5% of the grains contain inclusions, at least 50% of the grains containing at least about 500 nodules per mm 2 , at least about 96 wt % of the grains do not cross a 300 μm square mesh sieve and at most about 7 wt % of the grains do not cross a 500 μm square mesh sieve, and the loose packed density is between about 1.83 and about 2.00 g/cm 3 ; (6) not more than 5% of the grains contain inclusions, at least 50% of the grains containing at least about 500 nodules per mm 2 , at least to about 96 wt % of the grains do not cross a 250 μm square mesh sieve and at most about 3 wt % of the grains do not cross a 425 μm square mesh sieve, and the loose packed density is at least about 1.86 and not greater than about 1.93 g/cm 3 ; (7) not more than 5% of the grains contain inclusions, at least 50% of the grains containing at least about 500 nodules per mm 2 , at least about 96 wt % of the grains do not cross a 150 μm square mesh sieve and at most about 3 wt % of the grains do not cross a 250 μm square mesh sieve, and the loose packed density is between about 1.79 and about 1.93 g/cm 3 .