Abstract: Abrasive particles include: 0.50 to 5.00 weight percent of seed particles for alpha-alumina formation selected from the group consisting of alpha-Fe2O3 seed particles, alpha-Al2O3 seed particles, and combinations thereof; 0.50 to 5.00 weight percent of MgO; 0.02 to 0.40 weight percent of Li2O or a molar equivalent amount of at least one alkali metal oxide selected from the group consisting of: Na2O; K2O; combinations of Na2O and Li2O; combinations of K2O and Li2O; combinations of Na2O and K2O; and combinations of Li2O, Na2O, and K2O; and 91.08 to 99.48 weight percent of Al2O3. Methods of making the abrasive particles and abrasive articles incorporating them are also disclosed.

Abstract: Abrasive particles include: 0.50 to 5.00 weight percent of seed particles for alpha-alumina formation selected from the group consisting of alpha-Fe2O3 seed particles, alpha-Al2O3 seed particles, and combinations thereof; 0.50 to 5.00 weight percent of MgO; 0.02 to 0.40 weight percent of Li2O or a molar equivalent amount of at least one alkali metal oxide selected from the group consisting of: Na2O; K2O; combinations of Na2O and Li2O; combinations of K2O and Li2O; combinations of Na2O and K2O; and combinations of Li2O, Na2O, and K2O; and 91.08 to 99.48 weight percent of Al2O3. Methods of making the abrasive particles and abrasive articles incorporating them are also disclosed.

Abstract: Abrasive particles comprise an alpha-alumina crystalline phase and from 0.25 to 20 percent by weight of a beta-alumina crystalline phase, based on the total weight of the alpha-alumina crystalline phase and the beta-alumina crystalline phase combined. The beta-alumina crystalline phase is represented by the empirical formula (X)(Q)Al10O17, wherein: X is selected from the group consisting of Sr, Ca, and Ba; and Q is selected from the group consisting of Mg, Co, Ni, and Zn. Methods of making and using the abrasive articles and abrasive articles are also disclosed.

Abstract: Sintered alpha alumina-based abrasive particles comprising alpha alumina, Gd2O3, and ZnO, and methods of making the same. The abrasive particles can be incorporated, for example, into a variety of abrasive articles, including bonded abrasives, coated abrasives, nonwoven abrasives, and abrasive brushes.

Abstract: Alpha alumina-based abrasive grain. The abrasive grain can be incorporated into abrasive products such as coated abrasives, bonded abrasives, non-woven abrasives, and abrasive brushes.

Abstract: Method for making alpha alumina-based ceramic material (e.g., abrasive grain and fibers) from a hydrothermally treated boehmite dispersion comprising colloidal silica.

Abstract: Methods for making abrasive articles (e.g., coated abrasives, bonded wheels, and three dimensional, low density abrasives) comprising crystalline ceramic, alpha alumina-based abrasive grain.

Abstract: Methods for making abrasive articles (e.g., coated abrasives, bonded wheels, and three dimensional, low density abrasives) comprising crystalline ceramic, alpha alumina-based abrasive grain.

Abstract: A method of making an alpha alumina-based ceramic abrasive grain comprising, on a theoretical oxide basis, Al.sub.2 O.sub.3, Fe.sub.2 O.sub.3, and SiO.sub.2. The abrasive grain has a surface roughness height of greater than about 200 nanometers and a density of greater than about 3.50 g/cm.sup.3. Preferably, the alpha alumina-based ceramic abrasive grain has alpha alumina crystallites having an average crystallite size of less than about 0.5 micrometer (more preferably, less than about 0.3 micrometer). The presence of the SiO.sub.2 in combination with Fe.sub.2 O.sub.3 increases the amount of transgranular fracture of the abrasive grain, reduces the alpha alumina crystallite growth during sintering of the abrasive grain, dilates at least one of the unit cell dimensions of the abrasive grain, and generally improves the grinding performance of the abrasive grain.

Abstract: An alpha alumina-based ceramic abrasive grain comprising, on a theoretical oxide basis, Al.sub.2 O.sub.3, Fe.sub.2 O.sub.3, and SiO.sub.2. The abrasive grain has a surface roughness height of greater than about 200 nanometers and a density of greater than about 3.50 g/cm.sup.3. Preferably, the alpha alumina-based ceramic abrasive grain has alpha alumina crystallites having an average crystallite size of less than about 0.5 micrometer (more preferably, less than about 0.3 micrometer). The presence of the SiO.sub.2 in combination with Fe.sub.2 O.sub.3 increases the amount of transgranular fracture of the abrasive grain, reduces the alpha alumina crystallite growth during sintering of the abrasive grain, dilates at least one of the unit cell dimensions of the abrasive grain, and generally improves the grinding performance of the abrasive grain.

Abstract: Crystalline ceramic, alpha alumina-based abrasive grain and a method of making the same. The abrasive grain can be incorporated into abrasive products such as coated abrasives, bonded wheels, and three dimensional, low density abrasives.

Abstract: Ceramic abrasive grits comprising alpha alumina and at least about 0.5 percent by weight rare earth metal oxide are prepared by combining alumina hydrate and rare earth metal oxide or its precursors to produce a blend, drying the blend to produce a dried solid, crushing the dried solid to produce grits, calcining the dried grits to substantially remove bound volatile materials, and firing the grits to produce a ceramic material. The rare earth metal is selected from the group consisting of praseodymium, samarium, ytterbium, neodymium, lanthanum, gadolinium, cerium, dysprosium, erbium, and mixtures of one or more rare earth metal.

Abstract: Ceramic abrasive grits comprising alpha alumina and at least about 0.5 percent by weight yttria are prepared by mixing an aqueous dispersion of alpha alumina monohydrate and yttrium compound, gelling the resultant mixture, drying the gel to produce a dried solid, crushing the dried material to produce grits, calcining the dried grits to substantially remove bound volatile materials, and firing the grits to produce a ceramic material. The yttrium for the most part is in the form of a yttrium aluminum garnet. Abrasive products comprising the abrasive grits are also claimed as is a method of grinding a workpiece with such abrasive products.