A method for producing an alumina sintered body, including: a step of applying an alkaline earth metal compound onto a surface of an alumina raw material which is an unsintered alumina compact or an alumina sintered body; and a step of subjecting the alumina raw material to which the alkaline earth metal compound has been applied to heat treatment at a temperature of 1200 C. or more for 5 minutes or more and 300 minutes or less.

Various shaped abrasive particles are disclosed. Each shaped abrasive particle includes a body having at least one major surface and another surface extending from the major surface.

A particulate material having a body including a first phase including alumina having an average crystallite size of not greater than 5 microns, and the body further including a second phase having a platelet shape.

Ceramic particles for use in a solar power tower and methods for making and using the ceramic particles are disclosed. The ceramic particle can include a sintered ceramic material formed from a mixture of a ceramic raw material and a darkening component comprising MnO as Mn.sup.2+. The ceramic particle can have a size from about 8 mesh to about 170 mesh and a density of less than 4 g/cc.

An alumina sintered body including an inner layer in which alumina crystal grains contained have an average aspect ratio of 1.0 to 2.0 and an outer layer which covers at least a part of the inner layer from outside and in which alumina crystal grains contained have an average aspect ratio of more than 2.0, the alumina sintered body being free from silicon except unavoidable impurities.

A shaped abrasive particle including a body having a first major surface, a second major surface, and a side surface joined to the first major surface and the second major surface, and the body has at least one partial cut extending from the side surface into the interior of the body.

A precursor of an alumina sintered compact including aluminum, yttrium, and at least one metal selected from iron, zinc, cobalt, manganese, copper, niobium, antimony, tungsten, silver, and gallium. The aluminum content is 98.0% by mass or more as an oxide (Al.sub.2O.sub.3) in 100% by mass of the precursor of an alumina sintered compact; the yttrium content is 0.01 to 1.35 parts by mass as an oxide (Y.sub.2O.sub.3) based on 100 parts by mass of the content of the aluminum as an oxide; the total content of the metals selected from the foregoing group is 0.02 to 1.55 parts by mass as an oxide based on 100 parts by mass of the content of aluminum as an oxide; and the aluminum is contained as -alumina. Also disclosed is an alumina sintered compact, and a method for producing an alumina sintered compact and for producing abrasive grains.

Ceramic particles for use in a solar power tower and methods for making and using the ceramic particles are disclosed. The ceramic particle can include a sintered ceramic material formed from a mixture of a ceramic raw material and a darkening component comprising MnO as Mn.sup.2+. The ceramic particle can have a size from about 8 mesh to about 170 mesh and a density of less than 4 g/cc.

A method of making abrasive particles includes: providing a slurry comprising non-colloidal solid particles and a liquid vehicle; forming at least a portion of the slurry into shaped bodies contacting a substrate; at least partially drying the shaped bodies to provide shaped abrasive precursor particles; separating at least a portion of the shaped abrasive precursor particles from the substrate; and converting at least a portion of the shaped abrasive precursor particles into shaped abrasive particles. The shaped abrasive particles comprise alpha alumina having an average crystal grain size of 0.8 to 8 microns and an apparent density that is at least 92 percent of the true density. Each shaped abrasive particle has a respective surface comprising a plurality of smooth sides that form at least four vertexes. Shaped abrasive particles, abrasive articles including them, and methods of using are also disclosed.

Various shaped abrasive particles are disclosed. Each shaped abrasive particle includes a body having at least one major surface and another surface extending from the major surface.