Shaped ceramic abrasive particles include a first surface having a perimeter having a perimeter comprising at least first and second edges. A first region of the perimeter includes the second edge and extends inwardly and terminates at two corners defining first and second acute interior angles. The perimeter has at most four corners that define acute interior angles. A second surface is disposed opposite, and not contacting, the first surface. A peripheral surface is disposed between and connects the first and second surfaces. The peripheral surface has a first predetermined shape. Methods of making the shaped ceramic abrasive particles, and abrasive articles including them are also disclosed.

A ferrite ceramic composition includes, as main components, from 27.0 mol % to 41.0 mol % of Fe in terms of Fe.sub.2O.sub.3, from 16.0 mol % to 24.0 mol % of Ni in terms of NiO, from 23.0 mol % to 37.0 mol % of Zn in terms of ZnO, from 5.0 mol % to 9.0 mol % of Cu in terms of CuO, and from 4.0 mol % to 14.0 mol % of Si in terms of SiO.sub.2, and as sub-components, relative to 100 parts by mass of the main components, from 0.3 parts by mass to 1.2 parts by mass of Bi in terms of Bi.sub.2O.sub.3, from 0.3 parts by mass to 1.2 parts by mass of Co in terms of Co.sub.3O.sub.4, from 0.01 parts by mass to 0.25 parts by mass of Mn in terms of Mn.sub.2O.sub.3, and from 0.003 parts by mass to 0.030 parts by mass of Cr in terms of Cr.sub.2O.sub.3.

A wafer boat according to the present disclosure includes a plurality of support columns, each having a pillar shape and comprising a plurality of grooves configured to have a wafer placed thereon, and support plates configured to support both end portions of the plurality of support columns, respectively. Each of the plurality of support columns are formed of a ceramic containing aluminum oxide or silicon carbide as a main constituent, and an outer side surface of the plurality of support columns is a ground surface and/or a polished surface.

A member for optical glass production apparatus is a member exposed to a gas containing a halogen element in a high temperature environment; the member includes a first member (4) directly or indirectly supporting an optical glass (10) and a second member (5) supporting the first member (4).

A dense ceramic sintered body is appropriately manufactured. A manufacturing method for the ceramic sintered body includes: a step of performing heat treatment on a ceramic green body as a green body of ceramic powder under a first condition; a step of performing heat treatment, under a second condition with a higher pressure than the first condition, on the ceramic green body subjected to the heat treatment under the first condition; and a step of performing heat treatment, under a third condition with a higher pressure than the second condition, on the ceramic green body subjected to the heat treatment under the second condition to manufacture the ceramic sintered body.

A bonded abrasive article includes elongate shaped abrasive particles. The elongate shaped abrasive particles comprise an elongate shaped ceramic body having opposed first and second ends joined to each other by at least two longitudinal sidewalls. At least one of the at least two longitudinal sidewalls is concave along its length. At least one of the first and second ends is a fractured surface.

A method for machining by laser ablation or by micro-milling a raised and/or hollow structure on an impression of an injection mould. A method for manufacturing a ceramic or cermet item by injection using the injection mould to produce an item, and in particular a watch bezel, decorated directly during the injection.

A method for forming an abrasive article via an additive manufacturing technique including forming a layer of powder material comprising a precursor bond material and abrasive particles, compacting at least a portion of the layer to form a compacted layer, binding at least a portion of the compacted layer and repeating the steps of forming, compacting and binding to form a green body abrasive article.

Star-shaped ceramic body, wherein the cross-section of the body has six lobes, the ratio of the maximum radius r2 in the star to radius r1 of a circle connecting the intersections of the lobes being in the range from 1.0 to 3.61, preferably from 2.17 to 3.61, the ratio of the area F1 inside this circle to the summed area F2 of the lobes outside this circle being in the range of from 0.54 to 0.90, the ratio of the distance x2 between the two intersections I of one lobe with neighboring lobes and the radius r1 of the circle being in the range of from 0.67 to 1.11. The ceramic body is used as catalyst-support.

A method of manufacturing a shaped abrasive particle is disclosed. The method includes filling a cavity of a tool with an abrasive particle precursor material. The cavity has at least an interior surface that extends downward from a tool top surface at an angle. The method also includes leveling the abrasive particle precursor material such that a top surface of the abrasive particle precursor materials is flush with the tool surface, such that a sharp portion is formed along the intersection between the sloped wall of the tool cavity and the tool surface and the sharp portion is within the same plane as the tool surface. The method also includes removing a dried abrasive particle precursor from the cavity of the tool. The abrasive particle has a sharp portion formed along the intersection between the interior surface and the tool surface.