The present invention relates to sintered platelet-like randomly shaped abrasive particles based on alpha alumina having a hardness H.sub.V of at least 20 GPa and a crystal structure with an average crystal size between 100 nm and 300 nm, whereby the abrasive particles comprise a body having a first surface and a second surface opposite to the first surface, both surfaces are separated from each other by a randomly shaped sidewall having a thickness (T) between 20 ?m and 500 ?m.

An abrasive particle includes at most three surfaces and at least one edge which has a corner at at least one end. The abrasive particle may contain a ceramic material, particularly polycrystalline -Al.sub.2O.sub.3. Abrasive particles as a whole, methods for producing abrasive particles, moulds, abrasive articles, methods for producing abrasive articles, and methods for abrading a surface are also disclosed.

An article includes a ceramic wall that defines at least a side of a passage. The ceramic wall includes a flow turbulator that projects into the passage. The flow turbulator is formed of ceramic matrix composite.

A heater includes a base body, resistance heating element, and terminal part. The base body comprises ceramic, is plate shaped, and includes a hole on its lower surface. The resistance heating element is inside the base body. The terminal part is electrically connected to an internal conductor, is at least partially located inside the base body, and is exposed from a lower surface of the base body to an exterior of the base body. The terminal part includes a connection conductor that is inserted in the hole and connected to the internal conductor. A lower surface of the connection conductor is located on a side closer to the upper surface of the base body. The hole includes a reduced-diameter portion which has a diameter smaller than a diameter of the connection conductor between the lower surface of the connection conductor and the lower surface of the base body.

A method of making a heat exchanger is disclosed that includes identifying a space for a heat exchanger fluid flow path. A carbon template is formed in the shape of the flow path space, with void space in the shape of a fluid guide that forms the flow path space. A ceramic or a ceramic precursor fluid composition is deposited to the template void space, and a solid ceramic is formed from the fluid composition. The template is removed by oxidizing the carbon.

An abrasive particle includes at most three surfaces and at least one edge which has a corner at least one end. The abrasive particle may contain a ceramic material, particularly polycrystalline -Al.sub.2O.sub.3. Abrasive particles as a whole, methods for producing abrasive particles, moulds, abrasive articles, methods for producing abrasive articles, and methods for abrading a surface are also disclosed.

A method of fabricating a composite component is provided. The method includes forming a fibrous preform by: forming a first graphite powder and phenolic resin compound mixture layer over a first textile layer, the first graphite powder and phenolic resin compound mixture layer having a first group of graphite particles; disposing a second textile layer over the first graphite powder and phenolic resin compound mixture layer; forming a second graphite powder and phenolic resin compound mixture layer over the second textile layer, the second graphite powder and phenolic resin compound mixture layer having a second group of graphite particles; and disposing a third textile layer over the second graphite powder and phenolic resin compound mixture layer; and densifying the fibrous preform.

In a process for manufacturing molded ceramic composite materials, a preform of a ceramic composite material is provided in which ceramic particles having a platelet configuration are formed within a ceramic matrix. The preform is thermoformed within a mold by heating to a temperature greater than a melting or softening temperature of the ceramic matrix and applying a load to deform the preform to form the molded ceramic composite material in a desired configuration. The process is used to fabricate precisely molded ceramic composite materials and devices containing them. The materials and devices can be used for thermal management, such as for electronic components and other heat generating structures.

Components having coating systems that include mud cracks, methods for forming the coating systems, and vehicles including the components are provided. The components include a substrate having silicon nitride and a coating system on a surface of the substrate. The coating system includes a first layer of a first coating material on the substrate, wherein the first coating material includes a rare earth silicate and has a first thickness measured in a direction perpendicular to the surface of the substrate, and a second layer of a second coating material on the first layer, wherein the second coating material includes a rare earth silicate and has a second thickness that is greater than the first thickness. The second layer includes mud cracks that extend from an exterior surface thereof toward the substrate, and the mud cracks have widths in a range of about 50 to 200 micrometers.

A configuration for joining a ceramic layer has a thermal insulating material to a metallic layer. The configuration includes an interface layer made of metallic material located between the ceramic layer and the metallic layer, which includes a plurality of interlocking elements on one of its sides, facing the ceramic layer, the ceramic layer comprising a plurality of cavities aimed at connecting with the corresponding interlocking elements of the interface layer. The configuration also includes a brazing layer by means of which the interface layer is joint to the metallic layer. The invention also refers to a method for obtaining such a configuration.