Methods and apparatus for producing bulk silicon carbide and producing silicon carbide coatings are provided herein. The method includes feeding a mixture of silicon carbide and ceramic into a plasma sprayer. The plasma generates a stream towards a substrate forming a bulk material or optionally a coating on the substrate such as an article upon contact therewith. In embodiments, the substrate can be removed, leaving a component part fabricated from bulk silicon carbide.

An electret includes a composite oxide having an ABO.sub.3 type perovskite structure containing two different metal elements A and B. The composite oxide is in a polarized state, at least a part of one of the metal elements A and B is substituted with a dopant element having a lower valence than the one of the metal elements A and B, and the composite oxide has a bandgap energy of 4 eV or more.

An electret includes a composite oxide having an ABO.sub.3 type perovskite structure containing two different metal elements A and B. The composite oxide is in a polarized state, at least a part of one of the metal elements A and B is substituted with a dopant element having a lower valence than the one of the metal elements A and B, and the composite oxide has a bandgap energy of 4 eV or more.

An article comprises a body and a conformal protective layer on at least one surface of the body. The conformal protective layer is a plasma resistant rare earth oxide film having a thickness of less than 1000 μm, wherein the plasma resistant rare earth oxide film is selected from a group consisting of an Er—Y composition, an Er—Al—Y composition, an Er—Y—Zr composition, and an Er—Al composition.

An article comprises a body and a conformal protective layer on at least one surface of the body. The conformal protective layer is a plasma resistant rare earth oxide film having a thickness of less than 1000 μm, wherein the plasma resistant rare earth oxide film is selected from a group consisting of an Er—Y composition, an Er—Al—Y composition, an Er—Y—Zr composition, and an Er—Al composition.

A binder for an injection moulding composition, the binder includes, in percentage by mass and for a total of 100%: 35% to 60% of a component (a), or polymer base, made of a polymer or a mixture of polymers, each of the polymer being non-amphiphilic and having a mass average molar mass greater than or equal to 5,000 g/mol, 30% to 55% of a component (b), or wax, made of a polymer or a mixture of polymers, each of the polymer being non-amphiphilic and having a mass average molar mass less than 5,000 g/mol, and less than 10% of an amphiphilic component (c), or surfactant, and less than 10% of other components (d). The polymer base comprising 2% to 15% of a styrene-ethylene-butylene-styrene copolymer (SEBS), in percentage by mass based on the mass of the binder.

An article comprises a body and a conformal protective layer on at least one surface of the body. The conformal protective layer is a plasma resistant rare earth oxide film having a thickness of less than 1000 μm, wherein the plasma resistant rare earth oxide film consists essentially of 40 mol % to less than 100 mol % of Y.sub.2O.sub.3, over 0 mol % to 60 mol % of ZrO.sub.2, and 0 mol % to 9 mol % of Al.sub.2O.sub.3.

An article comprises a body and a conformal protective layer on at least one surface of the body. The conformal protective layer is a plasma resistant rare earth oxide film having a thickness of less than 1000 μm, wherein the plasma resistant rare earth oxide film consists essentially of 40 mol % to less than 100 mol % of Y.sub.2O.sub.3, over 0 mol % to 60 mol % of ZrO.sub.2, and 0 mol % to 9 mol % of Al.sub.2O.sub.3.

Provided are a powder for laser manufacturing which can be stably manufactured and from which a three-dimensional manufactured object ensuring a manufacturing accuracy can be obtained and a using method thereof. A powder for ceramic manufacturing for obtaining a manufactured object by repeatedly sintering or fusing and solidifying in sequence a powder in an irradiation portion with laser light, in which the powder includes a plurality of compositions, at least one composition of the compositions is an absorber that relatively strongly absorbs the laser light compared to other compositions, and at least a part of the absorber changes to a different composition that relatively weakly absorbs the laser light by irradiation with the laser light and a using method of a powder in which the powder is used.

Provided are a powder for laser manufacturing which can be stably manufactured and from which a three-dimensional manufactured object ensuring a manufacturing accuracy can be obtained and a using method thereof. A powder for ceramic manufacturing for obtaining a manufactured object by repeatedly sintering or fusing and solidifying in sequence a powder in an irradiation portion with laser light, in which the powder includes a plurality of compositions, at least one composition of the compositions is an absorber that relatively strongly absorbs the laser light compared to other compositions, and at least a part of the absorber changes to a different composition that relatively weakly absorbs the laser light by irradiation with the laser light and a using method of a powder in which the powder is used.