A method for molding a ceramic material includes: mixing a ceramic powder, a resin, a curing agent and a solvent to obtain a raw material slurry for a ceramic material; injecting the raw material slurry into an elastic container; curing the resin in the raw material slurry injected into the elastic container to form a molded body having a desired shape; and demolding the molded body from the elastic container.

The disclosure relates to methods of fabricating of ceramic structures, and more particularly to methods of fabricating ceramic structures having profiled surfaces and more particularly to methods of fabrication of ceramic mirror blanks. In one embodiment, a method of forming a shaped ceramic article, includes: forming, via one of a cold-pressing process or pressure casting process, a green ceramic article comprising a first surface, an opposing second surface and at least one high aspect ratio feature shaped into at least one surface; heating the green featured ceramic part to form a debound featured ceramic part; and densifying the debound featured ceramic part via one of a pressureless sintering process or a hot-pressing process.

A hydrogen gas producing apparatus includes a porous body (100) and a mixed gas source (300). The porous body (100) is permeable to hydrogen gas and carbon dioxide gas, and has a property of being more permeable to hydrogen gas than carbon dioxide gas. The mixed gas source (300) causes a mixed gas including carbon dioxide gas and hydrogen gas to flow into the porous body (100) under a condition that a pressure gradient represented by (P.sub.1P.sub.2)/L is below 50 MPa/m, where L represents the length of the porous body (100) in a direction in which the mixed gas permeates; P.sub.1 represents an inflow pressure of the mixed gas into the porous body (100); and P.sub.2 represents an outflow pressure thereof from the porous body (100).

A method for molding a ceramic material includes: mixing a ceramic powder, a resin, a curing agent and a solvent to obtain a raw material slurry for a ceramic material; injecting the raw material slurry into an elastic container; curing the resin in the raw material slurry injected into the elastic container to form a molded body having a desired shape; and demolding the molded body from the elastic container.

A silicon carbide member for a plasma processing apparatus is obtained by mixing an -silicon carbide powder having an average particle size of 0.3 to 3 m, with an amount of metal impurities in the -silicon carbide powder reduced to 20 ppm or less, and a sintering aid comprising B.sub.4C in amount of 0.5 to 5 weight parts or Al.sub.2O.sub.3 and Y.sub.2O.sub.3 in total amount of 3 to 15 weight parts; sintering a mixture of the -silicon carbide powder and the sintering aid in an argon atmosphere furnace or a high-frequency dielectric heating furnace; and then processing the resulting sintered body. The resulting silicon carbide member for a plasma processing apparatus is low cost and durable.

The present invention provides a focus ring having favorable plasma resistance. In addition, the present invention provides a method for producing a focus ring which enables the easy production of focus rings having favorable plasma resistance. The focus ring of the present invention is a focus ring made of a sintered body of silicon carbide, in which the sintered body includes a plurality of first crystal grains having an -SiC-type crystal structure and a plurality of second crystal grains having a -SiC-type crystal structure, a content of the first crystal grains is 70% by volume or more of a total of the first crystal grains and the second crystal grains, and a volume-average crystallite diameter of the first crystal grains is 10 m or less.

The invention relates to a method for producing a shaped body that contains at least 85 vol. % crystalline silicon carbide and at most 15 vol. % silicon, comprising the following steps: a) providing a powdered mixture that contains at least 60 vol. % amorphous silicon carbide and at most 40 vol. % silicon having a crystallite size of 3-50 nm; b) shaping the mixture by b1) hot pressing, or b2) compacting at room temperature and subsequent sintering or hot pressing, wherein the sintering or hot pressing is carried out in an inert gas or vacuum at a temperature of at least 1400 C. The volume ratio SiC:Si in the powdered mixture is 95:5-99:1.

A hydrogen gas producing apparatus includes a porous body (100) and a mixed gas source (300). The porous body (100) is permeable to hydrogen gas and carbon dioxide gas, and has a property of being more permeable to hydrogen gas than carbon dioxide gas. The mixed gas source (300) causes a mixed gas including carbon dioxide gas and hydrogen gas to flow into the porous body (100) under a condition that a pressure gradient represented by (P.sub.1?P.sub.2)/L is below 50 MPa/m, where L represents the length of the porous body (100) in a direction in which the mixed gas permeates; P.sub.1 represents an inflow pressure of the mixed gas into the porous body (100); and P.sub.2 represents an outflow pressure thereof from the porous body (100).

The present invention provides a focus ring having favorable plasma resistance. In addition, the present invention provides a method for producing a focus ring which enables the easy production of focus rings having favorable plasma resistance. The focus ring of the present invention is a focus ring made of a sintered body of silicon carbide, in which the sintered body includes a plurality of first crystal grains having an -SiC-type crystal structure and a plurality of second crystal grains having a -SiC-type crystal structure, a content of the first crystal grains is 70% by volume or more of a total of the first crystal grains and the second crystal grains, and a volume-average crystallite diameter of the first crystal grains is 10 m or less.

A silicon carbide member for a plasma processing apparatus is obtained by mixing an -silicon carbide powder having an average particle size of 0.3 to 3 m, with an amount of metal impurities in the -silicon carbide powder reduced to 20 ppm or less, and a sintering aid comprising B.sub.4C in amount of 0.5 to 5 weight parts or Al.sub.2O.sub.3 and Y.sub.2O.sub.3 in total amount of 3 to 15 weight parts; sintering a mixture of the -silicon carbide powder and the sintering aid in an argon atmosphere furnace or a high-frequency dielectric heating furnace; and then processing the resulting sintered body. The resulting silicon carbide member for a plasma processing apparatus is low cost and durable.