The present invention relates to a method of producing porous alpha-SiC containing shaped body and porous alpha-SiC containing shaped body produced by that method. The porous alpha-SiC containing shaped body shows a characteristic microstructure providing a high degree of mechanical stability.

Provided is a SiC sintered body which contains nitrogen atoms, wherein a ratio R.sub.max/R.sub.ave of a maximum volume resistivity R.sub.max of the sintered body to an average volume resistivity R.sub.ave of the sintered body is 1.5 or lower; a ratio R.sub.min/R.sub.ave of a minimum volume resistivity R.sub.min of the sintered body to the average volume resistivity R.sub.ave is 0.7 or higher; and a relative density of the sintered body is 98% or higher.

A low-cost, durable silicon carbide member for a plasma processing apparatus. The silicon carbide member for a plasma processing apparatus can be obtained by processing a sintered body which is produced with a method in which metal impurity is reduced to more than 20 ppm and 70 ppm or less, and an -structure silicon carbide power having an average particle diameter of 0.3 to 3 m and including 50 ppm or less of an Al impurity is mixed with 0.5 to 5 weight parts of a B.sub.4C sintering aid, or with a sintering aid comprising Al.sub.2O.sub.3 and Y.sub.2O.sub.3 with total amount of 3 to 15 weight parts, and then a mixture of the -structure silicon carbide power with the sintering aid is sintered in an argon atmosphere furnace or a high-frequency induction heating furnace.

Methods, apparatus and systems using heat exchanger reactors to form polymer derived ceramic materials, including methods for making polysilocarb (SiOC) precursors.

The present invention relates to a porous alpha-SiC-containing shaped body with a gas-permeable, open-pored pore structure comprising platelet-shaped crystallites which are connected to form an interconnected, continuous skeletal structure, wherein the skeletal structure consists of more than 80 wt.-% alpha-SiC, relative to the total weight of SiC, a process for producing same and its use as a filter component.

A body including a first phase having silicon carbide, a second phase comprising a metal oxide, the second phase being a discrete intergranular phase located at the grain boundaries of the first phase, and the body has an average strength of at least 700 MPa.

A silicon nitride substrate including silicon nitride crystal grains and a grain boundary phase and having a thermal conductivity of 50 W/m.Math.K or more, wherein, in a sectional structure of the silicon nitride substrate, a ratio (T2/T1) of a total length T2 of the grain boundary phase in a thickness direction with respect to a thickness T1 of the silicon nitride substrate is 0.01 to 0.30, and a variation from a dielectric strength mean value when measured by a four-terminal method in which electrodes are brought into contact with a front and a rear surfaces of the substrate is 20% or less. The dielectric strength mean value of the silicon nitride substrate can be 15 kV/mm or more. According to above structure, there can be obtained a silicon nitride substrate and a silicon nitride circuit board using the substrate in which variation in the dielectric strength is decreased.

This SiC heater includes a heating element having a thin plate-shaped silicon carbide sintered body and an insulating coat film formed on a surface of the silicon carbide sintered body, a pair of electrodes for conducting electricity in the heating element, and a heater base that holds the heating element from one surface side while insulating the heating element from heat from the heating element, the insulating coat film is located on a surface of the silicon carbide sintered body opposite to the heater base, an electrical resistivity at room temperature of the insulating coat film is 10.sup.9 .Math.cm or more, a thermal expansion coefficient of the insulating coat film is 210.sup.6/K or more and 610.sup.6/K or less, SiO.sub.2 is included as a matrix, 1% by weight or more and 35% by weight or less of a first additive component including at least one of B.sub.2O.sub.3 and Al.sub.2O.sub.3 is contained, and 1% by weight or more and 35% by weight or less of a second additive component including at least one of MgO and CaO is contained.

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.