A SiAlON sintered body according to the present invention is represented by Si.sub.6-zAl.sub.zO.sub.zN.sub.8-z (0<z4.2) and has an open porosity of 0.1% or less and a relative density of 99.9% or more. A ratio of a total of intensities of maximum peaks of components other than SiAlON to an intensity of a maximum peak of the SiAlON in an X-ray diffraction diagram is 0.005 or less.

Silicon particles for active materials and electro-chemical cells are provided. The active materials comprising silicon particles described herein can be utilized as an electrode material for a battery. In certain embodiments, the composite material includes greater than 0% and less than about 90% by weight of silicon particles. The silicon particles have an average particle size between about 0.1 m and about 30 m and a surface including nanometer-sized features. The composite material also includes greater than 0% and less than about 90% by weight of one or more types of carbon phases. At least one of the one or more types of carbon phases is a substantially continuous phase.

Silicon particles for active materials and electro-chemical cells are provided. The active materials comprising silicon particles described herein can be utilized as an electrode material for a battery. In certain embodiments, the composite material includes greater than 0% and less than about 90% by weight of silicon particles. The silicon particles have an average particle size between about 0.1 m and about 30 m and a surface including nanometer-sized features. The composite material also includes greater than 0% and less than about 90% by weight of one or more types of carbon phases. At least one of the one or more types of carbon phases is a substantially continuous phase.

Silicon particles for active materials and electro-chemical cells are provided. The active materials comprising silicon particles described herein can be utilized as an electrode material for a battery. In certain embodiments, the composite material includes greater than 0% and less than about 90% by weight of silicon particles. The silicon particles have an average particle size between about 0.1 m and about 30 m and a surface including nanometer-sized features. The composite material also includes greater than 0% and less than about 90% by weight of one or more types of carbon phases. At least one of the one or more types of carbon phases is a substantially continuous phase.

Silicon particles for active materials and electro-chemical cells are provided. The active materials comprising silicon particles described herein can be utilized as an electrode material for a battery. In certain embodiments, the composite material includes greater than 0% and less than about 90% by weight of silicon particles. The silicon particles have an average particle size between about 0.1 m and about 30 m and a surface including nanometer-sized features. The composite material also includes greater than 0% and less than about 90% by weight of one or more types of carbon phases. At least one of the one or more types of carbon phases is a substantially continuous phase.

A fused grain is provided with the following chemical composition, expressed in weight percent on the basis of the oxides: MgO: 2.5% to 5.8%; Cr.sub.2O.sub.3: 0.2% to 4.5%; oxides other than MgO, Cr.sub.2O.sub.3 and Al.sub.2O.sub.3: 1.5%; Al.sub.2O.sub.3: remainder up to 100%.

A silicon nitride sintered body includes a silicon nitride crystal grains and grain boundary phases. Further, when D stands for width of the silicon nitride sintered body before being subjected to surface processing, relations between an average grain diameter dA and an average aspect ratio rA of the silicon nitride crystal grain in a first region from an outermost surface to a depth of 0 to 0.01D and an average grain diameter dB and an average aspect ratio rB of the silicon nitride crystal grain in a second region inside the first region satisfy the inequalities:
0.8dA/dB1.2; and
0.8rA/rB1.2.

A silicon nitride sintered body includes a silicon nitride crystal grains and grain boundary phases. Further, when D stands for width of the silicon nitride sintered body before being subjected to surface processing, relations between an average grain diameter dA and an average aspect ratio rA of the silicon nitride crystal grain in a first region from an outermost surface to a depth of 0 to 0.01 D and an average grain diameter dB and an average aspect ratio rB of the silicon nitride crystal grain in a second region inside the first region satisfy the inequalities:

0.8dA/dB1.2; and

0.8rA/rB1.2.

A cutting tool (1) formed of a silicon nitride-based sintered body (2) including a matrix phase (3), a hard phase (4), and a grain boundary phase (10) in which a glass phase (11) and a crystal phase (12) exist. The sintered body (2) contains yttrium in an amount of 5.0 wt % to 15.0 wt % in terms of an oxide, and contains titanium nitride as the hard phase (4) in an amount of 5.0 wt % to 25.0 wt %. In an X-ray diffraction peak, a halo pattern appears at 2 ranging from 25 to 35 in an internal region of the sintered body (2). A ratio B/A of a maximum peak intensity B to a maximum peak intensity A satisfies 0.11B/A0.40 . . . Expression (1) in a surface region of the sintered body (2), and satisfies 0.00B/A0.10 . . . Expression (2) in the internal region of the sintered body (2).

A ceramic susceptor includes a substrate-mounting plate. The substrate-mounting plate contains aluminum nitride and a spinel. A content ratio of the aluminum nitride in the substrate-mounting plate is 95.0 mass % or more and 99.9 mass % or less. A content ratio of the spinel in the substrate-mounting plate is 0.1 mass % or more and 1.0 mass or less in terms of oxide. The aluminum nitride has a polycrystalline structure. The spinel is positioned at a grain boundary between crystal grains of the aluminum nitride. The spinel has a lattice constant of 8.040 or more and 8.110 or less.