Abstract: A sintered body and cutting tool, the sintered body (2) including: a first hard particle (10) containing TiCN; a second hard particle (20) containing (Ti, M) (C, N); a third hard particle (30) including a core portion (31) containing TiCN, and a peripheral portion (32) enclosing the core portion (31) and containing (Ti, M) (C, N) each as main components; a particle (40) containing at least one of Al, Zr, and Si; and a binding phase (50) containing at least one of Co and Ni and at least one of Re and Ru, and has a thickness of not greater than 5 nm. The third hard particle (30) has, in the core portion (31), a particle (33) containing at least one selected from Co, Ni, Re, and Ru, and has a dislocation (34) in each of the core portion (31) and the peripheral portion (32).

Abstract: A surface-coated cutting tool including a tool substrate containing WC crystal grains and insulating grains, and a coating layer composed of a multiple nitride of Ti, Al, and V and disposed on the surface of the tool substrate. The multiple nitride is represented by a compositional formula: TiaAlbVcN satisfying the following relations: 0.25?a?0.35, 0.64?b?0.74, 0<c?0.06, and a+b+c=1 wherein each of a, b, and c represents an atomic proportion. The coating layer is characterized by exhibiting a peak attributed to a hexagonal crystal phase and a peak attributed to a cubic crystal phase as observed through X-ray diffractometry.

Abstract: 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 0.11?B/A?0.40 . . . Expression (1) in a surface region of the sintered body (2), and satisfies 0.00?B/A?0.10 . . . Expression (2) in the internal region of the sintered body (2).

Abstract: To provide a surface-coated cutting tool exhibiting excellent wear resistance in a high-speed cutting process and having prolonged service life. The surface-coated cutting tool includes a tool substrate containing WC crystal grains and insulating grains, and a coating layer composed of a multiple nitride of Ti, Al, and V and disposed on the surface of the tool substrate. The multiple nitride is represented by a compositional formula: TiaAlbVcN satisfying the following relations: 0.25?a?0.35, 0.64?b?0.74, 0<c?0.06, and a+b+c=1 (wherein each of a, b, and c represents an atomic proportion). The coating layer is characterized by exhibiting a peak attributed to a hexagonal crystal phase and a peak attributed to a cubic crystal phase as observed through X-ray diffractometry.

Abstract: A sialon sintered body and a cutting insert each having thermal shock resistance and VB wear resistance. The sialon sintered body and the cutting insert contain ?-sialon and 21R-sialon and exhibit an X-ray diffraction peak intensity ratio [(I21R/IA)×100] of 5% or greater and smaller than 30%, wherein IA represents the sum of the peak intensities of the sialon species, and I21R represents the peak intensity of 21R-sialon, the ratio being calculated from the peak intensities of the sialon species obtained by using X-ray diffractometry.

Abstract: A sialon sintered body and a cutting insert each having thermal shock resistance and VB wear resistance. The sialon sintered body and the cutting insert contain ?-sialon and 21R-sialon and exhibit an X-ray diffraction peak intensity ratio R[(I21R/IA)×100] of 5% or greater and smaller than 30%, wherein IA represents the sum of the peak intensities of the sialon species, and I21R represents the peak intensity of 21R-sialon, the ratio being calculated from the peak intensities of the sialon species obtained by using X-ray diffractometry.

Abstract: A sialon sintered body includes a ?-sialon (Si6-ZAlZOZN8-Z) and at least one polytype sialon, wherein a Z value is 0.4 or greater and 1.0 or less, a proportion of a total of peak intensities of each polytype sialon to a total of peak intensities of each sialon, is 10% or greater and 50% or less, at least one rare earth element B selected from a group consisting of La and Ce and at least one rare earth element C selected from a group consisting of Y, Nd, Sm, Eu, Gd, Dy, Er, Yb, and Lu is included, a molar ratio of the rare earth element B and the rare earth element C is 1.0:0.06 to 1.0:3.5 in terms of an oxide, and a total content of the rare earth elements B and C is 0.8 mol % or greater and 4.0 mol % or less in terms of an oxide.

Abstract: A sialon sintered body includes a ?-sialon (Si6-ZAlZOZN8-Z) and at least one polytype sialon, wherein a Z value is 0.4 or greater and 1.0 or less, a proportion of a total of peak intensities of each polytype sialon to a total of peak intensities of each sialon, is 10% or greater and 50% or less, at least one rare earth element B selected from a group consisting of La and Ce and at least one rare earth element C selected from a group consisting of Y, Nd, Sm, Eu, Gd, Dy, Er, Yb, and Lu is included, a molar ratio of the rare earth element B and the rare earth element C is 1.0:0.06 to 1.0:3.5 in terms of an oxide, and a total content of the rare earth elements B and C is 0.8 mol % or greater and 4.0 mol % or less in terms of an oxide.

Abstract: The present invention provides a technique of improving wear resistance of a Sialon sintered body. The Sialon sintered body has a Sialon phase including at least a ?-Sialon and a 12H-Sialon among an ?-Sialon, the ?-Sialon and the 12H-Sialon. A ratio of a second Sialon total content, which is a sum of the contents of the ?-Sialon and the 12H-Sialon, to a first Sialon total content, which is a sum of contents of the ?-Sialon, the ?-Sialon and the 12H-Sialon, is greater than 20% and not greater than 55%, and a ratio of the content of the 12H-Sialon to the first Sialon total content is not less than 2% and not greater than 55%.

Abstract: An insert includes a silicon nitride sintered body including ?-Si3N4 as a main component, Mg, and a rare-earth element Re (Y, La, Ce, Er, Dy, Yb). A content of Mg in terms of MgO is 1.0-7.0 mol %, a content of Re in terms of an oxide thereof is 0.4-1.0 mol %, and a total content of Mg and Re is from 1.7 to less than 7.5 mol %. The insert has a graded composition in which oxygen content increases from a surface of the sintered body toward an inside thereof such that 0.8-1.5 mass % of oxygen is contained in a region of less than 0.5 mm inside from the surface, 1.1-2.3 mass % of oxygen is contained in a region of 0.5 mm or more inside from the surface, and a difference in oxygen content between the regions is 0.1-1.0 mass %.

Abstract: The present invention provides a technique of improving wear resistance of a Sialon sintered body. The Sialon sintered body has a Sialon phase including at least a ?-Sialon and a 12H-Sialon among an ?-Sialon, the ?-Sialon and the 12H-Sialon. A ratio of a second Sialon total content, which is a sum of the contents of the ?-Sialon and the 12H-Sialon, to a first Sialon total content, which is a sum of contents of the ?-Sialon, the ?-Sialon and the 12H-Sialon, is greater than 20% and not greater than 55%, and a ratio of the content of the 12H-Sialon to the first Sialon total content is not less than 2% and not greater than 55%.

Abstract: Provided are a cutting insert and a cutting tool, capable of maintaining cutting performance for a long time. The cutting insert has a cutting blade made of a ceramic including the base and the cutting blade integrated with each other, wherein the base has a first coefficient of thermal expansion larger than a second coefficient of thermal expansion that the cutting blade has; and a difference between the first coefficient and the second coefficient is from more than 0 ppm/K to not more than 3 ppm/K.

Abstract: An insert includes a silicon nitride sintered body including ?-Si3N4 as a main component, Mg, and a rare-earth element Re (Y, La, Ce, Er, Dy, Yb). A content of Mg in terms of MgO is 1.0-7.0 mol %, a content of Re in terms of an oxide thereof is 0.4-1.0 mol %, and a total content of Mg and Re is from 1.7 to less than 7.5 mol %. The insert has a graded composition in which oxygen content increases from a surface of the sintered body toward an inside thereof such that 0.8-1.5 mass % of oxygen is contained in a region of less than 0.5 mm inside from the surface, 1.1-2.3 mass % of oxygen is contained in a region of 0.5 mm or more inside from the surface, and a difference in oxygen content between the regions is 0.1-1.0 mass %.

Abstract: This invention provides a long-life Sialon insert, the cutting edge of which is resistant to wear and hard to fracture, and a cutting tool equipped with the Sialon insert. Provided are a Sialon insert made of a Sialon sintered body including a Sialon phase comprising an ?-Sialon and a ?-Sialon, and at least one element, originating from a sintering aid, selected from the group consisting of Sc, Y, Dy, Yb, and Lu in an amount of 0.5 to 5 mol % in terms of an oxide thereof, wherein an ?-value, which shows the proportion of the ?-Sialon in the Sialon phase, is from 10% to 40%; the ?-Sialon has a value of Z from 0.2 to 0.7 wherein Z is a variable of the formula Si6-ZAlZOZN8-Z and within a range: 0<Z?4.2; and the sintered body has an average thermal expansion coefficient of 3.5×10?6/K or less at temperatures of room temperature to 1000° C., and a thermal conductivity of 10 W/m·K or more at temperatures of room temperature to 1000° C., and a cutting tool comprising a holder equipped with the Sialon insert.