Abstract: A ceramic circuit substrate according to an embodiment includes a ceramic substrate and multiple metal parts. The ceramic substrate includes a first surface. The multiple metal parts are located respectively in multiple first regions of the first surface. The first surface includes a second region positioned between adjacent first regions of the multiple metal parts. An average length RSm of roughness curve elements in the second region is not less than 40 ?m. The average length RSm is preferably not more than 100 ?m. A maximum peak height Rp of a surface roughness curve in the second region is preferably not less than 1.0 ?m. A maximum valley depth Rv of a surface roughness curve in the second region is preferably not less than 1.0 ?m.

Abstract: In a silicon nitride sintered body including silicon nitride crystal grains and a grain boundary phase, dislocation defect portions exists inside at least some of the silicon nitride crystal grains. A percentage of a number of the at least some of the silicon nitride crystal grains among any 50 of the silicon nitride crystal grains having completely visible contours in any cross section or surface of the silicon nitride sintered body is not less than 50% and not more than 100%. It is favorable that a plate thickness of the silicon nitride substrate, in which the silicon nitride sintered body is used, is within the range not less than 0.1 mm and not more than 0.4 mm. The TCT characteristics can be improved by using the silicon nitride substrate in the silicon nitride circuit board.

Abstract: According to one embodiment, a crystal phase information extraction apparatus includes a first estimation unit and a second estimation unit. The first estimation unit estimates first crystal phase information on a first polycrystalline material. The second estimation unit performs, using the first crystal phase information, iterative optimization on diffraction data acquired from a second polycrystalline material having a component ratio of a crystal phase of interest smaller than that of the first polycrystalline material, and estimates second crystal phase information on the second polycrystalline material.

Abstract: A ceramic substrate for which the yield when forming a notched portion is improved is provided. A ceramic substrate according to an embodiment includes a front surface and a back surface. A notched portion is provided at one or more locations of the ceramic substrate. The notched portion has an opening portion. At least one angle (?3) where the ceramic substrate is present when viewed from the front surface among angles of end portions of the opening portion is greater than 90 degrees.

Abstract: According to an embodiment, a highly thermally conductive silicon nitride sintered body includes silicon nitride crystal grains and a grain boundary phase. A thermal conductivity of the silicon nitride sintered body is not less than 80 W/(m·K). An average value of solid solution oxygen amounts of the silicon nitride crystal grains existing in a 20 ?m×20 ?m unit area in any cross section is not more than 0.2 wt %. An average value of major diameters of the silicon nitride crystal grains existing in a 50 ?m×50 ?m unit area in any cross section is not less than 1 ?m and not more than 10 ?m. An average of aspect ratios of the silicon nitride crystal grains existing in the 50 ?m×50 ?m unit area is not less than 2 and not more than 10.

Abstract: A silicon nitride sintered body having improved wear resistance and a wear-resistant member using the silicon nitride sintered body are provided. A silicon nitride sintered body according to an embodiment includes silicon nitride crystal grains and a grain boundary phase. An average value of solid solution oxygen amounts of the silicon nitride crystal grains in a 20 ?m×20 ?m region at any cross section is not less than 0.2 wt %. In a 50 ?m×50 ?m region at any cross section, an average value of major diameters of the silicon nitride crystal grains is not less than 0.1 ?m and not more than 10 ?m, and an average value of aspect ratios of the silicon nitride crystal grains is not less than 1.5 and not more than 10.

Abstract: In a silicon nitride substrate including a silicon nitride sintered body including silicon nitride crystal grains and a grain boundary phase, a plate thickness of the silicon nitride substrate is 0.4 mm or les, and a percentage of a number of the silicon nitride crystal grains including dislocation defect portions inside the silicon nitride crystal grains in a 50 ?m×50 ?m observation region of any cross section or surface of the silicon nitride sintered body is not less than 0% and not more than 20%. Etching resistance can be increased when forming the circuit board.

Abstract: In a silicon nitride substrate including a silicon nitride sintered body including silicon nitride crystal grains and a grain boundary phase, a plate thickness of the silicon nitride substrate is 0.4 mm or les, and a percentage of a number of the silicon nitride crystal grains including dislocation defect portions inside the silicon nitride crystal grains in a 50 ?m×50 ?m observation region of any cross section or surface of the silicon nitride sintered body is not less than 0% and not more than 20%. Etching resistance can be increased when forming the circuit board.

Abstract: In a silicon nitride sintered body including silicon nitride crystal grains and a grain boundary phase, dislocation defect portions exists inside at least some of the silicon nitride crystal grains. A percentage of a number of the at least some of the silicon nitride crystal grains among any 50 of the silicon nitride crystal grains having completely visible contours in any cross section or surface of the silicon nitride sintered body is not less than 50% and not more than 100%. It is favorable that a plate thickness of the silicon nitride substrate, in which the silicon nitride sintered body is used, is within the range not less than 0.1 mm and not more than 0.4 mm. The TCT characteristics can be improved by using the silicon nitride substrate in the silicon nitride circuit board.