Abstract: A silicon nitride cutting tool comprising a sintered product is disclosed. The sintered product comprises silicon nitride, at least one rare earth element compound, and a magnesium compound. The silicon nitride cutting tool further comprises a surface region and an inside region comprising the sintered product with varying content ratios of component compounds to provide enhanced wear and fracture resistance.

Abstract: An object of embodiments according to the invention is to provide a cutting tool having good wear resistance, good sliding property and good fracture resistance. A cutting tool 1 comprising a substrate 2 and a coating layer 6 or a coating layer 9 which covers a surface of the substrate 2. The coating layer 6 or the coating layer 9 comprising a first layer 7 and a second layer 8. The first layer 7 comprises Ti1-a-b-c-dAlaWbSicMd(C1-xNx) when M is at least one selected from Nb, Mo, Hf and Y, 0.45?a?0.55, 0.01?b?0.1, 0?c?0.05, 0.01?d?0.1, 0?x?1). The second layer 8 comprises Ti1-e-f-gAleSifM?g(C1-yNy) when M? is at least one selected from Nb, Mo, Ta, Hf and Y, 0.50?e?0.60, 0?f?0.1, 0.05?g?0.15, 0?y?1).

Abstract: A sintered product of silicon nitride includes a crystal phase mainly having silicon nitride crystal grains and an amorphous grain-boundary phase located on the grain boundaries of the silicon nitride crystal grains. The grain-boundary phase contains lanthanum, aluminum, magnesium, silicon, and oxygen. The sintered product described above contains 0.1% by mass or more of lanthanum on an oxide basis, 0.05 to 0.6% by mass of aluminum on an oxide basis, 0.3% by mass or more of magnesium on an oxide basis, and 2.5% by mass or less of oxygen. The total amount of lanthanum on an oxide basis, aluminum on an oxide basis, and magnesium on an oxide basis is 3.5% by mass or less.

Abstract: An object of embodiments according to the invention is to provide a cutting tool having good wear resistance, good sliding property and good fracture resistance. A cutting tool 1 comprising a substrate 2 and a coating layer 6 or a coating layer 9 which covers a surface of the substrate 2. The coating layer 6 or the coating layer 9 comprising a first layer 7 and a second layer 8. The first layer 7 comprises Ti1-a-b-c-dAlaWbSicMd(C1-xNx) when M is at least one selected from Nb, Mo, Hf and Y, 0.45?a?0.55, 0.01?b?0.1, 0?c?0.05, 0.01?d?0.1, 0?x?1). The second layer 8 comprises Ti1-e-f-gAleSifM?g(C1-yNy) when M? is at least one selected from Nb, Mo, Ta, Hf and Y, 0.50?e?0.60, 0?f?0.1, 0.05?g?0.15, 0?y?1).

Abstract: A silicon nitride cutting tool comprising a sintered product is disclosed. The sintered product comprises silicon nitride, at least one rare earth element compound, and a magnesium compound. The silicon nitride cutting tool further comprises a surface region and an inside region comprising the sintered product with varying content ratios of component compounds to provide enhanced wear and fracture resistance.

Abstract: A sintered product of silicon nitride includes a crystal phase mainly having silicon nitride crystal grains and an amorphous grain-boundary phase located on the grain boundaries of the silicon nitride crystal grains. The grain-boundary phase contains lanthanum, aluminum, magnesium, silicon, and oxygen. The sintered product described above contains 0.1% by mass or more of lanthanum on an oxide basis, 0.05 to 0.6% by mass of aluminum on an oxide basis, 0.3% by mass or more of magnesium on an oxide basis, and 2.5% by mass or less of oxygen. The total amount of lanthanum on an oxide basis, aluminum on an oxide basis, and magnesium on an oxide basis is 3.5% by mass or less.

Abstract: A method of producing a circuit-parts sheet having a structure in which a light-nontransmitting circuit-forming pattern is secured in a photo-cured ceramic sheet and is exposed on both surfaces of said photo-cured ceramic sheet, comprising the steps of:

Abstract: A multilayer wiring board formed by laminating a plurality of circuit board units each including an insulating board containing at least a thermosetting resin, and a wiring circuit layer formed on the surface of said insulating board, wherein said insulating board is provided with via hole conducting passages so as to electrically connect the wiring circuit layers of the neighboring circuit board units, said via hole conducting passages are formed by filling via holes formed in the insulating board with a conducting paste, and said wiring circuit layer is buried in the surface of the insulating board in a manner that said insulating board possesses a flat surface. The multilayer wiring board has a satisfactory flatness required for mounting flip chips. Besides, the insulating board and the via hole conducting passages are not infiltrated by chemicals such as etching solution or plating solution.

Abstract: Disclosed is a composite ceramic sintered material comprising a surface layer of a composition which contains the silicon nitride and carbon, and an internal portion of the silicon carbide or a combination of the silicon carbide, silicon nitride and carbon, the content of carbon or the content of the silicon nitride being greater in the surface layer than in the internal portion.

Abstract: Disclosed is a composite ceramic sintered material comprising a surface layer of a composition which contains the silicon nitride and carbon, and an internal portion of the silicon carbide or a combination of the silicon carbide, silicon nitride and carbon, the content of carbon or the content of the silicon nitride being greater in the surface layer than in the internal portion.