Composite sintered material

Abstract

A composite sintered material includes: a plurality of diamond grains having an average grain size of less than or equal to 10 μm; a plurality of cubic boron nitride grains having an average grain size of less than or equal to 2 μm; and a remainder of a binder phase, wherein at least parts of adjacent diamond grains are bound to one another, the binder phase includes cobalt, in the composite sintered material, a content of the diamond grains is more than or equal to 30 volume % and less than or equal to 94 volume %, a content of the cubic boron nitride grains is more than or equal to 3 volume % and less than or equal to 40 volume %, and a content of the cobalt is more than or equal to 3 volume % and less than or equal to 30 volume %.

1 . A composite sintered material comprising:
 a plurality of diamond grains having an average grain size of less than or equal to 10 μm;   a plurality of cubic boron nitride grains having an average grain size of less than or equal to 2 μm; and   a remainder of a binder phase, wherein   at least parts of adjacent diamond grains are bound to one another,   the binder phase includes cobalt,   in the composite sintered material, a content of the diamond grains is more than or equal to 30 volume % and less than or equal to 94 volume %, a content of the cubic boron nitride grains is more than or equal to 3 volume % and less than or equal to 40 volume %, and a content of the cobalt is more than or equal to 3 volume % and less than or equal to 30 volume %.   
     
     
         2 . The composite sintered material according to  claim 1 , wherein
 the average grain size of the diamond grains is less than or equal to 2 μm, and the average grain size of the cubic boron nitride grains is less than or equal to 1 μm, and   in the composite sintered material, the content of the diamond grains is more than or equal to 50 volume % and less than or equal to 70 volume %, the content of the cubic boron nitride grains is more than or equal to 10 volume % and less than or equal to 30 volume %, and the content of the cobalt is more than or equal to 10 volume % and less than or equal to 20 volume %.   
     
     
         3 . The composite sintered material according to  claim 1  or  claim 2 , wherein
 the binder phase further includes a chemical component including at least one element selected from a group consisting of tungsten, titanium, zirconium, hafnium, niobium, tantalum, chromium, aluminum, silicon, and molybdenum, and 
 in the binder phase, the content of the cobalt is more than or equal to 50 mass % and less than or equal to 99.5 mass %, and a content of the chemical component is more than or equal to 0.5 mass % and less than or equal to 50 mass %. 
 
     
     
         4 . The composite sintered material according to  claim 3 , wherein at least a part of the chemical component included in the binder phase is at least one of a carbide, a carbonitride, a nitride, an oxide, a boride, and an oxynitride. 
     
     
         5 . The composite sintered material according to  claim 4 , wherein heat conductivity of the composite sintered material is more than or equal to 100 W·m −1 ·K−1. 
     
     
         6 . A composite sintered material comprising:
 a plurality of diamond grains having an average grain size of less than or equal to 2 μm;   a plurality of cubic boron nitride grains having an average grain size of less than or equal to 1 μm; and   a remainder of a binder phase, wherein   at least parts of adjacent diamond grains are bound to one another,   the binder phase includes cobalt and a chemical component including at least one element selected from a group consisting of tungsten, titanium, zirconium, hafnium, niobium, tantalum, chromium, aluminum, silicon, and molybdenum,   in the composite sintered material, a content of the diamond grains is more than or equal to 50 volume % and less than or equal to 70 volume %, a content of the cubic boron nitride grains is more than or equal to 10 volume % and less than or equal to 30 volume %, and a content of the cobalt is more than or equal to 10 volume % and less than or equal to 20 volume %,   in the binder phase, the content of the cobalt is more than or equal to 50 mass % and less than or equal to 99.5 mass %, and a content of the chemical component is more than or equal to 0.5 mass % and less than or equal to 50 mass %,   at least a part of the chemical component included in the binder phase is at least one of a carbide, a carbonitride, a nitride, an oxide, a boride, and an oxynitride, and   heat conductivity of the composite sintered material is more than or equal to 100 W·m−1·K−1.