Abstract: A sintered body contains a high pressure form boron nitride in the range of 20 to 70% by volume, a first binding material surrounding the high pressure form boron nitride with a thickness in the range of 5 nm to 300 nm and a second binding material of the balance. The first binding material is composed of at least one of nitride and boride of Ti and Al. The second binding material is composed of at least one selected from the group consisting of nitride, carbide, carbonitride, boride and oxide of Al and transition metals belonging to the group 4a, 5a and 6a in the periodic table and mutual solid solution thereof. Supposing that X is the amount of Al contained per unit volume in the first binding material and Y is the amount of Al contained per unit volume in the second binding material, the ratio X/Y is not less than 1.

Abstract: A diamond sintered body having high wear resistance, chipping resistance, shock resistance and thermal conductivity is provided. The diamond sintered body includes sintered diamond particles and a sintering aid as the remainder. The content of the sintered diamond particles is at least 80% by volume and less than 99% by volume. The sintered diamond particles have a particle size in the range from at least 0.1 &mgr;m to at most 70 &mgr;m. The sintered diamond particles next to each other are directly bonded. The sintering aid includes at least one kind selected from tungsten, iron, cobalt and nickel. The percentage of the tungsten in the sintered body is in the range from at least 0.01% by weight to at most 8% by weight.

Abstract: The present invention provides a coated sintered body which can be used in precious machining hardened steel. The coated PCBN cutting tool comprises a substrate which contains not less than 35 volume % and not more than 85 volume % of CBN, and a hard coated layer formed on the substrate. The hard coated layer comprises at least one compound layer consisting of at least one element selected from a group of 4a, 5a, 6a elements of the periodic table and Al, and at least one element selected from a group of C, N and O. The thickness of the layer is not less than 0.3 &mgr;m and not more than 10 &mgr;m. The center-line mean roughness of the hard coated layer is not more than 0.1 &mgr;m.

Abstract: A method of cutting hardened steel using a cBN sintered tool which can improve the surface roughness while maintaining high dimensional accuracy. The upper limit of the tool feed rate is set at such a value that a theoretical surface roughness calculated from the feed rate is between 2/3 and 1/1000 of the target surface roughness. The amount of change of the feed rate between the upper and lower limits of the tool feed rate is set to be between 0.002 and 0.05 mm/rev, and the amount of every feed rate change is set not to be equal to the original feed rate multiplied by an integer. The feed rate is changed forcibly for every number of workpieces for which the total cutting length is between 10 and 1000 meters.

Abstract: A high-pressure phase boron nitride-based high-hardness high-strength sintered body for cutting tools represented by a milling tool and an end mill etc., which is improved in wear resistance and chipping resistance, is obtained. The high-pressure phase boron nitride-based sintered body according to the present invention comprises a plurality of grains (1) of high-pressure phase boron nitride and a binder phase (2, 3), and the content of the aforementioned grains (1) is at least 20.0 volume % and not more than 99.7 volume %. The aforementioned binder phase (2, 3) includes a first binder phase (2) enclosing the aforementioned grains (1) and a second binder phase (3) other than that. The first binder phase (2) consists of the form of at least either a nitride of at least one of Ti, TiAl, Zr and Hf or a solid solution thereof.

Abstract: A sintered body consists of high-pressure phase boron nitride, a residual binder phase and an unavoidable impurity, and contains high-pressure phase boron nitride powder which is previously coated with a binder before sintering. The coating binder consists of an element belonging to the group 4a, 5a or 6a of the periodic table or the like, and has an average thickness of 5 to 300 nm. Binder powder other than the coating binder consists of an element belonging to the group 4a, 5a or 6a of the periodic table or the like, and a contact ratio of high-pressure phase boron nitride particles in surface-to-surface contact with each other is at least 20% and less than 50%. The resulting high-pressure phase boron nitride-based hard and tough sintered body for a cutting tool is improved in wear resistance and chipping resistance.

Abstract: An apparatus for sampling dust in a duct for the purpose of knowing, in advance a need for cleaning the inside of such a narrow duct as can not be accessed internally by a person, the kinds of accumulations in the duct and the state of accumulation and sticking or the like. The apparatus comprises a traveling truck enabled to travel forwardly and backwardly in the duct, a TV camera mounted on the traveling truck in order to observe the inside of the duct, a sampling bucket attached to the front of the traveling truck in order to sample accumulations in the duct and a remote control portion for remotely controlling the traveling truck, the TV camera and the sampling bucket.