摘要:
There is provided a joined product suitable as a cutting tool that is fit for high-speed cutting, CVD coating process and the like, and does not cause a reduction in joint strength of a joining layer even if a high temperature exceeding a temperature at which a brazing filler forms the liquid phase is reached during cutting. Specifically, the joined product includes a cemented carbide sintered compact serving as a first material to be joined and a cBN sintered compact or a diamond sintered compact serving as a second material to be joined. The first material to be joined and the second material to be joined are joined by a joining material that does not form a liquid phase at a temperature lower than 1000° C. and that is placed between the first material to be joined and the second material to be joined. The joining is performed by resistance heating and pressing at a pressure of 0.1 to 200 MPa.
摘要:
A method for producing an ammonium tungstate aqueous solution includes the steps of: adding sulfuric acid to a solution containing tungstate ions; bringing the solution having the sulfuric acid added therein, into contact with an anion exchange resin; and bringing the anion exchange resin into contact with an aqueous solution containing ammonium ions.
摘要:
Provided are a method for producing sodium tungstate by supplying an oxidant made of sodium nitrate or sodium nitrite to bring a tungsten containing material and the oxidant into contact with each other in an atmosphere containing oxygen to thereby continuously produce a reaction product; a method for collecting tungsten using the method; and an apparatus for producing sodium tungstate. Also provided are a method for producing a sodium tungstate aqueous solution in which a reductant is introduced into a melt containing the above-described reaction product which is then dissolved in water; and a method for collecting tungsten using the method.
摘要:
The present invention provides a composite material that is excellent in the bonding ability between a cemented carbide layer and a cermet layer is excellent and deformation after sintering can be suppressed and a coated cutting tool having a base containing the composite material. A composite material 10ii is obtained by laminating a cemented carbide layer 11 and a cermet layer 12 and has the cemented carbide layer 11 on the surface side. The boundary between both the layers 11 and 12 has a concave portion 23, and the maximum depth Dmax of the concave portion 23 is 50 μm or more and 500 μm or lower. When the thickness of the composite material is defined as h1 and the thickness of the cemented carbide layer 11 is defined as h2, h2/h1 is in the range of more than 0.02 and 0.4 or lower. By providing the concave portion 23 to the boundary, both the layers 11 and 12 are sufficiently bound and the bonding ability therebetween is excellent. Due to the fact the cemented carbide layer 11 satisfies the given thickness mentioned above, the composite material 10 is difficult to deform.
摘要:
The principal object of the present invention is to provide a coated cemented carbide tool whose both properties of breakage resistance and wear resistance are improved and whose life is lengthened. The present invention has been made to achieve this object and is related with a coated cemented carbide cutting tool comprising a substrate consisting of a matrix of WC and a binder phase of an iron group metal and a plurality of coated layers provided on a surface of the substrate, in which (a) an innermost layer, adjacent to the substrate, of the coated layers consists essentially of titanium nitride having a thickness of 0.1 to 3 &mgr;m, (b) on a mirror-polished cross-sectional microstructure of the said tool, an average crack interval in the coated film on a ridge of a cutting edge and/or rake face is smaller than an average crack interval in the coated layer on a flank face, (c) at least 50% of the cracks in the coated film on the said ridge of the cutting edge and/or rake face have ends of the cracks in the said innermost titanium nitride layer, in a layer above the titanium nitride layer or in an interface between these layers and (d) an average crack length in the coated film on the said ridge of the cutting edge and/or rake face is shorter than an average film thickness on the flank face. According to the present invention, quantitatively specifying the crack intervals and positions of the ends of the cracks in the coated layer results in excellent breakage resistance as well as wear resistance.
摘要:
Diamond having a large coefficient of thermal conductivity is prepared by a CVD method in which a reaction gas is decomposed and reacted under such condition that a concentration of carbon atoms in relation to hydrogen gas (A %), a concentration of nitrogen gas in relation to the whole reaction gas (B ppm) and a concentration of oxygen atoms in relation to the hydrogen gas (C %) satisfy the equation:.alpha.=B.times.(A-1.2C) (I)provided that a is not larger than 13, or B is not larger than 20.
摘要:
A material to be cut has a face to be cut with a cutting tool, and a cutout which temporarily brings the cutting tool into a noncontact state. Images of the cutting tool during the period when it attains an exposed state by passing over the cutout are captured with a camera mechanism at an interval of a predetermined delay time .tau.. A plurality of image information items obtained by these capturing operations include temperature change information of each location as the cutting tool gradually passes from the point of instant when it enters the cutout. Therefore, the image information items are arranged in relation to the exposure time from the point of instant, and a two-dimensional temperature distribution of the cutting tool at the point of instance is computed according to the tendency of change in image information.
摘要:
A diamond wafer including a substrate and a (100) oriented polycrystalline diamond film grown on the substrate for making surface acoustic wave devices, semiconductor devices or abrasion-resistant discs. The (100) oriented film is produced by changing a hydrocarbon ratio in a material gas halfway from a higher value to a lower value. The wafer is monotonously distorted with a distortion height H satisfying 2 .mu.m.ltoreq..vertline.H.vertline..ltoreq.150 .mu.m. The film is polished to a roughness of less than Rmax50 nm and Ra20 nm.
摘要:
A wire drawing die comprises first and second polycrystalline diamond layers made of gaseous phase synthesized diamond. The finest diamond particles of the diamond layers are made into the wire contact portion of the die.
摘要:
A flat free-standing diamond film is produced by growing alternately at least one pair of a potential-concave diamond layer and a potential-convex diamond layer on a non-diamond substrate and eliminating the substrate. The potential-concave films are made by a CVD method under a condition (b), which is characterized by of a substrate temperature of 880.degree. C. to 950.degree. C. and a hydrocarbon ratio of 2.5 vol % to 3.5 vol %. The potential-convex films are made by a CVD method under the condition (a) which is charcterized by of a substrate temperature of 800.degree. C. to 850.degree. C. and a hydrocarbon ratio of 0.5 vol % to 1.5 vol %. The condition (a) can make a potential-convex film of a good crystal quality in spite of a slow deposition speed. It is preferable to employ an assembly of thinner potential-convex films and thicker potential-concave films to curtail the total time of synthesis. A multilayered diamond film with an arbitrary curvature can be produced by selecting the production conditions (a) and (b), and the thicknesses of the potential-convex layers and the potential-concave layers.The diamond films still fixed on the substrate can be polished by an ordinary polishing apparatus, since the film is flat. A polished flat diamond film can be obtained by eliminating the substrate.