Abstract: A coated cubic boron nitride (cBN) sintered body most suitable for a cutting tool having excellent resistance to wear and heat in the high-speed cutting of steel has been developed. The sintered body comprises (a) a base material made of a sintered body comprising at least 99.5 vol. % cBN and (b) a hard coating 0.1 to 10 &mgr;m in thickness formed on at least part of the surface of the base material by the PVD method. It is desirable that the hard coating comprise at least one compound layer consisting mainly of (a) at least one metal element selected from Al and the IV a-group elements and (b) at least one element selected from C, N, and O. It is desirable to provide between the base material and the hard coating an intermediate layer comprising a compound consisting mainly of boron and at least one metal element selected from the IV a-group elements.

Abstract: A coated cubic boron nitride (cBN) sintered body most suitable for a cutting tool having excellent resistance to wear and heat in the high-speed cutting of steel has been developed. The sintered body comprises (a) a base material made of a sintered body comprising at least 99.5 vol. % cBN and (b) a hard coating 0.1 to 10 &mgr;m in thickness formed on at least part of the surface of the base material by the PVD method. It is desirable that the hard coating comprise at least one compound layer consisting mainly of (a) at least one metal element selected from Al and the IV a-group elements and (b) at least one element selected from C, N, and O. It is desirable to provide between the base material and the hard coating an intermediate layer comprising a compound consisting mainly of boron and at least one metal element selected from the IV a-group elements.

Abstract: A colorless and transparent, substantially inclusion-free diamond crystal which can be applied to decorative uses and optical parts is synthesized by a process using a temperature gradient method in an ultra-high pressure apparatus. This process comprises using, as a solvent for the growth of the crystal, at least one metal selected from the group consisting of Fe, Co, Ni, Mn and Cr (at least two metals in the case of containing Fe) and as a nitrogen getter for the removal of nitrogen in the solvent, at least one metal selected from the group consisting of Al, Ti, Zr, Hf, V, Nb and Ta in a proportion of 0.5 to 7% by weight (at most 2% by weight when using only Al) to the solvent metal.

Abstract: A cubic boron nitride sintered body has sufficient strength, hardness, heat resistance and heat dissipativity for serving as a cutting tool. A method of preparing a cubic boron nitride sintered body involves preparing a low-pressure phase boron nitride as a starting material by reducing a compound containing boron and oxygen with a compound containing nitrogen and carbon. Then, the low-pressure phase boron nitride starting material is directly converted to a cubic boron nitride sintered body by subjecting the starting material to a high temperature and a high pressure. In the obtained cubic boron nitride sintered body, the ratio I.sub.220 /I.sub.111 of X-ray diffraction intensity I.sub.220 on the (220) plane relative to X-ray diffraction intensity I.sub.111 on the (111) plane is at least 0.1.

Abstract: A high purity synthetic diamond with less impurities, crystals defects, strains, etc. can be provided, in which the nitrogen content is at most 10 ppm, preferably at most 0.1 ppm and the boron content is at most 1 ppm, preferably at most 0.1 ppm or in which nitrogen atoms and boron atoms are contained in the crystal and the difference between the number of the nitrogen atoms and that of the boron atoms is at most 1.times.10.sup.17 atoms/cm.sup.3. The strain-free synthetic diamond can be produced by a process for the production of a strain-free synthetic diamond by the temperature gradient method, which comprises using a carbon source having a boron content of at most 10 ppm and a solvent metal having a boron content of at most 1 ppm and adding a nitrogen getter to the solvent metal, thereby synthesizing the diamond.

Abstract: An improved diamond sintered body having an excellent breakage resistance, corrosion resistance, heat resistance and wear resistance and capable of being sintered at a relatively low pressure and low temperature can be provided. The feature thereof consists in a diamond sintered body comprising 50 to 99.9 volume % of diamond and the balance of a binder phase consisting of a single or mixed phase of a compound (C) or composite (C') of at least one element (A) selected from the group consisting of rare earth elements, Group 3B, 4A, 4B and 6B elements of Periodic Table, iron group, Mn, V, alkali metals and alkaline earth metals with a phosphorus compound (B), or of the above described compound (C) or composite (C') with an oxide of (A).

Abstract: A colorless, transparent low defect density, synthetic type IIa diamond single crystal, in which the etch pits due to needle-shaped defects are at most 3.times.10.sup.5 pieces/cm.sup.2, and which can be applied to uses needing high crystallinity of diamond, for example, monochromators, semiconductor substrates, spectroscopic crystals in X-ray range, electronic materials, etc., is provided by a process for the production of the colorless, transparent low defect density, synthetic diamond single crystal by growing new diamond crystal on a seed crystal of diamond by the temperature gradient method which comprises using a crystal defect-free diamond single crystal, as a seed crystal of diamond, and optionally subjecting to a heat treatment in a non-oxidizing atmosphere at a low pressure and a temperature of 1100 to 1600.degree. C.

Abstract: The present invention provides a diamond sintered compact having a higher strength as well as more excellent heat resistance, breakage resistance and corrosion resistance, as compared with those of the prior art, which thus can effectively be applied to tool materials for cutting or polishing of non-ferrous metals or ceramics, and edge materials of drill bits for excavating petroleum. The feature of the diamond sintered compact contains 0.1 to 30 volume % of at least one compound containing at least one element selected from the group consisting of silicon and titanium, and oxygen and the balance of diamond, for example, a titanate of a metal selected from the group consisting of iron, cobalt, nickel and manganese.

Abstract: Using a synthetic diamond as the material of a prism allows ATR spectral analysis to be conducted only by pushing it into contact with a measuring object for measurement at places with poor environment, measurement of structures themselves, or measurement of samples sticking to cloths or the like, an optical part such as an infrared microscope system oriented sample plate can withstand a large number of times of use. A measuring instrument employs an attenuated total reflection (ATR) prism 14 of the synthetic diamond, having a nitrogen content of not more than 3 ppm and a boron content of not more than 3 ppm as contained in crystal. In combination with this prism 14 are optical-use mirrors 12, 17, lenses 13, 16, or optical fiber, whereby measurement can be conducted by pushing the prism into direct contact with a sample 15 without using a holder or the like.

Abstract: A cubic boron nitride sintered compact is produced by adding to atmospheric pressure type boron nitride, a cubic boron nitride synthetic catalyst and 0.01 to 5.0 percent by weight of a hydroxide of an alkaline earth metal to form a mixture. Then, the mixture is subjected to a high temperature/high pressure treatment under a thermodynamically stable pressure condition for cubic boron nitride, whereby the atmospheric pressure type boron nitride is converted to cubic boron nitride under the action of the cubic boron nitride synthetic catalyst. The cubic boron nitride sintered compact thus obtained contains 0.01 to 5.0 percent by weight of an oxide of the alkaline earth metal only in triple points between the cubic boron nitride grains. The cubic boron nitride grains are densely bonded with each other.

Abstract: A boron nitride system starts with an hBN material and yields a directly converted sintered cBN body having a high heat conductivity within the range of at least 4 W/cm..degree.C. to about 6.2 W/cm..degree.C. For this purpose the hBN starting material of the system has diffused therein an additive of an alkaline earth metal or alkali metal in an amount of from 0.6 mol % to 1.3 mol %. This starting material is directly converted into the cBN at a sintering temperature of at least 1350.degree. C. under a thermodynamically stabilized condition for the cBN, which contains cBN within the range of 99.9 to 99.3 wt. % of the sintered body and a metal remainder from the additive of the starting material within the range of 0.1 to 0.7 wt. % of the sintered body, except for minute naturally occurring components.

Abstract: Diamond abrasive grains are produced by a process which comprises steps of: regularly arranging a plurality of diamond crystal seeds on a first metal solvent plate, stacking a second solvent metal plate on the first solvent metal plate so that the diamond crystal seeds are sandwiched by the first solvent metal plate and the second solvent metal plate, and stacking a graphite raw plate on the second solvent metal plate to construct a production system for the diamond abrasive grains, heating the system or heating the system with pressurizing to a temperature above a solvent metal-graphite eutectic point through a temperature and pressure condition in which diamond is thermodynamically unstable to establish a temperature and pressure condition in which diamond is thermodynamically unstable, and heating the system or heating the system with pressurizing to establish a temperature and pressure condition in which diamond is thermodynamically stable and maintaining said condition.

Abstract: A method for bonding a cubic boron nitride sintered compact to other cubic boron nitride sintered compact or to a body of shank material is disclosed. The method comprises forming a Ti layer of 0.01-1 .mu.m in thickness over a bonding interface between two cubic boron nitride sintered compacts or between a cubic boron nitride sintered compact and a body of shank material, forming a layer of Ni or Cu over the Ti layer to a thickness of 0.01-5 .mu.n, putting together the two cubic boron nitride sintered compacts or the cubic boron nitride sintered compact and the body of shank material with a 10-1,000 .mu.m foil of Al, Al-Ni alloy or Ag--Cu--In alloy being placed over the boding interface, and heating the cubic boron nitride sintered compact structure to temperatures above the meeting point of the metal foil and not exceeding 750.degree. C. in an inert atmosphere or in a vacuum.

Abstract: A clip-clinching device for a coil-spring unit includes an arch having a pair of laterally spaced upstanding poles and a horizontal bar connecting upper end portions of the poles. First and second carriers are positioned on the horizontal bar and are movable therealong. First and second members are respectively provided on the first and second carriers and are movable in the vertical direction. First and second clip-clinching tools having projecting tongues at which a jaw is defined are respectively mounted to the first and second members. A base member positioned under the horizontal bar supports a movable coil-spring unit transfer device for movement along a line perpendicular to the horizontal bar.

Abstract: A sintered compact of cubic boron nitride is made by adsorbing and/or diffusing 0.005 to 1.000 percent by weight of water into a boron nitride compact containing alkaline earth metal boron nitride as a catalyst. The so prepared compact is then subjected to a treatment under high pressure at a relatively low temperature to form a dense cubic boron nitride sintered compact of high purity.

Abstract: Cubic system boron nitride crystals are synthesized by using a synthesizing vessel separated into a plurality of synthesizing chambers by one or more partition layers. After preparing the synthesizing vessel it is heated under extra-high pressure to achieve a required temperature gradient from chamber to chamber. A plurality of solvents having different eutectic temperatures with respect to boron nitride (BN) sources are placed in the chambers according to the temperature gradient. The BN sources are placed in contact with solvent portions heated to relatively high temperatures. At least one seed crystal is placed in each solvent portion heated to relatively low temperatures. At least one cubic system boron nitride crystal is grown in each of the solvents in the chambers by the above heating of the synthesizing vessel under conditions of ultra-high pressure and temperatures assuring the required temperature gradient.