Abstract: A coated cemented carbide comprising: a substrate comprising a WC-based cemented carbide containing 4 to 10 wt. % of Co as a binder phase; based on a ratio in a mirror-polished texture of a cross section of the cemented carbide, 70% or more of WC crystals as a hard phase being classified into either of a group of fine particles A having a particle size of from 0.1 to 1 .mu.m and a group of coarse particles B having a particle size of from 3 to 10 .mu.m, the area ratio S.sub.A /S.sub.B of the fine particles A to the coarse particles B being in a range of from 0.22 to 0.45; and a coating layer disposed on a surface of the cemented carbide and having a total thickness in a range of from 5 to 100 .mu.m. The coating layer comprises at least one layer comprising at least one selected from the group consisting of: carbides, nitrides, carbonitrides, oxycarbides, and boronitrides of Ti, Zr, and/or Hf; and at least one layer comprising at least one selected from the group consisting of: Al.sub.2 O.sub.

Abstract: A coating film which can sufficiently improve the wear resistance of a cutting tool or a wear-resistant tool and which reveals excellent qualities as a wear-resistant or protective film for an electric or electronic part or a sliding or machine part. Such a coating film is in the form of an ultra-thin film laminate comprising at least one nitride or carbonitride of at least one element selected from the group consisting of the elements in the groups IVa, Va and VIa in the periodic table and Al and B and having a cubic crystal structure and having mainly metallic bonding properties, and at least one compound having a crystal structure other than the cubic crystal structure at normal temperature and normal pressure and under equilibrium state and having mainly covalent bonding properties, the at least one nitride or carbonitride and the compound being alternately laminated in the form of layers, each layer of the compound having a thickness of 0.

Abstract: A coating film which can sufficiently improve the wear resistance of a cutting tool or a wear-resistant tool and which reveals excellent qualities as a wear-resistant or protective film for an electric or electronic part or a sliding or machine part. Such a coating film is in the form of an ultra-thin film laminate comprising at least one nitride or carbonitride of at least one element selected from the group consisting of the elements in the groups IVa, Va and VIa in the periodic table and Al and B and having a cubic crystal structure and having mainly metallic bonding properties, and at least one compound having a crystal structure other than the cubic crystal structure at normal temperature and normal pressure and under equilibrium state and having mainly covalent bonding properties, the at least one nitride or carbonitride and the compound being alternately laminated in the form of layers, each layer of the compound having a thickness of 0.

Abstract: This invention relates to a diamond-coated hard material and a process for the production of the same. The feature of the diamond-coated hard material consists in that in a diamond-coated hard material comprising a substrate of a tungsten carbide-based cemented carbide having a diamond-coated layer provided on the surface of the substrate, a surface-modified layer containing no binder phase or containing a binder phase in a proportion of less than in the interior part of the substrate is present on the outermost surface of the substrate. This hard material can be produced by converting the substrate material into a sintered or heat treated surface or skin and then coating with diamond. The diamond-coated hard material of the present invention has such a high wear resistance and excellent bonding strength to the substrate that it can favorably be applied to various tools, parts, grinding wheels, etc.

Abstract: A tool or tool insert is formed of a silicon nitride sintered body which contains silicon nitride as well as a sintering aid and is sintered under a pressurized atmosphere. Freely grown .beta.-Si.sub.3 N.sub.4 including .beta.'-SIALON is removed from its sintering surface by steps other than grinding. A tool of a surface-coated silicon nitride sintered body is formed by coating the surface of a base material, which is formed in a manner similar to the above, with a layer of carbide of Ti or the like having a thickness of 0.1 to 10 .mu.m and/or a layer of Al.sub.2 O.sub.3 having a thickness of 0.4 to 10 .mu.m. Tools or inserts formed by a silicon nitride sintered body and the same tools provided with a surface coating have an excellent wear resistance as well as toughness and can be manufactured at a low cost since grinding is avoided.

Abstract: A tool comprised of a silicon nitride sintered body which is excellent in toughness as well as wear resistance can be provided in an economical manner. The novel feature of the tool is that the silicon nitride crystal grains comprise 50 to 90% by volume of hexagonal pillar crystals having a minor axis of at most 1.0 .mu.m and 5 to 30% by volume of hexagonal pillar or columnar crystals having a minor axis of at least 1.5 .mu.m. As the silicon nitride starting powder, there is preferably used a mixture of at least two silicon nitride powders prepared by the imide decomposition method, direct metallic silicon nitriding method and silica reducing method.

Abstract: A process for producing a cutting tool having a rake face and flank face which intersect to form a cutting edge, which cutting tool comprises a substrate consisting of a sintered hard metal and a coating film provided thereon consisting of a material with a higher hardness than the substrate, which method involves subjecting the substrate to a coating treatment and honing treatment in such a manner that the coating film near the cutting edge has such a thickness that the thickness continuously increases in directions away from the cutting edge along both the rake face and the flank face from a minimum value, including zero, at the cutting edge, such that the thickness of the coating at the rake face reaches a maximum thickness at a first distance from the cutting edge and the thickness at the flank face reaches a maximum thickness at a second distance from the cutting edge, wherein the first distance is greater than the second distance.

Abstract: A cutting insert having excellent toughness as well as wear resistance is provided comprising a substrate consisting of a sintered hard metal or alloy such as cemented carbides and a coating film provided thereon consisting of a material having a higher hardness than the substrate, characterized in that the coating film near the cutting edge is continuously made thinner or removed toward both the rake face and flank face.

Abstract: The present invention relates to a process of physical vapor deposition which homogeneously and tightly coats hard compounds on the surface of cutting tools, parts requiring wear resistance or ornaments such as a watch case and the like in order to improve wear resistance, heat resistance, corrosion resistance, appearance and the like of said tools, parts or ornaments.

Abstract: This invention relates to a highly hard material coated article which comprises a substrate of tool or part consisting of cermets, cemented carbides, tool steels or stainless steels and at least one highly hard material coated on the surface thereof, selected from the group consisting of carbides, nitrides and carbonitrides of at least one of titanium, zirconium and hafnium and those in which oxygen is dissolved, the coating being formed by an ion plating method wherein the accelerating voltage is high in a short time at the initial stage only, the crystals of the coated film being strongly orientated in the direction of <220> for the surface of the tool or part so that the diffraction intensity ratio of the peak from the {220} plane and the secondly strong diffraction peak in the X-ray diffraction using Cu-K.alpha.

Abstract: This invention relates to a highly hard material coated article which comprises a substrate of tool or part consisting of cermets, cemented carbides, tool steels or stainless steels and at least one highly hard material coated on the surface thereof, selected from the group consisting of carbides, nitrides and carbonitrides of at least one of titanium, zirconium and hafnium and those in which oxygen is dissolved, the coating being formed by an ion plating method wherein the accelerating voltage is high in a short time at the initial stage only, the crystals of the coated film being strongly orientated in the direction of <220> for the surface of the tool or part so that the diffraction intensity ratio of the peak from the {220} plane and the secondly strong diffraction peak in the X-ray diffraction using Cu-K.alpha.

Abstract: There is provided a coated tool steel having a tool steel substrate and at least one layer of a hard film overcoated on the substrate. The film consists of a B-1 type solid solution selected from carbides, nitrides and carbonitrides of at least one of titanium, zirconium or hafnium, and the breadth of the peak, at half maximum intensity, of Cu-K.alpha. diffraction from the (200) plane of the film, being not less than 0.4 degree on a 2 .theta. scale. The invention further provides a machine tool having at least one cutting part thereof formed from the coated tool steel described above. The coated steel provided herein has excellent wear resistance.

Abstract: A super hard metal roll assembly and a process for producing it are disclosed. Initially, a powdered mix of super hard metal materials is moulded into a hollow cylindrical moulding. The moulding is then fitted about a super hard metal cylindrical element such as roll, cylinder, pillar or shaft, and sintered to contract to a bushing tightly engaging the outer periphery of the cylindrical element to produce a super hard metal roll assembly. The roll assembly may be further treated in a high temperature and high pressure inert gas in order to eliminate voids at the interface between the bushing and the cylindrical element.