Sumitomo Electric Industries, Limited

Sumitomo Electric Hardmetal Corp.

Toshiya Takahashi

Akihiko Ikegaya

Keiichiro Tanabe

Naoji Fujimori

Yoshiki Nishibayashi

Hitoshi Sumiya

Akihiko Ueda

Yutaka Kobayashi

Yuichiro Seki

Katsuhito Yoshida

Takahisa Iguchi

Shigeru Yoshida

Fuminori Higuchi

Noaji Fujimori

A single crystal diamond () is provided as a single crystal diamond into which a defect portion () is introduced. The defect portion () can be detected by a phase difference occurring when the single crystal diamond () is irradiated with circularly polarized light. In the single crystal diamond (), a maximum value of average values of the phase differences measured within a measurement region (M) formed in a shape of a square having a side length of 1 mm is 30 nm or more.

Single crystal diamond and diamond tool

A single crystal diamond has a surface. In the single crystal diamond, a measurement region is defined in the surface, the measurement region includes a portion exhibiting a transmittance that is highest in the single crystal diamond and a portion exhibiting a transmittance that is lowest in the single crystal diamond, the measurement region has a plurality of square regions that are continuously arranged and each have a side having a length of 0.2 mm, and an average value of transmittances in each of the plurality of square regions is measured, wherein assuming that the average value of the transmittances in one square region is defined as Tand the average value of the transmittances in another square region adjacent to the one square region is defined as T, a relation of ((T&#x2212;T)/((T+T)/2)&#xd7;100)/0.2&#x2264;20 (%/mm) is satisfied throughout the measurement region.

A diamond electrode includes a conductive silicon substrate having a plurality of pores. The diamond electrode also includes a conductive diamond covering the conductive silicon substrate. The inner wall surfaces of the plurality of pores are at an angle of 60&#xb0; to 85&#xb0; with respect to a substrate of the conductive silicon substrate.

Diamond electrode, method for producing same, and electrolytic cell

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.

Diamond wire drawing die and process for manufacturing same

Diamond wire drawing die

A diamond cutting tool has a rake face (5) of a cutting edge member (2) consisting essentially of a (111) plane of diamond. The cutting edge member (2) of diamond is vapor-deposited by CVD or the like on an independently prepared base material. In this vapor deposition, the diamond is deposited while controlling and periodically varying the carbon to hydrogen ratio of the supplied raw material gas, in such a manner that a (111) crystal plane is oriented with a prescribed fluctuation or non-uniformity, but is substantially parallel to the base material surface. The as-formed diamond material is separated from the base material and cut into a desired shape, and then bonded as a cutting edge member (2) to a tool base (1) through a metallization layer (4) and a brazing layer (3), in such an orientation that the (111) plane defines the rake face (5). The tool having such a rake face (5) consisting essentially of the (111) plane, with a prescribed fluctuation of its orientation, is excellent in wear resistance and is resistant to cleavage damage.

Diamond cutting tool and method of manufacturing the same

A bonding tool has a head portion made essentially of vapor-deposited diamond, wherein a principal diamond crystal plane forming a head face is a (111) plane. Such a head face has high hardness and a good wear resistance. In order to improve the toughness of a bonding head which is mainly made of vapor-deposited diamond, a portion or ply forming the head face consists essentially of high-purity diamond, and another portion or ply supporting the head face consists essentially of low-purity diamond. The head face has a high rigidity, while the portion supporting the head face has a high toughness. In order to provide a bonding head portion which is mainly made of vapor-deposited diamond with electrical conductivity, a first portion or ply forming a head face consists essentially of polycrystalline diamond containing a relatively small amount of dopant, and another portion or ply supporting the first portion or ply contains a large amount of dopant. The head portion having electrical conductivity can be heated by energization. In a tool employing a coating containing vapor-deposited diamond as a bonding head portion, the coating is formed by a compound of a metal or ceramics and vapor-deposited diamond, in order to improve the strength of the coating and adhesion to a tool substrate.

Bonding tool having a diamond head and method of manufacturing the same

A diamond cutting tool has a tool substrate and a cutting edge member. The cutting edge member is formed of a material having a three-layer structure or a diamond composite material. When the material having a three-layer structure is employed, the cutting edge member is formed by a vapor-deposited diamond layer defining a rake face, a layer of a composite material of vapor-deposited diamond and a metal or ceramics, and a layer of the metal or ceramics. The metal is prepared from Mo, W, Cr, V, Nb, Ta, Co, Ni or Fe, while the ceramics is prepared from cBN, SiC, Si.sub.3 N.sub.4, WC, TiC, TaC, NbC, Cr.sub.3 C.sub.2, Mo.sub.2 C, VC, TiN or BN. The cutting edge member is brazed to the tool substrate through the metal or ceramics layer. When the diamond composite material is employed, on the other hand, the cutting edge member is formed of a composite material of particles or fibers of AlN, cBN or SiC and vapor-deposited diamond. The diamond cutting tool is excellent in heat resistance and durability.

Growing community of inventors

Hyogo, Japan

Toshiya Takahashi