Element Six Abrasives S.a.

Element Six Abrasives Holdings Limited

David Christian Bowes

Nedret Can

Cornelis Roelof Jonker

Thembinkosi Shabalala

Geoffrey John Davies

Moosa Mahomed Adia

A superhard structure comprises a body of polycrystalline superhard material comprising a first region and a second region. The second region is adjacent an exposed surface of the superhard structure and comprises a diamond material or cubic boron nitride with a density greater than 3.4&#xd7;103 kilograms per cubic meter when the second region comprises diamond material. The material(s) forming the first and second regions have a difference in coefficient of thermal expansion, the first and second regions being arranged such that this difference induces compression in the second region adjacent the exposed surface. The first/a further region has the highest coefficient of thermal expansion of the polycrystalline body and is separated in part from a peripheral free surface of the body by the second region or one or more further regions formed of a material(s) of a lower coefficient of thermal expansion. The regions comprise a plurality of grains of polycrystalline superhard material. The second region is peripherally discontinuous with a gap therein through which a portion of the region formed of the material of highest coefficient of thermal expansion extends to the free surface of the superhard structure. There is also disclosed a method for making such a structure.

Superhard structure and method of making same

A tip for a degradation tool, the tip comprising a PCD structure () joined to a cemented carbide substrate (); the PCD structure comprising a plurality of strata () arranged so that adjacent strata have alternating compressive and tensile stress states, adjacent strata comprising different PCD grades and being directly bonded to each other by inter-growth of diamond grains; each stratum having a mean thickness of at most 500 microns; the PCD structure defining a working end including a rounded conical apex () having a radius of curvature of 1.3 mm to 4 mm.

Tip for degradation tool and tool comprising same

A pick tool for degrading asphalt or rock, comprising a PCD element; the PCD element comprising a PCD structure () bonded to a cemented carbide support body () at an interface; the PCD structure comprising a first region () and a second region () adjacent the first region, the second region bonded to the first region by intergrowth of diamond grains; the first region () comprising a plurality of alternating strata (), each stratum having a thickness in the range of about 30 to 300 microns; the second region comprising a plurality of strata (), one or more strata in the second region () having a thickness greater than the thicknesses of the individual strata in the first region (), wherein the alternating strata in the first region () comprise first strata alternating with second strata, the first strata being in a state of residual compressive stress and the second strata being in a state of residual tensile stress.

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Springs, South Africa

David Christian Bowes