A tool having a cutting edge that includes a sintered body containing cubic boron nitride. The sintered body integrally and inseparably includes an inner region and a binder phase enriched layer formed on at least part of a surface of the inner region. The inner region includes: 15-90 volume % of cubic boron nitride; and 10-85 volume % of a mixture of a binder phase and impurities. The binder phase enriched layer includes: 90-100 volume % of the binder phase and impurities mixture; and 0-10 volume % of cubic boron nitride; and the binder phase contains at least one kind selected from the group consisting of: at least one element selected from the group consisting of Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Al, Co, Ni and Si; and a compound of the element and at least one element selected from the group consisting of C, N, O and B.

A cutting element has a thermally stable polycrystalline diamond layer formed on an upper side of a polycrystalline diamond layer and having a cutting face opposite the polycrystalline diamond layer, a transition layer on a side of the polycrystalline diamond layer opposite the thermally stable polycrystalline diamond layer, and a non-planar interface between the transition layer and the polycrystalline diamond layer, the non-planar interface having a perimeter exposed around a side surface of the cutting element and encircling an interior of the non-planar interface, and an uppermost portion of the perimeter being a distance from the cutting face greater than an axial distance between the cutting face and the interior.

A superhard polycrystalline construction comprises a body of polycrystalline superhard material comprising a superhard phase, and a second phase dispersed in the superhard phase, the superhard phase comprising a plurality of inter-bonded superhard grains. The second phase comprises particles or grains that do not chemically react with the superhard grains, and/or do not inter-grow, and form between around 1 to 30 volume % or wt % of the body of polycrystalline superhard material.

A cBN sintered compact includes a binder phase that contains a TiAl alloy containing at least one of the Si, Mg, and Zn elements, Ti.sub.2CN, TiB.sub.2, AlN, and Al.sub.2O.sub.3; the ratio I.sub.Ti2CN/I.sub.TiAl is 2.0 or more and 30.0 or less, wherein I.sub.Ti2CN represents the intensity of the Ti.sub.2CN peak appearing at 2? from 41.9? to 42.2? and I.sub.TiAl represents the intensity of the TiAl alloy peak appearing at 2? from 39.0? to 39.3? in XRD; and, in the mapped image of each element of Ti, Al, Si, Mg, and Zn by Auger electron spectroscopy, the ratio S.sub.TiAlM/S.sub.TiAl, is 0.05 or more and 0.98 or less wherein S.sub.TiAlM represents the average area of the portions wherein Ti, Al and at least one selected from the group consisting of Si, Mg, and Zn overlap and S.sub.TiAl represents the average area of the portions where Ti and Al overlap.

A composite sintered material includes: a plurality of diamond grains having an average grain size of less than or equal to 10 m; a plurality of cubic boron nitride grains having an average grain size of less than or equal to 2 m; and a plurality of aluminum oxide grains having an average grain size of less than or equal to 0.5 m; and a remainder of a binder phase, wherein at least parts of adjacent diamond grains are bound to one another, the binder phase includes cobalt, in the composite sintered material, a content of the diamond grains is from 30 to 92 volume %, a content of the cubic boron nitride grains is from 3 to 40 volume %, a content of the aluminum oxide grains is from 2 to 15 volume %, and a content of the cobalt is from 3 to 30 volume %.

A composite sintered material includes: a plurality of diamond grains having an average grain size of less than or equal to 10 m; a plurality of cubic boron nitride grains having an average grain size of less than or equal to 2 m; and a remainder of a binder phase, wherein at least parts of adjacent diamond grains are bound to one another, the binder phase includes cobalt, in the composite sintered material, a content of the diamond grains is more than or equal to 30 volume % and less than or equal to 94 volume %, a content of the cubic boron nitride grains is more than or equal to 3 volume % and less than or equal to 40 volume %, and a content of the cobalt is more than or equal to 3 volume % and less than or equal to 30 volume %.

A method of forming a super hard polycrystalline construction comprises forming a liquid suspension of a first mass of nano-ceramic particles and a mass of particles or grains of super hard material having an average particle or grain size of 1 or more microns, dispersing the particles or grains in the liquid suspension to form a substantially homogeneous suspension, drying the suspension to form an admix of the nano-ceramic and super hard grains or particles, and forming a pre-sinter assembly comprising the admix. The pre-sinter assembly is then sintered to form a body of polycrystalline super hard material comprising a first fraction of super hard grains and a second fraction, the nano-ceramic particles forming the second fraction. The super hard grains are spaced along at least a portion of the peripheral surface by one or more nano-ceramic grains, the super hard grains having a greater average grain size than that of the grains in the second fraction which have an average size of less than around 999 nm.

A drilling tip according to the disclosure has a tip body which is provided with a tip portion tapered toward a tip side of the tip body; and a hard layer which is formed on a surface of the tip portion of the tip body, an outermost layer of the hard layer is a cBN sintered material having 70 to 95 vol % of cBN grains, and when a cross-sectional structure of the outermost layer is observed, a binder phase having a width of 1 nm or greater and 30 nm or less and containing Al, B, and N, and in which a ratio of an O content to an Al content is 0.1 or less exists between neighboring cBN grains.

Polycrystalline diamond compacts having parting compound within the interstitial volumes are disclosed herein. In one embodiment, a polycrystalline diamond compact includes a polycrystalline diamond body having a plurality of diamond grains bonded together in diamond-to-diamond bonds, interstitial volumes positioned between the adjacent diamond grains, and a parting compound positioned in at least a portion of the interstitial volumes of the polycrystalline diamond body.

A method for treating a super-hard structure, the method including heating the super-hard structure to a treatment temperature of at least 500 degrees centigrade and cooling the super-hard structure from the treatment temperature to a temperature of less than 200 degrees centigrade at a mean cooling rate of at least 1 degree centigrade per second and at most 100 degrees centigrade per second to provide a treated super-hard structure. A PCBN structure produced by the method may have flexural strength of at least 650 MPa.