A superhard polycrystalline construction comprises a body of polycrystalline superhard material comprising a superhard phase, and a non-superhard phase dispersed in the superhard phase, the superhard phase comprising a plurality of inter-bonded superhard grains. The non-superhard phase comprises particles or grains that do not chemically react with the superhard grains and form less than around 10 volume % of the body of polycrystalline superhard material. There is also disclosed a method of forming such a superhard polycrystalline construction.

A superhard polycrystalline construction comprises a body of polycrystalline superhard material comprising a superhard phase, and a non-superhard phase dispersed in the superhard phase, the superhard phase comprising a plurality of inter-bonded superhard grains. The non-superhard phase comprises particles or grains that do not chemically react with the superhard grains and form less than around 10 volume % of the body of polycrystalline superhard material. There is also disclosed a method of forming such a superhard polycrystalline construction.

A cutter element for rock removal comprises a free standing PCD body (801, 1801) comprising one or more physical volumes (1702, 1703), the PCD material being invariant in terms of the diamond and metal network compositional ratio and metal elemental composition such that each physical volume does not differ to any other physical volume with respect to diamond and metal network compositional ratio and metal elemental composition. The PCD body has a functional working volume (803) forming in use the region which comes into contact with the rock. A functional support volume (804) extant in use and having a proximal free surface extends from the functional working volume. The PCD body has an aspect ratio such that the ratio of the length (ae) of the longest edge of the circumscribing rectangular parallelepiped of the overall PCD body to the largest width (ad) of the smallest rectangular face from which the functional working volume extends of the circumscribing rectangular parallelepiped, is greater than or equal to 1.0.

A polycrystalline diamond compact (PDC), which is attached or bonded to a substrate to form a cutter for a drill bit, is comprised of sintered polycrystalline diamond interspersed with a seed material which has a hexagonal close packed (HCP) crystalline structure. A region of the sintered polycrystalline diamond structure, near one or more of its working surfaces, which has been seeded with an HCP seed material prior to sintering, is leached to remove catalyst. Selectively seeding portions or regions of a sintered polycrystalline diamond structure permits differing leach rates to form leached regions with differing distances or depths and geometries.

A polycrystalline diamond compact (PDC), which is attached or bonded to a substrate to form a cutter for a drill bit, is comprised of sintered polycrystalline diamond interspersed with a seed material which has a hexagonal close packed (HCP) crystalline structure. A region of the sintered polycrystalline diamond structure, near one or more of its working surfaces, which has been seeded with an HCP seed material prior to sintering, is leached to remove catalyst. Selectively seeding portions or regions of a sintered polycrystalline diamond structure permits differing leach rates to form leached regions with differing distances or depths and geometries.

Embodiments relate to polycrystalline diamond compacts (PDCs) and methods of manufacturing such PDCs in which an at least partially leached polycrystalline diamond (PCD) table is infiltrated with a low viscosity cobalt-based alloy infiltrant. In an embodiment, a method includes forming a PCD table in the presence of a metal-solvent catalyst in a first high-pressure/high-temperature (HPHT) process. The method includes at least partially leaching the PCD table to remove at least a portion of the metal-solvent catalyst therefrom to form an at least partially leached PCD table. The method includes subjecting the at least partially leached PCD table and a substrate to a second HPHT process effective to at least partially infiltrate the at least partially leached PCD table with a cobalt-based alloy infiltrant having a composition at or near a eutectic composition of the cobalt-based alloy infiltrant.

Embodiments relate to polycrystalline diamond compacts (PDCs) and methods of manufacturing such PDCs in which an at least partially leached polycrystalline diamond (PCD) table is infiltrated with a low viscosity cobalt-based alloy infiltrant. In an embodiment, a method includes forming a PCD table in the presence of a metal-solvent catalyst in a first high-pressure/high-temperature (HPHT) process. The method includes at least partially leaching the PCD table to remove at least a portion of the metal-solvent catalyst therefrom to form an at least partially leached PCD table. The method includes subjecting the at least partially leached PCD table and a substrate to a second HPHT process effective to at least partially infiltrate the at least partially leached PCD table with a cobalt-based alloy infiltrant having a composition at or near a eutectic composition of the cobalt-based alloy infiltrant.

In an embodiment, a method of fabricating a leached polycrystalline diamond (PCD) body is disclosed. The PCD body includes bonded diamond grains defining interstitial regions at least a portion of which include at least one interstitial constituent disposed therein. The method includes leaching the PCD body with a leaching agent to remove at least a portion of the at least one interstitial constituent therefrom. The leaching agent includes a mixture having hydrofluoric acid in a first concentration of about 10 weight % to about 50 weight %, nitric acid in a second concentration of about 5 weight % to about 25 weight %, and water in a third concentration of about 25 weight % to about 85 weight %. Further embodiments relate to different leaching methods and different leaching agent compositions.

In an embodiment, a method of fabricating a leached polycrystalline diamond (PCD) body is disclosed. The PCD body includes bonded diamond grains defining interstitial regions at least a portion of which include at least one interstitial constituent disposed therein. The method includes leaching the PCD body with a leaching agent to remove at least a portion of the at least one interstitial constituent therefrom. The leaching agent includes a mixture having hydrofluoric acid in a first concentration of about 10 weight % to about 50 weight %, nitric acid in a second concentration of about 5 weight % to about 25 weight %, and water in a third concentration of about 25 weight % to about 85 weight %. Further embodiments relate to different leaching methods and different leaching agent compositions.

A cutting element may include: a substrate; and an ultrahard layer on the substrate, the ultrahard layer having a non-planar working surface, the non-planar working surface being formed from a first region and a second region, the first region, encompassing at least a cutting edge or tip of the cutting element and having a differing composition than the second region.