A superhard polycrystalline construction comprises a body of polycrystalline superhard material comprising a structure comprising superhard material, the structure having porosity greater than 20% by volume and up to around 80% by volume. A method of forming such a superhard polycrystalline construction comprises forming a skeleton structure of a first material having a plurality of voids, at least partially filling some or all of the voids with a second material to form a pre-sinter assembly, and treating the pre-sinter assembly to sinter together grains of superhard material to form a body of polycrystalline superhard material comprising a first region of superhard grains, and an interpenetrating second region; the second region being formed of the other of the first or second material that does not comprise the superhard grains; the superhard grains forming a sintered structure having a porosity greater than 20% by volume and up to around 80% by volume.

Methods of forming a polycrystalline table may involve disposing a plurality of particles comprising a superabrasive material, a substrate comprising a hard material, and a catalyst material in a mold. The plurality of particles may be partially sintered in the presence of the catalyst material to form a brown polycrystalline table having a first permeability attached to an end of the substrate. The substrate may be removed from the brown polycrystalline table and catalyst material may be removed from the brown polycrystalline table. The brown polycrystalline table may then be fully sintered to form a polycrystalline table having a reduced, second permeability. Intermediate structures formed during a process of attaching a polycrystalline table to a substrate may include a substantially fully leached brown polycrystalline table. The substantially fully leached brown polycrystalline table may include a plurality of interbonded grains of a superabrasive material.

The disclosure relates to a polycrystalline diamond composite sheet having a ripple-shaped gradient layer and a preparation method thereof. The polycrystalline diamond composite sheet consists of a cemented carbide substrate, a ripple-shaped gradient layer of a multi-layer structure, and a polycrystalline diamond layer from bottom to top. In the ripple-shaped gradient layer, a content of polycrystalline diamond increases from bottom to top, and a content of cemented carbide decreases from bottom to top. In the ripple-shaped gradient layer, an amplitude of a ripple-shaped structure is 0.2 to 0.6 mm, a wavelength is 1 to 2 mm, a spacing between an upper ripple and a lower ripple of a top layer is set to a gradient of (t/2 to t) mm to t mm from a peak to a trough, and spacings between an upper ripple and a lower ripple of remaining layers are all t mm, wherein t is 0.05 to 0.4.

Polycrystalline diamond compacts (PDCs) and methods of manufacturing such PDCs. In an embodiment, the PDC includes a polycrystalline diamond (PCD) table having at least a portion of a metal-solvent catalyst removed therefrom. Removing at least a portion of a metal-solvent catalyst from the PCD table may increase the porosity of the PCD table relative to a PCD table that has not been treated to remove the metal-solvent catalyst. Likewise, removing at least a portion of a metal-solvent catalyst from the PCD table may decrease the specific magnetic saturation and increase the coercivity of the PCD table relative to a PCD table that has not been treated to remove the metal-solvent catalyst.

Polycrystalline diamond constructions include a diamond body comprising a matrix phase of bonded together diamond crystals formed at high pressure/high temperature conditions with a catalyst material. The sintered body is treated remove the catalyst material disposed within interstitial regions, rendering it substantially free of the catalyst material used to initially sinter the body. Accelerating techniques can be used to remove the catalyst material. The body includes an infiltrant material disposed within interstitial regions in a first region of the construction. The body includes a second region adjacent the working surface and that is substantially free of the infiltrant material. The infiltrant material can be a Group VIII material not used to initially sinter the diamond body. A metallic substrate is attached to the diamond body, and can be the same or different from a substrate used as a source of the catalyst material used to initially sinter the diamond body.

Adhesive compositions and methods for bonding materials with different thermal expansion coefficients is provided. The adhesive is formulated using a flux material, a low flux material, and a filler material, where the filler material comprises particulate from at least one of the two components being bonded together. A thickening agent can also be used as part of the adhesive composition to aid in applying the adhesive and establishing a desired bond thickness. The method of forming a high strength bond using the disclosed adhesive does not require the use of intermediary layer or the use of high cure temperatures that could damage one or both of the components being bonded together.

Methods of fabricating polycrystalline diamond include subjecting a particle mixture to high pressure and high temperature (HPHT) conditions to form inter-granular diamond-to-diamond bonds. Before being subjected to HPHT conditions, the particle mixture includes a plurality of non-diamond nanoparticles, diamond nanoparticles, and diamond grit. The non-diamond nanoparticles includes carbon-free cores and at least one functional group attached to the cores. Cutting elements for use in an earth-boring tool include a polycrystalline diamond material formed by such processes. Earth-boring tools include such cutting elements.

Cutting elements include a diamond-bonded body attached with a substrate. The substrate has a coercivity of greater than about 200 Oe, and has a magnetic saturation of from about 73 to 90. The diamond-bonded body has a compressive stress at the surface of greater than about 0.9 GPa after heat treatment, and greater than about 1.2 GPa prior to heat treatment.

Adhesive compositions and methods for bonding materials with different thermal expansion coefficients is provided. The adhesive is formulated using a flux material, a low flux material, and a filler material, where the filler material comprises particulate from at least one of the two components being bonded together. A thickening agent can also be used as part of the adhesive composition to aid in applying the adhesive and establishing a desired bond thickness. The method of forming a high strength bond using the disclosed adhesive does not require the use of intermediary layer or the use of high cure temperatures that could damage one or both of the components being bonded together.

An improved method of sealing a ceramic part to a solid part made of ceramic, metal, cermet or a ceramic coated metal is provided. The improved method includes placing a bond agent comprising an Al.sub.2O.sub.3 and SiO.sub.2 based glass-ceramic material and organic binder material on adjoining surfaces of the ceramic part and the solid part. The assembly is heated to a first target temperature that removes or dissolves the organic binder material from the bond agent and the assembly is subjected to a second induction heating step at a temperature ramp rate of between about 100? C. and 200? C. per minute to temperatures where the glass-ceramic material flows and wets the interface between adjoining surfaces. The assembly is rapidly cooled at a cooling rate of about 140? C. per minute or more to induce nucleation and re-crystallization of the glass-ceramic material to form a dense, durable and gas-tight seal.