General Electric Company

Paul D Gigl

David E Slutz

Harold P Bovenkerk

Gary Martin Flood

Gary W Smith

Mahlon D Dennis

Francis R Corrigan

Hyun S Cho

Robert L Winegardner

Bonnie M Hammersley

Disclosed is a brazed implement comprising a thermally-stable polycrystalline diamond compact, e.g. a compact of self-bonded diamond particles having a network of inter-connected empty pores dispersed throughout the compact, bonded to another of said compact or bonded to a cemented carbide support by a brazing filler metal disposed therebetween. The brazing metal comprises an alloy having a liquidus above about 700.degree. C. and containing an effective amount of chromium. Translational shear strengths exceed about 50 kpsi even upon furnace cycling of the brazed implements and often exceed 90 kpsi. The method for fabricating the brazed implement also is disclosed.

Brazed thermally-stable polycrystalline diamond compact workpieces

Brazed thermally-stable polycrystalline diamond compact workpieces and

Disclosed is an improved polycrystalline compact of self-bonded diamond particles having a network of interconnected empty pores dispersed throughout. The improved porous polycrystalline diamond compact possesses enhanced oxidation resistance and comprises all of the exterior surfaces of the porous compact being enveloped with a continuous coating which is effective under metal bond fabrication conditions so that oxidation of the diamond in the compact does not exceed a threshold level whereat loss of diamond properties of the compact occurs. Metal bond fabrication conditions comprehend an atmosphere containing oxygen or water vapor. Metal coatings are preferred, especially in coating thicknesses in excess of about 8 microns, and applied by a chemical vapor deposition process.

Coated oxidation-resistant porous abrasive compact and method for making

Optical windows for hostile environments have been made from diamond and adamantine boron nitride compacts. The compact windows can comprise a single layer of large crystals bonded in a matrix. For example, they are made by exposing a sample of diamond (425-1700 micron) in a diamond and graphite matrix to high pressure-high temperature conditions (e.g., 50 Kbar at 1400.degree. C. to 85 Kbar at 1800.degree. C.). A typical boron nitride reaction zone assembly (cell) is shown in FIG. 1, in which carbon heater tube 1 is surrounded by tantalum foil sleeve 2. The sample of pyrolytic boron nitride 3 is disposed between carbon discs 5, tantalum foil discs 4 and hot pressed boron nitride plugs 6. The optical windows produced are capable of transmitting infrared light and visible light.

Process for making diamond and cubic boron nitride compacts

The high pressure/high temperature (HP/HT) process for making diamond or CBN compacts has been modified by placing partitions within the crystal mass before HP/HT processing. With reference to FIG. 3, within the shield metal sleeve 11 and shield metal cup 14 are placed pliable metal shapes 20 in a honeycomb pattern. The abrasive crystals within the tubes 18 and outside the tubes 26 is sintered, and a compact containing the tubes embedded therein results. This compact can be acid leached to give a plurality of small compacts which need little if any additional shaping. The partitions can also be left intact as chip arresters.

The high pressure/high temperature catalyst sweep through process for making diamond and cubic boron nitride compacts has been improved by adding an intermediate metal or metal alloy. The added metal (whether alone or contained in an alloy) has a melting point below that of the catalyst (e.g. cobalt), is miscible with the catalyst, and preferably sweeps through the mass of abrasive crystals first. This modification has reduced flaw formation in such compacts.

Sweep through process for making polycrystalline compacts

A process improvement is disclosed for making compacts containing diamond which reduces crystal flaws within the diamond. This is accomplished by isolating the single diamond crystals in an compressible matrix before exposing the sample to sintering conditions. One method for doing this (described with reference to FIG. 1) is embedding the diamond 14 in a mixture 16 of graphite and diamond fines. This mixture is disposed between two graphite discs 18 and 19 and two cobalt discs 22 and 23. This sub-assembly is contained within zirconium cup 10 on top of which is placed zirconium disc 12 and exposed to high pressure-high temperature sintering conditions.

Method for reducing damage to diamond crystals during sintering

In one embodiment, a compact for tools, such as cutting, drilling and shaping tools, consists essentially of self-bonded abrasive particles. The bonded particles define a substantially continuous interconnected network of pores, dispersed throughout the compact. The method for making such a compact comprises the steps of bonding a mass of abrasive particles, aided by a sintering aid material, under high temperatures and pressures (HP/HT) to form an abrasive body comprised of said particles in a self-bonded form and said material infiltrated throughout the body. The body is then treated to remove substantially all infiltrated material, thereby to produce a compact consisting essentially of the self-bonded abrasive particles. In another embodiment, a composite compact which is made in a similar manner to the first embodiment consists essentially of a layer of self-bonded abrasive particle and a substrate layer (preferably of cemented carbide) bonded to the abrasive particle layer.

Temperature resistant abrasive compact and method for making same

One or more masses of bonded particles of diamond, cubic boron nitride (CBN), and wurtzite boron nitride (WBN) are sandwiched between or encapsulated by two masses of cemented carbide bonded to the particle masses. In the preferred embodiment, the particle masses are comprised of (1) at least 70% by volume of said particles, and (2) a metallic phase comprised of the cementing agent of the carbide mass. The composite compacts find utility in drill bit, mining tool and wear part applications. A method for making such a composite compact comprises (1) placing within a reaction cell masses of abrasive particles and at least two carbide masses interleaved with the abrasive particle masses, (2) the masses are placed in the cell in such a manner to allow for the accommodation of pressure and (3) simultaneously subjecting the cell and the contents thereof to temperature and pressure conditions at which the particles are stable. A method for abrading or cutting a workpiece with a composite compact comprises providing (1) a tubular carbide mass and a bonded mass of abrasive particles disposed in and bonded to the carbide mass in a central cavity thereof and (2) moving either the compact or workpiece relative to the other to provide the cutting or abrading action.

Growing community of inventors

Worthington, OH, United States of America

Paul D Gigl