Abstract A component comprised of a composite compact, preferably diamond, and a substrate bonded to the compact. A preferred embodiment of the component is a cutter for a drill bit. The compact is comprised of a layer of bonded diamond or boron nitride particles and a base layer of cemented carbide bonded, preferably under high temperatures and pressures, to the particulate layer. The particulate layer is degradable by expvsure to temperatures above a predetermined temperature. The substrate is bonded to the base layer of the compact with a filler metal which, to form a bond, requires the exposure of the surface to be bonded to a temperature substantially greater than the degradation temperature of the particulate layer. The component is fabricated by heating the base layer, filler metal and substrate to a temperature in excess of the degradation temperature while maintaining the temperature of the particulate layer below the degradation temperature via a heat sink.
An improved brazing apparatus for bonding an abrasive composite compact, selected from cubic boron nitride and diamond composite compacts, to a substrate, using a brazing filler metal having a liquidus substantially greater than 700° C., said apparatus comprising: a frame, a localized heating means attached to said frame; a pair of vertically opposed, moveable cylinders attached to said frame, the upper cylinder comprising a plunger having a recessed head for receiving one end of the composite compact and the lower cylinder comprising a plunger with a head; and a driving means for raising and lowering said cylinders, whereby the component braze joint is positioned for localized heating; wherein the improvement comprises: (a) a heat sink which maintains the temperature of the diamond or cubic boron nitride below its degradation temperature, said heat sink comprising the head of the upper cylinder which head is provided with a coolant; (b) a lower cylinder head provided with a coolant flowing therethrough and which head is adapted to receive a; (c) ceramic insulator which supports the substrate.
Claim 2
Dependent Claim
173 words
An improved brazing apparatus for bonding an abrasive composite compact, selected from cubic boron nitride and diamond composite compacts, to a substrate, using a brazing filler metal having a liquidus substantially greater than 700° C., said apparatus comprising: a frame, a localized heating means attached to said frame; a pair of vertically opposed, moveable cylinders attached to said frame, the upper cylinder comprising a plunger having a recessed head for receiving one end of the composite compact and the lower cylinder comprising a plunger with a head; and a driving means for raising and lowering said cylinders, whereby the component braze joint is positioned for localized heating; wherein the improvement comprises: (a) a heat sink which maintains the temperature of the diamond or cubic boron nitride below its degradation temperature, said heat sink comprising the head of the upper cylinder which head is provided with a coolant; (b) a lower cylinder head provided with a coolant flowing therethrough and which head is adapted to receive a; (c) ceramic insulator which supports the substrate.
Claim 3
Dependent Claim
47 words
The improved apparatus of claim 1 wherein: (a) The localized heating means is an induction coil interconnected to a radio frequency generator; (b) the ceramic insulator is a ceramic cup; (c) the driving means is pressurized air furnished to the cylinders; and (d) the coolant is water.