Patent ID: 7757792
Filing Date: 2010-07-20
Classification: B22F,C22C,C23F,E21B,Y10T

Abstract:
1. In a method for improving the performance of a PDC drill bit having a plurality of PDC cutters mounted therein, comprising the steps of: coating the exterior surface of said drill bit and the exterior surface of at least one of said plurality of PDC cutters, each of said PDC cutters having a body of diamond crystals and a catalyzing material contained within said body, said coating comprising a material impervious to a given acid or a mixture of given acids; selectively removing a segment of said coating from said at least one PDC cutter; applying said given acid or mixture of given acids to said at least one PDC cutter to leach out at least some of the catalyzing material contained within said body of diamond crystals, thereby providing improved thermal stability to a first region of said at least one PDC cutter from which said coating has been removed while retaining improved impact strength within a second region of said at least one PDC cutter upon which said coating has been retained.