EDM cuttable, high CBN content solid PCBN compact
View Patent ↗The present disclosure relates to cubic boron nitride (cBN) cutting elements that have high cBN content and that are cuttable by electric discharge machining (EDM). A cutting element according to an embodiment includes a self-sintered polycrystalline cubic boron nitride (PCBN) compact, having a first phase of cubic boron nitride (cBN) particles and a ceramic binder phase with titanium compounds. The first phase occupies greater than 80% by volume of the self-sintered PCBN compact. The self-sintered PCBN compact has an electrical conductivity sufficient to be cuttable by electrical discharge machining.
1. A cutting element comprising: a self-sintered polycrystalline cubic boron nitride (PCBN) compact, comprising
a first phase of cubic boron nitride (cBN) particles and a conductive ceramic binder phase comprising titanium diboride, the first phase occupying greater than 80% by volume of the self-sintered PCBN compact,
wherein the conductive ceramic binder phase further comprises Aluminum compounds, and a ratio of Titanium to Aluminum in the self-sintered PCBN compact is approximately 2 or 3; and
wherein the self-sintered PCBN compact has an electrical conductivity sufficient to be cuttable by electrical discharge machining.
2. The cutting element of claim 1 , wherein the self-sintered PCBN compact comprises a Vickers hardness of greater than 3,200 kg/mm 2 .
3. The cutting element of claim 1 , wherein the self-sintered PCBN compact has a thickness in the range of about 1 mm to 50 mm.
4. The cutting element of claim 1 , wherein the binder phase further comprises titanium nitride and titanium carbide.
5. The cutting element of claim 1 , wherein the first phase occupies greater than 85% by volume of the self-sintered PCBN compact.
6. The cutting element of claim 1 , wherein the first phase occupies about 85% by volume of the self-sintered PCBN compact.
7. The cutting element of claim 1 , wherein the first phase occupies greater than 90% by volume of the self-sintered PCBN compact.
8. The cutting element of claim 1 , wherein the first phase occupies between about 85% to about 95% by volume of the self-sintered PCBN compact.
9. The cutting element of claim 1 , wherein the first phase occupies greater than 81% by volume of the self-sintered PCBN compact.
10. The cutting element of claim 1 , wherein the self-sintered PCBN compact has an electrical resistivity less than about 10 −2 ohm-m.