Polycrystalline diamond partially depleted of catalyzing material
View Patent ↗The present invention provides a superhard polycrystalline diamond or diamond-like element with greatly improved resistance to thermal degradation without loss of impact strength. Collectively called PCD elements, these elements are formed with a binder-catalyzing material in a high-temperature, high-pressure process. The PCD element has a plurality of partially bonded diamond or diamond-like crystals forming at least one continuous diamond matrix, and the interstices among the diamond crystals forming at least one continuous interstitial matrix containing a catalyzing material. The element has a working surface and a body, where a portion of the interstitial matrix in the body adjacent to the working surface is substantially free of the catalyzing material, and the remaining interstitial matrix contains the catalyzing material. This translates to higher wear resistance in cutting applications, higher heat transfer capacity in heat sink applications, and has advantages in numerous other applications including hollow dies, indentors, tool mandrels, and wear elements.
1. A polycrystalline diamond element comprising a body of bonded diamonds with a working surface, wherein a first volume of the body remote from the working surface contains a catalyzing material, a second volume of the body adjacent to the working surface is substantially free of the catalyzing material to a depth from the working surface, wherein said bonded diamonds exhibit a thermal characteristic such that a 950 degrees C. temperature at the working surface results in a temperature of less than 750 degrees C. at the depth.
2. The polycrystalline diamond element of claim 1 , wherein said bonded diamonds exhibit a thermal gradient greater than 1000 degrees C. per mm.
3. The polycrystalline diamond element of claim 2 , wherein said bonded diamonds exhibit a thermal gradient greater than 2000 degrees C. per mm.
4. The polycrystalline diamond element of claim 1 , wherein the second volume of the body has a diamond density higher than elsewhere in the body.
5. The polycrystalline diamond element of claim 1 , wherein a majority of the catalyzing material remaining in the second volume of the body adheres to surfaces of diamond crystals.
6. The polycrystalline diamond element of claim 1 wherein the body is bonded to a substrate of less hard material.
7. The polycrystalline diamond element of claim 6 wherein the less hard material is cemented tungsten carbide.
8. The polycrystalline diamond element of claim 1 , wherein the body of bonded diamonds comprises a plurality of partially bonded diamond crystals and an interstitial matrix, and wherein the part of the interstitial matrix located within the first volume contains the catalyzing material, and the part of the interstitial matrix located within the second volume is substantially free of the catalyzing material.
9. The polycrystalline diamond element of claim 8 , wherein said bonded diamonds exhibit a thermal gradient greater than 1000 degrees C. per mm.
10. The polycrystalline diamond element of claim 8 , wherein said bonded diamonds exhibit a thermal gradient greater than 2000 degrees C. per mm.
11. The polycrystalline diamond element of claim 8 , wherein the second volume of the body has a diamond density higher than elsewhere in the body.
12. The polycrystalline diamond element of claim 8 , wherein a majority of diamond crystals located within the second volume of the body have a surface which is substantially free of catalyzing material.
13. The polycrystalline diamond element of claim 8 , wherein a majority of the catalyzing material remaining in the second volume of the body adheres to surfaces of the diamond crystals.
14. The polycrystalline diamond element of claim 8 , wherein the diamond crystals in the second volume remote from the first volume have less catalyzing material adhering to their surfaces than the diamond crystals in the second volume which are adjacent to the first volume.
15. The polycrystalline diamond element of claim 8 , wherein an amount of catalyzing material within the second volume of the body continuously decreases with distance from the first volume.
16. The polycrystalline diamond element of claim 8 , wherein an amount of catalyzing material within the second volume of the body increases with increasing distance from the first volume.
17. The polycrystalline diamond element of claim 16 , wherein the amount of catalyzing material within the second volume increases in steps.