IRON GRADIENT IN POLYCRYSTALLINE DIAMOND COMPACTS; BLANKS, CUTTERS AND CUTTING TOOLS INCLUDING SAME; AND METHODS OF MANUFACTURE
Polycrystalline diamond compacts, polycrystalline diamond blanks, polycrystalline diamond cutters, and tools incorporating same for cutting, milling, grinding, drilling and other abrasive operations, particularly in metal cutting applications or geological formation drilling applications, include a diamond table having a gradient in iron content that increases as distance into the volume of the diamond table increases. The iron gradient increases resistance to wear, such as in interrupted milling tests. The disclosure further relates to methods of manufacturing polycrystalline diamond compacts having a gradient in iron concentration in the diamond table, blanks and cutters including polycrystalline diamond compacts, cutting tools incorporating such compacts, blanks and cutters, and methods of cutting, milling, grinding and drilling, particularly metal machining or rock drilling, using such compacts, blanks, cutters, cutting tools and drill bits.
1 . A method of manufacturing a polycrystalline diamond compact, the method comprising:
forming an assembly, wherein the assembly comprises a diamond catalyst source, a layer of diamond feed in contact with the diamond catalyst source, and a refractory container, the refractory container containing the diamond catalyst source and the layer of diamond feed; and
processing the assembly at elevated temperature and elevated pressure sufficient to sinter the diamond feed into a diamond body,
wherein the diamond feed includes 90 to 99 wt. % diamond particles and 1 to 10 wt. % of a cobalt-iron alloy,
wherein the diamond body includes a volume of crystalline diamond grains bond together by diamond-to-diamond bonds, a plurality of inter-grain regions disposed between the bonded crystalline diamond grains, a cobalt-based catalyst material present in at least a portion of the plurality of inter-grain regions, and an iron concentration gradient extending from an exterior surface of the diamond body into an interior volume of the diamond body.
2 . The method according to claim 1 , wherein the cobalt-iron alloy is Co x Fe Y , where 0.6≤x≤0.8, 0.2≤y≤0.4, and x+y=1.0.
3 . The method according to claim 2 , wherein the cobalt-iron alloy is Co x Fe Y , where 0.68≤x≤0.72, 0.28≤y≤0.32, and x+y=1.0.
4 . The method according to claim 3 , wherein the cobalt-iron alloy is Co x Fe Y , where x=0.7 and y=0.3.
5 . The method according to claim 1 , wherein an average diameter of the diamond particles is equal to or greater than 1 micron and equal to or less than 40 microns.
6 . The method according to claim 1 , wherein the diamond catalyst source is a hard metal substrate having a composition including cemented carbide or cobalt sintered tungsten carbide (WC—Co).
7 . The method according to claim 1 , wherein the composition is iron-free.
8 . The method according to claim 1 , wherein forming the assembly includes the steps of:
positioning the diamond catalyst source in the refractory container;
forming a layer of diamond feed in the refractory container in contact with the diamond catalyst source; and
positioning a cap over contents of the refractory container and sealing.