Back to results
US 4,525,179 AGranted
Process for making diamond and cubic boron nitride compacts
AssigneeGeneral Electric Company
InventorPaul D. Gigl
Life of this patent
Estimating the term…
Abstract
The high pressure/high temperature (HP/HT) process for making diamond or CBN compacts has been modified by placing partitions within the crystal mass before HP/HT processing. With reference to FIG. 3, within the shield metal sleeve 11 and shield metal cup 14 are placed pliable metal shapes 20 in a honeycomb pattern. The abrasive crystals within the tubes 18 and outside the tubes 26 is sintered, and a compact containing the tubes embedded therein results. This compact can be acid leached to give a plurality of small compacts which need little if any additional shaping. The partitions can also be left intact as chip arresters.
Claims37
In a process for preparing a compact which comprises:
- A. subjecting a mass of abrasive crystals selected from the group consisting of diamond, cubic boron nitride and mixtures thereof, which mass is in contact with a source of metallic catalyst/solvent for recrystallization of the abrasive crystals, to conditions of temperature, pressure and time which result in a compact having intercrystal bonding between adjacent crystal grains;
- B. recovering the compact produced;
- and
- C. removing substantially all of the metallic phase from the compact of step B;
- the improvement which comprises:
- (i) forming the compact with a sub-divided crystalline mass by embedding within the mass of abrasive crystals at least one metallic partition strip of a given shape subdividing the abrasive crystal mass before the mass is subjected to the temperature and pressure conditions of step A, which partition strip is characterized by maintaining segregation between the separate portions of the abrasive crystal mass throughout step A and being sufficiently pliable not to resist the compaction of the abrasive crystal mass;
- and
- (ii) recovering a compact in step C having a shape described at least in part by the partition strip.
5 more elements
In a process for preparing a compact which comprises:
- A. subjecting a mass of abrasive crystals selected from the group consisting of diamond, cubic boron nitride and mixtures thereof, thich mass is in contact with a mass of metal carbide containing a cementing agent which is a catalyst/solvent for recrystallization of the abrasive crystals, to conditions of temperature, pressure and time which result in a compact having intercrystal bonds between adjacent crystal grains;
- and
- b. recovering the composite compact produced;
- the improvement which comprises embedding within the mass of abrasive crystals, before it is subjected to the pressure and temperature conditions of step A, at least one partition strip extending through the shortest dimension of the abrasive crystal mass which partition strip is characterized by maintaining segregation between the separate portions of the abrasive crystal mass throughout step A and being sufficiently pliable not to resist the compaction of the abrasive crystal mass.
1 more element
An improved composite compact comprising:
- (a) a polycrystalline mass of abrasive grains selected from the group consisting of diamond, cubic boron nitride, and mixtures thereof bonded to a substrate material comprising
- (b) a cemented metal carbide wherein the cementing agent is a catalyst/solvent, said abrasive grains, in random orientation, being directly bonded to adjacent crystal grains in said mass thereof by intercrystal bonding;
- wherein the improvement comprises at least two partition strips subdividing the polycrystalline mass of abrasive grains, embedded within the polycrystalline mass and extending through its shortest dimension.
In a process for preparing a compact which comprises:
- A. subjecting a raw material selected from the group consisting of graphite, hexagonal boron nitride and wurtzite boron nitride, in the presence of a catalyst for diamond crystallization in the case of graphite or for cubic boron nitride crystallization in the case of hexagonal boron nitride and wurtzite boron nitride, to conditions of pressure, temperature and time which result in a compact having a polycrystalline mass made of a material selected from the group consisting of diamond in the case of graphite raw material and cubic boron nitride in the case of hexagonal or wurtzite boron nitride raw material;
- and
- B. recovering the compact produced;
- the improvement which comprises forming a compact with a subdivided polycrystalline mass by embedding within the raw material, before it is subjected to the pressure and temperature conditions of step A, at least one partition strip characterized by maintaining segregation between the separated portions of the raw material throughout step A, and being sufficiently pliable not to resist compaction of the raw material during step A.
1 more element
Dependencies are inferred from the claim text.