Composite polycrystalline diamond body

Abstract

In this novel PDC cutter, diamond powders of different composition and / or different grain size, are distributed, shaped, and compacted with a novel pressing tool, in multiple stages, spatially arranged into different regions of the PDC diamond body, then HPHT sintered to form one PDC body with spatially varying hardness, toughness and thermal resistance more optimal for machining, drilling and / or cutting of hard rock and stone.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS[0001]This application claims the benefit of no other prior applications.INVENTIVE FIELD[0002]Exemplary embodiments are directed to a body for use in cutting, machining, drilling and similar operations, and a method of manufacture of the body. More particularly, exemplary embodiments are directed to a composite polycrystalline diamond body and method of manufacture that may be used for cutting, machining, drilling and other similar operations.BACKGROUND[0003]As used in the following disclosure and claims, the term polycrystalline diamond (PCD) is intended to refer to the type of material that is made by subjecting diamond crystals to a high temperature and pressure that results in intercrystalline bonding of the individual diamond crystal. In exemplary embodiments, the intercrystalline bonding is usually facilitated by use of a specific catalyst family of transition metals, usually as molten fluid. Although catalysts greatly aid the sinter bond...

AI Technical Summary

Problems solved by technology

This is especially true for diamond granular materials that are difficult to contact with molten metals, such as fine particle size and / or highly textured diamond.

The presence of residual catalyst in the PCD generally changes its quality and compels design compromise between various desirable and undesirable properties of a cutting material.

Known PDCs have drawbacks that lead to the degradation wherein the PDC is unable to cut rock or stone.

One of the factors limiting the success of the PDC is that larger crystals that may be used to form the PDC, while easy to sinter completely with low residual catalyst, typically produce fewer diamond-to-diamond bonds per unit volume.

Residual catalyst metal expands far more than sintered diamond and tends to weaken the PDC.

On the contrary smaller crystals can generate more diamond-to-diamond intergranular bonds per unit volume but are more difficult to sinter completely to low residual catalyst metal content.

Higher residual catalyst lowers density of diamond-to-diamond bonds, catalyst taking the space diamond would otherwise, but more importantly lowers the heat tolerance of PDC.

The result is a range of grades of PDC representing the compromise of hardness and heat resistance achieved by coarse and fine grains, with varying residual catalyst content, which perform non-optimally.

In some embodiments, the rake may resist thermal spalling, chipping and adhesion wear, and be hard to resist abrasion of loose rock debris sliding over it.

PDC is very difficult to machine and attach to common drill materials, like steel or infiltrated carbide-metal.

Of course one of the factors limiting the success of PDC is the strength of the bond between the polycrystalline diamond layer and the cemented tungsten carbide substrate.

For example, analyses of the failure mode for drill bits used for deep hole rock drilling show that in approximately thirty-three percent of the cases, bit failure or wear is caused by delamination of the diamond from the metal carbide substrate.

This restriction on the thickness of the diamond layer limits both the life expectancy of the composite body in use as well as the designs for PDC diamond tools.

Yet another problem that has limited the thickness of the diamond layer in composite bodies is caused by the problem of “bridging”.

This results in high porosity which requires more catalyst and thus tends to leave more residual catalyst in the sintered PDC.

However, as a result of the high density, the abrasive mass of very fine crystals presents increased resistance to the catalyst metal or catalyst metal and carbide from sweeping through the crystal interstices as well as increased packing defects due to bridging.

The increased resistance may lead to soft spots of non- or weakly bonded abrasive material in the PDC.

However, coarser and / or larger abrasive crystals may provide larger channels and spaces in the compacted mass that may allow the catalyst metal to sweep through.

On the other hand, coarser materials may not provide the abrasion resistance that may be desired for a PDC material since they do not produce high diamond-to-diamond bonds per unit volume of PDC.

While grain and packing artifacts affect the quality of the PDC sintered mass, it also affects the quality of the bond of the PDC to the substrate.

Nonetheless, the issues of pressure and compaction affect this region of PDC perhaps more so than the PDC body.

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