High Diamond Frame Strength PCD Cutting Elements
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Solution Overview
Problem
Conventional polycrystalline diamond (PCD) cutting elements used in subterranean drilling face challenges with thermal stability and wear resistance due to the differential thermal expansion of catalyst materials and diamond, leading to thermal degradation, chipping, and reduced performance at elevated temperatures.
Innovation Solution
A PCD cutting element with a high diamond frame strength is developed by reducing the secondary phase content, specifically by forming a polycrystalline diamond body with a diamond frame strength of 1200 MPa or greater and an average sintered grain size of less than 10 microns, achieved through a high-pressure high-temperature sintering process and subsequent leaching to remove catalyst material from interstitial regions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If higher metal catalyst content is used to increase strength and toughness, then strength and impact resistance are improved, but hardness and wear resistance decrease
Solution Approach 1:
The patent removes the harmful secondary phase (metal catalyst) from the PCD body through a leaching process, extracting only the necessary diamond frame structure. This extraction eliminates the trade-off between strength and wear resistance by eliminating the source of thermal degradation while preserving the mechanical strength provided by the diamond lattice itself.
Solution Approach 2:
The patent changes the compositional parameter by reducing secondary phase content from conventional levels to less than 5 wt%, and modifies the microstructure to achieve a diamond frame strength of at least 1200 MPa. This parameter change resolves the contradiction by creating a PCD body where the diamond structure itself provides both strength and wear resistance without compromise.
2Strength
If solvent metal catalyst is used to facilitate intercrystalline bonding, then bonding strength is improved, but thermal stability deteriorates due to differential thermal expansion
Solution Approach 1:
The patent extracts and removes the solvent metal catalyst from the PCD body through leaching, eliminating the source of thermal degradation. The remaining diamond frame structure maintains bonding strength through pure diamond-to-diamond bonds, which are thermally stable and do not suffer from differential thermal expansion issues.
Solution Approach 2:
The patent uses a temporary catalyst during the sintering process that is subsequently removed. The catalyst serves its bonding function during manufacturing but is then discarded through leaching, as its presence would harm thermal stability during service. This allows the diamond structure to achieve both strong bonding and thermal stability.
3Strength
If catalyst material is present in interstitial regions, then strength is improved, but thermal degradation increases due to catalyzed phase transformation
Solution Approach 1:
The patent extracts and removes the catalyst material from interstitial regions through a leaching process, eliminating the harmful catalytic effect that causes phase transformation at elevated temperatures. The diamond frame structure maintains its strength without the presence of catalysts that would otherwise promote thermal degradation.
Solution Approach 2:
The patent converts the harmful presence of catalyst material into a beneficial process by using leaching to remove the catalyst. The leaching process transforms the harmful catalytic effect into a useful purification process, resulting in a PCD body with high thermal stability and maintained strength.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The high diamond frame strength PCD cutting elements exhibit improved wear resistance and thermal stability at elevated temperatures, outperforming conventional PCD bodies by maintaining strength and reducing wear, even at high drilling temperatures.
Implementation Method 1
PCD materials known in the art are formed from diamond grains (or crystals) and a catalyst material which are subjected to high pressure and high temperature conditions ('HPHT sintering process')
Implementation Method 2
subsequent leaching to remove catalyst material from interstitial regions
Implementation Method 3
This vulnerability results from the differential that exists between the thermal expansion characteristics of the solvent metal catalyst material disposed interstitially within the PCD body and the thermal expansion characteristics of the intercrystalline bonded diamond
Data Source
AI summary
The present disclosure relates to cutting elements incorporating polycrystalline diamond bodies used for subterranean drilling applications, and more particularly, to polycrystalline diamond bodies having high diamond frame strength and methods for forming and evaluating such polycrystalline diamond bodies. A polycrystalline diamond body is provided, having a top surface, a cutting edge meeting the top surface, and a first region including at least a portion of the cutting edge. The first portion exhibits a diamond frame strength of about 1200 MPa or greater, or about 1300 MPa or greater.