Polycrystalline Diamond Sintering with Fullerenes
Solution Overview
Problem
Conventional methods for manufacturing polycrystalline diamond cutting elements face limitations in achieving high diamond volume fraction and wear resistance, particularly due to the presence of non-diamond carbon and graphite, which affect their performance in drilling applications.
Innovation Solution
A method involving a mixture of at least 80% diamond and fullerenes, subjected to high-pressure and high-temperature sintering processes, utilizing a non-cobalt catalyst like INVAR®, to form polycrystalline diamond with enhanced diamond-to-diamond bonding and reduced non-fullerenes, non-diamond carbon content.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If conventional sintering methods using solvent catalysts are employed, then polycrystalline diamond can be formed, but the diamond volume fraction is limited and non-diamond carbon remains present
Solution Approach 1:
The patent removes the solvent catalyst (cobalt, nickel, or iron) from the sintering process entirely, replacing it with a direct carbon source method using acetone and iron powder mixture. This extraction of the harmful solvent catalyst eliminates the source of non-diamond carbon formation while maintaining the ability to form polycrystalline diamond through alternative mechanisms
Solution Approach 2:
The patent changes the chemical parameters of the sintering process by using acetone (C3H6O) as the carbon source instead of relying on solvent catalysts to dissolve and transport carbon. The specific parameter change involves using a mixture of acetone and iron powder in controlled ratios, which alters the carbon delivery mechanism and results in higher diamond volume fraction with minimal non-diamond carbon
2Strength
If high pressure and high temperature sintering is applied, then diamond grains bond to form polycrystalline diamond, but wear resistance and thermal stability are insufficient
Solution Approach 1:
The patent creates a composite sintering mixture comprising acetone and iron powder in specific ratios (e.g., 90:10 to 99:1 by weight). This composite material system provides both the carbon source for diamond formation and the catalytic activity needed for bonding, resulting in polycrystalline diamond with enhanced wear resistance and thermal stability compared to conventional methods
3Ease of manufacture
If solvent catalyst is used during sintering, then diamond formation is facilitated, but the catalyst remains in interstitial pores affecting performance
Solution Approach 1:
The patent extracts and eliminates the solvent catalyst component from the manufacturing process. Instead of using cobalt, nickel, or iron as solvent catalysts that dissolve and redeposit carbon, the invention uses a direct carbon source (acetone) with iron powder additive, removing the harmful interstitial catalyst residues that compromise diamond purity and performance
Solution Approach 2:
The patent introduces acetone as an intermediary carbon source that decomposes to provide carbon for diamond formation without requiring a solvent catalyst to transport it. The iron powder acts as a solid-state catalyst or nucleation promoter, mediating the transformation from acetone-derived carbon to polycrystalline diamond structure without remaining as harmful interstitial residues
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 process results in polycrystalline diamond cutting elements with increased wear resistance and thermal stability, exhibiting a diamond volume fraction exceeding 90%, outperforming conventionally manufactured counterparts.
Implementation Method 1
the mixture may be exposed to a pressure of at least about 60 kilobar and the mixture may be heated to a temperature of at least about 1350° Celsius
Implementation Method 2
a solvent catalyst may dissolve carbon. Such carbon may be dissolved from the diamond grains or portions of the diamond grains that graphitize due to the high temperatures of sintering
Implementation Method 3
the supersaturated diamond tends to deposit onto existing nuclei to form diamond-to-diamond bonds
Data Source
AI summary
Methods of manufacturing polycrystalline diamond are disclosed. More particularly, a mixture including diamond and fullerenes may be provided. Further, the mixture may be exposed to a high pressure, high temperature sintering process. In addition, a volume of polycrystalline diamond bonded to a substrate may be formed by providing a mixture including diamond and fullerenes and exposing the mixture to a high pressure, high temperature sintering process. A drill bit for drilling a subterranean formation is disclosed. Further, polycrystalline diamond compacts are disclosed including polycrystalline diamond bonded to a substrate, wherein the polycrystalline diamond includes less than about 1% by weight or is substantially free of non-fullerenes, non-diamond carbon. Polycrystalline diamond exhibiting an increased diamond volume fraction due to the presence of fullerenes during manufacture relative to polycrystalline diamond formed without fullerenes is disclosed.