Polycrystalline Diamond Compact Wear Resistance via Controlled Oxidation
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Solution Overview
Problem
Existing methods for producing polycrystalline diamond compacts often result in the presence of non-diamond carbon, which impairs their sintering and wear resistance, as the binder used in the process can leave behind residual carbon that hinders the bonding process and affects the material's performance.
Innovation Solution
A method involving the oxidation of diamond particle feeds and pre-compacts in an oxidizing atmosphere to burn off non-diamond carbon without over-oxidizing the diamond, followed by mixing with a binder, heating to drive off the binder, and then sintering at high pressure and high temperature to form a polycrystalline diamond compact with improved wear characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a binder is used in the HPHT sintering process to hold diamond particles, then the compact structure is maintained during processing, but residual non-diamond carbon remains after binder decomposition which impairs sintering and wear resistance
Solution Approach 1:
The patent applies preliminary oxidation treatment to the diamond particle feed before HPHT sintering. This pre-treatment converts residual non-diamond carbon from binder decomposition into oxidized forms that can be more easily removed or converted during sintering, thereby preventing wear resistance impairment while maintaining the compact structure during processing
Solution Approach 2:
The patent introduces an oxidation step that changes the chemical state of carbon residues from reduced non-diamond carbon to oxidized carbon species. This parameter change in carbon oxidation state facilitates subsequent removal or conversion of harmful residues during the HPHT process, resolving the contradiction between structure stability and wear resistance
2Reliability
If oxidation is applied to remove non-diamond carbon, then wear resistance is improved, but diamond particles may be over-oxidized and damaged
Solution Approach 1:
The patent applies controlled partial oxidation to the diamond particle feed, using sufficient oxidation to remove non-diamond carbon but limiting the extent to prevent over-oxidation of diamond particles. This controlled partial action achieves the desired removal of harmful carbon residues while preserving diamond particle integrity
Solution Approach 2:
The patent employs monitoring of oxidation conditions and characteristics of the diamond particle feed to control the oxidation process. By observing the oxidation state and adjusting parameters accordingly, the process prevents over-oxidation of diamond particles while ensuring adequate removal of non-diamond carbon, thus maintaining both wear resistance and particle integrity
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 effectively removes non-diamond carbon, enhancing the wear resistance and chipping resistance of the polycrystalline diamond compacts by ensuring a Raman spectrum free of non-diamond carbon peaks and achieving a favorable oxygen-to-nitrogen ratio, thereby improving their performance in abrasive applications.
Implementation Method 1
oxidizing a pre-compact in an oxidizing atmosphere at a temperature and for a time sufficient to burn off non-diamond carbon without over-oxidizing diamond
Implementation Method 2
heating the pre-compact in a non-oxidizing atmosphere to substantially drive off the binder
Implementation Method 3
sintering the pre-compact at high pressure and high temperature to form a polycrystalline diamond compact
Implementation Method 4
subjected to processing conditions selected as sufficient to affect intercrystalline bonding between adjacent grains of the abrasive particles... temperature of at least about 1200° C. and a pressure of at least about 20 kbar
Data Source
AI summary
A method of making a polycrystalline diamond compact includes mixing a diamond particle feed with a binder to form a mixture, forming the mixture into a precompact, heating the pre-compact in a non-oxidizing atmosphere to substantially drive off the binder, oxidizing the pre-compact in an oxidizing atmosphere at a temperature and for a time sufficient to burn off non-diamond carbon without overoxidizing diamond, and sintering the pre-compact at high pressure and high temperature to form a polycrystalline diamond compact. The method may also include oxidizing the diamond particle feed prior to mixing with the binder.