Composite Polycrystal with Nanoscale Carbon Phases for Chipping Resistance
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Solution Overview
Problem
Conventional polycrystalline diamond tools lack sufficient chipping resistance, especially under conditions of impact and vibration, which is crucial for applications like excavating tools and wear-resistant tools.
Innovation Solution
A composite polycrystal structure is developed, comprising a polycrystalline diamond phase and non-diamond phases of non-diamond carbon, such as graphite and amorphous carbon, with the non-diamond phases being finely distributed and having an average projected area equivalent circle diameter of not more than 1000 nm, and the composite not containing a metal component derived from a sintering aid or binder, to enhance chipping resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional polycrystalline diamond is manufactured without sintering aids, then diamond purity is high, but chipping resistance is insufficient
Solution Approach 1:
The patent applies local quality by introducing non-diamond carbon phases (graphite and amorphous carbon) as localized inclusions within the polycrystalline diamond structure. These non-diamond phases are distributed at specific locations (grain boundaries and interstitial regions) with controlled size (average projected area equivalent circle diameter of not more than 1000 nm), creating local regions that absorb impact energy while maintaining the overall high purity and hardness of the diamond matrix.
Solution Approach 2:
The patent creates a composite material structure by combining polycrystalline diamond with non-diamond carbon phases. This composite structure consists of a diamond phase (providing hardness and wear resistance) and non-diamond carbon phases (providing toughness and chipping resistance). The composite nature allows the material to exhibit both the high purity characteristics of diamond-free manufacturing and the enhanced mechanical properties of multi-phase materials.
2Reliability
If non-diamond phases are added to polycrystalline diamond, then chipping resistance increases, but manufacturing complexity increases
Solution Approach 1:
The patent applies preliminary action by pre-mixing the non-diamond carbon phases with the graphite raw material before the high-pressure high-temperature synthesis process. This preliminary distribution of non-diamond phases in the starting materials ensures their uniform dispersion throughout the final polycrystalline diamond product, eliminating the need for complex post-synthesis processing or multiple manufacturing steps to achieve the desired phase distribution.
3Reliability
If non-diamond phases are finely distributed with small diameter, then chipping resistance increases, but manufacturing precision requirements increase
Solution Approach 1:
The patent applies preliminary action by pre-mixing the non-diamond carbon phases with the graphite raw material before the high-pressure high-temperature synthesis process. This preliminary distribution of non-diamond phases in the starting materials ensures their uniform dispersion throughout the final polycrystalline diamond product, eliminating the need for complex post-synthesis processing or multiple manufacturing steps to achieve the desired phase distribution.
Solution Approach 2:
The patent applies parameter changes by utilizing the extreme conditions of high pressure (9-13 GPa) and high temperature (1800-2700°C) during the synthesis process. These parameter changes cause the non-diamond carbon phases to be incorporated into the diamond matrix at a nanoscale level, automatically achieving the desired fine distribution (average projected area equivalent circle diameter of not more than 1000 nm) without requiring precise manual control during manufacturing.
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 composite polycrystal exhibits increased chipping and wear resistance, making it suitable for tools requiring resistance to impact and vibration, with a Knoop hardness of not less than 50 GPa, allowing for extended tool life and improved performance in cutting and wear-resistant applications.
Implementation Method 1
pressurizing and heating step, converting and sintering step
Data Source
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AI summary
A composite polycrystal includes: a polycrystalline diamond phase including a plurality of diamond particles; and non-diamond phases composed of non-diamond carbon. The non-diamond phases are distributed in the polycrystalline diamond phase. An average value of projected area equivalent circle diameters of the non-diamond phases is not more than 1000 nm.