Diamond-Graphite Composite Sintered Body for Wear and Chipping Resistance
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Solution Overview
Problem
Diamond polycrystalline bodies used in wear-resistant tools and cutting tools face issues with increased pull-out resistance, wire breakage, local wear, and reduced tool lifetime due to high friction coefficients and thermal expansion, particularly when applied in wire drawing dies and scribe wheels.
Innovation Solution
A composite sintered body comprising a diamond phase and a non-diamond carbon phase with a non-diamond carbon phase occupancy rate between 10% and 30%, and average particle sizes of diamond and non-diamond carbon particles between 50 nm and 1000 nm and 100 nm to 2000 nm, respectively, which enhances wear resistance and chipping resistance without the use of sintering aids or catalysts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If diamond polycrystalline bodies are used in wear-resistant tools and cutting tools, then hardness and wear resistance are improved, but pull-out resistance increases and wire breakage occurs frequently
Solution Approach 1:
The invention uses a composite sintered body containing diamond particles (50-1000 nm) and graphite particles (100-2000 nm) where the graphite phase acts as a lubricant to reduce friction and prevent wire breakage, while the diamond phase provides hardness and wear resistance. This composite structure resolves the contradiction by combining materials with complementary properties.
Solution Approach 2:
The invention changes the particle size parameters of both diamond and graphite to specific ranges (diamond: 50-1000 nm, graphite: 100-2000 nm) and controls the graphite content (10-30 volume %) to optimize the balance between hardness and friction reduction, thereby resolving the technical contradiction.
2Strength
If diamond polycrystalline bodies are applied to scribe wheels and excavating bits, then cutting capability is improved, but tool lifetime becomes shorter due to local wear and chipping
Solution Approach 1:
The composite structure with diamond providing cutting edge hardness and graphite providing fracture resistance through its layered structure and lubrication effect extends tool lifetime while maintaining cutting capability.
Solution Approach 2:
The invention creates local quality differences by having diamond particles at the cutting edge for hardness and graphite particles distributed throughout for toughness, with each component performing its specific function to resolve the contradiction between cutting capability and tool lifetime.
3Ease of manufacture
If sintering aids and catalysts are added to diamond sintered bodies, then sintering processability is improved, but friction coefficient increases and wire drawing resistance increases
Solution Approach 1:
The invention extracts and eliminates sintering aids and catalysts from the composition, using only diamond and graphite particles that can be sintered together under high pressure and temperature without additional additives, thereby reducing friction coefficient and wire drawing resistance.
Solution Approach 2:
The invention uses a simple binary composition of diamond and graphite that requires no complex sintering aid systems, simplifying the manufacturing process and reducing the friction coefficient during subsequent wire drawing operations.
4Strength
If metal components are added to diamond sintered bodies, then strength and toughness are improved, but friction coefficient increases due to metal oxidation
Solution Approach 1:
The invention changes the material composition parameters by replacing metal components with graphite, which has a much lower friction coefficient and does not oxidize in the same way metals do, thereby maintaining toughness while reducing friction.
Solution Approach 2:
The invention uses graphite, a simple carbon allotrope, instead of complex metal alloy systems, eliminating the oxidation and high friction problems associated with metals while providing sufficient toughness through the composite structure.
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 sintered body exhibits high wear resistance, local wear resistance, and chipping resistance, reducing wire breakage frequency and tool wear, while maintaining a low friction coefficient and minimizing internal fractures.
Implementation Method 1
converted and sintered from a carbon substance of a graphite-type layered structure under ultrahigh pressure and ultrahigh temperature
Implementation Method 2
exhibits high wear resistance, local wear resistance, and chipping resistance, reducing wire breakage frequency and tool wear, while maintaining a low friction coefficient
Data Source
Figure 1
AI summary
A composite sintered body (10) includes a diamond phase (11) and a non-diamond carbon phase (12). A non-diamond carbon phase occupancy rate is higher than 0% and not higher than 30%. The non-diamond carbon phase occupancy rate is a percentage of an area of the non-diamond carbon phase (12) to a total area of one arbitrarily specified cross section of the composite sintered body (10). As a result, there is provided a high wear-resistant, high local wear-resistant and high chipping-resistant diamond-containing composite sintered body suitably used as a material for a wear-resistant tool, a cutting tool and the like.