Polycrystalline Diamond Sintering for Heat-Resistant Tough Tools
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Solution Overview
Problem
Conventional methods for producing polycrystalline diamond bodies face issues with heat resistance, mechanical strength, and crystal grain size uniformity, leading to poor performance in cutting and grinding tools due to the use of sintering aids and direct conversion methods that result in porous or weak diamond structures.
Innovation Solution
A method involving heat-treating high-pressure-phase carbon powder at elevated temperatures followed by sintering under specific high-pressure and high-temperature conditions to produce a polycrystalline diamond body with fine structures and enhanced toughness, eliminating the need for sintering aids and catalysts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If sintering aids and binding materials are used to produce polycrystalline diamond bodies, then the diamond particles can be bonded together, but the resulting structure becomes porous and weak, reducing mechanical strength and heat resistance
Solution Approach 1:
The invention removes sintering aids and binding materials from the polycrystalline diamond body production process. By using pure diamond powder without additives, the method eliminates the porous structure and weak bonding caused by these materials, achieving both high mechanical strength and heat resistance through direct diamond-diamond bonding.
Solution Approach 2:
The invention changes the sintering parameters to achieve direct diamond-diamond bonding without aids. By optimizing pressure (5-8 GPa), temperature (1300-2200°C), and time conditions, the method enables strong bonding between diamond particles while maintaining material purity and avoiding the formation of porous structures.
2Ease of manufacture
If direct conversion-sintering method is used at ultra-high pressure and temperature, then polycrystalline diamond bodies can be obtained without sintering aids, but the crystal grain size becomes non-uniform and material quality varies significantly
Solution Approach 1:
The invention performs preliminary classification of diamond powder before sintering to ensure uniform particle size distribution. By pre-sorting the diamond particles into narrow size ranges and using purified diamond powder without amorphous carbon, the method achieves uniform crystal grain size in the final product while maintaining the simplicity of the direct conversion-sintering approach.
3Ease of manufacture
If conventional sintering methods with aids are used, then the production process is well-established, but the resulting polycrystalline diamond bodies exhibit poor toughness and low durability
Solution Approach 1:
The invention extracts and eliminates sintering aids and binding materials from the conventional sintering process. By using only pure diamond powder under optimized sintering conditions, the method achieves strong diamond-diamond bonding that significantly improves toughness and durability while maintaining process feasibility.
Solution Approach 2:
The invention creates a composite structure at the micro-level through direct bonding of purified diamond particles. The resulting polycrystalline diamond body consists of uniformly sized crystal grains strongly bonded together, forming a composite material with superior toughness and durability compared to conventional sintered products.
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 method produces a tough polycrystalline diamond body with small diamond particle sizes and improved Knoop hardness, enhancing the durability and performance of cutting, wear-resistance, and grinding tools by eliminating porosity and ensuring strong diamond-diamond bonding.
Implementation Method 1
sintering the heat-treated carbon powder under conditions of greater than or equal to 12 GPa and less than or equal to 25 GPa and higher than or equal to 1200° C. and lower than or equal to 2300° C. to obtain a polycrystalline diamond body
Implementation Method 2
a first step of heat-treating a powder of high-pressure-phase carbon at higher than or equal to 1300° C. to obtain a heat-treated carbon powder
Implementation Method 3
a second step of sintering the heat-treated carbon powder under conditions of greater than or equal to 12 GPa and less than or equal to 25 GPa and higher than or equal to 1200° C. and lower than or equal to 2300° C. to obtain a polycrystalline diamond body
Data Source
AI summary
Provided is a method for producing a polycrystalline diamond body, the method including a first step of heat-treating a powder of high-pressure-phase carbon at higher than or equal to 1300° C. to obtain a heat-treated carbon powder, and a second step of sintering the heat-treated carbon powder under conditions of greater than or equal to 12 GPa and less than or equal to 25 GPa and higher than or equal to 1200° C. and lower than or equal to 2300° C. to obtain a polycrystalline diamond body.