Diamond Joined Body Interface Control to Suppress Carbon Precipitation
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Solution Overview
Problem
Conventional diamond joined body manufacturing methods result in carbon diffusion from diamond to the hard substrate during sintering, leading to low strength regions and increased risk of cracking, making tools prone to chipping and reducing their lifespan.
Innovation Solution
A diamond joined body with a hard substrate having a tungsten carbide grain size of 0.1 μm to 3 μm and a carbon grain area ratio less than 0.03% near the interface, manufactured by sintering a polycrystalline diamond layer under stable pressure and temperature conditions, which suppresses carbon precipitation in the substrate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If sintering is performed under high temperature and high pressure to join diamond to hard substrate, then diamond joined body is obtained, but carbon diffuses from diamond to hard substrate causing low strength regions and increased cracking risk
Solution Approach 1:
The patent applies parameter changes by precisely controlling sintering temperature (1300-1900°C) and pressure (5.0-8.0 GPa) within specific ranges where diamond remains stable. This controlled parameter approach prevents carbon diffusion to the hard substrate while maintaining effective joining, thereby resolving the contradiction between achieving reliable tool lifespan and preventing harmful carbon precipitation.
Solution Approach 2:
The patent implements preliminary anti-action by pre-establishing stable diamond structure through controlled sintering conditions before carbon diffusion can occur. By maintaining temperature and pressure within diamond stability ranges during the sintering process, the method preemptively prevents carbon from diffusing to the hard substrate, thus counteracting the harmful effect before it can develop.
2Ease of manufacture
If conventional sintering methods are used to manufacture diamond joined body, then joining is achieved, but carbon precipitates in hard substrate creating crack origins
Solution Approach 1:
The patent resolves this contradiction by changing the sintering parameters to specific temperature (1300-1900°C) and pressure (5.0-8.0 GPa) ranges that maintain diamond stability. These parameter changes enable effective joining while preventing carbon precipitation that would weaken the hard substrate, thus achieving both ease of manufacture and high strength.
Solution Approach 2:
The patent employs copying by using diamond grains as raw material that are sintered to form polycrystalline diamond layer. This copying approach maintains the diamond structure and properties throughout the joining process, ensuring that the joined structure retains high strength while preventing carbon diffusion to the substrate.
3Manufacturing precision
If diamond grains are sintered to hard substrate, then diamond joined body is formed, but carbon diffuses during sintering reducing tool performance
Solution Approach 1:
The patent applies parameter changes by defining precise sintering conditions (temperature: 1300-1900°C, pressure: 5.0-8.0 GPa) that fall within the diamond stability range. These controlled parameters enable precise joining of diamond to hard substrate while preventing carbon diffusion, thus achieving both manufacturing precision and preventing harmful effects.
Solution Approach 2:
The patent uses the controlled sintering environment as an intermediary that facilitates joining while preventing carbon diffusion. By maintaining temperature and pressure within specific ranges, the sintering process acts as a mediator that enables bond formation between diamond and substrate without allowing carbon to migrate to the hard substrate.
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 solution enhances the chipping resistance and tool life by reducing carbon precipitation in the hard substrate, thereby minimizing crack origins and improving fracture toughness.
Implementation Method 1
sintering the compact under pressure and temperature conditions in which diamond is stable, to thereby obtain a diamond joined body
Data Source
AI summary
A diamond joined body is a diamond joined body including a hard substrate and a polycrystalline diamond layer arranged on the hard substrate, wherein an area ratio of carbon grains in a region of the hard substrate is less than 0.03%, the region being a region enclosed by an interface between the hard substrate and the polycrystalline diamond layer and an imaginary line x in a cross section parallel to a normal direction of the interface, the imaginary line x being parallel to the interface on the hard substrate side and having a distance of 500 μm from the interface.