Pressureless Sintering of Cubic Boron Nitride Cemented Carbide
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Solution Overview
Problem
Current methods for producing sintered composite bodies with cubic boron nitride particles in a cemented carbide matrix are expensive due to the need for high-pressure sintering techniques, limiting their widespread industrial application.
Innovation Solution
A cost-effective method involving pressureless sintering of a mixture of cubic boron nitride particles and cemented carbide powder at a temperature below 1350°C, achieving a fully densified composite body with superior wear resistance by using conventional vacuum sintering and adjusting sintering parameters such as temperature and time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high pressure sintering techniques are used to produce sintered composite bodies with cubic boron nitride particles, then the desired density and wear resistance are achieved, but the production cost increases significantly
Solution Approach 1:
The patent changes the sintering temperature parameter to below 1350°C and eliminates pressure application, deviating from conventional high-pressure sintering methods. This parameter change enables the use of conventional vacuum sintering equipment instead of expensive high-pressure equipment, thereby reducing production costs while maintaining the desired density and wear resistance properties of the sintered composite body
Solution Approach 2:
The patent employs conventional vacuum sintering equipment that is already widely available in industrial settings, replacing the need for specialized expensive high-pressure sintering equipment. This substitution with cheaper, more accessible equipment directly addresses the production cost issue while achieving the same functional outcomes
2Stability of the object's composition
If high pressure sintering is applied to prevent formation of hexagonal boron nitride, then cubic boron nitride stability is maintained, but the manufacturing complexity and equipment requirements increase
Solution Approach 1:
The patent utilizes the temperature sensitivity of boron nitride polymorphs by conducting sintering below 1350°C, a parameter change that inherently stabilizes the cubic form without requiring pressure. This eliminates the need for complex pressure control systems and high-pressure equipment, significantly reducing device complexity while maintaining compositional stability
Solution Approach 2:
The patent replaces the mechanical pressure system with a thermal parameter control system. Instead of using high pressure to stabilize cubic boron nitride, the invention uses controlled low-temperature sintering, substituting a mechanical approach with a thermal one that is simpler to implement with conventional equipment
3Ease of manufacture
If sintering temperature is reduced below 1350°C without pressure, then production costs decrease, but achieving full density becomes more difficult
Solution Approach 1:
The patent optimizes the sintering temperature parameter to a specific range below 1350°C and extends the sintering time to compensate for the lower temperature. This parameter optimization enables full densification to be achieved without requiring high pressure, thereby reducing production costs while maintaining manufacturing precision regarding density
Solution Approach 2:
The patent incorporates a compaction step before sintering to pre-densify the green body, creating a more uniform and dense starting structure. This preliminary action facilitates achieving full density during the subsequent low-temperature, pressureless sintering process, overcoming the challenge of density achievement at reduced temperatures
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
This method reduces production costs while maintaining high wear resistance and density, making the sintered composite body suitable for industrial applications like cutting tools and wear parts.
Implementation Method 1
sintering a mixture comprising cubic boron nitride particles and a cemented carbide powder at a sintering temperature below 1350° C. without applying a pressure
Data Source
AI summary
The present invention relates to a method of producing a sintered composite body comprising cubic boron nitride particles dispersed in a cemented carbide matrix by sintering a mixture comprising cubic boron nitride particles and a cemented carbide powder at a sintering temperature below 1350° C. without applying a pressure.