Carbide Compact Sintering with Graphite Shielding for Flatness
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Solution Overview
Problem
Conventional methods for producing high temperature-resistant articles using metal carbides are costly and prone to defects such as shape deformation and carbon precipitates, while using graphite substrates results in lower heat resistance due to compressive stress and high production costs.
Innovation Solution
A method involving the sintering of thin plate-like carbide compacts with graphite shielding members to prevent decarburization and ensure flatness, combined with the use of a high temperature-resistant adhesive for bonding substrates, allowing for the production of complex shapes at reduced costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If injection molding metal carbide powder is used to obtain complicated shapes, then shape complexity is improved, but production cost increases and defects such as shape deformation and carbon precipitates occur
Solution Approach 1:
The invention divides the production process into two independent stages: first forming green compacts with simple geometries through pressing, then assembling multiple compacts into complex final shapes. This segmentation avoids the need for injection molding complicated single-piece structures, eliminating associated defects while maintaining shape complexity through modular assembly of reliable components
Solution Approach 2:
The invention performs preliminary forming of individual carbide compacts with simple geometries before final assembly. By pre-forming reliable, defect-free compact units through pressing rather than attempting to injection mold the final complex shape, the process achieves both shape complexity and high reliability by assembling pre-validated components
2Reliability
If graphite substrate is used as high temperature-resistant article, then production cost is reduced, but heat resistance deteriorates due to lower melting point
Solution Approach 1:
The invention creates a composite structure where carbide particles are embedded in a graphite matrix. The carbide phase provides high-temperature resistance while the graphite phase maintains structural integrity and reduces production cost. This composite approach allows the use of cheaper graphite as the base material while achieving the heat resistance of carbide through the distributed carbide reinforcement
Solution Approach 2:
The invention applies carbide particles locally within the graphite matrix at strategic locations where high-temperature resistance is needed. Rather than making the entire article from expensive carbide, the carbide is distributed as discrete phases within the graphite, providing localized heat resistance enhancement while maintaining overall cost-effectiveness through the use of cheaper graphite as the continuous matrix
3Temperature
If metal carbide bulk sintered body is used, then heat resistance is improved, but ease of manufacture deteriorates due to difficulty in processing
Solution Approach 1:
The invention segments the manufacturing process into pressing of green compacts followed by sintering, avoiding the need to process bulk sintered carbide. By forming parts in a green (unsintered) state where they are more ductile and easier to shape, then sintering the formed compacts, the process achieves high heat resistance while dramatically improving ease of manufacture compared to processing bulk sintered carbide
Solution Approach 2:
The invention inverts the conventional sequence by forming the part geometry in the green compact state rather than attempting to machine or process the final sintered carbide product. This reversal of the manufacturing sequence allows easy forming of complex shapes in the green state, which are then sintered to achieve the final high-temperature-resistant product, eliminating the processing difficulties of bulk sintered carbide
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 approach enables the production of high temperature-resistant articles with good flatness and heat resistance at lower costs, avoiding shape deformation and defects associated with traditional methods, while effectively utilizing expensive metal carbides and achieving high reproducibility in high-temperature applications.
Implementation Method 1
a sintering step of sintering the carbide compact into a carbide sintered body
Implementation Method 2
shielding members to prevent decarburization and ensure flatness
Implementation Method 3
use of a high temperature-resistant adhesive for bonding substrates
Data Source
AI summary
A method for producing a high temperature-resistant article comprises an assembling step of foaming an assembly of a first substrate and a second substrate with an adhesive layer interposed therebetween and comprising paste of powder of at least one carbide of niobium carbide, hafnium carbide, tantalum carbide and tungsten carbide; and a bonding step of heating the assembly to bond the first substrate and the second substrate by sintering, thereby obtaining a high temperature-resistant article comprising the assembly after sintering. Moreover, a method for producing a high temperature-resistant article comprises a coating step of coating a slurry comprising powder of at least one carbide of niobium carbide, hafnium carbide, tantalum carbide and tungsten carbide on a surface of a high temperature-resistant substrate; a drying step of drying the substrate after the coating step; and a film-forming step of heating the substrate after the drying step to form a carbide coating film on the surface of the substrate by sintering, thereby obtaining a high temperature-resistant article having the carbide coating film. A high temperature-resistant article of a complicated shape can be easily produced at low costs by these methods.