Silicon-Aided Sintered Metal Carbides for Pressureless Densification
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Solution Overview
Problem
Sintered metal carbides with high melting points, such as those from Group 4 and 5 elements, are difficult to produce with high relative density and mechanical strength without high-pressure sintering methods like hot pressing or HIP, making it challenging to create complex shapes suitable for heat-resistant applications in silicon carbide semiconductor manufacturing.
Innovation Solution
Incorporating a small amount of Si (0.1 wtppm to 10,000 wtppm) into the sintered metal carbides allows for sintering under normal pressure, achieving high relative density and mechanical strength without the need for high-pressure techniques, using Si as a sintering aid that melts and aids in densification.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If high-pressure sintering methods (hot pressing, HIP) are used for metal carbides with high melting points, then high relative density and mechanical strength are achieved, but manufacturing complexity and process difficulty increase significantly
Solution Approach 1:
Silicon acts as an intermediary substance that facilitates sintering of metal carbides at normal pressure. The silicon melts at the sintering temperature, creating a liquid phase that enables particle bonding and densification without requiring high pressure, thus resolving the contradiction between achieving high strength and avoiding complex high-pressure equipment
Solution Approach 2:
The invention changes the physical state parameter of silicon from solid to liquid at sintering temperature. By controlling the temperature to match silicon's melting point, the process transforms from solid-state sintering (requiring high pressure) to liquid-phase sintering (effective at normal pressure), thereby achieving high density without complex pressure equipment
2Volume of stationary object
If high-pressure sintering methods are used for metal carbides, then high relative density is achieved, but the ability to produce complex shapes is reduced
Solution Approach 1:
The liquid silicon phase serves as a mediator that flows and adapts to the mold cavity shape during sintering, enabling complex geometries to be formed. Unlike solid-state compaction under pressure, the liquid phase can conform to intricate mold designs, allowing high relative density to be achieved while maintaining shape complexity
Solution Approach 2:
The invention utilizes the phase transition of silicon from solid to liquid at sintering temperature. This phase transition enables the material to flow into complex mold cavities and then solidify upon cooling, preserving the complex shape while achieving high relative density through the liquid-phase densification mechanism
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 enables the production of sintered metal carbides with high relative density and excellent mechanical strength, suitable for use as heat-resistant members in silicon carbide semiconductor manufacturing devices, including complex shapes, without requiring high-pressure sintering processes.
Implementation Method 1
using Si as a sintering aid that melts and aids in densification
Implementation Method 2
the graphite will sublimate under the presence of such reactive gas, the heat resistance of the container is significantly lowered. Therefore, it is necessary to use a container made of a metal carbide having a melting point much higher than that of graphite
Data Source
AI summary
Out of sintered metal carbides having an extremely high melting point, there is provided a sintered metal carbide which can be produced without having to perform sintering under high pressure such as hot pressing or HIP, having a high relative density and excellent mechanical strength. A sintered metal carbide of at least one metal selected from the group consisting of elements of Groups 4 and 5 of the periodic table, wherein the sintered metal carbide contains Si element of 0.1 wtppm or more and 10,000 wtppm or less.