Silicon Carbide Laser Sintering Without Binders
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Solution Overview
Problem
Existing methods for manufacturing articles with silicon carbide using powder bed fusion face challenges due to the high cost and complexity of adding binders, and the difficulty in thermally decomposing silicon carbide within the necessary temperature range without sublimation, which affects fabrication accuracy and cost.
Innovation Solution
A method involving the use of silicon carbide powder with 95 mol % or more, where the laser beam is controlled to thermally decompose silicon carbide into silicon and carbon, using the melted silicon or carbon as a binder within the temperature range of 2830° C. to 3600° C., eliminating the need for organic or inorganic binders and reducing fabrication costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If metal boride is added to suppress decomposition of silicon carbide, then fabrication accuracy is improved, but fabrication cost increases
Solution Approach 1:
The invention extracts and eliminates the need for metal boride binder by using silicon carbide powder with 95 mol% or more purity. The high-purity silicon carbide decomposes into silicon and carbon during laser irradiation, and the melted silicon or carbon serves as the binder, removing the expensive metal boride component entirely while maintaining fabrication accuracy.
Solution Approach 2:
The invention replaces expensive metal boride with cheap silicon carbide powder that temporarily transforms into melted silicon or carbon during the fabrication process. This disposable approach uses the decomposed silicon carbide itself as the binder, eliminating the need for costly additive materials.
2Ease of manufacture
If molding resin is used in powder bed fusion, then fabrication process is enabled, but additional degreasing step is required and resin removal causes contraction
Solution Approach 1:
The invention extracts and eliminates the molding resin component entirely. By using silicon carbide powder with 95 mol% or more purity, the fabrication process avoids the need for resin binding, subsequent degreasing steps, and dimensional adjustments, directly achieving the desired article shape and size.
Solution Approach 2:
The silicon carbide powder serves dual functions: as the structural material and as the binder. During laser irradiation, the silicon carbide decomposes into silicon and carbon, which then serve as the binding agent, eliminating the need for separate resin-based binding systems and their associated processing steps.
3Temperature
If silicon carbide is irradiated at high temperature to decompose it, then melting and solidification can occur, but sublimation may occur affecting fabrication accuracy
Solution Approach 1:
The invention optimizes the laser irradiation parameters (power density, scanning speed, irradiation time) to precisely control the temperature of silicon carbide decomposition. By adjusting these parameters, the process achieves melting and solidification of silicon or carbon within the temperature range of 2830°C to 3600°C while suppressing sublimation, thereby maintaining fabrication accuracy.
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 allows for the accurate and cost-effective manufacturing of silicon carbide articles by stabilizing the temperature for millisecond-order melting and solidification, enhancing fabrication accuracy and reducing the need for expensive binder materials.
Implementation Method 1
a step of irradiating the raw material powder with a laser beam, wherein the raw material powder is irradiated with the laser beam to decompose the silicon carbide in at least a part of an irradiation portion of the laser beam into silicon and carbon and to turn the silicon or the carbon into melt
Implementation Method 2
the raw material powder is irradiated with the laser beam to decompose the silicon carbide in at least a part of an irradiation portion of the laser beam into silicon and carbon
Implementation Method 3
turn the silicon or the carbon into melt
Implementation Method 4
stabilizing the temperature for millisecond-order melting and solidification
Data Source
AI summary
A method of manufacturing an article containing silicon carbide as a main component includes a step of laying raw material powder, and a step of irradiating the raw material powder with a laser beam, wherein the raw material powder contains 95 mol % or more of silicon carbide, and wherein, in the step of irradiating the raw material powder with the laser beam, the raw material powder is irradiated with the laser beam to decompose the silicon carbide in at least a part of an irradiation portion of the laser beam into silicon and carbon and to turn the silicon or the carbon into melt.