SiC Particle Roundness for Dense 3D-Printed Ceramic Preforms
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Solution Overview
Problem
Existing 3D print methods for SiC preforms result in low density, coarser grain size, and higher Si content, leading to reduced mechanical and electrical properties, necessitating an impregnation step for improved density.
Innovation Solution
Utilizing SiC particles with a specific roundness of >0.55 and controlled grain size (2-70 µm) in a 3D print method to achieve high green density without the need for impregnation, using a binder system that forms carbon residue for subsequent siliconization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If conventional 3D print methods are used for SiC preforms, then the manufacturing flexibility and complexity reduction is improved, but the density and mechanical properties deteriorate
Solution Approach 1:
The invention changes the particle morphology parameter (roundness > 0.55) and size distribution parameters (d10, d50, d90 values) of SiC particles to achieve high green density in 3D printed preforms without requiring additional impregnation processes, thus maintaining process simplicity while improving density
Solution Approach 2:
The invention uses a composite powder composition comprising SiC particles with specific roundness and size distribution combined with organic binder and optional additives, creating a optimized green body that achieves high density through the synergistic effect of particle morphology and binder system
2Ease of operation
If SiC particles with conventional morphology are used in 3D printing, then the particle flowability and packing is improved, but the green density and final density deteriorate
Solution Approach 1:
The invention optimizes particle morphology parameters by specifying roundness > 0.55 and controlled size distribution (d10: 2-20 µm, d50: 10-50 µm, d90: 20-100 µm), which simultaneously ensures good flowability for 3D printing and high green density without requiring particle shaping processes
3Strength
If impregnation process is added to 3D printed preforms, then the density and mechanical properties are improved, but the process complexity and manufacturing time increase
Solution Approach 1:
The invention performs preliminary optimization of particle morphology (roundness > 0.55) and size distribution before 3D printing, which pre-establishes high green density and eliminates the need for subsequent impregnation processes, thereby reducing overall process complexity
Solution Approach 2:
The invention extracts and eliminates the impregnation step from the conventional 3D printing process by using specially optimized SiC particles with high roundness that achieve sufficient green density directly during printing, simplifying the manufacturing workflow
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 method produces SiC preforms with increased green density (up to 1.8 g/cm³) and final SiSiC density (up to 2.79 g/cm³), enhancing mechanical and electrical properties without additional processing steps.
Implementation Method 1
using a binder system that forms carbon residue for subsequent siliconization
Implementation Method 2
c) drying or curing the impregnated green body, d) carbonising the dried or cured green body, wherein a fine-pored, foam-like carbon skeleton is produced from the dried solution or a fine-pored, sponge-like carbon skeleton is produced from the cured resin system, e) siliconising the carbonised green body by infiltrating with liquid silicon. In the event of siliconisation of such a green body, the carbon skeleton is converted into silicon carbide and the pores of the green body are filled with silicon
Data Source
Figure 1A~1B
Figure 2A~2B
AI summary
The invention relates to the use of SiC particles (grains) in a 3D print method for providing a SiC ceramic preform (green body), wherein the SiC particles (grains) are characterized by - an average grain size (d50) of 2 to 70 µm, preferably 3 to 65 µm, more preferably 5 to 50 µm, such as 25 to 60 µm, preferably 40 to 55 µm, - a roundness of > 0.55, preferably > 0.58, more preferably > 0.6 (as described in experimental section , - bulk density of > 1.6 g/cm3, preferably > 1.65 g/cm3, more preferably > 1.7 g/cm3, even more preferably > 1.75 g/cm3 (according to DIN EN 725-9 ISO 23145-2).