Monolithic SiC Fluidic Modules via Isostatic Pressing
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Solution Overview
Problem
The production of silicon carbide (SiC) fluidic modules with tortuous internal passages faces challenges such as porous interfaces, mechanical failure, and rough internal surfaces due to existing fabrication methods like sandwich assembly and multiple layer approaches, which hinder smooth flow and cleaning.
Innovation Solution
A method involving positioning a positive mold within SiC powder coated with a binder, pressing to form a pressed body, and sintering to create a monolithic SiC structure with a tortuous fluid passage, achieving low porosity and surface roughness, using techniques like uniaxial or isostatic pressing and debinding to ensure a smooth, cleanable, and high-density module.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If sandwich assembly approach with intermediate joining layer is used, then modules can be joined, but porous interfaces form causing contamination and mechanical failure
Solution Approach 1:
The patent merges multiple SiC layers into a single monolithic structure formed by isostatic pressing, eliminating the need for joining layers and interfaces. This combines the advantages of modular construction with the benefits of a seamless, non-porous structure that prevents contamination and mechanical failure.
Solution Approach 2:
The patent eliminates the intermediate joining layer that acts as a harmful mediator between layers. By using isostatic pressing to form a monolithic structure, there is no intermediate material to create porous interfaces, thus removing the source of contamination and weakness.
2Manufacturing precision
If diffusion bonding without intermediate layer is used, then joining is achieved, but coarse ceramic grains produce rough internal channel surfaces
Solution Approach 1:
The patent replaces the mechanical joining process (diffusion bonding) with a consolidation process (isostatic pressing) that forms the monolithic structure in one step. This substitution eliminates the grain coarsening issue associated with diffusion bonding while achieving the joining effect, resulting in smooth internal surfaces.
3Shape
If multiple layers of green-state SiC sheets are assembled, then fluidic module can be built, but step-like structures form in curved profiles
Solution Approach 1:
The patent merges multiple green-state SiC layers into a single monolithic structure through isostatic pressing, eliminating the step-like interfaces between layers. This creates smooth curved profiles while maintaining the modular benefits of layer assembly, resolving the contradiction between shape quality and device complexity.
4Ease of operation
If conventional fabrication methods are used, then SiC structures can be produced, but high porosity and rough surfaces hinder fluid flow and cleaning
Solution Approach 1:
The patent changes the manufacturing parameters by using isostatic pressing with high pressure (100-500 MPa) and controlled heating, which densifies the SiC structure and reduces porosity. This parameter change results in smooth surfaces and low porosity that facilitate fluid flow and ease of cleaning.
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 results in SiC fluidic modules with very low open porosity and surface roughness, enhancing fluid resistance, ease of cleaning, and improved mixing and heat exchange performance.
Implementation Method 1
pressing the volume of SiC powder with the mold inside to form a pressed body
Implementation Method 2
heating the pressed body to remove the mold
Implementation Method 3
sintering the pressed body to form a monolithic SiC structure or fluidic module
Data Source
AI summary
A device and a process for forming a monolithic substantially closed-porosity ceramic fluidic device having a tortuous fluid passage extending through the device, the tortuous fluid passage having a smooth interior surface, a material of the ceramic body having a continuous and uniform distribution of grains at least between opposed major surfaces of the ceramic body. The process includes positioning a positive fluid passage mold within a volume of binder-coated ceramic powder, pressing the volume of ceramic powder with the mold inside to form a pressed body, heating the pressed body to remove the mold, and sintering the pressed body. A relationship between a first stability characteristic of the volume of ceramic powder and a second stability characteristic of the mold prevents discontinuities in the pressed body after pressing and/or during heating.