Silicon Carbide Filter Membrane Direct Coating Process
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Solution Overview
Problem
Traditional silicon carbide ceramic filter membranes require a complex and costly multi-step sintering process, including multiple coatings and high-temperature oxidations, which results in low flux and high production costs due to the need for an intermediate layer and multiple sintering cycles.
Innovation Solution
A method for preparing a high-flux silicon carbide ceramic filter membrane that omits the intermediate layer and associated sintering steps, by optimizing the coating slurry and process to allow direct coating and sintering of the separation layer on a support with a large pore size, without the need for carbon removal oxidation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If an intermediate layer is added to prevent particle penetration, then the mechanical strength and structural integrity are improved, but the flux is reduced due to the additional layer
Solution Approach 1:
The patent removes the intermediate layer from the traditional three-layer structure. By directly coating the separation layer on the support layer with large pore sizes (10 μm or more), the invention eliminates the flux-reducing intermediate layer while maintaining structural integrity through optimized coating parameters and particle size selection.
Solution Approach 2:
The invention changes critical parameters including support layer pore size (10 μm or more), coating particle size (0.1-3 μm), and coating thickness (1-10 μm) to enable direct coating without an intermediate layer. These parameter changes allow the separation layer to adhere properly while maintaining high flux through the large support pores.
2Manufacturing precision
If multiple coating and sintering cycles are used to build up the separation layer, then the filtration precision is improved, but the production cost and process complexity increase
Solution Approach 1:
The patent combines multiple coating operations into a single coating step followed by one sintering cycle. By using carefully controlled particle size distribution (0.1-3 μm) and optimized coating parameters, the invention achieves the required separation precision in one go, eliminating the need for multiple sequential coating and sintering cycles.
Solution Approach 2:
The invention performs preliminary optimization of coating slurry composition, particle size distribution, and coating parameters before the single coating step. This preliminary preparation ensures that one coating and sintering cycle is sufficient to achieve the desired filtration precision, avoiding the need for multiple corrective or additive coating stages.
3Reliability
If high-temperature oxidation is performed to remove carbon, then the hydrophilicity and coating adhesion are improved, but the production time and energy consumption increase
Solution Approach 1:
The patent removes the high-temperature oxidation step from the traditional process sequence. By using inert atmosphere protection during sintering and optimizing the coating slurry composition, the invention achieves sufficient coating adhesion and hydrophilicity without the time-consuming oxidation treatment.
Solution Approach 2:
The invention changes the sintering atmosphere parameter from oxidizing to inert (argon or nitrogen), and adjusts the sintering temperature and time parameters to achieve proper bonding without oxidation. This parameter change eliminates the separate oxidation step while maintaining coating adhesion through controlled atmospheric sintering.
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 significantly improves the flux of the ceramic filter membrane by 30% or more, reduces production costs, and simplifies the preparation process, while maintaining high mechanical strength and filtration efficiency.
Implementation Method 1
a solvent/water in a slurry is difficult to enter support pores through a capillary force during coating
Implementation Method 2
high-temperature oxidation (the oxidation is conducted at 700° C. to 1,200° C. with air introduced) is required to remove carbon left after the high-temperature sintering
Implementation Method 3
the traditional preparation process of a silicon carbide membrane requires at least three times of sintering
Data Source
AI summary
A high-flux silicon carbide ceramic filter membrane and a preparation method thereof are provided. In the preparation method, a separation layer is directly coated at a time on the basis of a support, that is, after the support is sintered, the separation layer is directly coated and then sintered for carbon removal. In the present disclosure, a sintering process and a coating formula are optimized to prevent fine silicon carbide particles from entering micropores of a support due to capillary filtration and film formation during coating, such that a separation layer with an average pore size of 0.2 μm or less can be directly coated on a silicon carbide support with an average pore size of 10 μm or more, and fine silicon carbide particles can be effectively prevented from entering micropores of the support during the coating.