Thin-Wall Ceramic Coating via Carbon Substrate Combustion
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Solution Overview
Problem
Conventional methods for producing thin-wall ceramic or metal articles often result in cracking and warpage, leading to reduced yields and increased costs due to the need for thicker initial molding, longer processing times, and excessive material usage.
Innovation Solution
Thermally spraying ceramic or metal particles onto a carbon substrate of cylindrical or cup shape, followed by combustion treatment to burn out the carbon substrate, thereby creating a thin-wall sprayed coating without the need for molding and sintering steps.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional molding methods are used to produce thin-wall articles, then the article can be manufactured with standard processes, but cracking occurs during molding and sintering leading to reduced yield
Solution Approach 1:
The invention applies preliminary action by pre-forming a green compact with controlled porosity distribution before sintering. The green compact is molded with a specific porous structure that prevents cracking during subsequent sintering, allowing thin-wall articles to be produced without the cracking issues that plague conventional methods.
Solution Approach 2:
The invention changes the physical parameters of the green compact by controlling its porosity and density distribution. The green compact is prepared with higher porosity in the wall regions, which reduces stress concentration during sintering and prevents cracking, while maintaining the desired final wall thickness.
2Reliability
If thicker compacts are molded to ensure higher yields, then compact formation success improves, but material usage increases and processing time extends
Solution Approach 1:
The invention changes the density and porosity parameters of the green compact to optimize both yield and material efficiency. By controlling the green compact to have non-uniform density distribution with higher porosity in wall regions, the process achieves high formation yield while using only the necessary amount of material, avoiding the waste associated with thicker initial molding.
Solution Approach 2:
The preliminary formation of a green compact with optimized porosity structure enables direct production of thin-wall articles without requiring excessive material. The green compact stage allows precise control of material distribution, ensuring that only the required amount of material is used while maintaining high formation yield.
3Reliability
If thicker compacts are molded to ensure higher yields, then compact formation success improves, but processing time increases due to longer sintering and machining required
Solution Approach 1:
The invention optimizes the sintering process parameters by controlling the green compact's porosity and density distribution. The pre-formed porous structure in the green compact allows for faster, more uniform sintering, reducing the time required while maintaining high formation yield and achieving the desired final wall thickness without extensive machining.
Solution Approach 2:
The preliminary formation of the green compact with controlled porosity structure prepares the material for efficient sintering. This pre-processing step ensures that the subsequent sintering occurs more rapidly and uniformly, reducing overall processing time while maintaining high yield, eliminating the need for time-consuming machining of thick walls.
4Ease of manufacture
If standard molding methods are used, then the process is straightforward, but warpage occurs during sintering substantially reducing overall yield
Solution Approach 1:
The invention changes the physical parameters of the green compact, specifically its porosity and density distribution, to prevent warpage during sintering. The green compact is prepared with higher porosity in wall regions, which promotes uniform thermal and stress distribution during sintering, eliminating warpage while maintaining process simplicity.
Solution Approach 2:
The preliminary formation of the green compact with optimized porosity structure prevents warpage before sintering occurs. This pre-control of material structure ensures uniform sintering behavior, maintaining dimensional accuracy and eliminating warpage issues without complicating the manufacturing process.
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 allows for the production of thin-wall articles with minimal warpage and deformation, reducing material waste and processing time, while providing articles with high inertness, heat resistance, abrasion resistance, corrosion resistance, and chemical resistance.
Implementation Method 1
thermally spraying ceramic particles of rare earth oxide or fluoride or metal particles of W, Mo or Ta onto a surface of a carbon substrate
Implementation Method 2
combustion treating the coated substrate to burn out the carbon substrate
Data Source
AI summary
A sprayed article is prepared by thermally spraying ceramic particles of rare earth oxide or fluoride or metal particles of W, Mo or Ta onto an outer or inner surface of a cylindrical carbon substrate to form a sprayed coating, and burning out the carbon substrate, thus leaving the ceramic or metal-base sprayed coating of cylindrical shape having a wall thickness of 0.5-5 mm.