Ceramic Fiber Coating Frame with Perforated Flow Distribution
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Solution Overview
Problem
Existing methods for coating ceramic fibers, such as CVD and wet drum winding, suffer from issues like broken fibers, 'fuzz,' and uneven coating, which degrade throughput and mechanical properties of ceramic matrix composite (CMC) materials.
Innovation Solution
A system and method for coating ceramic fibers using a frame with hollow frame members and perforated holes, allowing a coating material to flow through and uniformly coat the fibers, preventing adhesion to the frame and ensuring even distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional coating methods (CVD, wet drum winding) are used to coat ceramic fibers, then coating can be applied to protect fibers and modify interface strength, but fiber breakage and fuzz occur reducing throughput and mechanical properties
Solution Approach 1:
A porous coating layer is introduced as an intermediary between the ceramic fiber and the frame during winding. This coating layer prevents direct contact between the fiber surface and the frame, eliminating fiber breakage and fuzz at the contact points while allowing the winding process to continue at high speed without interruption
Solution Approach 2:
The coating material is applied in controlled amounts to form a porous layer with specific physical properties. The porosity and thickness of the coating are optimized to provide protection at fiber-frame contact points while maintaining the flexibility and integrity of the fiber during the winding process
2Reliability
If coating material is applied to protect fibers during processing, then fiber protection is achieved, but uneven coating distribution and adhesion to frame occur degrading coating quality
Solution Approach 1:
The porous coating acts as a mediator that distributes contact forces evenly along the fiber length. During winding, the coating material flows to and accumulates at the contact points between the fiber and frame, providing localized protection without causing adhesion issues, while maintaining uniform coating distribution along the entire fiber
Solution Approach 2:
The coating is designed to have varying properties along the fiber length - thicker and more porous at contact points with the frame where protection is needed, and thinner at non-contact regions. This local variation in coating quality provides optimal protection where required while maintaining overall coating uniformity and preventing adhesion problems
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 solution achieves uniform coating of ceramic fibers, reduces fiber breakage and adhesion to the frame, and improves the mechanical properties of CMCs by ensuring consistent coating thickness and distribution.
Implementation Method 1
CVD may be considered as being most successful in producing impervious coatings of uniform thickness and controlled composition. In a typical CVD process, the fibers and reactants are heated to an elevated temperature where coating precursors decompose and deposit as the coating.
Data Source
AI summary
A system for coating ceramic fibers for use in manufacturing a ceramic matric composite (CMC) article includes a frame having a plurality of frame members arranged so as to create a void therebetween. At least one of frame members includes a hollow body and at least one perforated hole defined in the hollow body. Thus, the ceramic fibers are securable at respective ends of the frame and extend across the void. The frame also includes an inlet in fluid communication with the perforated hole(s) so as to allow a coating material to flow into and through the hollow body and out of the perforated hole(s) at a location of at least a portion of one of the ceramic fibers. As such, the coating material is configured to cause the portion of one of the ceramic fibers to separate from the frame such that the portion is uniformly coated with the coating material.