Bulk Ceramic Components from Polymer Precursor Droplets
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Solution Overview
Problem
Current methods for producing bulk ceramic components from polymer-derived ceramics face challenges such as extensive shrinking and mass loss during high-temperature conversion, leading to cracking due to gas buildup, and require the use of limited open-cell sponge materials for gas pathways, which are time-consuming and restrictive in terms of size and thermal decomposition properties.
Innovation Solution
A spraying process that forms partially cured gelatinous polymer ceramic precursor resin droplets, which are then compressed into shapes, eliminating the need for sponge materials and allowing for controlled gas pathways and rapid production of bulk ceramic components with variable porosity, enabling the creation of large cross-section parts in hours rather than days or weeks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If polymer-derived ceramics are used for bulk ceramic components, then ceramic material can be formed with thick cross sections, but extensive shrinking and mass loss during high-temperature conversion causes gas buildup and cracking
Solution Approach 1:
The polymer precursor is divided into droplets rather than used as a continuous mass. Each droplet acts as an independent unit that converts to ceramic particles, distributing the shrinkage and gas evolution across many small units rather than one large continuous structure, thereby preventing crack formation in thick cross-section components
Solution Approach 2:
The method creates a porous green body structure where the space between ceramic particles is filled with a porous polymer matrix that provides gas pathways. This porous structure allows evolved gases to escape during conversion without building up internal pressure, enabling thick cross-section components to be produced without cracking
2Object-generated harmful factors
If open-cell sponge materials are used to provide gas pathways, then gas can escape during ceramic conversion, but the process becomes time-consuming and restrictive in terms of size and thermal decomposition properties
Solution Approach 1:
The gas pathway function is extracted from the bulk polymer matrix and concentrated into a separate porous filler material that is distributed throughout the green body. This allows the polymer to focus on providing structural support and the filler to provide gas escape pathways, eliminating the time-consuming requirement for the entire polymer structure to decompose
Solution Approach 2:
A porous filler material acts as an intermediary substance that provides gas pathways during the ceramic conversion process. This filler material decomposes at lower temperatures than the polymer precursor, creating channels for gas escape without requiring the polymer matrix to decompose, thereby reducing production time
3Stability of the object's composition
If the polymer precursor is fully cured before shaping, then the shape is stable, but gas pathways are blocked and internal pressure builds up during ceramic conversion
Solution Approach 1:
The polymer precursor is partially cured to a gel state rather than fully cured before shaping. This preliminary curing provides sufficient shape stability while leaving the structure porous and permeable to gases. The partial cure state allows gas pathways to remain open during subsequent ceramic conversion, preventing internal pressure buildup
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 enables the production of bulk ceramic components with porosity ranging from 2% to 98%, allowing for the creation of large cross-section parts without cracking, and facilitates the production of complex internal features and composite ceramic bodies with uniform properties, significantly reducing production time and expanding the range of possible ceramic structures.
Implementation Method 1
partially cured gelatinous polymer ceramic precursor resin droplets
Implementation Method 2
the polymer material is converted through chemical transformations into a ceramic material
Implementation Method 3
the evolving gas needs to diffuse through the solid polymer phase and out to the surface
Implementation Method 4
compressed into shapes, eliminating the need for sponge materials and allowing for controlled gas pathways
Data Source
AI summary
Methods, processes, and systems for producing bulk ceramics from agglomerations of partially cured gelatinous polymer ceramic precursor resin droplets, without using sponge materials to form gas pathways in the polymer bodies. Ceramics can be formed in hours. Resin droplets can be produced with a sprayer where liquid polymer precursors, mixed with a curing agent, are sprayed forming droplets which are partially cured, collected, and compressed into shapes. Ceramic porosity can be varied, droplet particle sizes can be controlled by adjusting liquid and gas pressure, orifice size, during spraying. Partially cured droplets can be formed via an emulsion process and size controlled by emulsion liquid and surfactant selection parameters.