Design of Highly Porous Ceramics from Preceramic Polymers
Event details
| Date | 30.03.2015 |
| Hour | 17:15 |
| Speaker | Prof. Paolo Colombo, University of Padova, Italy |
| Location | |
| Category | Conferences - Seminars |
Porous ceramics, and cellular ceramics in particular, possess an unique combination of favorable properties, such as low density, low thermal conductivity, low dielectric constant, high thermal shock resistance, high specific strength and high chemical resistance, which make them good candidates for both structural or functional applications in a variety of aggressive environments. In particular, highly porous ceramics find numerous applications in the field of energy as porous electrodes for SOFCs, membranes for hydrogen purification, components for CO2 sequestration, lightweight support structures, parts for high temperature thermal management, filters for the purification of various gases, components for thermal energy storage, catalyst support, battery components, etc.
There is a definite need to develop processing approaches capable of delivering cellular ceramics with varied characteristics, in terms of properties and architecture. This talk will discuss the use of preceramic polymers to fabricate highly porous ceramics with a wide variety of pore morphology and sizes, ranging from the micro-meso to the macro scales, using a variety of processing approaches. These include direct foaming, the use of sacrificial fillers, and the mixing of preceramic polymers of different characteristics. Furthermore, by using fabrication methods such as electro-spraying, micro- fluidics and emulsification, hollow microbeads particles and porous capsules were produced. Electrospinning of preceramic polymers enabled the fabrication of open-interconnected–network structures based on SiOC nano-fiber mats, while automated manufacturing techniques (direct and indirect 3D printing) were used for the reliable fabrication of highly porous ceramic parts with complex geometries and different compositions.
Bodies with a hierarchical porosity (e.g. micro-macro) or with graded porosity were also be obtained. The amount of porosity can be as high as >90 vol%, with pore size in the range from nm to mm, and thus most properties can be varied, rather continuously, in a wide range of values. Chlorination of polymer-derived-ceramics (PDCs) led to carbon-based materials with high specific surface area values, high pore volume and outstanding gas storage properties. Moreover, the direct growth of 1D nanostructures (e.g. nano-wires, nano-belts) on the cell wall surfaces of cellular bodies (including commercially available ceramic foams or honeycombs) enabled the production of components possessing a hierarchical pore structure, of interest for different applications (particle filtration, catalysis or catalyst support).
Finally, the introduction of filler powders allowed for the synthesis of functional cellular ceramics, possessing for instance electrical conductivity or magnetic properties in addition to a controlled porous architecture.
There is a definite need to develop processing approaches capable of delivering cellular ceramics with varied characteristics, in terms of properties and architecture. This talk will discuss the use of preceramic polymers to fabricate highly porous ceramics with a wide variety of pore morphology and sizes, ranging from the micro-meso to the macro scales, using a variety of processing approaches. These include direct foaming, the use of sacrificial fillers, and the mixing of preceramic polymers of different characteristics. Furthermore, by using fabrication methods such as electro-spraying, micro- fluidics and emulsification, hollow microbeads particles and porous capsules were produced. Electrospinning of preceramic polymers enabled the fabrication of open-interconnected–network structures based on SiOC nano-fiber mats, while automated manufacturing techniques (direct and indirect 3D printing) were used for the reliable fabrication of highly porous ceramic parts with complex geometries and different compositions.
Bodies with a hierarchical porosity (e.g. micro-macro) or with graded porosity were also be obtained. The amount of porosity can be as high as >90 vol%, with pore size in the range from nm to mm, and thus most properties can be varied, rather continuously, in a wide range of values. Chlorination of polymer-derived-ceramics (PDCs) led to carbon-based materials with high specific surface area values, high pore volume and outstanding gas storage properties. Moreover, the direct growth of 1D nanostructures (e.g. nano-wires, nano-belts) on the cell wall surfaces of cellular bodies (including commercially available ceramic foams or honeycombs) enabled the production of components possessing a hierarchical pore structure, of interest for different applications (particle filtration, catalysis or catalyst support).
Finally, the introduction of filler powders allowed for the synthesis of functional cellular ceramics, possessing for instance electrical conductivity or magnetic properties in addition to a controlled porous architecture.
Practical information
- General public
- Free
Organizer
- Prof. Juergen Brugger
Contact
- Isabelle Schafer