Hierarchical porous ceramics via two-stage freeze casting of preceramic polymers

2019 ◽  
Vol 162 ◽  
pp. 72-76 ◽  
Author(s):  
Noriaki Arai ◽  
Katherine T. Faber
Keyword(s):  
Porous Ceramics ◽  
Freeze Casting ◽  
Two Stage ◽  
Preceramic Polymers ◽  
Hierarchical Porous

scholarly journals Radial-Concentric Freeze Casting Inspired by Porcupine Fish Spines

Ceramics ◽  
2019 ◽  
Vol 2 (1) ◽  
pp. 161-179 ◽  
Author(s):  
Frances Su ◽  
Joyce Mok ◽  
Joanna McKittrick
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Axial Compression ◽  
Porous Ceramics ◽  
Compressive Modulus ◽  
Splitting Tensile Strength ◽  
High Porosity ◽  
Freeze Casting ◽  
Casting Method ◽  
Multiphase Materials

Freeze casting is a technique used to manufacture porous ceramics with aligned microstructures. In conventional freeze casting, these microstructures are aligned along a single direction of freezing. However, a caveat to these ceramics has been their ensuing lack of strength and toughness due to their high porosity, especially in the direction orthogonal to the direction of alignment. In this work, a novel freezing casting method referred to as “radial-concentric freeze casting” is presented, which takes its inspiration from the radially and concentrically aligned structure of the defensive spines of the porcupine fish. The method builds off the radial freeze casting method, in which the microstructure is aligned radially, and imposes a concentric alignment. Axial compression and Brazilian tests were performed to obtain axial compressive strengths, axial compressive moduli, and splitting tensile strengths of freeze cast samples with and without epoxy infiltration. Notably, radial-concentric freeze cast samples had the greatest improvements in axial compressive modulus and splitting tensile strength with infiltration, when compared against the changes in mechanical properties of conventional and radial freeze cast ceramics with infiltration. These results provide further evidence for the importance of structure in multiphase materials and the possibility of enhancing mechanical properties through the controlled alignment of microstructures.

Hierarchical porous SiOC via freeze casting and self-assembly of block copolymers

2021 ◽  
Vol 191 ◽  
pp. 204-209 ◽  
Author(s):  
Taijung Kuo ◽  
Lisa M. Rueschhoff ◽  
Matthew B. Dickerson ◽  
Tulsi A. Patel ◽  
Katherine T. Faber
Keyword(s):  
Block Copolymers ◽  
Self Assembly ◽  
Freeze Casting ◽  
Hierarchical Porous

Hierarchically Nanostructured Porous Functional Ceramics

2007 ◽  
Vol 336-338 ◽  
pp. 1933-1938 ◽  
Author(s):  
A. Vantomme ◽  
A. Léonard ◽  
Zhong Yong Yuan ◽  
Bao Lian Su
Keyword(s):  
Porous Ceramics ◽  
Biological Molecules ◽  
Hierarchical Porous ◽  
Self Formation ◽  
Hydrolysis And Polycondensation ◽  
Functional Ceramics

We demonstrate here a self-formation phenomenon of hierarchy with multiple-scaled porosity. Macrochanneled structures, labelled as CMI-7, with openings ranging from 0.5 to 5.0 microns and wormhole-like mesoporous walls with various ceramic compositions, such as ZrO2, TiO2, Al2O3, Y2O3, ZrO2-SiO2, ZrO2-TiO2, ZrO2-Y2O3,…, aluminosilicates, aluminophosphates, silicoaluminophosphates, metallophosphates, can be prepared by just controlling the hydrolysis and polycondensation rates of the pre-selected ceramic sources. The macrochannels (funnel-like or straight) are well parallel each other and perpendicular to the tangent of the particles’ surface. These hierarchical porous ceramics can be used in catalysis, separation and for immobilization of biological molecules and even microorganisms for filtration and bioreactor applications.

scholarly journals Hierarchical porous ceramics with multiple open pores from boehmite gel emulsions

2020 ◽  
Author(s):  
Yu Zheng ◽  
Xudong Luo ◽  
Jiegang You ◽  
Ting Li ◽  
Qingdong Hou
Keyword(s):  
Porous Ceramics ◽  
Hierarchical Porous

Freeze casting of aqueous coal fly ash/alumina slurries for preparation of porous ceramics

2010 ◽  
Vol 71 (4) ◽  
pp. 503-506 ◽  
Author(s):  
Hyung Bin Ji ◽  
Won Young Kim ◽  
Tae Young Yang ◽  
Seog Young Yoon ◽  
Byung Kyu Kim ◽  
...  
Keyword(s):  
Fly Ash ◽  
Coal Fly Ash ◽  
Porous Ceramics ◽  
Freeze Casting

Preparation, Microstructure and Properties of ZrO2 Gradient Porous Ceramics by Freeze-Casting Process

2015 ◽  
Vol 816 ◽  
pp. 226-230 ◽  
Author(s):  
Tao Tao Ai
Keyword(s):  
Electron Microscopy ◽  
Compressive Strength ◽  
Porous Structure ◽  
Cross Section ◽  
Lamellar Structure ◽  
Sintering Temperature ◽  
Casting Process ◽  
Porous Ceramics ◽  
Freeze Casting ◽  
Scanning Electron

The ZrO2gradient porous ceramics were prepared by a novel freeze-casting process. The porous structure of the ZrO2ceramics was investigated by scanning electron microscopy (SEM). And the porosity and compressive strength were also measured. Experimental results indicated that the porous structure of the specimens was remarkably affected by the sintering temperature. The dendritic pores were obtained after sintered at 1300 °C. The porosity and compressive strength of the specimen were 56.79% and 4.37 MPa, respectively. As the sintering temperature reached to 1500 °C, a lamellar structure was obtained on the cross-section of the specimen. Meanwhile, the porosity decreased to 26.77% and the compressive strength increased to 8.26 MPa. The ceramics can be divided subsequently into three distinctive zones along the solidification direction, i.e. lamellar zone, transition zone and cellular zone.

scholarly journals Nucleation-controlled freeze casting of preceramic polymers for uniaxial pores in Si-based ceramics

2017 ◽  
Vol 130 ◽  
pp. 32-36 ◽  
Author(s):  
Maninpat Naviroj ◽  
Melody M. Wang ◽  
Matthew T. Johnson ◽  
Katherine T. Faber
Keyword(s):  
Freeze Casting ◽  
Preceramic Polymers
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