scholarly journals External Field Assisted Freeze Casting

Ceramics ◽  
2019 ◽  
Vol 2 (1) ◽  
pp. 208-234 ◽  
Author(s):  
Pooya Niksiar ◽  
Frances Su ◽  
Michael Frank ◽  
Taylor Ogden ◽  
Steven Naleway ◽  
...  
Keyword(s):  
Acoustic Radiation ◽  
Colloidal Suspension ◽  
Porous Ceramics ◽  
External Control ◽  
External Fields ◽  
Freeze Casting ◽  
Anisotropic Mechanical Properties ◽  
Range Alignment ◽  
Shell Ring ◽  
Casting Porosity

Freeze casting under external fields (magnetic, electric, or acoustic) produces porous materials having local, regional, and global microstructural order in specific directions. In freeze casting, porosity is typically formed by the directional solidification of a liquid colloidal suspension. Adding external fields to the process allows for structured nucleation of ice and manipulation of particles during solidification. External control over the distribution of particles is governed by a competition of forces between constitutional supercooling and electromagnetism or acoustic radiation. Here, we review studies that apply external fields to create porous ceramics with different microstructural patterns, gradients, and anisotropic alignments. The resulting materials possess distinct gradient, core–shell, ring, helical, or long-range alignment and enhanced anisotropic mechanical properties.

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.

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.

Functionally graded porous ceramics with dense surface layer produced by freeze-casting

2011 ◽  
Vol 37 (8) ◽  
pp. 3717-3722 ◽  
Author(s):  
Changqing Hong ◽  
Jiancong Du ◽  
Jun Liang ◽  
Xinghong Zhang ◽  
Jiecai Han
Keyword(s):  
Surface Layer ◽  
Porous Ceramics ◽  
Functionally Graded ◽  
Freeze Casting

Suspension- and solution-based freeze casting for porous ceramics

2017 ◽  
Vol 32 (17) ◽  
pp. 3372-3382 ◽  
Author(s):  
Maninpat Naviroj ◽  
Peter W. Voorhees ◽  
Katherine T. Faber
Keyword(s):  
Porous Ceramics ◽  
Freeze Casting ◽  
Image Position

Abstract

scholarly journals Alumina Porous Ceramics Obtained by Freeze Casting: Structure and Mechanical Behaviour under Compression

Ceramics ◽  
2018 ◽  
Vol 1 (1) ◽  
pp. 83-97 ◽  
Author(s):  
Dominique Hautcoeur ◽  
Maurice Gonon ◽  
Carmen Baudin ◽  
Véronique Lardot ◽  
Anne Leriche ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Mechanical Behaviour ◽  
Volume Fraction ◽  
Mechanical Test ◽  
Porous Alumina ◽  
Microstructural Analysis ◽  
Porous Ceramics ◽  
Sem Analysis ◽  
Deformation Pattern ◽  
Freeze Casting

The aim of the work is to analyse the mechanical behaviour of anisotropic porous alumina ceramics processed by freeze casting (ice templating). The freeze cast specimens were characterised by a lamellar structure with ellipsoidal pore shape, with a size ranging from 6 to 42 µm and 13 to 300 µm for the minor and major axes, respectively, as a function of the freezing rate and the powder and binder contents. The pore volume fraction ranged from 40 to 57%. SEM analysis of the porous structures after the compression test showed a typical deformation pattern caused by the porosity gradient through the specimen, as determined by X-ray radiography. The apparent elastic modulus of the anisotropic porous alumina ranged from 0.2 to 14 GPa and the compressive strength from 6 to 111 MPa, varying as a function of the process parameters which determine the pore network characteristics. The relationships between stress-strain behaviour in compression and the microstructure and texture were established. An analytical model based on a Gibson and Ashby relationship was used and adapted from SEM microstructural analysis after a mechanical test in order to predict the compressive strength of processed anisotropic alumina.

Microstructure of TiO2 porous ceramics by freeze casting of nanoparticle suspensions

2017 ◽  
Vol 43 (17) ◽  
pp. 14593-14598 ◽  
Author(s):  
Jingzhong Zhao ◽  
Yu Li ◽  
Yuan Wu ◽  
Shanshan Lv ◽  
Kathy Lu
Keyword(s):  
Porous Ceramics ◽  
Freeze Casting ◽  
Nanoparticle Suspensions
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