Influence of Particle Size on Ice Nucleation and Growth During the Ice‐Templating Process

The solidification behavior of suspensions of alumina particles during directional solidification is investigated here by in situ observations using X-ray radiography and tomography. The objective of this study was to assess the influence of particle size on the solidification behavior of the suspensions during the early stages of solidification. Four powders with particle size in the range of 0.2–3.4 μm (median size) were investigated. Solidification is obtained by cooling at a constant rate, starting from room temperature. Attention is specifically paid to the nucleation and growth behavior of the ice crystals in these suspensions. We propose that the nucleation of ice crystals is controlled by the particle size, the surface of the particles acting as nucleation sites. Smaller particle size leads to a lower degree of supercooling because nucleation and growth can proceed at a higher temperature than with larger particles. The initial interface velocity is dependent on the degree of supercooling, and controls the extent of the initial structural gradient in the resulting porous materials.

[1]  Igor Lubomirsky,et al.  Water Freezes Differently on Positively and Negatively Charged Surfaces of Pyroelectric Materials , 2010, Science.

[2]  E. Maire,et al.  Metastable and unstable cellular solidification of colloidal suspensions. , 2009, Nature materials.

[3]  E. Maire,et al.  In situ X-ray radiography and tomography observations of the solidification of aqueous alumina particle suspensions. Part I: Initial instants , 2009, 1710.04929.

[4]  Yumin Zhang,et al.  Preparation of a Dense/Porous BiLayered Ceramic by Applying an Electric Field During Freeze Casting , 2009 .

[5]  J. Covington,et al.  Conducting Nanocomposite Polymer Foams from Ice‐Crystal‐Templated Assembly of Mixtures of Colloids , 2009 .

[6]  Hyoun‐Ee Kim,et al.  Fabrication of porous titanium scaffolds with high compressive strength using camphene-based freeze casting , 2009 .

[7]  E. Saiz,et al.  Architectural Control of Freeze‐Cast Ceramics Through Additives and Templating , 2009, 1710.04095.

[8]  M. Gutiérrez,et al.  Ice-Templated Materials: Sophisticated Structures Exhibiting Enhanced Functionalities Obtained after Unidirectional Freezing and Ice-Segregation-Induced Self-Assembly† , 2008 .

[9]  S. Sofie.  Fabrication of Functionally Graded and Aligned Porosity in Thin Ceramic Substrates With the Novel Freeze–Tape‐Casting Process , 2007 .

[10]  T. Moritz,et al.  Ice-mould freeze casting of porous ceramic components , 2007 .

[11]  M. Worster,et al.  Morphological instability in freezing colloidal suspensions , 2007, Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences.

[12]  T. Moritz,et al.  Ceramic Bodies with Complex Geometries and Ceramic Shells by Freeze Casting Using Ice as Mold Material , 2006 .

[13]  P. Gielisse,et al.  Engineered porous ceramics using a directional freeze-drying process , 2005, 28th International Spring Seminar on Electronics Technology: Meeting the Challenges of Electronics Technology Progress, 2005..