The present study reports an innovative way to produce large pore channels with a size 4100 lm for applications in bone tissue engineering using the camphene-based freeze casting method, and using an unusually high freezing temperature, which is close to the solidification temperature of the slurry, in order to allow the formation of excessively overgrown camphene dendrites due to the extremely low solidification velocity. To accomplish this, hydroxyapatite (HA)/slurries with various solid loadings (10, 15, and 20 vol%) were frozen at 351C for 20 h. The frozen samples were freeze dried and sintered at 12501C for 3 h. All of the fabricated samples showed highly porous structures with large pore channels 4100 lm in size and dense HA walls without any noticeable defects, such as cracks or pores. As the initial solid loading was increased from 10 to 20 vol%, the porosity of the sample decreased linearly from 76% to 55%, while the pore channels became narrower. However, the compressive strength was remarkably improved from 2.5 to 16.7 MPa.

Calcium sulfate hemihydrate (CSH) powders were synthesized for use as bone cement by heat treating calcium sulfate dihydrate (CSD) powders in boiling CaCl 2 solutions with various CaCl 2 concentrations, ranging from 23.5 to 35.5 wt%, in order to control their morphology. All of the prepared CSH powders showed X-ray diffraction peaks corresponding to the CSH structure without any secondary phases, implying complete conversion from the CSD phase to the CSH phase. It was also observed that the concentration of CaCl 2 significantly affected the morphology of the CSH powder that was synthesized. In other words, as the CaCl 2 concentration was decreased from 35.5 to 23.5 wt%, the morphology notably changed from long-and-slim hexagonal rods with an aspect ratio of 5.5 to fat-and-short hexagonal columns with an aspect ratio of 1.4. This reduction in the aspect ratio led to a significant improvement in the compressive strength of the CSD cement prepared by mixing the CSH powders with water.

We fabricated highly aligned porous silicon carbide (SiC) ceramics decorated with SiC nanowires by the unidirectional freeze casting of SiC/camphene slurries with various polycarbosilane (PCS) contents, ranging from 0 to 20 wt% in relation to the SiC powders, in which the PCS preceramic was used as a binder and source for the in situ growth of the SiC nanowires. In this method, aligned pore channels were formed as a replica of the unidirectionally grown camphene dendrites, while SiC nanowires were formed within the pores in situ via a vapor–liquid–solid (VLS) mechanism during the heat treatment of the porous green bodies at 1400°C for 1 h in a flowing Ar atmosphere. The pore channels were well decorated with single‐crystalline SiC nanowires. It was also observed that the growth of the SiC nanowires was strongly affected by the initial PCS content and heat‐treatment temperature.

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