It doesn't require high pressure equipment or powerful furnaces (drying temperatures are only just above water's boiling point), yet it creates a useful product which takes the shape of the mold very accurately.
In terms of being simply a process by which powder can be made into a monolith, freeze casting could be as old as the earth.
A material called laminar opaline silica or LOS is believed to be formed by the freeze casting of volcanic ash, some soils containing the required sols to make the gel.
Lottermoser, a German, wrote a paper on 'das Ausfrieren von Hydrosolen' (the Freezing of Hydrosols) in 1908.
Through the 20th century various people have patented techniques using freeze-gelation, most being centred on the use of ceramics as refractory materials.
A furnace lining brick, or an investment casting mold, can be easily fabricated using this method.
Recently there was a flurry of interest in freeze-casting at the University of Bath, UK, which led most significantly to two doctoral theses, by J. Laurie in 1995 and by M. Statham in 1998.
Taken together in chronological order, these form a good introduction to the technique for the interested party.
However, with suitable post-processing, they could fulfil many other applications, such as silicon chip mounts, or even engine blocks.
On freezing of the sol, the silica particles are rejected away from the solidifying interface and forced into the interstices between the ice crystals.