GSRush, could you confirm you seek Li7
, not the Li12
indicated everywhere? Just to be sure.
[...] The Li12Si7 phase will solidify at 648°C regardless of the cooling speed [...]
Ultrafast cooling achieves unexpected things. I used an Al alloy containing >10% Zn (for >700MPa yield strength, wow!)
which couldn't have existed from casting nor extrusionhttp://www.rsp-technology.com/site-media/user-uploads/rsp_alloys_overview_2018lr.pdf
But "ultrafast" isn't the usual water-cooling tinkering. It's like 1MK/s,
faster than microscopic precipitates form
. The usual process sprays droplets of the liquid alloy on a highly conductive drum that spins quickly and is cooled actively. The droplets freeze by contact before precipitates form.
[Later edit: I've probably understood it wrongly. Precipitates seem to form, only much finer and uniform than usual. Therehttp://www.rsp-technology.com/technology/microstructure.html
"The various intermetallic compounds as well as the components with a low solubility are distributed finely and homogeneously over the metal matrix, thereby forming a very homogeneous microstructure."]
Then, the obtained flakes are sintered together, hence with convincing pressure, at a temperature low enough that precipitates can't form - but the flakes must be somewhat malleable, which Li7
could be or not. Optionally, the obtained material undergoes some heat treatment.
A semiconductor hypothetically obtained that way would be amorphous or polycrystalline, hence my question, whether a single-crystal is sought. Recrystallisation would probably lead to the wrong compounds and allotropes, unless a seed or pressure suffices to favour the desired one.
I wonder if atomic layer deposition
(ALD) can produce the Li7
. For that, some orientation of Li7
must show alternating planes of pure Si and pure Li. Ideally, standard Si would match two lattice constants of Li7
if Si is cut at the proper and accurate angle, to serve as a seed.