I had this effectively a shower thought idea - why don't we have ceramic 3d printing?
Let me clarify - before posting, I looked it up, and I could not find exactly what I was looking for. There are already commercial offereings for Clay 3D printing, but that is not forming the ceramic in situ, we are depositing what is effectively ceramic in a solvent, and drying it. What I was thinking was making the ceramic on site.
Here is a example setup
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Imagine a regular polymer 3D printing setup
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imagine instead of filament, we have a tank of Ca(OH)~2~ (calcium hydroxide, or slaked lime) (not necessarily just this, but for example, consider this combination)
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imagine we instead of droping a full thread like layer of semi-solid polymer, we form a trail of really tiny water drops
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we sprinkle in Ca(OH)~2~ onto the drops (or this step can be skipped if we can pre mix it with water, and then somehow figure how to deposit really tiny drops of what is effectively a very strong base
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now we let CO~2~ in, and form CaCO~3~
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deposit a layer to fill voids in this layer (we dropped a non continous strings of drops earlier)
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evaporate remainning water
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repeat this step until this layer is complete.
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repeat process for next layer
Now I can think of many problems here
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how to handle very strong base - maybe a tip of refractory alloys, or something like Inconnel (or Ni Cr alloys in general), or ceramic (maybe alumina) coated metal (probably cheapest, but hard to make)
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how to control solidification - we are effectively doing a solidification reaction, and growth of crystal would largely be dependant on the crystal facettes, and we would not be able to have any sharp angles. Also, we would not be able to have a very small width with this.
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surface tension of water will not allow to easily create uniform small dots - only thing I can think of is using something mechanical to hit the water droplets at tips to effectively launch tiny droplets. (Imagine shuriken (stars or blades) breaking droplet, and water landing) - still we would not have control
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how to control solidification rate in exothermic process - maybe easy, but we would need something like fans or coolant, otherwise we would form big drops at a spot due increased nucleation rate
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how to introduce CO~2~ fast enough - we would have to have a very strong CO~2~ environment, somehow not let it solidify at tip. Also this reaction is very slow (maybe that is only the case at bulk solidification). Maybe the whole process would be very slow
Does this process already exist? If it does - any resources related to it would be helpful. If not, Why? Is it because we have not been able to solve the issues I listed, something I did not list? Would this be practical (economically)? I can definitely see both artistic and engineering use cases, and both of those can allow some big budgets.
A(dissolved) + B (gas) -> Delta (energy released) + C(precipitate)
since a was dissolved - there was some eenrgy of dissolution, now that there is a precipitate (and lets for simplicity assume K~sp~ = 0) then there is some energy required to create this surface.
for reaction to be energetically favorable (Gibs free energy, so entropy is also accounted)
abs(Delta) > abs(dissolution energy) + abs(surface creation)
this is going to maintained always. Now if Delta is very large reaction will almost run to completion (provided activation energy is given, lets say in form of temperature or mechanical agitation to increase the reaction probability of A and B)
You are getting to this :
A + B → C (metastable and insoluble)
https://en.m.wikipedia.org/wiki/Classical_nucleation_theory
Classical nucleation theory ...
Description ...
Homogeneous nucleation ...
C (metastable) → C(powder precipitate)
... unless you have heterogeneous nucleation
... first you have to eliminate all particle that can be nucleus on which powder can form, then,
... you need to stay away from homogeneous nucleation as described above.
... of course you have to provide a substrate on which C will nucleate, and grow,
... and this is why, in practice, (for large heterogeneous nucleated solids production) this process is very slow.