How can I increase the packing factor and at the same time create more void space in a crystalline structure of a refractory material?

Question

How can I optimize the packing factor and at the same time create more void space in a crystalline structure of a refractory material?

Answer 1

Well, if you do the one, you probably also do the other, unless you have migration of material (and probably change of object outside dimensions). But, why would you necessarily seek to do that? Perhaps to optimize an optical or electronic property. If you have voids, I don't think you win, optically (example: amorphous titanium dioxide -> anatase -> rutile; this only works to improve index of refraction b/c the TiO2 recrystallizes into a densely crystalline layer).