Real Materials

Voids

· In a crystalline material, such as the UO₂ sample shown, vacancies in the lattice can aggregate to form negative crystals, voids bounded by crystallographic planes. The photograph has a magnification of 18,000 x.
· In amorphous materials, such as the porcelain ceramic shown, voids can adopt shapes of minimum surface area. This photograph is 95 x.

From: Kingery, Bowen, & Uhlmann, "Introduction to Ceramics," Wiley (1976)