Ceramic Solid Solution – coupled substitution
- Every oxide compound can be broken up into a simple oxide compound, 1:1:6
Substitution of Ca in structure:
NaAlSi 3 O8
+
+2
+3
4
Na1x Ca x Al1+xSi3x O8

CaAl2Si2 O8 or
if x = .02  Na.98 Ca.02 Al 1.02Si 2.98O8
Ca10Na 2 Al 20P10Si6 H3 12 O 86 16H 2O

i.e.
A12B86O96 16H2 O
Cations in
8 fold sites
4 fold
sites
Corners and faces
in FCC array
Imperfections/Defects:
A. If crystals were perfect  Actuality
- Strengths of 1,000,000 psi  Strengths les than 1,000,000 psi
- No diffusion  Alloys; Solutions (lots of diffusion)
- No plasticity  Easily deformed
- Perfect electrical conductivity  Not perfect, except for superconductors, because of
grain boundaries
B. Imperfections  classified by dimensions
Zero  point defects
One  line defects
Two  surface defects
Three  volume defects