MgO-”FeO”-SiO 2 FeO and MgO showing a solid soln
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Transcript of MgO-”FeO”-SiO 2 FeO and MgO showing a solid soln
• MgO-”FeO”-SiO2
FeO and MgO showing a solid soln
Fig. 6.59. System MgO-”FeO”-SiO2 including binary systems.
Fig. 6.57. System MgO-”FeO”-SiO2 (oxide phases in equilibrium with metallic iron) (after E. F. Osborn and A. Muan, Phase Equilibrium Diagrams of Oxide Systems. American Ceramic Society, Columbus, Ohio, 1960).
SiO2
MgO FeO
2900°C
L
2700°C
L
L+M
2000°C
Magnesiowustite
1870°C
1860°C
L+MM
solidsolubility
1800°C
Mag
nesi
owus
tite
+Fo
rste
rite
-Fay
alite(
Oliv
ine)
M+O M+L
O+L
P+L
O+P
M+O
O+L
X+L
1550°C
X+L
M+L
M+O
O+L
X+P
O+PP+L
1527°C
two pts meet at 1543°C
T+L
P+T
O+P
M+O
M+L
O+L
P+L
1450°C
T+P+L and O+P+L meet at 1305°C, and P+L disappears
pyroxene (P) is (MgO,FeO)SiO2
cristobalite (X) transformed to tridymite (T) at 1470oC
P L
T
O
T
P
O+L
T decrease
M+L
• the relation between the structure of a ternary diffusion couple and the phase diagram