Phase equilibria in the system ZrO2-InO1.5 have been investigated in t
he temperature range from 800-degrees to 1700-degrees-C. Up to 4 mol%,
InO1.5 is soluble in t-ZrO2 at 1500-degrees-C. The martensitic transf
ormation temperature m --> t of ZrO2 containing InO1.5 is compared wit
h that of ZrO2 solid solutions with various other trivalent ions with
different ionic radii. The diffusionless c --> t' phase transformation
is discussed. Extended solid solubility from 12.4 +/- 0.8 to 56.5 +/-
3 mol% InO1.5 is found at 1700-degrees-C in the cubic ZrO2 phase. The
eutectoid composition and temperature for the decomposition of c-ZrO2
solid solution into t-ZrO2 + InO1.5 solid solutions were determined.
A maximum of about 1 mol% ZrO2 is soluble in bcc InO1.5 phase. Metasta
ble supersaturation of ZrO2 in bcc InO1.5 and conditions for phase sep
aration are discussed.