July 2007
Reaction Between Titanium and Zirconia Powders
2225
(4) Relatively large Ti/ZrO2 ratios resulted in the formation
of a-Ti(Zr, O) as well as Ti2ZrO in the specimens with ꢀ 50
mol% Ti, with no TiO being found.
Table IV. Reaction Products, Crystal Structures, and
Morphology in Ti/ZrO2 Composites
Specimens
Reaction products
Crystal structures
Morphology
(5) Both m-ZrO2ꢁx and t-ZrO2ꢁx were found in specimens
with r50 mol% Ti; however, c-ZrO2ꢁx was formed in the spec-
imens with 70 mol% Ti as it contained a high concentration of
retained yttria and oxygen vacancies in ZrO2.
(6) In the specimen with 90 mol% Ti, ZrO2 particles were
almost dissolved in Ti, being accompanied of simultaneous pre-
cipitation of Y2Ti2O7.
90T10Z
a-Ti(Zr, O)
Ti2ZrO
Y2Ti2O7
a-Ti(Zr, O)
Ti2ZrO
c-ZrO2ꢁx
a-Ti(Zr, O)
Ti2ZrO
m-ZrO2ꢁx
t-ZrO2ꢁx
a-Ti(Zr, O)
TiO
m-ZrO2ꢁx
t-ZrO2ꢁx
TiO
m-ZrO2ꢁx
t-ZrO2ꢁx
Hexagonal
Irregular
Lamellar
Round
Irregular
Lamellar
Equiaxed
Irregular
Lamellar
Twined
Equiaxed
Irregular
Irregular
Twined
Equiaxed
Irregular
Twined
Orthorhombic
Pyrochlore
Hexagonal
Orthorhombic
Cubic
Hexagonal
Orthorhombic
Monoclinic
Tetragonal
70T30Z
50T50Z
Acknowledgments
The authors would like to express their sincere gratitude to Mr. Ming-Chung Li
and Wei-Chen Wang for preparing the Ti/ZrO2 composite specimens.
30T70Z
10T90Z
Hexagonal
Cubic (NaCl type)
Monoclinic
Tetragonal
Cubic (NaCl type)
Monoclinic
Tetragonal
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simultaneously diffused into ZrO2. The TiO was formed in the
sintered 10T90Z and 30T70Z, because a sufficient amount of
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ZrO2 composites depended on the Ti/ZrO2 ratio.
(2) Ti reacted with and was mutually soluble in ZrO2, re-
sulting in the formation of a-Ti(O, Zr), Ti2ZrO, and/or TiO.
Oxygen atoms, contained in a-Ti(O, Zr), Ti2ZrO, and/or TiO,
were extracted from ZrO2, whereby oxygen-deficient ZrO2 was
produced.
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¨
2
3
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¨
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sufficiently supplied by excess ZrO2.
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