Interfacial reactions between zirconia and titanium

Abstract

Titanium alloys have excellent properties such as high specific strength and good corrosion resistance. However, they are extremely reactive to ceramics at high temperatures, resulting in a chemical reaction affected-surface. The interstitial elements (e.g., C,N,O,H) from the ceramic have a great tendency to enter into the titanium alloys and cause the deterioration of mechanical properties. Economos and Kingery found that titanium melt could penetrate along the grain boundaries of oxides, such as Al{sub 2}O{sub 3}, ZrO{sub 2}, and MgO, at 1,800 C, leading to the alternation of these oxides. Ruh indicated that the titanium could react with zirconia and up to 10 at% of Zr and O elements from ZrO{sub 2} were retained in the solid solution of Ti, while the zirconia was transformed into oxygen deficient zirconia. Saha also revealed that ZrO{sub 2{minus}x} and {alpha}-Ti(O) were formed after Ti reacted with ZrO{sub 2}. However, the interfacial reactions between zirconia and titanium has not been fully elucidated to date. In this study, the microstructure of the interface between zirconia and titanium has been investigated using an analytical transmission electron microscope with a dedicated energy dispersive spectrometer (TEM/EDS), and the mechanism of the interface reactions is also discussed.