ISSN:
0142-2421
Keywords:
Chemistry
;
Polymer and Materials Science
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Physics
Notes:
In this study, the oxidation of the surface of a 50/50 (at.%) NiTi alloy was studied by XPS, AES and SEM. Samples of the NiTi alloy were oxidized at 23°C and high temperatures at an oxygen pressure of 10-4 Torr and in atmosphere. At 10-4 Torr of O2 and 23°C, titanium was oxidized preferentially while nickel remained in the metallic form even after 40 min of exposure. At the same oxygen partial pressure and 400°C, a mixture of TiOx, Ti2O3 and TiO2 was formed, and nickel remained metallic. Eventually, after 40 min of O2 exposure, the whole surface was covered with a layer of TiO2. In atmosphere and at 23°C, titanium again was oxidized preferentially, but NiO was detected on the surface after the first minute of air exposure. At a higher temperature of 450°C, areas comprising a mixture of NiO and TiO2, and areas consisting of TiO2 only were found. Below the top surface layer, a complete layer of TiO2 was detected. Underneath the TiO2 layer, a nickel-rich layer was present.
Additional Material:
12 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/sia.740150602
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