| Effect of heat treatment on the formation of Ni-Ti-O nanotube arrays on NiTi alloy |
| Paper ID : 1062-UFGNSM-FULL |
| Authors: |
|
fatemeh Mohammadi *1, Mahshid Kharaziha2, Ali Ashrafi2 1fatemehmohammadi,No174, Nobahar 22st Alley, North Nobahar St, KhaneEsfahan, Esfahan, Esfahan, Iran 2department of materials science, Isfahan university of technology |
| Abstract: |
| In recent years, Nickel-titanium-oxide nanotube arrays (NTAs) prepared on NiTi alloy have attracted recent attention for various applications, such as solar energy conversion, electrochromic devices, electrochemical energy storage and biomedicine. In the current study, the effect of heat treatment and following cooling rate of the NiTi substrates as a surface modification process on the formation of nanotubes has been investigated. For this purpose, the samples were treated at 900°C for 1 h in a vacuum tube furnace to minimize the oxidation of the samples at high temperatures. The specimens were then cooled down to room temperature in various cooling rates: furnace-cooling and water-quenching. Two different tempraturs were applied for water quenching, the samples have been tempered at 300 and 500C. After heat treatment, the samples were anodized in ethylene glycol solution containing 0.25 wt%NH4F and 1.5 wt % H2O. The morphology of the films prepared by electrochemical anodizing Ni-Ti alloy was characterized using scanning electron microscopy and X-ray diffraction. The morphology, crystal structure and composition of the Ni-Ti-O films were found to depend on the preparation conditions (heat treatment and anodization voltage). Our results showed that heat treatment and cooling rate were effective on the anodization voltage so that at the same time NTAs were formed on specimens at different voltages. For instance, while NTAs were formed on the sample cooled in furnace at 60V for 10 min, 80 V was required for fabrication of NTAs on the sample quenched in water and then tempered in 300°C for 10 min. |
| Keywords: |
| NiTi alloy, nanotube, heat treatment, anodization |
| Status : Paper Accepted (Poster Presentation) |
