Laser-induced surface alloying in nanosized Ni/Ti multilayer structures
Gaković, Biljana M.
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Laser-induced alloying effects on the composition and structure of different Ni/Ti multilayer structures were studied. Thin films composed of one, five, and ten (Ni/Ti) bilayers were deposited by DC ion sputtering on (1 0 0) Si wafers. Laser irradiations were performed by 150 ps pulses of a Nd:YAG laser operating at 1064 nm. The samples were characterized by Rutherford backscattering spectrometry (RBS), Auger electron spectroscopy (AES), X-ray diffraction (XRD), atomic force microscopy (AFM) and scanning electron microscopy (SEM). At a laser fluence of 0.9 J cm(-2), interaction between Ni and Ti layers was initiated, and NiTi alloy formed in 5- and 10-bilayered samples. Progressed alloying was achieved at a laser fluence of 1.2 J cm(-2). The alloy was formed mostly within the heat affected zone (HAZ) of the sample. Surface segregation of titanium was followed by formation of a 25 nm thin TiO2 film on the surface of the multilayered structures. In addition, parallel periodic surface str...uctures on the surfaces of the 5- and 10-bilayered samples were clearly recorded. Their period in the case of the 5-bilayered system (0.77 mu m) agrees very well with the predictions of the common theory, whereas, in the case of the 10-bilayered system, two periods of such structures are observed (1.43 mu m and 0.4 mu m), and none of them coincides with the prediction. (C) 2012 Elsevier B. V. All rights reserved.
Keywords:Ni/Ti multilayer / Laser alloying / Diffusion / Surface segregation / Ripple structure
Source:Applied Surface Science, 2013, 264, 273-279
- SPIRIT - Support of Public and Industrial Research using Ion Beam Technology (EU-227012)
- Effects of laser radiation and plasma on novel materials in their synthesis, modification, and analysis (RS-172019)
- COST Action [MP0903 Nanoalloy], Center for Multidisciplinary Studies, Serbia