Influence of surface modification of nitinol with silicon using plasma-immersion ion implantation on the alloy corrosion resistance in chloride-containing solutions

Andrey V. Korshunov, Alexander I. Lotkov, Oleg A. Kashin, Polina V. Abramova, Dmitri P. Borisov

Результат исследований: Материалы для журналаСтатья

2 Цитирования (Scopus)


The relevance of the research is caused by the need to find a way to increase corrosion resistance of nitinol in chloride-containing solu- tions. High strength of NiTi combined with ductility and corrosion resistance determine the prospects of application of the alloy under cyclic mechanical and thermal impacts (mining and processing of mineral raw materials, engineering, medicine), so nitinol oxidation and corrosion in chloride solutions (sea water, biological environment) are the subject of intensive study in modern physical chemistry of me- tallic materials. The aim of the work was to study the electrochemical behavior and corrosion resistance of nitinol modified with silicon in artificial phy- siological solutions (0,9 % NaCl, artificial blood plasma). The methods used in the study: plasma-immersion Si-ion implantation of nitinol surface, profilometry, Auger-spectrometry, optical mic- roscopy, scanning and transmission electron microscopy, energy-dispersive X-ray spectroscopy, X-ray diffraction, cyclic voltammetry. The results. It was found out that at the surface of nitinol after plasma-immersion ion implantation with silicon the modified Si-conta- ining surface layers up to 80 nm thick are formed, which contain Si up to 50 at. % at 5-6 nm depth, and also Si-coatings of 300 nm thick can be obtained. Treatment of the alloy in plasma allows decreasing roughness of the surface, and leads to formation of outer oxide films (TiO2, SiO2) which are resistant to chloride-containing solutions. Between the oxide film and the volume of the alloy there is an in- termediate layer (amorphous Si, solid solution of Si in TiNi, Ti2Ni and Ti3Ni4) with decreased Ni concentration regarding to the alloy volume. Continuous, and also homogeneous in composition, thin Si-containing layers are resistant to corrosion damage at high positive potenti- als in chloride solutions (0,9 % NaCl) due to formation of stable passive films. The value of breakdown potential of Si-modified NiTi de-pends on the character of silicon and Ni distribution at the alloy surface, its value amounted to 0,9-1,5 V (Ag/AgCl/KCl sat.) for the al- loy samples with continuous Si-containing surface layers and with decreased Ni surface concentration. Continuous and homogeneous by Si-contant surface layers are resistant to corrosion damage; non-homogeneous layers do not prevent pitting formation at high positive potentials bacause of local selective Ni emission from the alloy surface to solution. The paper demonstrates the definite similarity in elec- trochemical behavior and in morphological changes during anodic oxidation at high positive potentials for NiTi samples, modified with Si under conditions of plasma-immersion and of ion-beam treatment.

Язык оригиналаАнглийский
Страницы (с-по)114-123
Число страниц10
ЖурналBulletin of the Tomsk Polytechnic University, Geo Assets Engineering
Номер выпуска9
СостояниеОпубликовано - 2015

ASJC Scopus subject areas

  • Economic Geology
  • Geotechnical Engineering and Engineering Geology
  • Fuel Technology
  • Management, Monitoring, Policy and Law
  • Waste Management and Disposal
  • Materials Science (miscellaneous)

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