R M Wang

Publications (3)2.1 Total impact

• Source

  Available from: Kelvin Yeung

  Article: Effects of anodic oxidation in H2SO4 electrolyte on the biocompatibility of NiTi shape memory alloy

  C L Chu, R M Wang, L H Yin, Y P Pu, P H Lin, Y S Dong, C Y Chung, K W K Yeung, P K Chu
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  ABSTRACT: Effects of anodic oxidation in H 2 SO 4 electrolyte on the biocompatibility of NiTi shape memory alloy (SMA) were investigated by characterizing surface structure, blood compatibility, wettability, release of harmful Ni ions of anodized NiTi SMA. Although titania film resulting from anodic oxidation in H 2 SO 4 electrolyte has a porous structure, it can effectively block out-diffusion of Ni from NiTi SMA to simulated body fluid (SBF). Comparing with chemical polishing, anodic oxidation in H 2 SO 4 electrolyte can also improve the wettability, blood compatibility, thromboresistance of NiTi SMA.
  04/2008;
• Article: Surface structure and biomedical properties of chemically polished and electropolished NiTi shape memory alloys

  C.L. Chu, R.M. Wang, T. Hu, L.H. Yin, Y.P. Pu, P.H. Lin, S.L. Wu, C.Y. Chung, K.W.K. Yeung, Paul K. Chu
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  ABSTRACT: The surface structure and biomedical properties of NiTi shape memory alloy (SMA) samples after undergoing electropolishing and chemical polishing are determined and compared employing scanning electron microscopy, X-ray photoelectron spectroscopy, inductively-coupled plasma mass spectrometry, hemolysis analysis, blood platelet adhesion test, and MTT test. The results indicate that after chemical polishing, there is still a high Ni concentration on the surface of the NiTi SMA. On the other hand, electropolishing can form a thin surface titanium oxide film (about 10 nm thickness) with depleted Ni. In addition to the TiO2 phase, some titanium suboxides (TiO and Ti2O3) are found in the surface film. Compared to chemical polishing, electropolishing can more effectively mitigate out-diffusion of Ni ions and the wettability, blood compatibility, and thromboresistance are also better. However, no difference on the cytocompatibility can be observed from samples that have been chemically polished or electropolished.
  Materials Science and Engineering: C. 28(8):1430-1434.
• Article: Surface XPS characterization of NiTi shape memory alloy after advanced oxidation processes in UV/H2O2 photocatalytic system

  R.M. Wang, C.L. Chu, T. Hu, Y.S. Dong, C. Guo, X.B. Sheng, P.H. Lin, C.Y. Chung, P.K. Chu
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  ABSTRACT: Surface structure of NiTi shape memory alloy (SMA) was modified by advanced oxidation processes (AOP) in an ultraviolet (UV)/H2O2 photocatalytic system, and then systematically characterized with x-ray photoelectron spectroscopy (XPS). It is found that the AOP in UV/H2O2 photocatalytic system leads to formation of titanium oxides film on NiTi substrate. Depth profiles of O, Ni and Ti show such a film possesses a graded interface structure to NiTi substrate and there is no intermediate Ni-rich layer like that produced in conventional high temperature oxidation. Except TiO2 phase, some titanium suboxides (TiO, Ti2O3) may also exist in the titanium oxides film. Oxygen mainly presents in metal oxides and some chemisorbed water and OH− are found in titanium oxides film. Ni nearly reaches zero on the upper surface and relatively depleted in the whole titanium oxides film. The work indicates the AOP in UV/H2O2 photocatalytic system is a promising way to favor the widespread application of biomedical NiTi SMA by improving its biocompatibility.
  Applied Surface Science 253(20):8507-8512. · 2.10 Impact Factor