Preparation and corrosion behavior of NiTi shape memory alloy coated with biocompatable layer

Abstract EN

In this paper NiTi shape memory alloy has prepared from elemental Nickel and Titanium powders by powder metallurgy Technique, the is 620 MPa compacting pressure , 850 ˚C temperature and10-3 torr vacuum atmosphere.

The Porosity and density before and after sintering have been calculated.

X-ray diffraction analysis showed that Nickel and Titanium are completely transformed into NiTi and Ni3Ti phase.

Poly Methyl Methane Acrylate and Poly Methyl Methane Acrylate / Hydroxy apatite coating are applied to the surface of the alloy.

Optical microscopy technique is used to characterize the surface of each sample.

The corrosion rate has been studied in vitro by using electrochemical technique by a potentiostate in Hank’s Solution, Artificial saliva and 0.9% NaCl solution at 37 ºC.

Atomic Absorption Spectroscopy technique is used to detect the Ni ion release from the alloy in 0.9% NaCl solution.

The corrosion test results shows that the corrosion rate after Poly Methyl Methane Acrylate / Hydroxyapatite coating decreased from 12.14 mpy for bare sample into 0.132 mpy in 0.9% NaCl solution , from 4.94 mpy into 0.39 mpy Artificial saliva and from 12.66 mpy into 0.217 mpy in Hank Solution.

The Ni release test shows that the amount of releasing Ni ion decreased into undetectable amount after coating with Poly Methyl Methane Acrylate and Poly Methyl Methane Acrylate / Hydroxyapatite.