Journal
SURFACE & COATINGS TECHNOLOGY
Volume 301, Issue -, Pages 54-62Publisher
ELSEVIER SCIENCE SA
DOI: 10.1016/j.surfcoat.2016.02.035
Keywords
Calcium orthophosphates; Plasma electrolytic oxidation; Impedance spectroscopy; Titanium; Process diagnostics
Funding
- European Research Council under the ERC [320879]
- UK EPSRC [EP/L017563/1]
- Russian Presidential Grant for young D.Sc. scientists [MD-2870.2014.8]
- EPSRC [EP/L017563/1] Funding Source: UKRI
- Engineering and Physical Sciences Research Council [EP/L017563/1] Funding Source: researchfish
- European Research Council (ERC) [320879] Funding Source: European Research Council (ERC)
Ask authors/readers for more resources
Pulsed bipolar plasma electrolytic oxidation (PEO) processes carried out under potentiostatic control in electrolytes containing calcium acetate and sodium phosphate with Ca:P ratio of 2 were investigated by in situ impedance spectroscopy in order to achieve insights in the coating formation mechanisms and identify suitable means for real-time control of essential coating characteristics and properties. The coating thickness, morphology, chemical and phase compositions have been studied by non-destructive eddy current techniques, scanning electron microscopy, energy dispersive X-ray spectroscopy and X-ray diffraction analysis. The results demonstrate successful deposition of about 25 pm thick porous surface layers composed of amorphous calcium phosphates along with crystalline hydroxyapatite, tricalcium phosphate perovskite and titania phases. It was established that the growth of the PEO is controlled by anodic process of titanium oxidation, whereas precipitation of calcium phosphate containing compounds occurred via chemical mechanisms. Plasma discharge was responsible for partial crystallisation and decomposition of the deposited compounds. Characteristic responses related to anodic oxidation of Ti and processes associated with plasma discharge were identified in the impedance spectra of the PEO process. Kinetic parameters of charge transfer under conditions of high-voltage electrolysis have been evaluated and discussed. (C) 2016 Elsevier B.V. All rights reserved.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available