Comparative investigations of structure and properties of micro-arc wollastonite-calcium phosphate coatings on titanium and zirconium-niobium alloy

- Investigations of microarc wollastonite-calcium phosphate biocoatings on the titanium and Zr-1wt.%Nb alloy were presented.
- The thin coatings 10-11 μm with wollastonite particles formed under the low process voltage of 130-150 V.
- The increase of the process voltage to 300 V leads to the dissociation of the wollastonite.
- Coatings on both substrates have not toxic effect on the morphofunctional status of AMMSCs culture in vitro.

Investigation results of micro-arc wollastonite-calcium phosphate (W-CaP) biocoatings on the pure titanium (Ti) and Zr-1wt.%Nb (Zr-1Nb) alloy were presented. The voltages of 150-300 V generate the micro-arc oxidation (MAO) process with the initial amplitude current of 150-550 A and 100-350 A for Ti and Zr-1Nb substrates, respectively. The identical dependencies of changes of the coating thickness, surface roughness and adhesion strength on the process voltage were revealed for the both substrates. The W-CaP coatings with the thickness of 10-11 μm were formed on Ti and Zr-1Nb under the low process voltage of 130-150 V. Elongated wollastonite particles with the size in the range of 40-100 μm were observed in such coatings. The structure of the coatings on Ti was presented by the X-ray amorphous and crystalline phases. The X-ray reflexes relating to the crystalline phases of Ti and wollastonite were observed only in XRD patterns of the coatings deposited under 130-200 V on Ti. While, the crystalline structure with phases of CaZr4(PO4)6, β-ZrP2O7, ZrO2, and Zr was detected in the coatings on Zr-1Nb. FT-IRS, XRD, SEM, and TEM data confirmed that the increase of the process voltage to 300 V leads to the dissociation of the wollastonite. No toxic effect of specimens on a viability, morphology and motility of human adipose-derived multipotent mesenchymal stem cells was revealed in vitro.

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