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

Abstract

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.

Calcium Phosphate Coating Prepared by Microarc Oxidation Affects hTERT Expression, Molecular Presentation, and Cytokine Secretion in Tumor-Derived Jurkat T Cells

“…Thus, we established the range of the applied MAO voltage of 150–300 V provided to form the MAO coatings with a combination of properties required usually for biological applications. The applied voltage of more than 250 V leads to dramatic decrease in the adhesion strength of thick CaP coating to Ti substrate [ 5 ] that limits its employment in orthopedic practice. Therefore, the range of the applied MAO voltage of 150–250 V was used to deposit the coatings as follows: Ca/P atomic ratio of 0.3–0.5, thickness of 24–80 µm, mass of 5–25 mg, and roughness index R a of 2.0–5.0 µm.…”

“…Plasma electrolytic or microarc oxidation (MAO) is one the most applicable techniques to prepare metal-oxide and CaP coatings [ 3 , 4 , 5 , 6 ] that can be relatively easily improved and innovate traumatological and orthopedic practice. We have previously detected the synthetic microterritories in microarc CaP coating which promote osteogenic differentiation and maturation of mesenchymal stem cells in vitro [ 7 ].…”

Surface Modification of Biomedical Titanium Alloy: Micromorphology, Microstructure Evolution and Biomedical Applications

“…Furthermore, Li et al [27] studied the two-step micro-arc oxidation method to prepare super-hydrophilic biomedical coatings with macro/micro/nano three-layer structures. In addition, Wang et al [28] and Sedelnikova et al [29] prepared coatings on Ti-based alloy with different surface morphology, thickness and adhesion strength with MAO through controlling voltage. The SEM micrograph is shown in Figure 2.…”

“…x FOR PEER REVIEW 3 of SEM micrographs of the wollastonite-calcium phosphate (W-CaP) coatings on Ti (a-c) and SEM micrographs of the cross-sectional W-CaP coatings on Ti (d-f) produced under different voltages[29].…”

Gene Expression Regulation and Secretory Activity of Mesenchymal Stem Cells upon In Vitro Contact with Microarc Calcium Phosphate Coating

“…Microarc oxidation (MAO) or plasma electrolytic oxidation (PEO) is one the appropriate method to deposit CaP coatings for biomedical applications [ 18 , 19 , 20 ]. We found previously ECM mineralization of 21-day MSC culture both on rough surface [ 21 ] and on plastic around the microarc CaP-coated titanium (Ti) samples [ 22 ].…”