Influence of the electrophoretic deposition route on the microstructure and properties of nano-hydroxyapatite/chitosan coatings on the Ti-13Nb-13Zr alloy

• Published in: Surface & coatings technology 2017-09, Vol.324, p.64-79
• Main Authors: Jugowiec, Dawid, Łukaszczyk, Alicja, Cieniek, Łukasz, Kowalski, Kazimierz, Rumian, Łucja, Pietryga, Krzysztof, Kot, M., Pamuła, Elżbieta, Moskalewicz, Tomasz
• Format: Article
• Language: English
• Subjects: Agglomerates; Alloys; Biocompatibility; Biological properties; Chemical composition; Chitosan; Composite coatings; Corrosion resistance; Corrosion resistant alloys; Electrochemical corrosion; Electrokinetics; Electrophoretic deposition; Electrophoretic deposition (EPD); Ethanol; Hydroxyapatite; Hydroxyapatite (HA); Microstructure; Nanocomposites; Nanoparticles; Protective coatings; Surgical implants; Ti-13Nb-13Zr alloy; Titanium base alloys
• ISSN: 0257-8972; 1879-3347
• DOI: 10.1016/j.surfcoat.2017.05.056

In this work, nanocomposite HA/chitosan coatings were electrophoretically deposited (EPD) on a near-β Ti-13Nb-13Zr alloy. The influence of the state of the HA particles introduced to the colloidal solution of chitosan (nc-HA-p as a nanopowder and nc-HA-s as nanoparticles suspended in ethanol), as well as the chemical composition of a multi-component HA-chitosan suspension and EPD parameters, on the homogeneity of coatings has been studied. It was established that the pH value and the chemical composition of the suspension have a substantial effect on the electrokinetic properties of suspended HA and chitosan particles. These are also influenced by the deposition kinetics of EPD and the uniformity of as-deposited coatings. The thickness of the nc-HA-p/chitosan and nc-HA-s/chitosan coatings was up to 750nm and 1.5μm, respectively. The nc-HA-s/chitosan coating microstructure consisted of HA nanoparticles, homogeneously embedded in an amorphous chitosan matrix. The nc-HA-p/chitosan coating microstructure was non-homogeneous, composed of HA agglomerates in a chitosan matrix. The presence of thin oxide layer was observed on the coatings/titanium alloy interface. The nc-HA-s/chitosan coating exhibited better adhesion to the titanium alloy substrate than the nc-HA-p/chitosan coating. It was found that the nc-HA-s/chitosan coating improves the electrochemical corrosion resistance of the Ti-13Nb-13Zr alloy in Ringer's solution, as well as its bioactivity and other biological properties. [Display omitted] •Uniform nc-HA/chitosan coatings were produced on the Ti-13Nb-13Zr alloy by EPD.•Coating homogeneity depends on the HA state introduced to the suspension.•The nc-HA-s/chitosan coatings exhibited good adhesion to the alloy.•The nc-HA-s/chitosan coatings improved corrosion resistance of titanium alloy.•Bioactivity of the alloy was enhanced by nc-HA-s/chitosan coatings.