title: Formation of Solution-derived Hydroxyapatite Coatings on Titanium Alloy in the Presence of Magnetron-sputtered Alumina Bond Coats.
abstract: Hydroxyapatite Ca10(PO4)6(OH)2 (HAp) and calcium phosphate ceramic materials and coatings are widely used in medicine and dentistry because of their ability to enhance the tissue response to implant surfaces and promote bone ingrowth and osseoconduction processes. The deposition conditions have a great influence on the structure and biofunctionality of calcium phosphate coatings. Corrosion processes and poor adhesion to substrate material reduce the lifetime of implants with calcium phosphate coatings. The research has focused on the development of advanced methods to deposit double-layered ceramic oxide/calcium phosphate coatings by a hybrid technique of magnetron sputtering and thermal methods. The thermal method can promote the crystallization and the formation of HAp coatings on titanium alloy Ti6Al4V substrates at low temperature, based on the principle that the solubility of HAp in aqueous solutions decreases with increasing substrate temperature. By this method, hydroxyapatite directly coated the substrate without precipitation in the initial solution. Using a thermal substrate method, calcium phosphate coatings were prepared at substrate temperatures of 100-105 (o)C. The coated metallic implant surfaces with ceramic bond coats and calcium phosphate layers combine the excellent mechanical properties of metals with the chemical stability of ceramic materials. The corrosion test results show that the ceramic oxide (alumina) coatings and the double-layered alumina-calcium phosphate coatings improve the corrosion resistance compared with uncoated Ti6Al4V and single-layered Ti6Al4V/calcium phosphate substrates. In addition, the double-layered alumina/hydroxyapatite coatings demonstrate the best biocompatibility during in vitro tests.
authors.affiliation: National Science Centre, Kharkov Institute of Physics and Technology, Kharkov, Ukraine.
authors.forename: Anna
authors.initials: A
authors.lastname: Zykova
authors.affiliation: National Science Centre, Kharkov Institute of Physics and Technology, Kharkov, Ukraine.
authors.forename: Vladimir
authors.initials: V
authors.lastname: Safonov
authors.affiliation: Institute of Applied Physics National Academy of Sciences of Ukraine, Sumy, Ukraine ; Sumy State University, Medical Institute, Ministry of Education and Science, Sumy, Ukraine.
authors.forename: Anna
authors.initials: A
authors.lastname: Yanovska
authors.affiliation: Sumy State University, Medical Institute, Ministry of Education and Science, Sumy, Ukraine.
authors.forename: Leonid
authors.initials: L
authors.lastname: Sukhodub
authors.affiliation: Institute for Sustainable Technologies, National Research Institute, Radom, Poland.
authors.forename: Renata
authors.initials: R
authors.lastname: Rogovskaya
authors.affiliation: Institute for Sustainable Technologies, National Research Institute, Radom, Poland.
authors.forename: Jerzy
authors.initials: J
authors.lastname: Smolik
authors.affiliation: Department of Physical Technologies, Kharkov National University, Kharkov, Ukraine.
authors.forename: Stas
authors.initials: S
authors.lastname: Yakovin
keywords: Alumina; biocompatibility; hydroxyapatite; magnetron sputtering; potentiodynamic testing; thermal method