title: Preparation and characteristics of nano-grained calcium phosphate coatings on titanium from ultrasonated bath at acidic pH.
abstract: Electrochemically deposited nano-grained calcium phosphate coatings were produced on titanium substrates using aqueous electrolyte at acidic pH. Different coatings were produced by using cathodic current densities ranging from 10 to 50 mA/cm(2) from an ultrasonated electrolytic bath. These coatings contained dicalcium phosphate dihydrate as the predominant phase and hydroxyapatite as the minor phase. With increasing current density, hydroxyapatite content in the coatings increased. Dicalcium phosphate grains had size in the range of 55-85 nm and hydroxyapatite had grains in the size range of 20-25 nm. Scanning electron microscopy showed that the morphology of the coatings obtained at lower current densities had acicular structure. With increasing current densities, the needles became blunt and small and finally, at 50 mA/cm(2) the coating had globular deposits. Surface roughness of the coatings also increased with increasing deposition current density. Tensile bond strengths of the coatings were in the range of 3.6-6.9 MPa and decreased with increase of deposition current density. Heat-treatment of the coatings for 2 h at 500 degrees C completely eliminated the dicalcium phosphate phase and resulted in mono hydroxyapatite phase containing grains in the size range of 20-30 nm.
authors.affiliation: Department of Dental Biomaterials, College of Dentistry, Institute for Biomaterials Research and Development, KNU School of Dentistry BK21, Kyungpook National University, Daegu, Korea.
authors.forename: R
authors.initials: R
authors.lastname: Narayanan
authors.forename: Tae-Yub
authors.initials: TY
authors.lastname: Kwon
authors.forename: Kyo-Han
authors.initials: KH
authors.lastname: Kim
mesh_terms: D000268:Adhesiveness; D002118:Calcium / Q000737:chemistry; D002130:Calcium Phosphates / Q000737:chemistry*; D020099:Coated Materials, Biocompatible / Q000737:chemistry*; D017886:Durapatite / Q000737:chemistry; D004563:Electrochemistry; D006801:Humans; D006863:Hydrogen-Ion Concentration; D008422:Materials Testing; D049329:Nanostructures; D010316:Particle Size; D013499:Surface Properties; D013718:Tensile Strength; D014025:Titanium / Q000737:chemistry*; D014465:Ultrasonics
chemical_list: D002130:Calcium Phosphates; D020099:Coated Materials, Biocompatible; D017886:Durapatite; C020243:calcium phosphate; D014025:Titanium; D002118:Calcium