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.

Ion implantation of titanium based biomaterials

“…DCPD is normally obtained as the primary crystalline product when calcium phosphate is precipitated at low pH and temperatures. For example, DCPD is the product obtained on electrolysis at room temperature, from solutions containing dissolved calcium and phosphorus compounds at acidic pH [17].…”

“…Like the oxygen ion [76], nitrogen ion implantation at high doses and energy, was detrimental with regard to corrosion [91]. Maximum improvement of the corrosion resistance was observed with a dose of 10 17 [93] to significantly improve the material's resistance to wear-accelerated corrosion in both saline and serum solutions. Moreover, thin nitride film-formed titanium exhibiting high wear resistance [94] is commercially used in bone plates, dental implants, and artificial hip joints.…”

Hydroxylapatite nanorods: An efficient and promising carrier for gene transfection

“…Actually, some researches have been reported on the study of the synthesis of CaP nanostructures [9,10]. However, those CaP nanoparticles reported are mostly amorphous, and it is difficult to control the shape and prevent agglomeration.…”

Electrochemical surface modification of titanium in dentistry

“…At lower current densities the deposits have needle structure; with increasing currents these needles become blunt (Fig. 13) and show coarse structure [60].…”

“…Fig. 12 shows that dicalcium phosphate is the main constituent at current densities less than 5 mA/cm 2 ; HA is the main constituent above 40 mA/cm 2 [60]. Other then the electrochemical treatment, the brushite coatings can also be aged to convert them to apatite [54; 57; 61-62].…”