Coating of hydroxyapatite films on titanium substrates by electrodeposition under pulse current

Abstract

Titanium (Ti) metal substrates were etched in sulfuric acid (H 2 SO 4 ) with concentrations of 25, 50, 75 and 97 at 60°C for 30 min. Hydroxyapatite (HA) films were deposited onto unetched and etched substrates by an electrodeposition method under a pulse current. The electrolyte was metastable calcium phosphate solution that had 1.5 times the ion concentrations of human body fluid, but did not contain magnesium ion at 36.5°C. Deposition times were 90 min. We used the average current density of 0.01 A/cm 2 and ON time equal to OFF time of 15 s. In the electrodeposition, hydrogen was incorporated into the surface of the Ti substrates to form titanium hydride (TiH 2 ) on the substrate surfaces. After the electrodeposition, all specimens were heated at 600°C for 60 min. The adhesion between apatite and substrates were greatly improved by the heat treatment for the substrates etched in 50 and 75 H 2 SO 4 . It is considered that in these specimens the anchoring effect due to the microstructural roughness formed by etching was enhanced by the shrinking of HA crystals during the heat treatment.

Single-step pulsed electrodeposition of calcium phosphate coatings on titanium for drug delivery

“…However, during conventional electrochemical deposition hydrogen bubbles (H 2 ) are produced at the vicinity of the cathode acting as a boundary layer which lowers the throughput of the ions. In order to circumvent this issue, pulsed cathodic electrochemical deposition has been used for coating titanium substrates [16][17][18][19]. Indeed the relaxation time (time off) between two unipolar pulses reduces the emission of H 2 .…”

Biofunctionalization of titanium for dental implant

“…This technique is useful for the treatment of thin wire and fiber without the dissolution of Ti. HA is electrodeposited with pulse current [16].…”

Electrodeposition of hydroxyapatite (HAp) coatings on etched titanium mesh substrate

“…In terms of preparation of HAp coatings by electrodeposition, it was reported that hydrogen, H 2 is also produced at the same time as the hydroxide, OHwhich leads to the formation of gas bubbles that can adhere themselves to the surface of the substrate [16][17]. This inhibits the nucleation and growth of HAp coatings and also prevents further deposition of Ca-P ions.…”

“…Etching Ti substrates into hot acid solution also can promote the nucleation of HAp coatings by increasing the 978-1-4673-4617-7/12/$31.00 ©2012 IEEE surface roughness of the Ti substrates [17]. Surface roughness of Ti also affects the rate of osseointegration and biomedical fixation.…”