title: Galvanic deposition and characterization of brushite/hydroxyapatite coatings on 316L stainless steel.
abstract: In this work, brushite and brushite/hydroxyapatite (BS, CaHPO4·H2O; HA, Ca10(PO4)6(OH)2) coatings were deposited on 316L stainless steel (316LSS) from a solution containing Ca(NO3)2·4H2O and NH4H2PO4 by a displacement reaction based on a galvanic contact, where zinc acts as sacrificial anode. Driving force for the cementation reaction arises from the difference in the electrochemical standard potentials of two different metallic materials (316LSS and Zn) immersed in an electrolyte, so forming a galvanic contact leading to the deposition of BS/HA on nobler metal. We found that temperature and deposition time affect coating features (morphology, structure, and composition). Deposits were characterized by means of several techniques. The morphology was investigated by scanning electron microscopy, the elemental composition was obtained by X-ray energy dispersive spectroscopy, whilst the structure was identified by Raman spectroscopy and X-ray diffraction. BS was deposited at all investigated temperatures covering the 316LSS surface. At low and moderate temperature, BS coatings were compact, uniform and with good crystalline degree. On BS layers, HA crystals were obtained at 50°C for all deposition times, while at 25°C, its presence was revealed only after long deposition time. Electrochemical studies show remarkable improvement in corrosion resistance.
authors.affiliation: Laboratorio di Chimica Fisica Applicata, Dipartimento di Ingegneria Chimica Gestionale Informatica Meccanica, Università di Palermo, Viale delle Scienze, 90128 Palermo, Italy.
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Blanda
authors.affiliation: Dipartimento di Ingegneria Civile, Ambientale, Aerospaziale, dei Materiali, Università di Palermo, Viale delle Scienze, 90128 Palermo, Italy.
authors.forename: Valerio
authors.initials: V
authors.lastname: Brucato
authors.affiliation: Dipartimento di Ingegneria Civile, Ambientale, Aerospaziale, dei Materiali, Università di Palermo, Viale delle Scienze, 90128 Palermo, Italy.
authors.forename: Francesco Carfì
authors.initials: FC
authors.lastname: Pavia
authors.affiliation: Dipartimento di Ingegneria Civile, Ambientale, Aerospaziale, dei Materiali, Università di Palermo, Viale delle Scienze, 90128 Palermo, Italy.
authors.forename: Silvia
authors.initials: S
authors.lastname: Greco
authors.affiliation: Laboratorio di Chimica Fisica Applicata, Dipartimento di Ingegneria Chimica Gestionale Informatica Meccanica, Università di Palermo, Viale delle Scienze, 90128 Palermo, Italy.
authors.forename: Salvatore
authors.initials: S
authors.lastname: Piazza
authors.affiliation: Laboratorio di Chimica Fisica Applicata, Dipartimento di Ingegneria Chimica Gestionale Informatica Meccanica, Università di Palermo, Viale delle Scienze, 90128 Palermo, Italy.
authors.forename: Carmelo
authors.initials: C
authors.lastname: Sunseri
authors.affiliation: Laboratorio di Chimica Fisica Applicata, Dipartimento di Ingegneria Chimica Gestionale Informatica Meccanica, Università di Palermo, Viale delle Scienze, 90128 Palermo, Italy. Electronic address: rosalinda.inguanta@unipa.it.
authors.forename: Rosalinda
authors.initials: R
authors.lastname: Inguanta
mesh_terms: D002130:Calcium Phosphates / Q000737:chemistry*; D017886:Durapatite / Q000737:chemistry*; D055664:Electrochemical Techniques; D013193:Stainless Steel / Q000737:chemistry*
chemical_list: D002130:Calcium Phosphates; D013193:Stainless Steel; D017886:Durapatite; C494366:calcium phosphate, dibasic, dihydrate
keywords: 316LSS; Biomedical application; Brushite; Galvanic deposition; Hydroxyapatite