title: In vitro investigation of biodegradable polymeric coating for corrosion resistance of Mg-6Zn-Ca alloy in simulated body fluid.
abstract: A silane-based biodegradable coating was developed and investigated to improve corrosion resistance of an Mg-6Zn-Ca magnesium alloy to delay the biodegradation of the alloy in the physiological environment. Conditions were optimized to develop a stable and uniform hydroxide layer on the alloys surface-known to facilitate silane-substrate adhesion. A composite coating of two silanes, namely, diethylphosphatoethyltriethoxysilane (DEPETES) and bis-[3-(triethoxysilyl) propyl] tetrasulfide (BTESPT), was developed, by the sol-gel route. Corrosion resistance of the coated alloy was characterized in a modified-simulated body fluid (m-SBF), using potentiodynamic polarization and electrochemical impedance spectroscopy (EIS). The silane coating provided significant and durable corrosion resistance. During the course of this, hydrogen evolution and pH variation, if any, were monitored for both bare and coated alloys. The coating morphology was characterized using scanning electron microscopy (SEM) and energy dispersive X-ray analysis (EDAX) and the cross-linking in the coating was studied using Fourier transform infrared spectroscopy (FTIR). As indicated by X-ray diffraction (XRD) results, an important finding was the presence of hydrated magnesium phosphate on the sample that was subjected to immersion in m-SBF for 216h. Magnesium phosphate is reported to support osteoblast formation and tissue healing.
authors: IITB-Monash Research Academy, IIT Bombay, Powai, Mumbai 400076, India. Electronic address: gaurswat@gmail.com.
authors: Swati
authors: S
authors: Gaur
authors: Department of Mechanical, Monash University, Clayton, VIC-3800, Australia; Department of Aerospace Engineering, Monash University, Clayton, VIC-3800, Australia; Department of Chemical Engineering, Monash University, Clayton, VIC-3800, Australia.
authors: R K
authors: RK
authors: Singh Raman
authors: Department of Metallurgical Engineering & Materials Science, IIT Bombay, Powai, Mumbai 400076, India.
authors: A S
authors: AS
authors: Khanna
mesh_terms: D000497:Alloys / Q000737:chemistry*; D002118:Calcium / Q000737:chemistry*; D003343:Corrosion; D006859:Hydrogen; D006863:Hydrogen-Ion Concentration; D008274:Magnesium / Q000737:chemistry*; D008422:Materials Testing / Q000379:methods*; D008954:Models, Biological; D011108:Polymers / Q000737:chemistry; D019736:Prostheses and Implants; D012821:Silanes / Q000737:chemistry*; D013499:Surface Properties; D015032:Zinc / Q000737:chemistry*
chemical_list: D000497:Alloys; D011108:Polymers; D012821:Silanes; D006859:Hydrogen; D008274:Magnesium; D015032:Zinc; D002118:Calcium
keywords: Body implant; Corrosion; Electrochemical impedance spectroscopy; Hydrogen evolution; Magnesium alloy; Silanes