Effects of Silver doping in Hydroxyapatite and its coatings on 316L Stainless Steel

Abstract

In this work, hydroxyapatite (HA) and silver doped hydroxyapatite nanopowder (Ag2HA and Ag4HA) were
synthesized by the sol-gel method using precursors like calcium nitrate tetra-hydrate (CNT) for calcium, tri-ethyl
phosphate (TEP) for phosphorous and silver nitrate (AgNT) for silver and their coatings were deposited using spin
coating technique on 316L stainless steel (SS). Then the powders and coated samples were calcined and sintered at
400oC respectively. The Ca/P ratio of the synthesized HA, Ag2HA and Ag4HA nanoparticles were maintained in the
range of 1.58–1.70. Various characterization techniques were used to study the compositional structure, functionality
and phase changes of powders and microstructure of coatings by using XRF, FTIR, XRD and FE-SEM respectively. The
mechanical properties of coatings like micro hardness, surface roughness and adhesion strength were also
characterized. Potentiodynamic linear polarization was also done to study the corrosion behavior of coated samples.
XRF confirms that silver has been doped successfully and HA, Ag2HA and Ag4HA coatings were successfully and
uniformly deposited on 316L SS. Ag4HA showed the good mechanical behavior like its micro hardness and adhesion
strength was high and low surface roughness. Corrosion study reveals that Ag4HA has good corrosion resistance.