Operating parameters effect on physico-chemical characteristics of nanocrystalline apatite coatings electrodeposited on 316L stainless steel

Thi Nam Pham, Thi Mai Thanh Dinh, Thi Thom Nguyen, Thu Phuong Nguyen, E Kergourlay, D Grossin, G Bertrand, N Pebere, S J Marcelin, C Charvillat and C Drouet

Abstract

Hydroxyapatite (HAp) was known as a bone implant material due to its biocompatibility, bioactive, chemical stability and its compositional similarity to natural bone. In this work nanocrystalline HAp coatings were prepared on 316L stainless steel (316LSS) substrates using a potentio-dynamic method (potential scanning in the range from 0 to  −1.6 V/SCE) in the presence of dissolved 3  ×  10⁻² M Ca(NO₃)₂  +  1.8  ×  10⁻² M NH₄H₂PO₄  +  0.15 M NaNO₃ and 6% H₂O₂ (w/w). We report the influence of experimental conditions such as temperature (25 °C–60 °C), scanning rate (1 mV s⁻¹–10 mV s⁻¹) and scanning times (1 times–7 times) on the morphology, structure and composition of the HAp coatings by FTIR, XRD and SEM analysis. The results show that the morphology and purity of the HAp coating were greatly affected by temperature, scanning rate and reaction time with rate of 5 mV s⁻¹, reaction time of 26.67 min (corresponding 5 scanning times) and 25 °C, giving better coatings. The in vivo test results after 3 months grafting on femur of dogs of HAp/316LSS material showed that: the material did not induce any osteitis, osteomyelitis or structural abnormalities. The osteitis and osteomyelitis were not observed in microscopy images