In-vitro viability of laser cladded Fe-based metallic glass as a promising bioactive material for improved osseointegration of orthopedic implants.

The commonly used metallic biomaterials fail to prove durability for orthopedics due to their lack of biocompatibility and poor bioactivity which weakens the bonding to bones. Metallic glasses (MGs) have attracted attention as an alternative biomaterial for orthopedics owing to their superior mechanical properties and acceptable biocompatibility. Nevertheless, their uses are limited due to geometrical constraints and brittleness. In this research, the in-vitro bioactivity of laser cladded FeCrMoCB MG on nickel-free stainless-steel was investigated. The proposed MG coating exhibited a remarkable in-vitro bioactivity behavior without prior treatment after immersion in simulated body fluid which is a key factor for better osseointegration. The surface morphology showed that apatite nucleated from the first day and completely covered the surface after 21 days. The energy dispersive spectroscopy spectra showed an increase in the Ca/P ratio from 0.51 at 3 days to 1.61 at 21 days, thus approaching the stoichiometric ratio of bone apatite. The infra-red examination revealed the existence of Ca+2, PO4-2 and OH- indicating the nucleation of brushite and B-type apatite. Additionally, the X-ray diffraction examination revealed the existence of amorphous and nanocrystalline calcium phosphates. These results show the potential of FeCrMoCB MGs as a promising bioactive coating for excellent osseointegration of metallic implants with bone tissue.

Fabrication and deformation behaviour of multilayer Al2O3/Ti/TiO2 nanotube arrays.

In this study, titanium thin films were deposited on alumina substrates by radio frequency (RF) magnetron sputtering. The mechanical properties of the Ti coatings were evaluated in terms of adhesion strength at various RF powers, temperatures, and substrate bias voltages. The coating conditions of 400W of RF power, 250°C, and a 75V substrate bias voltage produced the strongest coating adhesion, as obtained by the Taguchi optimisation method. TiO2 nanotube arrays were grown as a second layer on the Ti substrates using electrochemical anodisation at a constant potential of 20V and anodisation times of 15min, 45min, and 75min in a NH4F electrolyte solution (75 ethylene glycol: 25 water). The anodised titanium was annealed at 450°C and 650°C in a N2 gas furnace to obtain different phases of titania, anatase and rutile, respectively. The mechanical properties of the anodised layer were investigated by nanoindentation. The results indicate that Young's modulus and hardness increased with annealing temperature to 650°C.