Metallic materials are commonly used in orthopedic implants due to their high mechanical strength. Implant loosening and bacterial infection are the two major causes of implant failure in most of the cases, and they arise from inadequate bioactivity and anti-bacterial effect at the surface of the implant. Hydroxyapatite (HA) is well known to be bioactive while silver (Ag) possesses strong anti-bacterial effect. It is the aim of the present paper to fabricate an Ag-containing HA layer on Ti6Al4V substrate. Ag-containing powder was first prepared via a chemical route and then used in laser cladding on Ti6Al4V substrate. The Ag-containing HA powder and laser clad layer were characterized using SEM, EDS, and XRD. It is found that the composition and phases in the Ag-containing HA powder were essentially retained after laser cladding.
AbstractAbstractExcimer laser surface treatment of aluminium alloy 6013-T651 was conducted with the aim of improving the intergranular corrosion resistance of the alloy. Laser surface treatment was performed under two different gas environments: air and nitrogen. The microstructure, phase, and composition of the modified surface structure were analysed using TEM, X-ray photoelectron spectroscopy, and EDX; the electrochemical and the intergranular corrosion cracking behaviours of the untreated and the laser treated specimens were evaluated by electrochemical polarisation test and immersion test respectively. Excimer laser surface treatment significantly increased the pitting potential and the intergranular corrosion resistance of the alloy, especially when the material was treated in nitrogen gas. A reduction in corrosion current density of three orders of magnitude was obtained for the N2 treated material. The improvement is considered to be primarily owing to the reduction of large harmful intermetallics within the grains and the absence of precipitate free zones and Al–Cu–Si bearing needle like precipitates at the grain boundaries. The superior corrosion resistance of the N2 treated material is attributed to the presence of the chemically stable AlN phase in the surface.
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