Publication

Abstract : Hydroxyapatite (HAp) was deposited by plasma spraying technique with TiSiN adhesive interlayer on the medical-grade 316 LVM stainless steel. The surface topographies of HAp and HAp/TiSiN were evaluated using X-ray diffraction (XRD), Raman spectroscopy, atomic force microscopy (AFM), scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS). The important mechanical properties of the films such as hardness ( H ) and elastic modulus ( E ) were determined by the nanoindentation test. Lastly, the adhesion and anti-scratch behaviors of the films were evaluated by Rockwell-C indentation and nanoscratch test, respectively. The elemental analysis showed the values of Ca/P (at.%/at.%) ratio to be 1.80 and 1.59 in HAp and HAp/TiSiN coatings, respectively. The mechanical properties of HAp film with TiSiN interlayer were greatly improved from 1.23 ± 0.26GPa to 10.6 ± 1.12GPa for hardness and from 18 ± 3GPa and 29.8 ± 5GPa for elastic modulus, respectively. The results of the Rockwell-C indentation test showed a significant reduction in HAp coating delamination with TiSiN interlayer which can be categorized with HF2 or HF3 Daimler–Benz quality ranking. What is more, the nanoscratch profile of HAp coating showed wider scratch with evidence of deformation at the edges which got significantly reduced with the TiSiN interlayer. The results are suggestive of improved mechanical properties, viz. hardness and elastic modulus, and improved adhesion strength of HAp coating with TiSiN interlayer.