Depth-Resolved Strain Investigation of Plasma Sprayed Hydroxyapatite Coatings Exposed to Simulated Body Fluid

Depth-Resolved Strain Investigation of Plasma Sprayed Hydroxyapatite Coatings Exposed to Simulated Body Fluid

T. Ntsoane, C. Theron, M. Topic, M. Härting, R. Heimann

download PDF

The influence of exposure to simulated body fluid (SBF) on plasma sprayed hydroxyapatite (HAp) coatings on medical grade Ti6Al4V samples has been investigated. Through-thickness residual strain investigations of HAp coatings deposited on flat substrate surfaces incubated for 7, 28 and 56 days were performed using high-energy synchrotron diffraction techniques. In the as-sprayed condition, the results show the top half of the HAp coating to be under compression with the maximum around the near-surface region, relaxing with depth below the surface reaching a strain-free point around the coating thickness midpoint. On the contrary, the remainder of the coating is under tension increasing with further depth; the maximum tension is observed near the coating-substrate interface region. Upon immersion in SBF, both the slope of the normal strain components 11 and 33 relax, with the former experiencing a change in slope before saturating after 7 days; the highest change was observed within the first week of incubation.

Plasma-Sprayed Hydroxyapatite Coatings, In-Vitro Investigation, High-Energy Diffraction, Residual Stress

Published online 4/20/2018, 6 pages
Copyright © 2018 by the author(s)
Published under license by Materials Research Forum LLC., Millersville PA, USA

Citation: T. Ntsoane, C. Theron, M. Topic, M. Härting, R. Heimann, ‘Depth-Resolved Strain Investigation of Plasma Sprayed Hydroxyapatite Coatings Exposed to Simulated Body Fluid’, Materials Research Proceedings, Vol. 4, pp 123-114, 2018


The article was published as article 19 of the book

Content from this work may be used under the terms of the Creative Commons Attribution 3.0 licence. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI.

[1] T. Yamamoto, T. Onga, T. Marui and K. Mizuno, Use of hydroxyapatite to fill cavities after excision of benign bone tumours, J. Bone Joint Surg. (Br.), 82B, (2000) 1117.
[2] R.G.T. Geesink, K. de Groot and C.P.A.T. Klein, Chemical implant fixation using hydroxyl-apatite coatings The development of a human total hip prosthesis for chemical fixation to bone using hydroxyl-apatite coatings on titanium substrates, Clin. Orthop. Relat. Res., 225 (1987) 147.
[3] K. de Groot, R. Geesink, C.P.A.T. Klein and P. Serekian, Plasma sprayed coatings of hydroxylapatite, J. Biomed. Mater. Res., 21 (1987) 1375.
[4] R.B. Heimann and H.D. Lehmann, Bioceramic Coatings for Medical Implants Bioceramic Coatings for Medical Implants. Trends and Techniques. Wiley-VCH, Weinheim, Germany. (2015) 467 pp. 113.
[5] R.B. Heimann, Thermal spraying of biomaterials, Surf. Coat. Technol., 201 (2006) 2012.
[6] M. Topić, T. Ntsoane, T. Hüttel and R.B. Heimann, Microstructural characterisation and stress determination in as-plasma sprayed and incubated bioconductive hydroxyapatite coatings, Surf. Coating Technol. 201(6) (2006) 3633.
[7] K.A. Gross, C.C. Berndt and H. Herman, Amorphous phase formation in plasma-sprayed hydroxyapatite coatings, J. Biomed. Mater. Res., 39 (1998) 407.;2-N
[8] P. Ducheyne, S. Radin and L. King, The effect of calcium phosphate ceramic composition and structure on in vitro behavior. I. Dissolution, J. Biomed. Mater. Res, 27 (1993) 25.
[9] TP Ntsoane, M. Topic’, M. Härting, R.B. Heimann and C. Theron, Spatial and depth-resolved studies of air plasma-sprayed hydroxyapatite coatings by means of diffraction techniques: Part I, Surf. Coating Technol, 294 (2016) 153-183.
[10] T. Kokubo, H. Kushitani, S. Sakka, T. Kitsugi and T. Yamamuro, Solutions able to reproduce in vivo surface-structure changes in bioactive glass-ceramic A-W, J Biomed Mater Res, 24 (1990) 721-734.
[11] TOPAS 4.2 2009 Bruker AXS.
[12] J. Almer and U. Lienert, Unpublished document for the Neutron/Synchrotron Summer School, Argonne National Laboratory, 2001.
[13] B. Cofino, P. Fogarassy, P. Millet and A. Lodino, Thermal residual stresses near the interface between plasma-sprayed hydroxyapatite coating and titanium substrate: Finite element analysis and synchrotron radiation measurements, J Biomed Mater Res A, (2004) 1-70.
[14] A.R. Nimkerdphol, Y. Otsuka and Y. Mutoh, Effect of dissolution/precipitation on the residual stress redistribution of plasma-sprayed hydroxyapatite coating on titanium substrate in simulated body fluid (SBF), J. Mech. Behaviour Biomed. Mater., 36 (2014) 98-109.