Electrophoretic deposition of hydroxyapatite coatings on metal substrates: A nanoparticulate dual-coating approach

Wei, M; Ruys, AJ; Milthorpe, BK; Sorrell, CC; Evans, JH

Electrophoretic deposition of hydroxyapatite coatings on metal substrates: A nanoparticulate dual-coating approach

Wei, M Ruys, AJ Milthorpe, BK

Sorrell, CC Evans, JH

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Publication Type:: Journal Article
Citation:: Journal of Sol-Gel Science and Technology, 2001, 21 (1-2), pp. 39 - 48
Issue Date:: 2001-06-01

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Field	Value	Language
dc.contributor.author	Wei, M	en_US
dc.contributor.author	Ruys, AJ	en_US
dc.contributor.author	Milthorpe, BK https://orcid.org/0000-0002-0867-9586	en_US
dc.contributor.author	Sorrell, CC	en_US
dc.contributor.author	Evans, JH	en_US
dc.date.issued	2001-06-01	en_US
dc.identifier.citation	Journal of Sol-Gel Science and Technology, 2001, 21 (1-2), pp. 39 - 48	en_US
dc.identifier.issn	0928-0707	en_US
dc.identifier.uri	http://hdl.handle.net/10453/9206
dc.description.abstract	Hydroxyapatite coatings can be readily deposited on metal substrates by electrophoretic deposition. However, subsequent sintering is highly problematic owing to the fact that temperatures in excess of 1100 °C are required for commercial hydroxyapatite powders to achieve high density. Such temperatures damage the metal and induce metal-catalysed decomposition of the hydroxyapatite. Furthermore, the firing shrinkage of the hydroxyapatite coating on a constraining metal substrate leads to severe cracking. The present study has overcome these problems using a novel approach: the use of aged nanoparticulate hydroxyapatite sols (lower sintering temperature) and a dual coating strategy that overcomes the cracking problem. Dual layers of uncalcined hydroxyapatite (HAp) powder were electrophoretically coated on Ti, Ti6A14V and 316L stainless steel metal substrates, sintered at 875-1000 ° C, and characterised by SEM and XRD, and interfacial shear strength measurement. Dual coatings on stainless steel had an average high bond strength (about 23 MPa), and dual coatings on titanium and titanium alloy had moderate strengths (about 14 and 11 MPa, respectively), in comparison with the measured shear strength of bone (35 MPa). SEM and XRD demonstrated that the second layer blended seamlessly with the first and filled the cracks in the first. The superior result on stainless steel is attributed to a more appropriate thermal expansion match with hydroxyapatite, the thinner oxide layer, or a combination of these factors.	en_US
dc.relation.ispartof	Journal of Sol-Gel Science and Technology	en_US
dc.relation.isbasedon	10.1023/A:1011201414651	en_US
dc.subject.classification	Materials	en_US
dc.title	Electrophoretic deposition of hydroxyapatite coatings on metal substrates: A nanoparticulate dual-coating approach	en_US
dc.type	Journal Article
utslib.citation.volume	1-2	en_US
utslib.citation.volume	21	en_US
utslib.for	090301 Biomaterials	en_US
utslib.for	0912 Materials Engineering	en_US
pubs.embargo.period	Not known	en_US
pubs.organisational-group	/University of Technology Sydney
pubs.organisational-group	/University of Technology Sydney/Faculty of Science
pubs.organisational-group	/University of Technology Sydney/Strength - CHT - Health Technologies
utslib.copyright.status	closed_access
pubs.issue	1-2	en_US
pubs.publication-status	Published	en_US
pubs.volume	21	en_US

Abstract:

Hydroxyapatite coatings can be readily deposited on metal substrates by electrophoretic deposition. However, subsequent sintering is highly problematic owing to the fact that temperatures in excess of 1100 °C are required for commercial hydroxyapatite powders to achieve high density. Such temperatures damage the metal and induce metal-catalysed decomposition of the hydroxyapatite. Furthermore, the firing shrinkage of the hydroxyapatite coating on a constraining metal substrate leads to severe cracking. The present study has overcome these problems using a novel approach: the use of aged nanoparticulate hydroxyapatite sols (lower sintering temperature) and a dual coating strategy that overcomes the cracking problem. Dual layers of uncalcined hydroxyapatite (HAp) powder were electrophoretically coated on Ti, Ti6A14V and 316L stainless steel metal substrates, sintered at 875-1000 ° C, and characterised by SEM and XRD, and interfacial shear strength measurement. Dual coatings on stainless steel had an average high bond strength (about 23 MPa), and dual coatings on titanium and titanium alloy had moderate strengths (about 14 and 11 MPa, respectively), in comparison with the measured shear strength of bone (35 MPa). SEM and XRD demonstrated that the second layer blended seamlessly with the first and filled the cracks in the first. The superior result on stainless steel is attributed to a more appropriate thermal expansion match with hydroxyapatite, the thinner oxide layer, or a combination of these factors.

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http://hdl.handle.net/10453/9206