Effect of the deposition route on the microstructure of plasma-sprayed hydroxyapatite coatings

Marine Chambard (1, 2) , Olivier Marsan (1) , Cédric Charvillat (1) , David Grossin (1) , P. Fort (3) , Christian Rey (1, 2) , François Gitzhofer (2) , Ghislaine Bertrand (1)

1 CIRIMAT - Centre interuniversitaire de recherche et d'ingenierie des matériaux
2 UdeS - Université de Sherbrooke
3 Projection Plasma Système - 2PS (FRANCE)

Plasma-spray (PS) is the most common technique used to cover orthopaedic titanium-based implant surfaces with hydroxyapatite (HA - Ca10(PO4)6OH2). The objective of the current work was to explore the influence of the precursor nature and characteristics (mainly powder size, Ca/P ratio, and density) on the morphology and the microstructure of HA coatings, deposited either by conventional atmospheric plasma spray (APS) or by rf-suspension plasma spray (rf-SPS). Two powders with different size distribution, density and shape were sprayed with same operating APS conditions. In parallel two water-based suspensions with distinct particle size and chemistry (Ca/P ratio) were implemented in rf-SPS. The morphology of both APS and rf-SPS coatings observed by SEM exhibits micro and sub-micro sized structures respectively, with similar porosity and thickness. The difference in precursor particle size does not affect the coating structure in rf-SPS, unlike in APS conditions. Superimposition of topography and phases maps performed from profilometry and Raman cartographies showed no direct correlation between the surface profile and composition. But such analysis highlighted the heterogeneity of the phases composing the coating surface, opening the possibility of a better understanding of biological behaviour.

Mots clés: Rf; suspension plasma spraying; APS; Hydroxyapatite coating; Microstructure; Precursor nature

Domaines: Matériaux

Marine Chambard, Olivier Marsan, Cédric Charvillat, David Grossin, P. Fort, et al.. Effect of the deposition route on the microstructure of plasma-sprayed hydroxyapatite coatings. Surface and Coatings Technology, 2019, 371, pp.68-77. ⟨10.1016/j.surfcoat.2019.01.027⟩. ⟨hal-02498605⟩