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Title

Effects of spraying parameters on phase formation and distribution in plasma-sprayed hydroxyapatite coatings

Author(s)

Sun, Limin;  Berndt, Christopher C.;  Lima, Rogerio S.;  Kucuk, Ahmet;  Khor, Khiam Aik

Abstract

Calcined spray-dried hydroxyapatite (Ca10(PO 4)(OH)6; i.e., HA) powders were atmospherically plasma sprayed (APS) using various process parameters. The resulting phases within the coating surface and the interface between the coating and the substrate were analyzed using X-ray diffraction (XRD) methods. This XRD revealed the presence of both amorphous (i.e., amorphous calcium phosphate: ACP) and crystalline phases. The crystalline phases included both HA and some impurity phases from the decomposition of HA, such as tricalcium phosphate (α-TCP and β-TCP), tetracalcium phosphate (TTCP) and calcium oxide (CaO). The crystallinity of HA decreased with increasing spray power and stand-off distance (SOD). The percentage of all impurity phases increased with the spray power. The percentage of both TCP and TTCP decreased with the SOD while the CaO percentage increased. In addition, the percentage of ACP and CaO were higher in the interface than at the surface of the coating while the percentage of TCP and TTCP exhibited the opposite effect.

Publication type

Conference paper

Source

Proceedings of the 1st International Thermal Spray Conference, 'Thermal spray surface engineering via applied research', Montreal, Quebec, Canada, 09-11 May 2000 / Christopher C. Berndt (ed.), pp. 803-811

Publication year

2000

Keyword(s)

ACP;  Amorphous materials;  APS;  Atmospheric plasma spray;  Biocompatibility;  Coatings;  Cooling;  Crystallization;  HA;  Hydroxyapatite;  Impurities;  Phase formation;  Plasma flames;  Plasma spraying;  TCP;  Tetracalcium phosphate;  Tricalcium phosphate;  TTCP;  X-ray diffraction analysis

Publisher

ASM International

ISBN

9780871706805, 0871706806

Full text

Peer reviewed