Design of Experiment Analysis of the Sulzer Metco DJ High Velocity Oxy-Fuel Coating of Hydroxyapatite for Orthopedic Applications

Abstract

High Velocity Oxy-Fuel (HVOF) has the potential to produce hydroxyapatite (HA; Bio-ceramic) coatings based on its experience with other sprayed ceramic materials. This technique should offer mechanical and biological results comparable to other thermal spraying processes, such as atmospheric plasma thermal spray, currently FDA approved for HA deposition. Deposition of HA via HVOF is a new venture especially using the Sulzer Metco Diamond Jet (DJ) process, and the aim of this article was to establish this technique's potential in providing superior HA coating results compared to the FDAapproved plasma spray technique. In this research, a Design of Experiment (DOE) model was developed to optimize the Sulzer Metco DJ HVOF process for the deposition of HA. In order to select suitable ranges for the production of HA coatings, the parameters were first investigated. Five parameters (factors) were researched over two levels namely: oxygen flow rate, propylene flow rate, air flow rate, spray distance, and powder flow rate. Coating crystallinity and purity were measured at the surface of each sample as the responses to the factors used. The research showed that propylene, air flow rate, spray distance, and powder feed rate had the largest effect on the responses, and the study aimed to find the preferred optimized settings to achieve high crystallinity and purity of percentages of up to 95%. This research found crystallinity and purity values of 93.8 and 99.8%, respectively, for a set of HVOF parameters which showed improvement compared to the crystallinity and purity values of 87.6 and 99.4%, respectively, found using the FDA-approved Sulzer Metco Atmospheric Plasma thermal spray process. Hence, a new technique for HA deposition now exists using the DJ HVOF facility; however, other mechanical and biorelated properties must also be assessed.

Calcium orthophosphate deposits: Preparation, properties and biomedical applications

“…A C C E P T E D M A N U S C R I P T ACCEPTED MANUSCRIPT 16 To conclude this section, plasma spayed [202][203][204][205][206][207][208][209]. Sometimes, this deposition process is also called thermal printing [210].…”

Calcium orthophosphate coatings, films and layers

“…The powder partially melts in the stream and deposits upon the substrate. The resulting calcium orthophosphate coatings, layers and films have a low porosity and a high adhesion strength (Oguchi et al 1992; Sobolev and Guilemany 1996; Haman et al 1999; Li et al 2000, 2002a; Khor et al 2003a, 2003b, 2004; Hasan and Stokes 2011). …”

Induction suspension plasma sprayed biological-like hydroxyapatite coatings

“…34 Numerous studies have reported the production of HA coatings by thermal spray processes. [35][36][37][38][39][40] However, few have attempted to produce HA by the induction suspension plasma spray process. 41,42 HA production by induction suspension plasma spraying was first achieved by Bouyer et al 41 at the Universite de Sherbrooke Plasma Center.…”