title: Effect of substrate temperature on mechanical properties of calcium phosphate coatings.
abstract: The effect of substrate temperature and processing parameters on mechanical properties of nanoscale calcium phosphate coatings are being studied in order to refine the processing technique for Functionally Graded Hydroxyapatite (FGHA) coatings. Coatings were deposited on titanium substrates with a set substrate temperature of 450, 550, 650, or 750 degrees C in an Ion Beam Assisted Deposition (IBAD) system using a sintered hydroxyapatite (HA) target. Mechanical properties of the coatings deposited with a set substrate temperature such as, bonding/adhesion strength to the substrate, nanohardness, and Young's Modulus as well as coating thickness were evaluated and compared with commercial plasma spray HA coatings. It is concluded that depositing FGHA coatings would better be started at 550-650 degrees C to maintain superior properties of the film at the interface. It can also be concluded that the residual stresses caused by different Coefficient of Thermal Expansions (CTEs) between the substrate and coatings are not the only factor controlling the bonding strength and mechanical properties of these samples. Other parameters such as the nature of the interface layers and their bonding to each other as well as the density and grain structure of the coatings must be taken into consideration for an appropriate evaluation of mechanical properties of calcium phosphate coatings deposited on heated substrate.
authors: Department of Mechanical and Aerospace Engineering, North Carolina State University, 2601 Stinson Drive, Raleigh, North Carolina 27695-7910, USA.
authors: Travis L
authors: TL
authors: Blalock
authors: Xiao
authors: X
authors: Bai
authors: Roger
authors: R
authors: Narayan
authors: Afsaneh
authors: A
authors: Rabiei
mesh_terms: D000268:Adhesiveness; D002130:Calcium Phosphates / Q000737:chemistry*; D020099:Coated Materials, Biocompatible / Q000737:chemistry*; D017886:Durapatite / Q000737:chemistry; D008422:Materials Testing; D013499:Surface Properties; D013696:Temperature; D014025:Titanium / Q000737:chemistry
chemical_list: D002130:Calcium Phosphates; D020099:Coated Materials, Biocompatible; D017886:Durapatite; C020243:calcium phosphate; D014025:Titanium