title: Microstructures and bond strengths of plasma-sprayed hydroxyapatite coatings on porous titanium substrates.
abstract: Hydroxyapatite (HA) coating was carried out by plasma spraying on bulk Ti substrates and porous Ti substrates having a Young's modulus similar to that of human bone. The microstructures and bond strengths of HA coatings were investigated in this study. The HA coatings with thickness of 200-250 microm were free from cracks at interfaces between the coating and Ti substrates. XRD analysis revealed that the HA powder used for plasma spraying had a highly crystallized apatite structure, while the HA coating contained several phases other than HA. The bond strength between the HA coating and the Ti substrates evaluated by standard bonding test (ASTM C633-01) were strongly affected by the failure behavior of the HA coating. A mechanism to explain the failure is discussed in terms of surface roughness of the plasma-sprayed HA coatings on the bulk and porous Ti substrates.
authors.affiliation: Korea Institute of Industrial Technology (KITECH), P.O. Box #1, Wolgye-Dong, Gwangsan-gu, Gwangju, 506-824, South Korea. ihoh@kitech.re.kr
authors.forename: Ik-Hyun
authors.initials: IH
authors.lastname: Oh
authors.forename: N
authors.initials: N
authors.lastname: Nomura
authors.forename: A
authors.initials: A
authors.lastname: Chiba
authors.forename: Y
authors.initials: Y
authors.lastname: Murayama
authors.forename: N
authors.initials: N
authors.lastname: Masahashi
authors.forename: Byong-Taek
authors.initials: BT
authors.lastname: Lee
authors.forename: S
authors.initials: S
authors.lastname: Hanada
mesh_terms: D000268:Adhesiveness; D018786:Bone Substitutes / Q000032:analysis / Q000737:chemistry*; D020099:Coated Materials, Biocompatible / Q000032:analysis / Q000737:chemistry*; D003460:Crystallization / Q000379:methods*; D004548:Elasticity; D005740:Gases / Q000737:chemistry; D006244:Hardness; D006358:Hot Temperature; D008422:Materials Testing; D008968:Molecular Conformation; D010316:Particle Size; D016062:Porosity; D011208:Powders; D013499:Surface Properties; D014025:Titanium / Q000032:analysis / Q000737:chemistry*
chemical_list: D018786:Bone Substitutes; D020099:Coated Materials, Biocompatible; D005740:Gases; D011208:Powders; D014025:Titanium