



@article {2634,
	title = {Liquid phase sintering of hydroxyapatite by phosphate and silicate glass additions: Structure and properties of the composites},
	journal = {Journal of Materials Science: Materials in MedicineJ. MATER. SCI. MATER. MED.},
	volume = {6},
	year = {1995},
	note = {Cited By (since 1996): 41Export Date: 21 November 2012Source: ScopusCODEN: JSMMEdoi: 10.1007/BF00120303Language of Original Document: EnglishCorrespondence Address: Santos, J.D.; INEB-National Inst. Biomedical Engn., Department Metallurgical Engineering, FEUP, University of Porto, Rua dos Bragas 4099-Porto Codex, Portugal},
	month = {1995///},
	pages = {348 - 352},
	publisher = {Chapman \& Hall Ltd},
	abstract = {Phosphate- and silicate-based glasses were added to hydroxyapatite in order to improve its mechanical properties and to fabricate composites with different degrees of bioactivity. A strong chemical bonding was obtained between hydroxyapatite and the phosphate-based glasses leading to samples approaching theoretical density, according to density measurements and scanning electron microscopy. Bioglass{\textregistered} additions led to the formation of a complex calcium phosphate silicate which hampered the reinforcement process. The fracture toughness of the hydroxyapatite-glass composites was shown to be within the 1.1-1.2 MPam(1/2) range, which is double that determined for sintered hydroxyapatite. A 2 μm thick apatite layer was observed on the surface of the hydroxyapatite-glass composites after 48 h immersion in a simulated human blood plasma, whereas only a few apatite crystals were detected on sintered hydroxyapatite after 7 days immersion. From the results obtained we anticipate that the composites might show a higher rate of bone bonding, leading to enhanced bioactivity.Phosphate- and silicate-based glasses were added to hydroxyapatite in order to improve its mechanical properties and to fabricate composites with different degrees of bioactivity. A strong chemical bonding was obtained between hydroxyapatite and the phosphate-based glasses leading to samples approaching theoretical density, according to density measurements and scanning electron microscopy. Bioglass
                        (R) additions led to the formation of a complex calcium phosphate silicate which hampered the reinforcement process. The fracture toughness of the hydroxyapatite-glass composites was shown to be within the 1.1-1.2 MPa m
                        1/2 range, which is double that determined for sintered hydroxyapatite. A 2 μm thick apatite layer was observed on the surface of the hydroxyapatite-glass composites after 48 h immersion in a simulated human blood plasma, whereas only a few apatite crystals were detected on sintered hydroxyapatite after 7 days immersion. From the results obtained we anticipate that the composites might show a higher rate of bone bonding, leading to enhanced bioactivity.
},
	keywords = {Adhesion, article, Bioactivity, Bioglass, Biomaterials, Bone, bone prosthesis, calcium phosphate, chemical binding, Chemical bonds, chemical composition, Chemical structure, Complex calcium phosphate silicate, Composite materials, crystal, density, Density measurement (specific gravity), glass, Human blood plasma, hydroxyapatite, Liquid phase sintering, Mechanical properties, Mechanics, phosphate, Phosphates, plasma, priority journal, Scanning electron microscopy, silicate, Silicates, Sintering, Structure (composition), surface property, thickness},
	isbn = {09574530 (ISSN)},
	url = {http://www.scopus.com/inward/record.url?eid=2-s2.0-0029311049\&partnerID=40\&md5=433498e286bfad74a296d1fafc50c223},
	author = {Santos, J.D. and Reis, R.L. and Monteiro, F.J. and Knowles, J.C. and Hastings, G.W.}
}
@article {2639,
	title = {Stability of hydroxylapatite plasma-sprayed coated Ti-6Al-4V under cyclic bending in simulated physiological solutions},
	journal = {Journal of Materials Science: Materials in MedicineJ. MATER. SCI. MATER. MED.},
	volume = {5},
	year = {1994},
	note = {Cited By (since 1996): 35Export Date: 21 November 2012Source: ScopusCODEN: JSMMEdoi: 10.1007/BF00058983Language of Original Document: EnglishCorrespondence Address: Reis, R.L.; INEB-National Inst. Biomedical Engn., Faculty of Engineering, University of Porto, Rua dos Bragas, 4099 Porto Codex, Portugal},
	month = {1994///},
	pages = {457 - 462},
	publisher = {Chapman \& Hall Ltd},
	abstract = {The aim of this research was to study the stability of plasma-sprayed coated metal systems and to evaluate their susceptibility to the occurrence of corrosion fatigue. Hydroxylapatite plasma-sprayed coated samples of Ti-6Al-4V were studied under cyclic bending. During fatigue testing samples were immersed in a simulated physiological solution and mechanical and electrochemical degradation were monitored. Applied loads were intended to crack the ceramic coating and not the metal substrate. Electrochemical impedance spectroscopy was used to further characterize the electrochemical behaviour. No increase in tendency to corrode was detected in open-circuit corrosion fatigue testing. It appears as if the coating cracking does not increase metal substrate corrosion susceptibility. The coating integrity has been seriously affected, with marked decrease in thickness, due to the synergistic effect of load and presence of simulated body fluids environment. Impedance results, however, show a general tendency to an increase in corrosion kinetics after corrosion fatigue testing.The aim of this research was to study the stability of plasma-sprayed coated metal systems and to evaluate their susceptibility to the occurrence of corrosion fatigue. Hydroxylapatite plasma-sprayed coated samples of Ti-6Al-4V were studied under cyclic bending. During fatigue testing samples were immersed in a simulated physiological solution and mechanical and electrochemical degradation were monitored. Applied loads were intended to crack the ceramic coating and not the metal substrate. Electrochemical impedance spectroscopy was used to further characterize the electrochemical behaviour. No increase in tendency to corrode was detected in open-circuit corrosion fatigue testing. It appears as if the coating cracking does not increase metal substrate corrosion susceptibility. The coating integrity has been seriously affected, with marked decrease in thickness, due to the synergistic effect of load and presence of simulated body fluids environment. Impedance results, however, show a general tendency to an increase in corrosion kinetics after corrosion fatigue testing.
},
	keywords = {article, Bending (deformation), biomaterial, biomechanics, body fluid, Ceramic coatings, ceramics, controlled study, Corrosion, Corrosion fatigue, Corrosion susceptibility, Degradation, Electrochemical impedance spectroscopy, electrochemistry, fatigue, Fatigue testing, hydroxyapatite, impedance, mechanical stress, Physiological solutions, Plasma spraying, priority journal, sodium chloride, Solutions, Spectroscopy, Stability, Substrates, thickness, Titanium, Titanium alloys},
	isbn = {09574530 (ISSN)},
	url = {http://www.scopus.com/inward/record.url?eid=2-s2.0-0028447410\&partnerID=40\&md5=f863751be3003b31534dd128601835f8},
	author = {Reis, R.L. and Monteiro, F.J. and Hastings, G.W.}
}
