title: Structure, phases, and mechanical response of Ti-alloy bioactive glass composite coatings.
abstract: Porous titanium alloy-bioactive glass composite coatings were manufactured via the flame spray deposition process. The porous coatings, targeted for orthodontic and bone-fixation applications, were made from bioactive glass (45S5) powder blended with either commercially pure titanium (Cp-Ti) or Ti-6Al-4V alloy powder. Two sets of spray conditions, two metallic particle size distributions, and two glass particle size distributions were used for this study. Negative control coatings consisting of pure Ti-6Al-4V alloy or Cp-Ti were sprayed under both conditions. The as-sprayed coatings were characterized through quantitative optical cross-sectional metallography, X-ray diffraction (XRD), and ASTM Standard C633 tensile adhesion testing. Determination of the porosity and glassy phase distribution was achieved by using image analysis in accordance with ASTM Standard E2109. Theoretical thermodynamic and heat transfer modeling was conducted to explain experimental observations. Thermodynamic modeling was performed to estimate the flame temperature and chemical environment for each spray condition and a lumped capacitance heat transfer model was developed to estimate the temperatures attained by each particle. These models were used to establish trends among the choice of alloy, spray condition, and particle size distribution. The deposition parameters, alloy composition, and alteration of the feedstock powder size distribution had a significant effect on the coating microstructure, porosity, phases present, mechanical response, and theoretical particle temperatures that were attained. The most promising coatings were the Ti-6Al-4V-based composite coatings, which had bond strength of 20±2MPa (n=5) and received reinforcement and strengthening from the inclusion of a glassy phase. It was shown that the use of the Ti-6Al-4V-bioactive glass composite coatings may be a superior choice due to the possible osteoproductivity from the bioactive glass, the potential ability to support tissue ingrowth and vascular tissue, and the comparable strength to similar coatings.
authors.affiliation: Department of Chemical and Materials Engineering, University of Alberta, 7th Floor, Electrical & Computer Engineering Research Facility, Edmonton, Alberta T6G 2V4, Canada.
authors.forename: G M
authors.initials: GM
authors.lastname: Nelson
authors.affiliation: Department of Chemical and Materials Engineering, University of Alberta, 7th Floor, Electrical & Computer Engineering Research Facility, Edmonton, Alberta T6G 2V4, Canada.
authors.forename: J A
authors.initials: JA
authors.lastname: Nychka
authors.affiliation: Department of Mechanical Engineering, University of Alberta, 4-9 Mechanical Engineering Building, Edmonton, Alberta T6G 2G8, Canada. Electronic address: andre2@ualberta.ca.
authors.forename: A G
authors.initials: AG
authors.lastname: McDonald
mesh_terms: D000268:Adhesiveness / Q000187:drug effects; D000497:Alloys; D002516:Ceramics / Q000737:chemistry*; D020099:Coated Materials, Biocompatible / Q000737:chemistry*; D005740:Gases / Q000737:chemistry; D005898:Glass / Q000737:chemistry*; D055595:Mechanical Phenomena; D008855:Microscopy, Electron, Scanning; D010316:Particle Size; D016062:Porosity; D011208:Powders; D013314:Stress, Mechanical; D013696:Temperature; D013718:Tensile Strength / Q000187:drug effects; D014025:Titanium / Q000737:chemistry*; D014961:X-Ray Diffraction
chemical_list: D000497:Alloys; D020099:Coated Materials, Biocompatible; D005740:Gases; D011208:Powders; C425330:bioactive glass 45S5; C031462:titanium alloy (TiAl6V4); D014025:Titanium
keywords: Adhesion strength; Biocompatibility; Flame spraying; Thermal spraying