Bond strength determination of hydroxyapatite coatings on Ti-6Al-4V substrates using the LAser Shock Adhesion Test (LASAT)

• Published in: Journal of biomedical materials research. Part A Vol. 95A; no. 4; pp. 1096 - 1104
• Main Authors: Guipont, Vincent, Jeandin, Michel, Bansard, Sebastien, Khor, Khiam Aik, Nivard, Mariette, Berthe, Laurent, Cuq-Lelandais, Jean-Paul, Boustie, Michel
• Format: Journal Article
• Language: English
• Published: Hoboken Wiley Subscription Services, Inc., A Wiley Company 15-12-2010; Wiley-Blackwell; Wiley
• Subjects: Adhesion tests; Adhesiveness - drug effects; Adhesiveness - radiation effects; Biocompatibility; Biological and medical sciences; Body Fluids - drug effects; Body Fluids - radiation effects; bond strength; Calibration; Coated Materials, Biocompatible - chemistry; Coated Materials, Biocompatible - pharmacology; Coatings; Durapatite - chemistry; Engineering Sciences; Hydroxyapatite; laser spallation; Lasers; Materials; Materials Testing - methods; Medical sciences; Microscopy, Atomic Force; Microscopy, Electron, Scanning; Plasma Gases; plasma spraying; Pressure; Protective coatings; Reproducibility of Results; shock wave; Stress, Mechanical; Surgery (general aspects). Transplantations, organ and tissue grafts. Graft diseases; Surgical implants; Technology. Biomaterials. Equipments; Titanium - chemistry; Titanium - pharmacology; Titanium base alloys; Titanium dioxide; Titanium alloy; Coating material; Mechanical properties; bond strength; Hydroxyapatite; Adhesion; laser spallation; Surface treatment; shock wave; Laser; Surface properties; Biomaterial; Measurement method; Plasma spraying; Strength; Biomedical engineering; plasma spraying
• ISSN: 1549-3296; 1552-4965; 1552-4965
• DOI: 10.1002/jbm.a.32907

An adhesion test procedure applied to plasma‐sprayed hydroxyapatite (HA) coatings to measure the “LASAT threshold” (LAser Shock Adhesion test) is described. The good repeatability and minimal discrepancy of the laser‐driven adhesion test data were ascertained for conventional plasma sprayed HA coatings. As a further demonstration, the procedure was applied to HA coatings with diverse characteristics on the ceramic/metal interface. Different preheating and grit blasting conditions and the presence of a thick plasma‐sprayed Ti sublayer or a thin TiO2 layer prepared by oxidation were investigated through LASAT. It was assessed that a rough surface can significantly improve the coating's bond strength. However, it was also demonstrated that a thin TiO2 layer on a smooth Ti‐6Al‐4V substrate can have a major influence on adhesion as well. Preheating up to 270°C just prior to the first HA spraying pass had no effect on the adhesion strength. Further development of the procedure was done to achieve an in situ LASAT with in vitro conditions applied on HA coatings. To that end, different crystalline HA contents were soaked in simulated body fluid (SBF). Beyond the demonstration of the capability of this laser‐driven adhesion test devoted to HA coatings in dry or liquid environment, the present study provided empirical information on pertinent processing characteristics that could strengthen or weaken the HA/Ti‐6Al‐4V bond. © 2010 Wiley Periodicals, Inc. J Biomed Mater Res Part A, 2010.