Bond strength determination of hydroxyapatite coatings on Ti-6Al-4V substrates using the LAser Shock Adhesion Test (LASAT).
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 TiO(2) 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 TiO(2) 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.
Guipont
Vincent
V
MINES ParisTech, Centre des Matériaux, CNRS UMR 7633, Centre de Compétence en Procédés de Projection, Evry, France. vincent.guipont@mines-paristech.fr
Jeandin
Michel
M
Bansard
Sebastien
S
Khor
Khiam Aik
KA
Nivard
Mariette
M
Berthe
Laurent
L
Cuq-Lelandais
Jean-Paul
JP
Boustie
Michel
M
D000268:Adhesiveness / Q000187:drug effects / Q000528:radiation effects; D000497:Alloys; D001826:Body Fluids / Q000187:drug effects / Q000528:radiation effects; D002138:Calibration; D020099:Coated Materials, Biocompatible / Q000737:chemistry* / Q000494:pharmacology; D017886:Durapatite / Q000737:chemistry*; D007834:Lasers; D008422:Materials Testing / Q000379:methods*; D018625:Microscopy, Atomic Force; D008855:Microscopy, Electron, Scanning; D058626:Plasma Gases; D011312:Pressure; D015203:Reproducibility of Results; D013314:Stress, Mechanical; D014025:Titanium / Q000737:chemistry* / Q000494:pharmacology
D000497:Alloys; D020099:Coated Materials, Biocompatible; D058626:Plasma Gases; C031462:titanium alloy (TiAl6V4); D017886:Durapatite; D014025:Titanium