TY - JOUR
T1 - Selective pulsed laser stripping of TiAlN erosion-resistant coatings
T2 - Effect of wavelength and pulse duration
AU - Ragusich, A.
AU - Taillon, G.
AU - Meunier, M.
AU - Martinu, L.
AU - Klemberg-Sapieha, J. E.
N1 - Funding Information:
The authors wish to thank Mr. Yves Drolet for his technical assistance as well as Dr. Etienne Bousser and Dr. Thomas Schmitt for their help regarding the evaluation of the mechanical properties. This work has been supported by NSERC and CRIAQ through the CRDPJ 380442-08 project. Partial support from the FQRNT of Quebec through the Quebec Consortium of Advanced Materials (RQMP) is acknowledged.
PY - 2013/10/15
Y1 - 2013/10/15
N2 - The lifetime of titanium-alloy aerospace parts can be greatly enhanced by the application of erosion-resistant coatings (ERC). After many hours in service, the coating will inevitably begin to deteriorate. To permit re-coating and repair of the parts, the coating should be removed. We present here a first attempt to strip TiN-based, 20. μm-thick, coatings while comparing the suitability of two pulsed lasers: a femtosecond Ti:Sapphire laser emitting at 800. nm, and a nanosecond excimer laser centered at 248. nm. Following initial comparison of ablation thresholds for each laser, we optimized four critical laser parameters: power, beam diameter, stage speed and step distance. The results indicate that surface roughness can be improved by 35% with the femtosecond laser in comparison with the nanosecond laser, while the higher energy per pulse offered by the latter one accelerates the etch rate by one order of magnitude. Surface composition analysis confirmed full removal of the coating and higher oxidization of the substrate with the excimer laser. Nanoindentation measurements on the polished cross-section of stripped samples show that the ablation process does not influence the hardness of the remaining substrate. To increase selectivity, plume emission spectroscopy has been investigated, in order to control, in real time, the material removal in regions where the coating thickness may vary.
AB - The lifetime of titanium-alloy aerospace parts can be greatly enhanced by the application of erosion-resistant coatings (ERC). After many hours in service, the coating will inevitably begin to deteriorate. To permit re-coating and repair of the parts, the coating should be removed. We present here a first attempt to strip TiN-based, 20. μm-thick, coatings while comparing the suitability of two pulsed lasers: a femtosecond Ti:Sapphire laser emitting at 800. nm, and a nanosecond excimer laser centered at 248. nm. Following initial comparison of ablation thresholds for each laser, we optimized four critical laser parameters: power, beam diameter, stage speed and step distance. The results indicate that surface roughness can be improved by 35% with the femtosecond laser in comparison with the nanosecond laser, while the higher energy per pulse offered by the latter one accelerates the etch rate by one order of magnitude. Surface composition analysis confirmed full removal of the coating and higher oxidization of the substrate with the excimer laser. Nanoindentation measurements on the polished cross-section of stripped samples show that the ablation process does not influence the hardness of the remaining substrate. To increase selectivity, plume emission spectroscopy has been investigated, in order to control, in real time, the material removal in regions where the coating thickness may vary.
KW - Erosion-resistant coatings
KW - Laser ablation
KW - Mechanical properties
KW - Plume emission spectroscopy
KW - TiAlN coating
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U2 - 10.1016/j.surfcoat.2013.06.092
DO - 10.1016/j.surfcoat.2013.06.092
M3 - Article
AN - SCOPUS:84883463907
SN - 0257-8972
VL - 232
SP - 758
EP - 766
JO - Surface and Coatings Technology
JF - Surface and Coatings Technology
ER -