TEA CO2 laser surface modification of titanium ceramic thin films
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The surface modification of titanium based ceramics thin films, induced by pulsed laser beam, was investigated in this work. Thin films of titanium nitride (TiN) and titanium diboride (TiB2) were deposited on austenitic stainless steel substrate by two Physical Vapor Deposition (PVD) techniques and exposed in air atmosphere to a focused Transversely Excited Atmospheric (TEA) CO2 laser irradiation. In these. experiments two types of laser pulses have been used. One pulse was composed of an initial spike (FWHM = 120 ns) with a tail (duration about 2 microseconds) while the other contained only the initial spike (FWHM = 80 ns). Morphological changes of deposited ceramics,. induced by successive laser pulses, have shown a dependence on the laser beam parameters (pulse energy, laser pulse duration, peak power density, number of pulses, etc.) and thin films characteristics. Thin films, investigated in this work, possessed reflectivity above 90% at wavelength of about 10 microns. Pulse peak p...ower densities of 100 and 170 MW/cm(2) were used in these experiments and have induced the surface modifications of TiN and TiB2 thin films. Depending on laser beam parameters, a change of color, grain growth, hydrodynamic effects, on TiN thin film were registered while on TiB2 we noticed a change in color of the thin film, cracking and exfoliation.
Keywords:TEA CO2 / laser ablation / thin films / TiN / TiB2 / titanium ceramics
Source:2002, 4760, 1006-1013
- Proceedings of the Society of Photo-Optical Instrumentation Engineers (SPIE), Conference on High-Power Laser Ablation IV, Apr 22-26, 2002, Taos, NM