Pulsed laser irradiation-induced reflectivity decrease of metal surfaces is a well-established phenomenon, which is extensively utilized in numerous applications. Since the stability of these black surfaces is often a demand, we investigated the resistance of darkened copper and titanium surfaces against optical and mechanical damages. For optical stability studies, samples were irradiated by a probe laser beam (λ = 775 nm, FWHM = 150 fs, f = 1 kHz) at different fluences (0–300 mJ/cm2), while the mechanical stability was studied with scratch test using 2.5 µm radius tip and applying normal force in 29.4–147 µN range. The observed reflectivity and morphological changes indicated that the optical damage threshold fluence is 130 and 160 mJ/cm2 for copper and titanium surfaces, respectively. Mechanical damage only in case of copper could be detected in the applied parameter range indicating a scratch hardness of 21.5 MPa.
|Journal||Applied Physics A: Materials Science and Processing|
|Publication status||Published - Sep 1 2017|
ASJC Scopus subject areas
- Materials Science(all)