研究目的
To examine and compare femtosecond laser-induced periodic surface structure (LIPSS), graphitization, and swelling on ultra-hard, hydrogen-free tetrahedral amorphous carbon (ta-C) films with those on hydrogenated amorphous carbon (a-C:H) films, nitride films, and glassy carbon plates.
研究成果
The study concluded that femtosecond laser irradiation induces LIPSS, graphitization, and swelling on ta-C films, with unique behaviors at high fluences such as rapid increases in LIPSS period and ablation rates, and sudden crystallinity deterioration. These phenomena are common among disordered carbons, offering potential for new surface modification technologies.
研究不足
The study's limitations include the specific conditions under which the experiments were conducted, such as the use of a single laser wavelength and pulse duration, which may not cover all possible scenarios for LIPSS formation and graphitization.
1:Experimental Design and Method Selection
The study involved irradiating ta-C, a-C:H, TiN, CrN films, and glassy carbon plates with femtosecond laser pulses to observe LIPSS formation, graphitization, and swelling. The methodology included fixed spot and scanned spot irradiation techniques.
2:Sample Selection and Data Sources
Specimens included ta-C films on WC-Co substrates, a-C:H, TiN, and CrN films on stainless steel plates, and glassy carbon plates. Physical properties such as surface roughness and hardness were measured.
3:List of Experimental Equipment and Materials
Equipment used included a Ti:sapphire chirped-pulse amplification system for laser irradiation, FE-SEM and SPM for morphological analysis, and Raman spectroscopy for structural analysis.
4:Experimental Procedures and Operational Workflow
The specimens were irradiated with linearly polarized, 800 nm, 180 fs laser pulses at various fluences and pulse numbers. Surface modifications were analyzed using SEM, SPM, and Raman spectroscopy.
5:Data Analysis Methods
Data analysis involved measuring LIPSS periods, ablation rates, and crystallinity changes through Raman spectroscopy, including the analysis of D and G peaks.
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