ISSN:
0142-2421
Keywords:
laser-plasma
;
depth profiling
;
LIBS
;
coated steels
;
Chemistry
;
Polymer and Materials Science
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Physics
Notes:
The 581 nm output from a dye laser in a fluence range between 2.86 and 11.47 J cm-2 was used to ablate pure Zn and Fe foils. The average ablation rate (AAR, μm per shot) was calculated for different experimental variables (buffer gas, pressure, laser fluence and focal conditions). Deposition of previously ablated material in the ablation crater results in large variation of the observed AAR values. This effect was observed in air and argon buffer gases at atmospheric pressure. The situation is largely alleviated at reduced pressure due to free expansion of the ablated material. Under these circumstances the capability of laser-induced plasmas to resolve interfacial structures is improved. The effect on depth-resolved studies was checked with a commercial Zn-coated steel sample. Due to the Gaussian-like energy distribution of the incident laser beam, the material is ablated to produce a conical crater. This fact ensures that the Zn signal remains for a longer time because the ablated region spreads over the edge gradually. At low pressure the emission peaks are better defined and the background becomes flat. However, these conditions produce also the lowest net intensities and some peaks are not detected. An Ar atmosphere produces more intense spectral lines at both pressure levels. Best analytical results were obtained at reduced pressure, with a slight improvement in depth resolution in the presence of Ar. © 1998 John Wiley & Sons, Ltd.
Additional Material:
6 Ill.
Type of Medium:
Electronic Resource
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