Laser-induced ablation with inductively coupled plasma (LA-ICP) is a powerful analytical technique that combines laser sputtering of material and subsequent ionization in an inductively coupled plasma for mass spectrometric analysis. The application of LA-ICP to the study of complex materials such as Al–Cu–Fe alloys and quasicrystals is of considerable interest due to the possibility of elemental analysis with high spatial resolution and minimal sample preparation.
The aim of this study is to investigate the processes of laser sputtering from the surface of Al–Cu–Fe alloy and quasicrystal using inductively coupled plasma mass spectrometry. Particular attention is paid to the determination of the elemental composition, ablation rate and fractionation of elements depending on the laser radiation parameters and plasma conditions.
The experiments were performed using a laser ablation system coupled to a quadrupole mass spectrometer equipped with an inductively coupled plasma. Both standard Al–Cu–Fe alloys and synthesized quasicrystalline samples were studied. Laser parameters such as power, pulse repetition rate, and wavelength were varied, as were plasma parameters such as carrier gas flow rate and RF generator power.
The results of mass spectrometric measurements provide information on the elemental composition of the ablation plume, the ablation rate and the degree of fractionation of the elements Al, Cu and Fe. Data analysis is performed using specially developed software that takes into account matrix effects and mass spectrometer calibration. The results are compared with theoretical calculations and data obtained by other analytical methods.
The behavior of intermetallic CuFe alloys and Al65Cu23Fe12 quasicrystals under laser desorption and ablation is studied. The fractionation of components during laser action on samples is investigated using inductively coupled plasma mass spectrometry. Experiments were carried out using a Nd:YAG laser (266 nm, 6 ns) in two power density ranges.
At high power density (above 0.04–0.07 GW/cm²), the effect of laser radiation on ablation was similar for both materials. In the low power density mode (below 0.04–0.07 GW/cm²), significant differences in the behavior of the alloy and the quasicrystal were observed. The obtained data are explained in terms of the thermodynamics of evaporation of the intermetallic alloy. A model based on localized electron excitation is proposed to explain the process of material removal from the quasicrystal surface.
Author:
Aldo Mele, Haichen Liu, Richard
E. Russo, Xianglei Mao, Anna Giardini, Mauro Satta
Institute:
Department of Chemistry, University of Rome La Sapienza, Piazza A. Moro 5, Rome 00185, Italy
Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
Institute of Special Materials, CNR, Via Loja, Tito Scalo (PZ) 85050, Italy
Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou, 510640, People’s Republic of China