Grimm glow discharge spectrometry was used to analyze metal coatings on various metal substrates to determine the sputter broadening characteristics of the glow discharge lamp, especially at the interface. The sputter broadening Characteristics are important when the depth profile is to be found. The samples of Cu/Ni, Ni/Cu, Sn/Ni, Xi/%, Fe/Ni, Ni/Fe metal coatings investigated, indicate tbat the poor depth resolution of glow discharge spectrometry is due to uneven profiling since the central portion of the sputtered surface is sputtered away faster than the edges. This depth resolution problem is fundamentally different from that of depth profiling in AES or SIMS. Besides being dependent on the usual sputtering parameters the depth profile is also dependent on the glow discharge characteristics of the coating metal and substrate metal combination. From the plots of plasma composition YS. fraction of metal coating sputtered, plasma composition vs. depth sputtered and fraction of metal coating sputtered vs. depth sputtered, the development of the crater profile can be followed and the cause of the depth resolution problem evaluated.
Depth profiles of Cu/Ni, Zo/Fe and Ni/Fe metal coatiogs obtaioed with a Grimm glow discharge lamp using ao argodielium gas mixture and pure argon gas were compared. Copper aod zinc showed a large iocrease io intensity for the argobbelium gas mixture, but Ni showed a small decrease. The sputter time for all three coatiog metals almost doubled, indicating a smaller sputteriog rate for the argoo-helium gas mixture. A broadened interface due to the differeot manoer in which the surface was eroded was also observed for the argoo-helium sputtered profiles. Iotensity eohaocemeot in Cu aod Zo was explained by the higher excitation and iooizatioo potential of helium and the simple energy levels (simple spectra) of these elements. 00 the other hand, the demx energy levels of the Ni atom (complex spectra) does not lead to intensity eohamemeot.
Alloy coatings of Fe-Ni and Cu-Zn electrodeposited on Cu and Fe substrates were analysed with glow discharge spectrometry (GDS) to determine the coating weights of the alloying elements and the concentration depth profile. The coating weight of each element was determined from the integrated intensity which is the area under the intensity-time curve of the element. A linear relationship is observed between the GDS integrated intensity and the coating weight indicating that GDS is able to quantify the alloy coating. The depth profile obtained was however not the true depth profile because of the effects of sputter broadening (due to differing sputtering rates between the central portion and the edges) and possibly bombardment-induced segregation (diffusion of zinc towards surface due to the effects of Ar' bombardment and surface segregation due to heating of the sample) for the Cu-Zn alloy coatings. The use of references of a series of Fe-Ni and Cu-Zn block samples were considered for the determination of the alloy composition. While it is practical for the Fe-Ni system, it is not for the Cu-Zn system because of the eflects of surface segregation and bombardment-induced segregation.
Spectroscopic analysis has become an essential part of the rapidly growing field of microplastic (MP) research. Here we introduce a simple sample preparation method which dramatically improves results from Fourier Transform Infrared (FTIR) analysis of MP and other environmental fibres. Our method provides cost-effective, reliable, high-quality spectra that achieve high-matching scores to polymer libraries. The efficacy of this method is demonstrated with two environmental datasets from Singapore and Phnom Penh that were collected while sampling for atmospheric MPs. The method developed and applied in this study is a simplification of the KBr method, where the analysed fibre is pressed to a thickness of <10 μm, however no KBr powder is required. For the combined dataset, 379 non-pressed fibres were analysed with 193 (51%) returning a Search score of ≥80% (chosen minimum Search score threshold), and 259 pressed fibres, with 254 (98%) returning a Search score of ≥80%. Direct comparisons of fibres before and after pressing show that the highest individual Search score, and average Search score from multiple single-point measurements, are overwhelmingly higher following our method. Our method immobilises and improves the surface of the fibre, by creating a wider and uniform area for measurements to be taken. For FTIR operators, this saves considerable time, improves reliability of the analysis, and importantly, provides reproducibility of the spectra generated.
Sputtering procedures are often employed in the field of material preparation such as thin films and surface analysis. In this report the atomic absorption spectroscopic technique is applied to observe sputtering phenomena of typical binary alloys of copper-nickel and copper-silver, as occurring in a hollow cathode glow discharge. A parameter pa+ correlating the composition of the sample with the composition of the produced plasma which was measured with atomic absorption spectroscopy, is used to monitor changes in the surface composition. Measurements at a natural high surface temperature of the sample during glow discharge and at a lower temperature by cooling with liquid nitrogen were performed. AES analysis of the glow discharge sputtered surfaces of uncooled samples show that a very deep altered layer can be produced.
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