Zinc depth profile

Figure 3 North Pacific zinc speciation (A) depth profile of zinc-complexing organic ligand presented as percentage of organically complexed zinc (B) dissovled zinc depth profile (C) Zn + ion depth profile as logarithmic concentration values.

The potential of LA-based techniques for depth profiling of coated and multilayer samples have been exemplified in recent publications. The depth profiling of the zinc-coated steels by LIBS has been demonstrated [4.242]. An XeCl excimer laser with 28 ns pulse duration and variable pulse energy was used for ablation. The emission of the laser plume was monitored by use of a Czerny-Turner grating spectrometer with a CCD two-dimensional detector. The dependence of the intensities of the Zn and Fe lines on the number of laser shots applied to the same spot was measured and the depth profile of Zn coating was constructed by using the estimated ablation rate per laser shot. To obtain the true Zn-Fe profile the measured intensities of both analytes were normalized to the sum of the line intensities. The LIBS profile thus obtained correlated very well with the GD-OES profile of the same sample. Both profiles are shown in Fig. 4.40. The ablation rate of approximately 8 nm shot ... 

The Auger depth profile obtained from a plasma polymerized acetylene film that was reacted with the same model rubber compound referred to earlier for 65 min is shown in Fig. 39 [45]. The sulfur profile is especially interesting, demonstrating a peak very near the surface, another peak just below the surface, and a third peak near the interface between the primer film and the substrate. Interestingly, the peak at the surface seems to be related to a peak in the zinc concentration while the peak just below the surface seems to be related to a peak in the cobalt concentration. These observations probably indicate the formation of zinc and cobalt complexes that are responsible for the insertion of polysulfidic pendant groups into the model rubber compound and the plasma polymer. Since zinc is located on the surface while cobalt is somewhat below the surface, it is likely that the cobalt complexes were formed first and zinc complexes were mostly formed in the later stages of the reaction, after the cobalt had been consumed. 

Fig. 42. AES depth profiles of copper and sulfur (top) and zinc and oxygen (bottom) for the brass-on-glass adhesion specimens as a function of curing temperature. Reproduced by permission of Gordon and Breach Science Publishers from Ref. [46].

Baudoin etal. [168,169] first presented qualitative depth profiles of lacquer and polymer coatings by means of r.f. GD-OES. Quantitative depth profiles were successively obtained by Payling et al. [170] on prepainted metal coated steel. Samples comprised a (rutile) pigmented silicone-modified polyester topcoat over a polymer primer, on top of an aluminium-zinc-silicon alloy coated steel substrate. With GD-OES in r.f. mode, it was possible to determine the depth profile through the polymer topcoat, polymer primer coat, metal alloy coating, and alloy layer binding to the steel substrate with a total depth of 50 im, all in about 60 min on the one sample. GD-OES depth profiles of unexposed and weathered silicone-modified polyesters were also reported [171]. Radiofrequency GD-OES has further been used to... 

The soil depth profile was sampled 600 m to the Southwest of the Hettstedt metallurgical works from a clayey soil (>35% clay) of the Wipper meadow. Fig. 9-12 shows that the heavy metal emission in the Hettstedt district originated from the copper metallurgical industry [UMWELTBUNDESAMT, 1991]. The heavy metal emission was at a maximum in 1983 and 1985 and is nowadays at a low level because of the closure of most of the emitters. As would be expected from the high values of heavy metal dust emission in recent years, high soil concentrations were found for the elements zinc, copper,... 

The record of zinc pollution in a sediment depth profile at Tites Point, Severn Estuary, UK a case study... 

Figure 2 Depth profiles for major nufrienfs (nifrafe (Pacific only), phosphate, and silicic acid) and filterable concentrations (that passing a 0.4-nm filter) of frace nufrienf elemenfs (zinc, cadmium, nickel, copper, and manganese) in the central North Pacific (diamonds, 32.7° N, 145.0° W, Sep. 1977) and North Atlantic (squares, 34.1° N, 66.1 °W, Jul. 1979). Manganese concentrations in the Pacific were analyzed in acidified, unfiltered seawater samples. The units molkg are defined as moles per kilogram of seawater. Data from Bruland KW and Franks RP (1983) Mn, Ni, Cu, Zn and Cd in the western North Atlantic. In Wong CS, Boyle E, Bruland KW, Burton JD, and Goldberg ED (eds.) Trace Metals in Sea Water, pp. 395-414. New York Plenum.

Figure 3 Depth profiles for nitrate and filterable concentrations of trace element nutrients (iron, zinc, and cobalt) in the subarctic North Pacific Ocean (ocean station Papa, 50.0°N, 145.0°W, Aug. 1987). Data from Martin JH, Gordon RM, Fitzwater S, and Broenkow WW (1989) VERTEX Phytoplankton/iron studies in the Gulf of Alaska. Deep-Sea Research 36 649-680.

FTIR-ATR spectra of a laminate (PMMA/polyvinyl alcohol) were presented at different base layer thicknesses and different angles of incidence on a zinc selenide substrate. By varying the thickness of the PMMA barrier film, different effective penetration depths in the polyvinyl alcohol were achieved. These results agreed well with the calculated electric fields as a function of distance away from the substrate surface. The work provided the basis for depth profiling measurements to detect interfacial interactions. 18 refs. 

A multi-technique surface analytical study (XPS depth profiling, iSIMS, SEM/EDX, RAIRS) of automotive anti wear (zinc dialkyl dithiophosphate) films was reported [103]. XPS and SEM have been used for distribution analysis of T1O2 and Zn phosphate in polypyrrole (PPy) [104]. 

Depth profiling of automotive parts containing calcium stearate and zinc stearate was done by photoelectron spectroscopy, ESCA. " The depth thickness of measurement was 5 nm. Using time of flight secondary ion mass spectroscopy, ToF-SIMS, the depth thickness monitored was 1 nm. The ToF SIMS technique was used to measure the relative concentration of erucamide as a function of depth for a pol mier film at equilibrium." ESCA data gave useful information on migration of stearates to the surface. " ... 

Figure 12. Quantified GDOES depth profiles from three hot-dip zinc-coated steel samples [100],...

The biological pump influences, to varying degrees, the distribution of many elements in seawater besides carbon, nitrogen, phosphorus, and silicon. Barium, cadmium, germanium, zinc, nickel, iron, selenium, yttrium, and many of the REEs show depth distributions that very closely resemble profiles of the major nutrients. Additionally, beryllium, scandium, titanium, copper, zirconium, and radium have profiles where concentrations increase with depth, although the correspondence of these profiles with nutrient profiles is not as tight (Nozaki, 1997). 

Figure 2.6 Variation in the saltmarsh sediment concentration of total zinc with depth in a dated and archaeological evidence) profile from Tites Point, Severn Estuary, UK.

Figure 2.7 Variation in the saltmarsh sediment concentration of zinc with depth in four fractions, defined according to the sequential extraction scheme of Tessier, Campbell Bisson (1979) as F2, carbonate F3, Fe and Mn oxide and hydroxide F4, organic F5, residual. The location of the profile is Tites Point, Severn Estuary, UK.

A certain relationship, which exists between the bulk and surface properties of semiconducting materials and their electrochemical behavior, enables, in principle, electrochemical measurements to be used to characterize these materials. Since 1960, when Dewald was the first to determine the donor concentration in a zinc oxide electrode using Mott-Schottky plots, differential capacity measurements have frequently been used for this purpose in several materials. If possible sources of errors that were discussed in Section III.3 are taken into account correctly, the capacity method enables one to determine the distribution of the doping impurity concentration over the surface" and, in combination with the layer-by-layer etching method, also into the specimen depth. The impurity concentration profile can be constructed by this method. It has recently been developed in greatest detail as applied to gallium arsenide crystals and multilayer structures. 

The concentration profiles of all elements analysed exhibited similar trends, but on different concentration levels. Lead, copper and zinc occurred in significantly higher concentrations as compared to cadmium, nickel and chromium with values ranging from 95 to 400 pg/g for Pb, from 56 to 430 pg/g for Cu and from 517 to 2373 pg/g for Zn. These data correspond to values measured for other study areas on the Lippe river, which are highly influenced by industrial emissions (Poppe et al., 1991). Lower concentrations were determined for Cd (2.7 to 15.7 pg/g), Ni (28 to 62 pg/g) and Cr (34 to 199 pg/g). With respect to the concentration trends, two significant maxima at a depth of approx. 25 cm and between 88 and 115 cm were observed for most of the metals analysed as indicated by the hatched areas in Fig. 4. These horizons are correspond to sedimentation periods from 1975 to 1980 and from 1945 to 1955, respectively. 

In detail, most of the concentration profiles reveal increasing values from the bottom of the core up to a depth of 100 cm, reaching a first maximum there. Subsequently, the values decrease to a fairly constant level at a depth between 80 cm and 30 cm. The averaged values in this zone are Cd 6 pg/g, Ni 50 pg/g, Cr 85 pg/g, Cu 180 pg/g, Pb 240 pg/g and Zn 1100 pg/g. A second concentration maximum was observed at a depth of approx. 25 cm. In the top layers of the sediment core the concentrations decrease down to values similar to those in the 30-80 cm zone. These trends are best developed in the concentration profiles of lead, copper, zinc and cadmium (Fig. 4). 

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