Steel spectral analysis

Plutonium is electrodeposited onto a stainless steel disk to obtain a thin and uniform source for counting alpha particles. Counting is by spectral analysis to identify the plutonium alpha particles by peak energy and determine their activity by the integral of the count rate at the peak. 

In large storage tanks (30 x 10 x 10 m) used for spent fuel rods from nuclear power plants, which are lined with stainless steel (no further details given) and filled with demineralised water, the corrosion rate after many years of service was determined [130]. Under the conditions 20°C 5 °C, pH 5 1, 0.1 mg/1 oxygen as well as 0.1 mg/1 chloride ions a total container weight loss of 150 mg/a was found by spectral analysis, which corresponds to a corrosion rate of 0.01 pm/a. This means absolutely negligible corrosion attack. Information since only Fe, Cr and Ni, and no Mo were found in the spectral analytical data, the described stainless steel involved was assumed to be an 18/8 CrNi steel. 

Small pieces of rubber are cut from the ASTM sheets using a razor blade and placed in aluminium crucibles for direct mass spectral analysis. El and Cl spectra were acquired by using the same MAT 311A instrument with the conditions as described above. Spectra were acquired as the probe was heated from 50 to 300°C. For direct FAB analysis, the vulcanizates were cut into strips (8x3x2 mm) which were attached to the stainless steel FAB probe with scotch 924 transfer tape. The experimental conditions for FAB were the same as described above (no FAB solvent was used with the samples). 

The composition of steels or other metals is commonly analyzed by emission or X-ray spectrometry during and after the production process. Both methods have to be calibrated by solid samples. These are either exactly analyzed samples taken from the same process or synthetic melted mixtures of the matrix with added accompanying elements (RMs). Available CRMs are then used to control the slope of the calibration function. Today, available RMs and CRMs are increasingly and exclusively used in spectral laboratories as the chemical analysis became much restricted and typical control laboratories were totally closed (Slickers 1993). 

This overall approach remains basically the same for analysis of steel, brass, zinc, or other metals, although there are specific differences in spectrometers, analyte spectral lines, sample-preparation techniques, and excitation conditions. 

A second advantage of Fourier transform instruments is their extremely high resolving power and wavelength reproducibility that make possible the analysis of complex spectra in which the sheer number of lines and spectral overlap make the determination of individual spectral features difficult. Figure 7-40. which is papt of an emission spectrum for a steel, illustrates this advantage. The spectrum, which extends from only 299.85 to 300.75 nm, contains thirteen well-separated lines of three elements. The wavelength resolution (AA/A) for the closest pair of lines is about 6 ppm. 

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