Gas Element Analysis of Direct Reading Spectrometers <br> Gas elements in metals refer to C, S, N, O, H. Before the 1990s, photoelectric direct reading spectrometers could only analyze C, S. With the improvement of the spectral processing technology, the advent of the photomultiplier tube for the far-ultraviolet light and the re-recognition and improvement of the inert gas-filled optical system have led to the development of gas elemental analysis of the photoelectric direct reading spectrum in recent years. Compared with the 1990s, the analytical line (nm) of each gas element is as follows:
Previously, the carbon was only measured by the 193.09 nm line. The detection limit of steel was 5 ppm. Now, the 165.70 nm line can be used as needed. The detection limit of carbon in steel and copper can reach 1 ppm.
Photoelectric direct reading spectroscopy analysis of nitrogen is a new breakthrough, began to measure with 174.27nm line, due to poor measurement stability, and can only analyze high levels of nitrogen, rarely used for actual analysis, and later used 149.47nm line to determine nitrogen in steel, The detection limit is up to 5ppm. The stability is very good.
Oxygen photoelectric direct reading spectroscopy is carried out in recent years. The detection limit of copper is 10ppm, and that of steel is 15ppm. The detection limit of hydrogen in photoelectric direct reading spectrum is 8ppm.
At present, ultra-low carbon analysis using photoelectric direct reading spectroscopy, nitrogen analysis in steel, analysis of carbon, sulfur and oxygen in pure copper, and analysis of hydrogen in Qinzhong have entered the practical stage. Domestic nitrogen determination in steel, pure copper The work of oxygenation has also been gradually carried out. Ordinary photomultiplier tubes strongly absorb far-ultraviolet lines, so photomultiplier tubes for the determination of nitrogen, oxygen, and hydrogen use special optical materials to reduce their own absorption of spectral lines. These photomultiplier tubes are more expensive than conventional types. The price at which the instrument is configured for these channels is also higher than the average channel.
Although the direct reading spectrometer has made great progress in the analysis of gas elements, there is still a certain gap in the detection limit compared with the dedicated carbon-sulfur analyzer, oxygen-nitrogen analyzer and hydrogen analyzer.
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