Vol. 15, No. 4 (1959)
A STUDY ON THE TRANSPORT OF VAPOR STREAM AND ARC TEMPERATURE IN THE EXCITATION SOURCE OF THE CUP SOLUTION METHOD
1959, 15 (4): 167-172. doi: 10.7498/aps.15.167
The cup electrode solution arc method is a new technique for spectrographic analysis. With this we analysed a variety of slags as well as some steel samples. Fractional distillation is found to be absent. In order to improve the sensitivity and precision of this method the authors studied the transport of the vapor stream and distribution of arc temperature in the light source.To begin with, we found that the arc column consists of two parts: (1) a very bright central column, (2) a moving arc flame around the central part, between the [upper electrodes and the surface of the cup electrode. Experimental results show that the area of contact between the surface of the sample solution and flame determines the intensities of spectral lines. According to the OH rotational band spectra the temperature of the central part of the arc is higher than that of the flame by about 1000°K. In the spectrogram of the flame we could not find any line of the metallic elements besides that of the alkali and alkali earths (Na, K, Ca, Mg). In contrary all the metal spectral lines appeared in the spectrogram of the central column. In the discharge column the intensity of spectral lines is not uniform which is closely related to the variation of arc temperature.It is also found, that the stabilization of the position of arc flame by anexternal magnetic field results more stable volatilization of the sample solutionthus increase of precision could be attained. By focusing the image of the part with maximum intensity on the slit of the spectrograph increases sensitivity in practice.
1959, 15 (4): 173-177. doi: 10.7498/aps.15.173
In order to simplify the preparation of standards and to reduce the effects of micro-structure and physical state of samples in the spectrochemical analysis of alloy steels, universal methodg are developed in this laboratory. For the solution method, steel samples dissolved in acid and dropped on the flat tip of carbon electrodes are excited in a spark source. For the powder method, oxides prepared from the steel samples are put in cavities of carbon electrodes and excited in an a. c. are. Experiments show that these procedures give satisfactory analytical results.
1959, 15 (4): 178-185. doi: 10.7498/aps.15.178
In order to show if the relationshop obtained for Si 2516 between the slope of the calibration curve and its concentration has more general significance we carried out experiments on 13 spectral lines of two nultiplets belonging to the cobalt and nickel spectra. Results show that for a particular spectral line the slope depends on concentration and fur a definite range of the concentration, slope of the curves of spectral lines of the same mnltiplet varies linearly with log of the natural intensity of the corresponding lines. Thus, we may say that in spectrochemical analysis, slope b of the calibration curve essentially depends on the intensity of the spectral line and this in turn depends on the concentration of the constituent and the natural intensity of the line concerned. We believe that an understanding of the physical significance of b is helpful in actual analysis as to find the condition which gives a better slope of the working curve.