Configuration Of The Testing Platform For Direct Reading Spectrum And Analysis Of Elemental Spectrum Lines

Direct reading spectral analysis is a method of emission spectrum analysis.Various elements under the high temperature and energy excitation produce their own unique spectrum,and then through the photoelectric conversion,the characteristic spectrum of element can be read,thus the material composition and content can be detected and analyzed.Direct reading spectrum can be used not only for constant and trace element analysis,but also for surface and depth profiles analysis.By means of external energy excitation such as spark discharge and glow discharge,direct reading spectrum own the advantages of fast analysis,convenient operation,high analytical precision and board application,which greatly promoted the development of high stability,high precision,rapid and automatic development in the production process.In this paper,a testing platform for direct reading spectrum based on Roland circle structure is designed.With the existing energy excitation source and acquisition system,the optical system is designed and the optics are assigned to meet the elemental analysis requirements,and then the optical system of the testing platform is debugged.Consequently,the full spectrum measurement from 200 nm to 400nm(near ultraviolet band)is realized,and the dispersion rate is less than 1.04nm/mm.Theoretical resolution of the optical system is related to many factors,in which the influence of the slit width is the most vital.However,the actual resolution will be lower than the theoretical value due to the intensity of the spectrum line and the installation error.Through the elemental spark spectrum excitation,the measured distinguishable minimum wavelength difference is about 0.17 nm,which is in line with design requirements.The spark discharge spectrum was obtained by self-built direct reading spectrum testing platform.After assigning the discharge parameters and the elemental analytical spectrum lines,the pure metal elements which consisted of stainless steel are measured and analyzed,and the calibration pixel position of each spectrum line is determined.Then,the analytical spectrum lines of Fe,Cr and Ni element in 304 stainless steel is measured,and a low content of Mo element in 316 stainless steel is detected,which achieved the qualitative analysis of the spark discharge spectrum.The glow discharge spectrum isobtained by GD-Profiler spectrometer.After the test parameters is assigned,the intensity of glow discharge spectrum line and depth distribution of Fe,Cr,Ni and O elements in304 stainless steel were analyzed.To acquire the elemental concentration,a semi-quantitative analysis method based on the known substrate content of 304 stainless steel was established,and the depth distribution of elemental content is obtained.The error analysis results show that the semi-quantitative analysis is very reliable in the trend prediction.