Elemental Analysis By Laser Probe In Ceramics And Raw Materials

Nowadays, ceramics have been widely used in electronic, chemical, military and otherfields due to their high hardness and strengths, excellent corrosion resistance and insulatingproperties. As the compositions of ceramics and raw materials are key factors to determinethe performance, the real-time detection and control of the contents of ceramics and rawmaterials are very important to produce high-performance ceramics. Traditional ceramicanalysis methods cannot meet the requirement of rapid detection due to its complexprocedures and time-consuming. In this thesis, laser probe technology was used to analysethe compositions of aluminum oxide ceramics and their raw materials due to thecharacteristics of fast, real-time and multielement adapted.Based on the self-developed laser probe machine, the compositions of aluminum oxideceramics were analysed qualitatively. Eight kinds of main elements and their characteristicspectral lines were identified at atmosphere and experimental parameters were optimized.The results show that plasma signals with better S/N ratio can be obtained at a defocuseddistance of3mm below the sample surface, a pulse enegy of50mJ, a time delay of1.5μsand a pressure of1500Pa in argon.In additon, the spectral lines of AlO free radical molecular are found during theinteraction of laser with the aluminum oxide ceramics. The shape and evolution of AlOspectral lines with time delay and energy，as well as the causes were discussed, whichprovides references of investigating other molecular spectral lines by laser probe.Finally, elements of Mg、K、Ca、Fe、Na and Ti of ceramic raw materials werequantitative analysed by laser probe based on internal calibration method. The results showthat all the linearly dependent coefficients of calibration curves reach0.94. Furthermore, thespectral intensity, stability and linear correlation coefficient of calibration curves are allimproved to some extent after heating the standard sample. Importantly, laser probetechnology has the same analysis level as the EDXRF (Energy Dispersive X-RayFluorescence) but is inferior to the chemical analysis method. Especially for the mainceramic elements of Mg, K and Ca, the detection accuracy of laser probe is better than thatof EDXRF.