抄録
To study effects of atmosphere on spectral emission of laser-induced plasmas, spectral line intensities of elements in metal samples were investigated in air, oxygen, nitrogen, argon, and helium-oxygen atmospheres using a normal laser microprobe with auxiliary spark excita tion. Except for silicon lines, the strongest intensities were observed in the case of argon atmosphere. For the practical use, however, it was required to mix a small amount of oxygen in argon for keeping high spark voltages, because use of pure argon caused a decrease in the minimum spark voltage between auxiliary electrodes. A mixture of argon (2l/min.) and oxygen (100 cc/min.) can be used to improve the analytical sensitivity of particular elements such as magnesium and zinc in aluminum alloys. Little difference was observed between the erosion amounts in air and in argon-oxygen atmospheres. On the basis of excitation temperatures measured in the both atmospheres, enchancement effect of intensities are discussed.
