Application of the double pulse Nd:YAG laser induced breakdown spectroscopy to on-site analysis of carbon in steel

Abstract

On-site analysis of carbon in steels by laser induced breakdown spectroscopy (LIBS) was studied for the purpose of shortening of the analysis time. The LIBS system that consisted of double pulse Nd: YAG laser, an echell spectroscope and an ICCD detector was constructed. The highest emission intensity of carbon 193.09 nm line was obtained in the double pulse irradiation of the laser at wavelength 1064 nm with pulse energy of 10OmJ and 2μs delay time of double pulses. The relative standard deviations obtained by repetition analysis of standard steel samples are about 5% in the carbon concentration range of more than 0.3 wt%. The grinding process omission was examined as a simplification of the sample pretreatment. The analytical results of carbon in steel by LIBS were compared to that by Spark-OES using samples taken at steel works for process control. It is confirmed that the analytical precision by LIBS without grinding is equivalent to that by SparkOES with grinding. It is concluded that the LIBS technique can be applied to on-site analysis in steel works.