Laser-induced breakdown spectroscopy of iron oxide powder

Iron oxide Fe2O3 nano-particle powder is investigated by laser-induced breakdown spectroscopy (LIBS). Laser ablation of loose Fe2O3 powder (density 0.43 g cm(-3)) leads to the ejection of particles and generates a plasma channel along the laser beam path. LIBS spectra are obtained by spatially integrated and time-gated measurement in flushed N-2 gas background. A simple powder delivery system allows for investigation of the nano-particle powder directly without any pre-treatment and fixation of the loose material. The Saha-Boltzmann analysis of spectra yields plasma temperature T = (10250 +/- 200) K and electron density N-e = (11 +/- 3) x 10(16) cm(-3) for the loose Fe2O3 powder and for pressed Fe2O3 powder pellets that are investigated for comparison. LIBS analysis of more than 20 different powder samples establishes calibration curves for Al, Si, Ni and Mn element impurities. The limits of detection derived from such curves are 8, 15, 66 and 860 ppm for Al, Si, Ni and Mn, respectively.