Regular paper

Temperature effect on the optical emission intensity in laser induced breakdown spectroscopy of super alloys

¹ Faculty of Science, Department of Physics, University of Isfahan, Isfahan, Iran
² Optics & Laser Science and Technology Research Center, Malek Ashtar University of Technology, Isfahan, Iran
³ Electrical Engineering & Electronic Department, Malek Ashtar University of Technology, Tehran, Iran

^* soltan@sci.ui.ac.ir

Received: 8 September 2014
Revised: 13 November 2014

Abstract

In this paper, the influence of heating and cooling samples on the optical emission spectra and plasma parameters of laser-induced breakdown spectroscopy for Titanium 64, Inconel 718 super alloys, and Aluminum 6061 alloy is investigated. Samples are uniformly heated up to approximately 200°C and cooled down to -78°C by an external heater and liquid nitrogen, respectively. Variations of plasma parameters like electron temperature and electron density with sample temperature are determined by using Boltzmann plot and Stark broadening methods, respectively. Heating the samples improves LIBS signal strength and broadens the width of the spectrum. On the other hand, cooling alloys causes fluctuations in the LIBS signal and decrease it to some extent, and some of the spectral peaks diminish. In addition, our results show that electron temperature and electron density depend on the sample temperature variations.