Investigation of local thermodynamic equilibrium of laser induced Al2O3–TiC plasma in argon by spatially resolved optical emission spectroscopy

K Alnama,A K Jazmati,A Alkhawwam

doi:10.1063/1.4954059

Abstract

Plasma plume of Al2O3–TiC is generated by third harmonic Q-switched Nd:YAG nanosecond laser. It is characterized using Optical Emission Spectroscopy (OES) at different argon background gas pressures 10, 102, 103, 104 and 105 Pa. Spatial evolution of excitation and ionic temperatures is deduced from spectral data analysis. Temporal evolution of Ti I emission originated from different energy states is probed. The correlation between the temporal behavior and the spatial temperature evolution are investigated under LTE condition for the possibility to use the temporal profile of Ti I emission as an indicator for LTE validity in the plasma.

Highlights

IntroductionAl2O3–TiC is one of the exceptional ceramic materials due to their high hardness and low wear rate and micromechanical properties that make it extremely advantageous for high precision parts in the manufacture of mechanical and electromechanical devices such as cutting tools magnetic head sliders.[1,2,3] Over the past twenty years, laser induced breakdown spectroscopy (LIBS) has emerged as valuable technique used in many applications in analytical, academic and governmental laboratories in different scientific and technological fields such as pulsed laser deposition (PLD) of thin films, laser treatment of surfaces, qualitative and quantitative elemental analysis, and nanotechnology.[4,5,6,7]
The correlation between the temporal behavior and the spatial temperature evolution are investigated under LTE condition for the possibility to use the temporal profile of Ti I emission as an indicator for LTE validity in the plasma
Over the past twenty years, laser induced breakdown spectroscopy (LIBS) has emerged as valuable technique used in many applications in analytical, academic and governmental laboratories in different scientific and technological fields such as pulsed laser deposition (PLD) of thin films, laser treatment of surfaces, qualitative and quantitative elemental analysis, and nanotechnology.[4,5,6,7]

Summary

Introduction

Al2O3–TiC is one of the exceptional ceramic materials due to their high hardness and low wear rate and micromechanical properties that make it extremely advantageous for high precision parts in the manufacture of mechanical and electromechanical devices such as cutting tools magnetic head sliders.[1,2,3] Over the past twenty years, laser induced breakdown spectroscopy (LIBS) has emerged as valuable technique used in many applications in analytical, academic and governmental laboratories in different scientific and technological fields such as pulsed laser deposition (PLD) of thin films, laser treatment of surfaces, qualitative and quantitative elemental analysis, and nanotechnology.[4,5,6,7]. In ns-LIBS, a high-powered nanosecond laser pulse is focused on a solid, liquid, or gaseous sample, yielding a surface power density of order 108-1010 W/cm[2]. The free and loosely-bound electrons of the sample absorb energy from the laser pulse during hundreds of picoseconds through inverse Bremsstrahlung processes and release additional electrons through collisions. The released electrons interact with atoms and molecules of the plume generating a high density of electrons. The formed plasma lasts for microseconds during which atomic, ionic, and molecular emissions characteristic of the plasma can be measured.[4,5]

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Results

Conclusion