Spectroscopic investigation of laser produced plasma of carbon nanotube reinforced AlMg5 metal matrix nanocomposites

Abstract

Laser produced plasma of carbon nanotube reinforced AlMg5 metal matrix nanocomposites (AlMg5–CNT) is investigated by optical emission spectroscopy which dominantly consists of neutral aluminum (Al I) and magnesium (Mg I) atomic species. The blue-green (B2Σ−X2Σ) band system of AlO and green (1Σ → 1Σ) system of MgO are observed in the optical emission spectra of AlMg5–CNT plasma recorded without Ar shielding gas due to oxidation of Al I and Mg I species in air. The AlO blue-green (B2Σ−X2Σ) band system is also observed with Ar shielding gas in the optical emission spectra of plasma of AlMg5–CNT having oxidized grain boundaries which is irradiated by one or more laser pulses prior to plasma creation. The oxidation of grain boundaries in AlMg5–CNT is found to be nullified as the concentration of CNT reinforcement increases. Furthermore, the intensity ratio (IMgI/IAlI) of Mg I to Al I emission is found to be more for pristine AlMg5–CNT than that for AlMg5–CNT which is shot by one laser pulse prior to plasma creation, indicating more depletion of magnesium relative to aluminum.