Mechanisms of laser cleaning induced oxidation and corrosion property changes in AA5083 aluminum alloy

Abstract

Laser cleaning of metallic alloys for the purpose of removal of metal oxide layers is based on laser thermal ablation. In laser thermal ablation, the interaction between the laser beam and oxide layer may generate significant thermal effects to induce additional thermal oxidation or even melting a thin layer of the underlying surface. The change of surface oxide status may subsequently affect corrosion behavior of the metallic alloys. In this work, the effects of laser cleaning on corrosion behavior of hot-rolled AA5083-O aluminum alloy were investigated using electrochemical impedance spectroscopy. The results showed that the laser-cleaned surfaces exhibited higher corrosion resistance in 3.5 wt. % NaCl solution than the as-received alloy, with a significant increase in impedance and reduction in capacitance. The corrosion behavior was correlated to the change of surface oxide status measured by glow discharge optical emission spectrometry, x-ray photoelectron spectroscopy, and high-resolution transmission electron microscopy. It was concluded that the laser cleaning removed the original, less protective oxide layer consisting of a discontinuous MgO/MgAl2O4 outer layer (∼20 nm) and MgO/MgAl2O4 particles dispersed inner layer (∼300 nm) on the as-received surface but resulted in the formation of more protective oxide layer containing mainly Al2O3 and MgO, which were responsible for the improvement of the corrosion performance. The laser fluence played an important role in determining the thickness of the newly formed oxide layers that subsequently affected the corrosion performance of laser-cleaned alloy.

Investigations on 2Cr13 Stainless Valves after Dry-Type Laser Degumming

“…9.9%), and C (wt. 5.3%), where O content was from the oxidation of metal [ 27 ]. After laser processing, obvious changes in chemical composition of Fe and C were observed.…”

Research Progress and Challenges in Laser-Controlled Cleaning of Aluminum Alloy Surfaces

“…The change in the laser energy density significantly impacted the removal effect of the oxide films and paint layers from aluminum alloy surfaces. Many studies have shown that the removal effect of oxide film on the aluminum alloy surface initially rises and then falls with increased energy density [ 13 , 33 , 55 , 56 , 57 , 58 , 59 ]. The energy-dispersive X-ray spectroscopy and the X-ray photoelectron spectroscopy (XPS) were used to detect the surface composition of the aluminum alloy.…”

Effect of narrow pulse width laser cleaning on corrosion resistance of A5083-H111 aluminum alloy

“…In most of the cases, the laser cleaning would induce the increase of surface roughness (Dong et al, 2017). The laser power, pulse frequency, cleaning speed and other parameters changed surface roughness through the way of changing energy density and overlap ratio (Zhang et al, 2019a(Zhang et al, , 2019b. When the pulse width is wide, the aluminum alloy substrate may be ablated.…”

“…It was reported by Dong et al (2017) that using laser at 100 ns pulse width to remove the oxide film of 7A52 aluminum alloy, it was found that the laser ablated the aluminum alloy substrate, formed corrugated grooves and increased the surface roughness. Although three mechanisms have been reported so far in the laser removal of oxide layers from metallic alloys, including thermal ablation, mechanical effect and combined thermal ablation and mechanical effects, the removal of oxide layers on aluminum alloys was dominated by thermal ablation, and the associated thermal effects (Zhang et al, 2019a(Zhang et al, , 2019b. The thermal ablation and associated thermal of the aluminum alloy surface make it easy to reoxidize and form a new oxide film on the substrate.…”