An advanced ultraviolet nanosecond pulsed laser cleaning oceanic micro-biofouling from steel surface

Abstract

An advanced nanosecond ultraviolet (UV) laser is innovatively conducted in cleaning micro biofoulings from the AH36 steel substrate surface. Natural micro biofoulings are formed utilizing a seawater immersion method. The field emission scanning electron microscopy (SEM) in conjunction with energy dispersive spectroscopy (EDS), digital ultra-depth-of-field microscope and optical profiler (OP) are adopted to evaluate the morphologies, topologies, and chemical compositions correspondingly. The surface wettability properties of UV laser cleaned surface are characterized by contact angle meter, which indicates that the created surfaces even possess superhydrophobic properties (163.5°) at the laser fluence of 6 J/cm². The results indicate that a laser fluence of 6 J/cm² illuminates outstanding cleaning effectiveness, topography height 25 μm and a surface roughness of 4.132 μm respectively. Furthermore, a tailored one-dimensional heat conduction model is developed according to the UV laser cleaning micro biofouling. Based on the Beer-Lambert law, the calculated cleaning threshold of the micro biofouling is 2.4 J/cm². The cleaning efficiency is approximately 58.4 $\times$ 10^-6 m³/h at the laser fluence of 8 J/cm². This study elaborates briefly the interaction mechanism of UV laser cleaning micro biofouling surface and provides practical guidance for maritime industries applications.