Thermal behavior of superwetting alumina coated on copper mesh during laser cladding for enhanced oil/water separation

Abstract

In this work, superwetting alumina coating was coated onto flexible copper mesh by one-step laser cladding treatment. In order to understand the formation mechanism of microstructured coating, the dynamic temperature field distribution during laser cladding is investigated by establishing a three-dimensional finite element simulation model based on the transient thermal analysis method. As the heat source moves, the temperature of the substrate surface increases from room temperature to over 660℃, allowing the aluminum to reach its melting point where melting occurs on the substrate surface. The effect of laser power on the distribution of alumina nanoparticles deposited on copper mesh was further investigated in consideration of temperature field distribution. When the laser power was increased to 1.2 times the initial power, the maximum temperature of the cladding layer increased to about 1930℃, which facilitated the formation of smaller size nanoparticles. It was found that the as-prepared substrate transits from hydrophobicity in air with WCA~125 ° to superhydrophilicity in air with WCA near 0°, while turning oleophobicity with OCA 110°to superoleophobicity with OCA~160°underwater. Oil/water separation was performed on as-prepared superwetting alumina coating coated copper meshes to reveal the enhancement mechanism behind.