Nonlinear laser lithography to control surface properties of stainless steel

Abstract

In the present work a novel method to improve the surface properties of stainless steel is presented and discussed. The method, based on the use of a high repetition rate femtosecond Yb fibre laser, permits generation of highly reproducible, robust, uniform and periodic nanoscale structures over a large surface area. The technique is characterized by high productivity, which, in its most simple form, does not require special environmental conditioning. Surface morphology is scrutinized through SEM and AFM analyses and wettability behaviour is investigated by means of the sessile drop method using distilled–deionized water. It is shown that optimization of process parameters promotes anisotropic wetting behaviour of the material surface

The contact angle of nanofluids as thermophysical property

“…Upper plot reference fluid DI-water and lower plot graphene oxide nanofluid. Independent data (upper plot) are indicated by black dots [33], dark grey dot [5], light grey dots [35], and pale grey [34].…”

“…The majority of the data is found in the error band of ±10 %. To confirm the found dependency, data from several independent references [5,[33][34][35] are utilised. Because temperature, droplet size, and experimentally obtained contact angle are given in these publications the contact angle according to eq.…”

Controlling the Wettability of Steel Surfaces Processed with Femtosecond Laser Pulses

“…Therefore, the control of the wettability of a surface under given conditions remains as an elusive task. − Different strategies have been applied to achieve wetting changes on steel surfaces either to produce an entirely different wetting behavior over the whole surface or to produce areas with combined wetting behaviors (known as high-contrast wetting surfaces) on the same substrate. Usually, this requires the use of processes such as the modification of the chemical properties of the surface via plasma or chemical etching, , the over-coating with an extra hydrophobic/hydrophilic top layer, , or the use of chemically assisted laser processing . The identification of robust strategies to confer the surface of a given steel with a user-defined wettability to extend its intended use to different applications remains as a challenge.…”

Thin‐wall injection molding of polypropylene using molds with different laser‐induced periodic surface structures

“…Laser‐induced periodic surface structures (LIPSS) are well‐known surface nano‐structures that are generated with linearly polarized laser using ultrashort pulse . The ablation with femtosecond‐lasers generates topographies characterized by periodic nano‐structured ripples that were recently used to modify the surface properties for an increasing number of applications . In particular, LIPSS have been successfully used to modify the wettability of steel surfaces , improve their tribological behavior , and increase hardness and wear resistance .…”