Search Results (2)

Laser-induced periodic surface structures (LIPSS) enable advanced surface functionalization with broad applications in various fields such as micro- and nanoelectronics, medicine, microbiology, tribology, anti-icing systems, and more. This study demonstrates the possibility of achieving anisotropy in the tribological behavior of C45-grade steel structured by nanosecond laser radiation using the LIPSS method. The lateral surface of the steel roller was irradiated with a pulsed Nd:YAG laser at an optimum intensity I = 870 MW/cm² for the formation of LIPSS. Two sets of samples were formed with LIPSS that were perpendicular and parallel to the roller’s rotational motion direction. The Raman intensity maps revealed that the LIPSS structure consisted of periodically arranged oxides at the top of hills. At the same time, the valleys of the LIPSS structures were almost not oxidized. These results correlated well with scanning electron microscopy energy dispersive X-ray spectroscopy mapping and atomic force microscopy measurements. A comparison of Raman and X-ray photoelectron spectroscopy spectra revealed that both the magnetite phase and traces of the hematite phase were present on the surface of the samples. Tribological tests were performed in two cycles with periodic changes in the normal clamping force and sliding speed. It was found that the LIPSS structures which were formed perpendicularly to the sliding direction on the roller had a significantly greater impact on the friction processes. Structures oriented perpendicular to the direction of motion had a positive influence on reducing the energy consumption of a friction process as well as increasing the wear resistance compared to LIPSS formed parallel to the direction of motion or ones having a non-texturized surface. Laser texturing to produce LIPSS perpendicular to the direction of motion could be recommended for friction pairs operating under low-load conditions. Full article

As the world moves towards sustainable and renewable energy sources, there is a need for reliable energy storage systems. A good candidate for such an application could be to improve secondary aqueous zinc–manganese dioxide (Zn-MnO₂) batteries. For this reason, different aqueous Zn-MnO₂ battery technologies are discussed in this short review, focusing on how electrolytes with different pH affect the battery. Improvements and achievements in alkaline aqueous Zn-MnO₂ batteries the recent years have been briefly reviewed. Additionally, mild to acidic aqueous electrolyte employment in Zn-MnO₂ batteries has been described, acknowledging their potential success, as such a battery design can increase the potential by up to 2 V. However, we have also recognized a novel battery electrolyte type that could increase even more scientific interest in aqueous Zn-MnO₂ batteries. Consisting of an alkaline electrolyte in the anode compartment and an acidic electrolyte in the cathode compartment, this dual (amphoteric) electrolyte system permits the extension of the battery cell potential above 2 V without water decomposition. In addition, papers describing pH immobilization in aqueous zinc–manganese compound batteries and the achieved results are reported and discussed. Full article