Plasma nitriding of steels

This book focuses on the effect of plasma nitriding on the properties of steels. Parameters of different grades of steels are considered, such as structural and constructional steels, stainless steels and tools steels. The reader will find within the text an introduction to nitriding treatment, the basis of plasma and its roll in nitriding. The authors also address the advantages and disadvantages of plasma nitriding in comparison with other nitriding methods.

Evaluation of electrochemical hydrogen storage capability of three-dimensional nano-structured nitrogen-doped graphene

In this work, nitrogen-doped graphene foam was synthesized by using hydrothermal routes. In the first step, graphene was synthesized by utilizing a modified Hummer's method and nitrogen-doped graphene foam was then synthesized at 180 °C by using an ammonia and graphene solution for 12 h. X-ray photon spectroscopy (XPS) was applied to determine the extent of doping by nitrogen on the graphene foam; three N-peaks were observed at 398.25, 399.69, and 401.46 eV, and XPS also showed that 6 at% of the synthesized graphene foam consisted of nitrogen atoms. The capability of this foam to absorb hydrogen was evaluated in a 6 M KOH solution through electrochemical impedance spectroscopy (EIS), galvanostatic charge/discharge, and cyclic voltammetry (CV) analysis. The hydrogen storage capacity of the achieved N-doped GF, showing the value of 1916.5 mAh.g−1 significantly improved in comparison to that of pure graphene in previous work, due to the increasing electronegative sites at the surface of the graphene foam

An Assessment of the Bactericidal and Virucidal Properties of ZrN-Cu Nanostructured Coatings Deposited by an Industrial PVD System

Pathogenic microbes, such as bacteria and viruses, can spread quickly via contaminated surfaces. Most of these pathogenic microorganisms can survive on surfaces for a long time. Touching these surfaces can lead to the transmission of the microorganisms to the human body and cause serious illnesses. ZrN-Cu coatings containing different amounts of Cu were deposited using an industrial PVD system, and their ability to inhibit bacteria and inactivate the SARS-CoV-2 virus was tested. Microstructural studies showed the formation of two distinct ZrN and Cu phases when Cu content was sufficiently high. Hardness and elastic modulus were inversely proportional to the Cu content. The coatings showed outstanding bactericidal properties against Escherichia coli and Pseudomonas aeruginosa, especially when Cu content was more than 12 at.% and exposure time was longer than 40 min. The coatings, however, did not exhibit any significant virucidal properties. Good mechanical properties, along with excellent antibacterial effects, make these coatings suitable for use as self-sanitizing surfaces on objects that people regularly touch and that are prone to bacterial contamination. Their use would thus allow for only minimal transmission or multiplication of bacteria, and the treated surface would not serve as another source of infection

Thermodynamically Study of Phase Formation of Ni-Ti-Si Nanocomposites Produced by Self-propagating High-temperature Synthesis Method

Understanding the phase formation mechanisms in self-propagating high-temperature synthesis from the thermodynamical aspect of view is important. In this study, the phase formation of the ternary system of nickel-titanium-silicon was studied by using the HSC software V6.0, and phase formation is predicted by calculating the adiabatic temperature of exothermic reaction between reagents. Then, by using X-ray diffractometer analysis, the results of the simulation were evaluated by experimental achievements. Results showed a good correlation between thermodynamical calculation and prediction with experimental. It could be concluded that the equilibrium mechanism is the dominant mechanism in phase formation in the SHS synthesis method. NiTiSi solid solution phase is obtained from the reaction between Ti5Si3 and Ni2Si and Ni