Iranian Journal of Materials Science and Engineering

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Nitriding is a surface treatment technique used to introduce nitrogen into metallic materials to improve their surface hardness, mechanical properties, wear resistance and corrosion resistance. In this research, the effects of plasma nitriding parameters including frequency and duty cycle were investigated on samples with different grooves dimensions. Steel blocks prepared from DIN1.2344 hot working steel were plasma nitride at 500 °C under the atmosphere contents of %75H2-%25N2, the duty cycles of 40%, 60%, 80%, and the frequencies of 8, 10 kHz for 5 hours. Then characteristics and micro hardness's of the nitrided samples were investigated using SEM, XRD, and Vickers Micro Hardness method. The results of the experiments indicated that with increasing frequency, the duty cycle, and the thickness of the grooves, the roughness of the surfaces increased. With an increase in duty cycle from 40% to 80%, the hardness of the surface rose and the thickness of the compound layer built up. Hollow cathode effect occurred in the samples with small grooves and high duty cycle in plasma nitriding. This will result in over heating of the sample which leads to a decrease in the slope of hardness values from the surface to the core of the sample and also a decrease in the diffused depth of nitrogen. The compound layer of the treated samples consisted of @ : Fe4N and : Fe2-3N phases and the proportion of the A to @ increased with the decrease in the duty cycle. Increasing the frequency did not affect the proportion of phases and micro hardness of the samples.

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Elevating component performance through advanced surface coatings finds its epitome in the domain of laser cladding technology. This technique facilitates the precision deposition of metallic, ceramic, or cermet coatings, accentuating their superiority over conventional methods. The application spectrum for laser-clad metallic coatings is extensive, encompassing critical components. Central to the efficacy of laser cladding is the modulation of laser parameters—encompassing power, speed, and gas flow—which decisively influence both process efficiency and coating properties. The meticulous calibration of these parameters holds the key to producing components endowed with refined attributes while ensuring the sustainable continuation of the process. As such, this study embarks on an empirical investigation aimed at transcending existing process limitations. It delves into the characterization of laser-clad WC-17Co coatings on AISI H13 and AISI 4140 steels. The importance of WC-17Co coatings lies in their capacity to enhance wear resistance, extend component life, reduce maintenance costs, and improve the performance of various industrial components across diverse sectors. On the other hand, the substrates have pivotal roles. AISI H13 is lauded for its exceptional hot work capabilities, while AISI 4140 steel is renowned for its robust strength and endurance. Through rigorous evaluation, the resultant deposited coatings offer crucial insights into the efficacy of manufacturing parameters. Employing a comprehensive suite of analytical techniques including laser confocal microscopy, Vickers microhardness assessment, and micro-adhesive wear testing, the study thoroughly characterizes the samples. The outcomes underscore the achievement of homogenous coatings marked by elevated hardness and exceptional wear resistance, thereby signifying a substantial enhancement over the substrate materials.