Combined plasma treatment of AISI-1045 steel by hastelloy deposition and plasma nitriding

Abstract

AISI-1045 steel is medium strength steel, and it needs surface modification to use in machine components. The surface properties of steel can be improved by plasma nitriding. The nitriding performance can be upgraded by introducing special alloying elements (nitride forming elements such as chromium, molybdenum), which have a strong affinity with nitrogen. Here, the combination of cathodic cage plasma nitriding (equipped with hastelloy cathodic cage, containing nitride forming elements) and conventional plasma nitriding is used to improve the surface properties. Thus, it is used to deposit such alloying elements, and subsequent plasma nitriding is performed to cause nitrogen diffusion to improve the coating adhesion and hardness gradient formation. The substrate hardness (346 HV) is increased up to 982 HV, 1426 HV, and 1692 HV by hastelloy deposition and post-nitriding at 400 and 450 °C, respectively. Additionally, the duplex treated samples show a favorable hardness gradient. The treated samples show the formation of iron nitrides Fe4N, Fe2−3N, chromium, and nickel phases. The voids and pores have appeared on the hastelloy deposited sample, removed by post-nitriding. The wear resistance is significantly improved by duplex treatment. The duplex treatment reported here can be used effectively to improve the surface hardness and wear resistance of AISI-1045 steel. Additionally, a single processing unit is required, needs low-processing temperature, surface uniformity, the whole processing time is relatively short, and the compatibility of this system with the industry proposed that this work would be helpful for the industrial requirement.