Enhancing Corrosion Resistance of High-Carbon Steel by Formation of Surface Layers Using Wastes as Input

Abstract

Series of super-hard ceramic layers have been successfully developed on high carbon steels, with a significant improvement of corrosion resistance and hardness, without changing the original properties, which were derived from mixtures of slag (electric arc furnace), waste glass (bottles), and automotive shredder residue (ASR) plastics (polypropylene) via the single step surface modification technique. Microstructural analysis by laser scanning confocal microscopy (LSCM), crystallography analysis by X-ray diffraction (XRD), micro-level chemical analysis by scanning electron microscopy and energy dispersive spectroscopy (SEM and EDS), and depth profile surface analysis with three-dimensional chemical mapping by time-of-flight secondary ion mass spectrometry (TOF-SIMS), followed by electrochemical corrosion test by the Tafel method and hardness test—Vickers hardness measurement. Three areas have been classified, modified surface, interface, and main substrate areas as the synthesis of ceramic layers into surface of the steels that thermodynamically formed during the heat treatment process. Chemical composition analyses have revealed that generated layers consisting of chromium (Cr)- and magnesium (Mg)-based compound have shown an improved corrosion resistance to 52% and hardness to 70% without modifying the initial volume fraction of constituent phases–martensite and retained austenite. These findings have substantially highlighted to the potential use of waste-integrated inputs as raw materials for production in cost-effective way, concurrently decreasing the demand on new resource for coating, alleviating the disadvantageous impact to the environment from waste disposal in landfills.

Comparison on corrosion performance of waste-based multi-hybrid structure high carbon steel and high Cr cast steel

“…In Fig. 1, it showed polarised light microscopy images of microstructures of HCCS at different magnification, in comparison with the previous study of multi-hybrid structure high carbon steel, sample HCS-C [14]. The dark colour represented martensite (M) phase, whereas ferrite (F) phase in bright colour.…”

“…High C steel with nominal composition of 1.1%C, 0.15%Mn, 0.40%Si, 0.65-0.70%Cr, 0.02 Mo and balance, units are in wt%, was utilised in this investigation. Different multi-hybrid layer has been successfully bonded on the surface of high C steel samples, derived from various wastes from the previous studies [14][15][16]. The evidence of the existence of multi-hybrid layer of the steels with different mixture of wastes approach and in-depth characterisations of the coatings were clearly described in these previous researches [14][15][16].…”

“…Different multi-hybrid layer has been successfully bonded on the surface of high C steel samples, derived from various wastes from the previous studies [14][15][16]. The evidence of the existence of multi-hybrid layer of the steels with different mixture of wastes approach and in-depth characterisations of the coatings were clearly described in these previous researches [14][15][16]. The corrosion resistance that HCCS alloys with similar composition with different Cr content (18.5-19.0%Cr on sample-A and 16.0-16.5% Cr on sample-B) have been used to overview and compared its corrosion resistance properties in 3.5% NaCl solution condition.…”

“…A reference SEM and EDS analysis of the waste-based multi-hybrid structure high carbon steel is referred to the previous study [14]-sample HCS-C, where the multihybrid layer composed from chromium nitride (CrN), magnesium nitride (Mg 3 N 2 ) and other metallic phases, such as TiN and TiO 2 , in comparison with the current results of HCCS alloys. In-depth analysis to observe the presence of Mo and V carbides in HCCS is presented in Fig.…”