Corrosion and wear protection of AISI 4140 carbon steel using a laser modified high speed oxide fuel thermal sputtered coatings http://dx.doi.org/10.5599/jese.1320 865 J. Electrochem. Sci. Eng. 12(5) (2022) 865-876; http://dx.doi.org/10.5599/jese.1320 Open Access : : ISSN 1847-9286 www.jESE-online.org Original scientific paper Corrosion and wear protection of AISI 4140 carbon steel using a laser-modified high-velocity oxygen fuel thermal sprayed coatings Shanmugasundaram Sivarajan1, , Adwait Joshi1, Karthikeyan Palani2, Raghupathy Padmanabhan1 and Joseph Stokes3 1Vellore Institute of Technology, Vandalur Kelambakkam road, Chennai, Pin 600127, India 2Saveetha Engineering College, Saveetha nagar, Thandalam, Chennai, Pin 602105, India 3Dublin City University – Glasnevin Campus Dublin 9 - D09 NA55, Ireland Corresponding author: sivarajan.s@vit.ac.in; Tel.: 919841617961 Received: March 4, 2022; Accepted: June 1, 2022; Published: July 21, 2022 Abstract Inconel and micro and nano WC-12Co powders were deposited on AISI 4140 carbon steel by high-velocity oxy fuel (HVOF) coating and followed by laser surface modification. Laser power and scan speed were varied at different levels. Microstructure and microhardness were investigated. Nanocoatings performed better than microcoatings. Nanostructured WC powder coatings exhibited greater hardness compared to microstructured powder coating. When the laser power is increased to 170 W, a small cellular dendrite microstructure through multiphase solidification is formed due to the difference in thermal properties of Inconel 625 and WC particles. Adequate laser power and low scan speed were preferred to produce a high-quality coating. From the electrochemical corrosion test results, it was observed that the corrosion rate of laser-modified HVOF sprayed coating is lower than the carbon steel sample. This shows that the Inconel sprayed by laser-modified HVOF coating enhanced the corrosion resistance of the substrate steel material. The porosity percentage was higher for all the samples when laser scan speed was increased. Keywords Inconel-625; tungsten carbide; WC-12Co Introduction AISI 4140 carbon steel is extensively used in petrochemical and other industrial applications. However, this steel cannot be used in an aggressive corrosive atmosphere due to its poor corrosion resistance. Many coating techniques like physical vapor deposition (PVD), chemical vapor deposition CVD, thermally sprayed coatings, and laser surface modification can be employed to improve the corrosion resistance of carbon steel. Machine component degradation occurs in petrochemical and related industries due to wear and tribo-corrosion. A material deterioration is troublesome to http://dx.doi.org/10.5599/jese.1320 http://dx.doi.org/10.5599/jese.1320 http://www.jese-online.org/ mailto:sivarajan.s@vit.ac.in J. Electrochem. Sci. Eng. 12(5) (2022) 865-876 AISI 4140 CARBON STEEL CORROSION PROTECTION 866 production and plant workers and expensive to prevent. Many researchers worldwide have tried to combat material degradation by developing new advanced materials. To minimize material degradation, protective coatings produced by the electrolytic hard chromium process are not recommended due to environmental issues. Moreover, water plays a crucial role in hard chrome plating; today, its depletion limits its use [1]. PVD and CVD coatings are not preferred to combat material degradation due to inferior properties and high application costs [2]. Thermal spraying is an extensively used coating technique to protect materials from wear and corrosive atmosphere [3-14]. However, this process induces changes to the coating powder, resulting in defective coatings. Additionally, the oxide formation during thermal spraying can affect the efficiency of coatings in extreme and aggressive surroundings [15]. The adhesive strength between coating and substrate is also not very good in thermal sprayed coatings. Hence, it is unsuitable for protecting the surface of materials in severe conditions. Laser surface modification can be considered a probable technique to minimize the flaws of the coatings. Laser surface modification via heat treatment offers advantages like accurately controlled dimensions, and least heat-affected zones, producing no thermal effects on the substrate. The laser surface modification can also be employed for parts with complex shapes. Furthermore, automation can be easily achieved in laser processing. Laser processing as a post-treatment process for high-velocity oxy fuel (HVOF) coatings to enhance corrosion resistance has been reported by many researchers [16-23]. Nanostructured materials are of great interest because of their superior properties, which differ from bulk materials. Nanostructured WC-12Co powder is used to enhance for wear resistance of various metallic surfaces. Nevertheless, a spray of nano-sized powder is difficult owing to its low weight. Inconel 625 coatings are widely used to improve the corrosion resistance of steel. Inconel 625 coatings find many applications in petrochemical and power generation industries to protect the equipment operating in severe conditions. The influence of laser heating on the hardness of WC-CoCr HVOF sprayed coating was examin- ed [24]. The average value of the microhardness of the coating increased after laser heating from 1161.7 Hv to 1579.8 Hv. Furthermore, the microhardness is improved with reduced porosity of the coating. Coatings produced by a laser-assisted spraying process; also called laser hybrid spraying, where thermal spraying and laser melting processes were combined to get denser coatings of dif- ferent Ni-base materials on low carbon steel substrate were reported [25]. Laser-hybrid Inconel 625 coatings showed poor corrosion behavior due to cracks and high iron dilution from the substrate. The influence of laser melting on the mechanical properties of Inconel 625 and Inconel 625 with WC as MMC HVOF sprayed on 316L steel substrate was investigated [26]. It was observed that wear resistance increases by increasing the percentage of WC in the coating material. The residual stress profile and room temperature wear behavior of WC-Co coatings deposited by kinetic metallization were characterized [27]. The SEM imaging and etched optical micrographs showed significant plastic deformation and particle penetration at the interface due to the high energy impact of feedstock particles. The wear resistance measured by the pin-on-disk method showed a wear performance comparable to conventionally sprayed WC-Co coatings. The laser cladding technology, a modern joining technique to fulfill the requirements of many industrial applications, is reviewed [28]. The purpose is to facilitate researchers by providing comprehensive knowledge about this technology to encourage them to explore it in future research and innovation efforts. It was reported that shorter spray distance and higher fuel flow increased the particle velocity during HVOF spraying of FeMnCrSi coatings [29]. Higher particle velocity showed higher compressive residual stress. The lower powder S. Sivarajan et al. J. Electrochem. Sci. Eng. 12(5) (2022) 865-876 http://dx.doi.org/10.5599/jese.1320 867 feed rate promoted an increase in compressive residual stress. Cavitation wear resistance is higher for higher compressive residual stress. The performance of two coating processes to combat the water droplet impingement erosion (WDIE) phenomenon was compared [30]. High-velocity air fuel (HVAF) and high-velocity oxygen fuel (HVOF) processes are used to spray WC-10Co-4Cr powder on Ti-6Al-4V. At 250 m/s and 300 m/s, gradual damage occurs due to accumulated impact and jetting, where HVAF outperformed HVOF coating. HVOF's lower performance is attributable to the formation of an unwanted brittle W2C phase. Suspension-high velocity oxygen fuel spraying (S-HVOF) and suspension plasma spraying (SPS) were applied to produce Al2O3 coatings using homemade and commercially available Al2O3 water-based liquid feedstocks containing 40 wt.% of sub-micrometer-sized raw powders [31]. The influence of feedstock characteristics and spray process conditions on the mechanical and tribological properties was analyzed. Furthermore, the corrosion behavior of superalloys used in turbines is studied and reviewed [32]. Grey cast iron (CI) substrate was coated with Inconel718- based composite coating with a high-velocity oxy-fuel technique [33]. The coating with 10 wt.% Al2O3 content exhibited the maximum corrosion resistance. In thermal power plants, protection of materials surface from degradation is crucial since it leads to plant inefficiency [34]. The role of thermal spray coatings has been investigated to protect different steel grades exposed to such degrading conditions at high temperatures in coal-based power plants. The bimodal composite coatings developed with Inconel and Al2O3 protect the underlying substrate due to their hardness and fracture toughness [35]. This paper aims to investigate the viability of laser remelting of the HVOF spraying process to coat nano-sized WC-12 Co mixed with Inconel 625 on steel substrates. In addition, the effect of laser parameters on these coatings will be evaluated by microstructure and microhardness measurements. Experimental Coating powders To protect the AISI carbon steel from corrosion and wear, three different powders were used for deposition using HVOF thermally sprayed coating. The first was Inconel-625 (Diamalloy 1005). The chemical composition of Diamalloy 1005 is 66.5 wt.% Ni, 21.5 wt.% Cr, 8.5.wt.% Mo, 3 wt.% Fe and 0.5.wt.% Co. Tungsten carbide WC-12Co (Diamalloy 2004- Sintered) was also used to improve wear resistance. The chemical compositions for (Diamalloy 2004) are 88 wt.% WC and 12 wt.% Co. A nanostructure superfine WC-12Co Infralloy TM S7412 was used in the composite mixture to compare against conventional coatings. Its chemical composition is as follows: 88 wt.% WC and 12 wt.% Co. The substrate material used is made up of AISI 4140 carbon steel. In each sample, two of the three powders were mixed to various compositions, as shown in Table 1. The coating powders were deposited on AISI carbon steel using an A1050 DJH automated HVOF gun spray device. Grit blasting was performed on these AISI carbon steel samples with the help of honite powder particles. Moisture was removed from steel samples by heating them to 110 °C. The parameters were selected based on the powder composition to avoid decomposition. Laser equipment and processing parameters Laser surface modification was carried out on HVOF sprayed steel samples using a pulsed laser system. The CO2 Rofin laser has a power rating of 1.5 kW. Compressed argon was provided coaxially as a shielding gas. The PRF (pulse repetition frequency) was kept constant at 400 Hz. The focal point position was kept at –5 mm. In the first set of six experiments, the laser power was varied at six http://dx.doi.org/10.5599/jese.1320 J. Electrochem. Sci. Eng. 12(5) (2022) 865-876 AISI 4140 CARBON STEEL CORROSION PROTECTION 868 levels at a constant scan speed of 1000 mm min-1. Laser power levels used were 20, 55, 105,170, 240, and 290 W. In the second set of experiments, the laser scanning speed varied at six levels at a constant laser power of 55 W. Scanning speed levels were 750, 1000, 1250, 1500, and 2000 mm min- 1. In addition, the scanning electron micrographs were taken. Table 1. Composition of powders in sample Sample Content, wt.% WC-12Co (nano) WC-12Co (micro) Inconel 625 (micro) S1 25 0 75 S2 50 0 50 S3 75 0 25 S4 0 75 25 S5 0 50 50 S6 0 25 75 Mechanical characterization of coatings The hardness of the coatings was measured by Vickers microhardness testing machine manufactured by SHIMADZU (Model: HMV-G). The resolution was 0.01 μm, and the load used was 100 g. The duration of the load applied was 10 seconds. Indentation was made on different parts of the heat-affected zone and the shape of indentation observed was of the rhombus. The length of both the diagonals was measured and based on that measurement Vickers hardness number was directly calculated and graphs plotted. Three sets of readings were taken to ensure consistency in results. Electrochemical corrosion tests The Tafel tests of laser-modified HVOF sprayed sample and carbon steel sample were performed in salt solution at 36.5 °C using a potentiostat (Interface 1010, Gamry Instruments) by exposing 0.375 cm2 area of the samples. The corrosion cell consists of a saturated calomel electrode (SCE) and a platinum wire as reference and counter electrodes. Tafel plots were created by polarizing the specimen about 0.3 V anodically and cathodically with reference to open circuit potential (OCP) at a scan rate of 0.5 mV s-1 after an initial delay of 60 minutes. After the measurements were obtained, the Tafel data were analyzed by curve fitting and equivalent circuit modeling using Gamry Echem Analyst software. Porosity measurement Assuming that resolution limits are considered, porosity within a microstructure can be easily detected by image analysis due to the high degree of contrast between the dark pores (voids) and the more highly reflective coating material. In this study, the SEM images were used to check the porosity using ImageJ software. The areas of porosity were selected in the SEM image and the percentage of porosity was analyzed and processed by ImageJ software Results and discussion The detailed microstructure analysis of HVOF sprayed WC-12Co-Inconel-625 coatings exhibits spat-like layered morphologies due to the re-solidification of molten and semi-molten powder particles. During HVOF spraying, WC-12Co-Inconel 625 coatings under different powder compo- sitions contain three distinct zones: fully, partially, and unmelted core. The formation of molten, semi-molten and unmelted zones is due to variation in melting temperature of WC-12Co and Inconel particles relative to flame temperature. The formation of three separate zones was confirmed by S. Sivarajan et al. J. Electrochem. Sci. Eng. 12(5) (2022) 865-876 http://dx.doi.org/10.5599/jese.1320 869 previous research work [36]. In addition, defects such as pores, micro defects and cracks are found in most HVOF coatings. Figure 1. SEM image of laser-modified HVOF thermally sprayed Inconel 625 and WC-12Co coatings; laser power = 55 W; laser scan speed = 1000 mm min-1 microstructured powder Figure 2. SEM Image of laser-modified HVOF thermally sprayed Inconel 625 and WC-12Co coatings; laser power = 55 W; laser scan speed = 1500 mm min-1 microstructured powder Partially molten and fully molten particles of HVOF coatings were modified by laser with a reduction in cracks and porosity. The minimization of discrete splats and porosity by laser modification will improve the wear resistance. Figure 1 shows the SEM image of laser-modified HVOF coating with laser power of 55 Watts and a scan speed of 1000 mm min-1. It can be seen that the pores present in the HVOF coating are minimized to a larger extent in the laser-modified zone. Also, the pore size is considerably reduced compared to those present elsewhere. The occurrence of porosity is minimal in the laser-treated region compared to other regions, as can be observed in Figure 2. The SEM image (Figure 2) also shows that the diffusion of coating constituents into the substrate is less, which has helped maintain the original properties of coatings. Improved material consolidation is found to be more effective through laser. Figure 3 shows the SEM image of the coatings in which splats, pores, and cracks are visible in the microstructure. This is because the laser power is too low to melt WC and Inconel particles with nanostructured powder. Figure 4 shows an SEM image of coating in which a fine-grained homogenous poly phase microstructure is developed due to low laser scan speed while maintaining low laser power (55 W). When the laser power is increased to 170 W, a small cellular dendrite microstructure through multiphase solidification is formed due to the difference in thermal properties of Inconel 625 and WC particles, as observed in Figure 5. The surface is made up of coating material and the substrate, leading to a differential cooling rate; hence, the cell size and orientation vary in the coating [37-38]. Figure 6 shows the SEM image in which large pores are seen due to higher scan speed. When the scan speed and power are high, the time of contact is less and there is less time for the gases and bubbles formed during the coating powder reactions to escape, resulting in pores in the coating remelting zone. A dendrite microstructure is observed at higher magnification in the SEM image due to multiphase solidification, as shown in Figure 7. http://dx.doi.org/10.5599/jese.1320 J. Electrochem. Sci. Eng. 12(5) (2022) 865-876 AISI 4140 CARBON STEEL CORROSION PROTECTION 870 Figure 3. SEM image of laser modified HVOF thermally sprayed Inconel 625 and WC-12Co coatings; laser power 55 W laser scan speed = 1250 mm min-1 nanostructured powder Figure 4. SEM image of laser modified HVOF thermally sprayed Inconel 625 and WC-12Co coatings; laser power 55 W laser scan speed = 1000 mm min-1 nanostructured powder Figure 5. SEM image of laser modified HVOF thermally sprayed Inconel 625 and WC-12Co coatings; laser power 170 W. laser scan speed = 1500 mm min-1. nanostructured powder Figure 6. SEM image of laser modified HVOF thermally sprayed Inconel 625 and WC-12Co coatings; laser power 170 W. laser scan speed 1750 mm min-1. micro structured powder The influence of laser scan speed on the microhardness of laser melted high-velocity oxy fuel coated samples is shown in Figure 8. The first three coated samples (nano-sized powder coatings) showed higher hardness than the remaining three coated samples (micro-sized powder coatings). The maximum hardness with nano powder coatings is Hv1199 and with micro-sized powder coatings, it is Hv775. Nano powder coatings exhibited better melting leading to the dense coating of higher microhardness. When the laser scan speed was between 1250 to 2000 mm min-1, proper powder melting and consolidation took place, resulting in uniform high microhardness in all three cases. The S. Sivarajan et al. J. Electrochem. Sci. Eng. 12(5) (2022) 865-876 http://dx.doi.org/10.5599/jese.1320 871 influence of laser power on the microhardness of laser melted high-velocity oxy fuel coated samples is shown in Figure 9. When laser power is increased, the micro-hardness of coated samples improves. An increase in laser power combined with low scan speed ensures proper melting and less porosity, leading to high hardness. It was observed that coatings produced by spraying nanopowders show higher hardness than coatings produced by micro-sized powders. Figure 7. SEM Image of laser modified HVOF thermally sprayed Inconel 625 and WC-12Co coatings; laser power = 170 W. laser scan speed = 1750 mm min-1. nanostructured powder Figure 8. Variation of microhardness of coatings with laser scan speed; Laser power = 55 W Figure 9. Variation of microhardness of coating with laser power; laser scan speed = 1000 mm min-1 Figure 10. Microscopic pictures of laser modified HVOF sprayed WC-12CO-Inconel coatings. Sample S1; laser power = 55 W; laser scan speed: (a) 750 (b) 1000 (c) 1250 (d) 1500 (e) 1750 (f) 2000 mm min-1 0 200 400 600 800 1000 1200 1400 700 1200 1700 2200 M ic ro h a rd n e ss , H v Laser speed, mm min --1 S1 S2 S3 S4 S5 S6 0 200 400 600 800 1000 1200 1400 0 200 400 M ic ro h a rd n e ss , H v Laser power, W S1 S3 S3 S4 S5 S6 http://dx.doi.org/10.5599/jese.1320 J. Electrochem. Sci. Eng. 12(5) (2022) 865-876 AISI 4140 CARBON STEEL CORROSION PROTECTION 872 Figure 11. Microscopic pictures of laser-modified HVOF sprayed WC-12CO-Inconel coatings; sample S2; laser power = 55 W.; laser scan speed: (a) 750 (b) 1000 (c) 1500 (d) 1750 (e) 2000 mm min-1 Figure 12. Microscopic pictures of laser-modified HVOF sprayed WC-12CO-Inconel coatings; sample S3; laser power = 55 W.; laser scan speed: (a) 750 (b) 1000 (c) 1250 (d) 1500 (e) 1750 mm min-1 Figure 13. Microscopic pictures of laser-modified HVOF sprayed WC-12CO-Inconel coatings; sample S; laser power = 55 W; laser scan speed: a) 750 (b) 1000 (c) 1250 (d) 1500 (f) 2000 mm min-1 Figure 14. Microscopic pictures of laser-modified HVOF sprayed WC-12CO-Inconel coatings, sample S5; laser power = 55 W; laser scan speed: (a) 750 (b) 1000 (c) 1250 (d) 1500 mm min-1 From the electrochemical corrosion test results (Table 2 and Figure 17), it was observed that the laser-modified HVOF sprayed coating exhibited lower corrosion current density when compared with the plain carbon steel sample. The corrosion rate of laser-modified HVOF sprayed coating is also lower than that of the carbon steel sample. This shows that the Inconel sprayed by laser- modified HVOF coating has enhanced the corrosion resistance of the substrate steel material. S. Sivarajan et al. J. Electrochem. Sci. Eng. 12(5) (2022) 865-876 http://dx.doi.org/10.5599/jese.1320 873 Figure 15. Microscopic pictures of laser-modified HVOF sprayed WC-12CO-Inconel coatings.; sample S6; laser power 55 W; laser scan speed: (a) 750 (b) 1000 (c) 1250 (d) 1500 (e) 1750 (f) 2000 mm min-1 Figure 16. Microscopic pictures of laser-modified HVOF sprayed WC-12CO-Inconel coatings; sample S1; laser scan speed: 1000 mm min-1; laser power: (a) 20 (b) 55 (c) 105 (d) 170 (e) 240 (f) 290 W Figure 17. Tafel curve of laser modified HVOF sprayed coating and carbon steel substrate during the corrosion tests Table 2. Electrochemical corrosion tests results Laser-modified HVOF sprayed sample Carbon steel sample icorr / A cm-2 22.10 808.0 Ecorr / mV -110.0 -27.00 Corrosion rate, mm year-1 0.26035 9.53262 -0.4 -0.3 -0.2 -0.1 0.0 0.1 0.2 0.3 0.4 -10 -8 -6 -4 -2 0 P o te n ti a l, V v s. S C E log (i / A cm-2) Carbon steel sample Laser modifies HVOF sprayed coating http://dx.doi.org/10.5599/jese.1320 J. Electrochem. Sci. Eng. 12(5) (2022) 865-876 AISI 4140 CARBON STEEL CORROSION PROTECTION 874 Table 3. Porosity measurement results Sample Laser power, W Laser scan speed, mm min-1 Porosity, % Sample Laser power, W Laser scan speed, mm min-1 Porosity, % S1 55 750 1.300 S4 55 750 1.951 S1 55 1000 1.780 S4 55 1000 2.130 S1 55 1250 2.186 S4 55 1250 2.550 S1 55 1500 2.753 S4 55 1500 2.980 S1 55 1750 3.020 S4 55 1750 3.921 S1 55 2000 4.124 S4 55 2000 5.128 S1 20 1000 2.110 S4 20 1000 3.021 S1 55 1000 2.770 S4 55 1000 2.982 S1 105 1000 1.991 S4 105 1000 2.100 S1 170 1000 2.670 S4 170 1000 2.990 S1 240 1000 3.121 S4 240 1000 3.050 S1 290 1000 2.770 S4 290 1000 3.100 S2 55 750 2.100 S5 55 750 2.020 S2 55 1000 2.320 S5 55 1000 2.760 S2 55 1250 2.952 S5 55 1250 3.320 S2 55 1500 2.380 S5 55 1500 3.641 S2 55 1750 3.456 S5 55 1750 4.124 S2 55 2000 3.950 S5 55 2000 4.985 S2 20 1000 2.220 S5 20 1000 2.650 S2 55 1000 2.780 S5 55 1000 2.550 S2 105 1000 2.640 S5 105 1000 2.450 S2 170 1000 2.561 S5 170 1000 3.050 S2 240 1000 1.792 S5 240 1000 2.760 S2 290 1000 2.650 S5 290 1000 3.110 S3 55 750 1.890 S6 55 750 2.123 S3 55 1000 1.720 S6 55 1000 2.520 S3 55 1250 2.456 S6 55 1250 3.820 S3 55 1500 2.670 S6 55 1500 3.621 S3 55 1750 3.222 S6 55 1750 4.980 S3 55 2000 3.992 S6 55 2000 5.320 S3 20 1000 2.051 S6 20 1000 2.990 S3 55 1000 2.221 S6 55 1000 3.290 S3 105 1000 2.781 S6 105 1000 2.870 S3 170 1000 2.450 S6 170 1000 2.560 S3 240 1000 2.680 S6 240 1000 2.740 S3 290 1000 2.730 S6 290 1000 2.690 The porosity measurement is made using ImageJ software [39]. The average porosity of nano samples (S1, S2, S3) is 2.59 % and the average porosity is 3.13 %. In all six samples, the porosity increased with an increase in laser scan speed. When the scan speed and power are high, the time of contact is less and there is less time for the gases and bubbles formed during the coating powder reactions to escape and this has resulted in the occurrence of pores in the coating remelting zone. Conclusions In conclusion, WC powder particle size, laser power and laser scan speed were varied, and its effects on the microhardness and microstructure developed in the coating were examined. Micro- Hardness measurements performed on laser-modified HVOF coatings displayed constantly greater values for coatings produced by nanopowder compared to coatings made by micro powder. When the laser power is increased to 170 W, a small cellular dendrite microstructure through multiphase solidification is formed due to the difference in thermal properties of Inconel 625 and WC particles. S. Sivarajan et al. J. Electrochem. Sci. Eng. 12(5) (2022) 865-876 http://dx.doi.org/10.5599/jese.1320 875 Adequate laser power and low scan speed will be preferred to produce a coating with high quality. The electrochemical corrosion test results showed that the corrosion rate of laser-modified HVOF sprayed coating is lower than the carbon steel sample. This shows that the Inconel sprayed by laser- modified HVOF coating has enhanced the corrosion resistance of the substrate steel material. The porosity percentage is higher for all the samples when laser scan speed increases. Therefore, for AISI 4140 carbon steel, to improve the wear and corrosion resistance, laser-modified HVOF nano- sized WC-12Co –Inconel-625 coatings show the promising result. Acknowledgements: The authors would like to express their sincere gratitude to Vellore Institute of Technology, Chennai, India and Dublin City University, Ireland for the support given in carrying out this research work. The authors would like to express their sincere gratitude to Dr. R. Radha and Mr. Babu of Materials Engineering Lab of Vellore Institute of Technology, Chennai, India for their support in performing electrochemical corrosion tests. References [1] S. Abdi, S. Lebaili, Physics Procedia 2 (2009) 1005-1014. https://doi.org/10.1016/j.phpro.2009.11.056 [2] T. S. Sidhu, S. Prakash, R. D. Agrawal, Surface and Coatings Technology 201 (2005) 273-281. https://doi.org/10.1016/j.surfcoat.2005.11.108 [3] D. Chidambaram, C. R. Clayton, M. R.Dorfman, Surface and Coating Technology 176(3) (2004) 307-317. https://doi.org/10.1016/S0257-8972(03)00809-0 [4] E. Chikarakara, S. Aquida, D. Brabazon, S. Naher, S. J. A. Picas,M. Punset , A. Forn, International Journal of Material Forming 3 (2010) 801-804. https://doi.org/10.1007/s12289-010-0891-0 [5] T. S. Sidhu, S. Prakash, R. D. Agrawal, Surface and Coating Technology 200 (2006) 5542-5549. https://doi.org/10.1016/j.surfcoat.2005.07.101 [6] K. Kanchan Kumari, K. Anand, M. Bellacci, M. Giannozzi, Wear 268 (2010) 1309-1319. https://doi.org/10.1016/j.wear.2010.02.001 [7] S. At-Mutairi, M. S. J. Hashmi, B. S. Yilbas, J. Stokes, Surface and Coating Technology 264 (2015) 175-186. https://doi.org/10.1016/j.surfcoat.2014.12.050 [8] I. Iordanova, M. Surtchev, K. S. Forcey, Surface and Coatings Technology 139 (2001) 118-126. https://doi.org/10.1016/S0257-8972(01)00991-4 [9] H.S.Grewal, H.Singh, Anupam Agrawal, Surface and Coatings Technology 216 (2013) 78-92. https://doi.org/10.1016/j.surfcoat.2012.11.029 [10] T. Sahraoui, S. Guessasma, A. Jeridane, M. Hadji, Materials and Design 31 (2010) 1431-1437. https://doi.org/10.1016/j.matdes.2009.08.037 [11] M. Ashokkumar, D. Thirumalaikumarasamy, P. Thirumal, R. Barathiraja, Materials Today Proceedings 46(17) (2021) 7581-7587. https://doi.org/10.1016/j.matpr.2021.01.664 [12] A. S. Bolokang, M. Ntsoaki Mathabathe, in: Handbooks in Advanced Manufacturing, Advanced Welding and Deforming, Elsevier, Amsterdam, Netherlands, 2021, p.291-319. [13] M. A. Javed, A. S. M. Ang, C. M. Bhadra, R. Piola, W. C. Neil, C. C. Berndt, M. Leigh, H. Howse, S. A. Wade, Surface Coating Technology 418 (2021). https://doi.org/10.1016/j.surfcoat.2021.12 7239 [14] S. Sivarajan, R. Padmanabhan, Advances in Materials and Processing Technologies 7 (2021) 227-240. https://doi.org/10.1080/2374068X.2020.1758605 [15] A. Scrivani , S. Ianelli , A. Rossi R. Groppetti , F. Casadei , G. Rizzi, Wear 250 (2001) 107-113. https://doi.org/10.1016/S0043-1648(01)00621-4 [16] D. Brabazon,S. Naher, P. Biggs, Solid State Phenonena 141-143 (2008) 255-260. https://doi.org/10.4028/www.scientific.net/SSP.141-143.255 http://dx.doi.org/10.5599/jese.1320 https://doi.org/10.1016/j.phpro.2009.11.056 https://doi.org/10.1016/j.surfcoat.2005.11.108 https://doi.org/10.1016/S0257-8972(03)00809-0 https://doi.org/10.1007/s12289-010-0891-0 https://doi.org/10.1016/j.surfcoat.2005.07.101 https://doi.org/10.1016/j.wear.2010.02.001 https://doi.org/10.1016/j.surfcoat.2014.12.050 https://doi.org/10.1016/S0257-8972(01)00991-4 https://doi.org/10.1016/j.surfcoat.2012.11.029 https://doi.org/10.1016/j.matdes.2009.08.037 https://doi.org/10.1016/j.matpr.2021.01.664 https://doi.org/10.1016/j.surfcoat.2021.127239 https://doi.org/10.1016/j.surfcoat.2021.127239 https://doi.org/10.1080/2374068X.2020.1758605 https://doi.org/10.1016/S0043-1648(01)00621-4 https://doi.org/10.4028/www.scientific.net/SSP.141-143.255 J. Electrochem. Sci. Eng. 12(5) (2022) 865-876 AISI 4140 CARBON STEEL CORROSION PROTECTION 876 [17] H. J. Shin, Y. T. Yoo, Journal of Material Processing Technology 201 (2008)342-347. https://doi.org/10.1016/j.jmatprotec.2007.11.232 [18] A. Gisario, M. Barletta, F. Veniali, Optics Laser Technology 44 (2012) 1942-1958. https://doi.org/10.1016/j.optlastec.2012.02.011 [19] J. C. Abboud, K. Y. Benyounis, A. G. Olabi, M. S. J. Hashmi, Journal of Material Processing Technology 182 (2007) 427-431. https://doi.org/10.1016/j.jmatprotec.2006.08.026 [20] M. A. Montealegra, G. Castro, P. Rey, J. Larias, P. Vasquez, M. Gonzalez, Contemporary Materials I-1 (2010) 19-30. https://doi.org/10.5767/anurs.cmat.100101.en.019M [21] P. Poza, C. J. Múnez, M. A. Garrido-Maneiro, S. Vezzù, S. Rech, A. Trentin, Surface and Coatings Technology 243 (2014) 51-57. https://doi.org/10.1016/j.surfcoat.2012.03.018 [22] V. C. Kumar, Surface and Coatings Technology 201 (2006) 3174-3180. https://doi.org/10.1016/j.surfcoat.2006.06.035 [23] Z. Y. Taha-al, M. S. J. Hashmi, B. S. Yilbas, Journal of Material Processing Technology 209 (2009) 3172-3181. https://doi.org/10.1016/j.jmatprotec.2008.07.027 [24] S.-H. Zhang,T.-Y. Cho, J.-H. Yoon, W. Fang, K.-O Song, M.-X. Li, Y.-K. Joo, C. G. Lee, Materials Characterization 59 (2008) 1412-1418. https://doi.org/10.1016/j.matchar.2008.01.003 [25] J. Suutala, J. Tuominen, P. Vuoristo, Surface and Coatings Technology 201 (2006) 1981-1987. https://doi.org/10.1016/j.surfcoat.2006.04.042 [26] Z. Liu, Surface and Coatings Technology 201 (2007) 7149-7158. https://doi.org/10.1016/j.surfcoat.2007.01.032 [27] A. Meghwal, C. C. Berndt, V. Luzin, C. Schulz, T. Crowe, H. Gabel, A. S. M. Ang, Surface and Coatings Technology 421 (2021) 127359. https://doi.org/10.1016/j.surfcoat.2021.127359 [28] A. A. Siddiqui, A. K. Dubey, Optics Laser Technology 134 (2021) 106619. https://doi.org/10.1016/j.optlastec.2020.106619 [29] A. G. M. Pukasiewicz, H. E. de Boer, G. B. Sucharski, R. F. Vaz, L. A. J. Procopiak, Surface and Coatings Technology 327 (2017) 158-166. https://doi.org/10.1016/j.surfcoat.2017.07.073 [30] A. K. Gujba, M. S. Mahdipoor, M. Medraj, Wear 484-485 (2021) 203904. https://doi.org/10.1016/j.wear.2021.203904 [31] M. Michalak, L. Latka, P. Sokolowski, F.-L. Toma, H. Myalska, A. Denoirjean, H, Ageorges, Surface and Coatings Technology 404 (2020) 126463. https://doi.org/10.1016/j.surfcoat.2020.126463 [32] G. Prashar, H. Vasudev, Materials Today: Proceedings 26(2) (2020) 1131-1135. https://doi.org/10.1016/j.matpr.2020.02.226 [33] H. Vasudev, G. P. L. Thakur, A. Bansal, Surface Review and Letters 29(2) (2022) 2250017. https://doi.org/10.1142/S0218625X22500172 [34] D. D. Kumar, P. Grewal, J. Singh, Corrosion Reviews 39 (2021) 243-268. https://doi.org/10.1515/corrrev-2020-0043 [35] G. Prashar, H. Vasudev, Surface and Coatings Technology 439 (2022) 128450 https://doi.org/10.1016/j.surfcoat.2022.128450 [36] T. S. Sidhu, S. Prakash, R. D. Agrawal, Materials Science 41(6) (2005) 805-823. https://doi.org/10.1007/s11003-006-0047-z [37] B. S. Yilbas, S. S. Akhtar, Journal of Material Processing Technology 212 (2012) 2569-2577. https://doi.org/10.1016/j.jmatprotec.2012.07.012 [38] B. S. Yilbas, A. F. M. Arif, M. A.Gondal, Journal of Material Processing Technology 164-165 (2005) 964-957. https://doi.org/10.1016/j.jmatprotec.2005.02.091 [39] Image J https://imagej.net/software/imagej/ (5/31/2022) ©2022 by the authors; licensee IAPC, Zagreb, Croatia. 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