Next Article in Journal
Simplified Chemical Treatments for Improved Adhesive Bonding Durability and Corrosion Protection of High-Pressure Die-Cast Aluminum Alloy AlSi10MnMg
Previous Article in Journal
Synthesis and Characterization of Bioactive Coatings with Bone Regeneration Potential and Anti-Resorptive Effect
 
 
Search for Articles:
Title / Keyword
Author / Affiliation / Email
Journal
Article Type
 
 
Advanced Search
 
Section
Special Issue
Volume
Issue
Number
Page
 
Journals
Coatings
Volume 15
Issue 10
10.3390/coatings15101121
coatings-logo
Submit to this Journal Review for this Journal Propose a Special Issue
► Article Menu

Article Menu

share Share announcement Help format_quote Cite question_answer Discuss in SciProfiles
first_page
settings
Order Article Reprints
Font Type:
Arial Georgia Verdana
Font Size:
Aa Aa Aa
Line Spacing:
Column Width:
Background:
Article

Enhancing Adhesion of Si-Doped Diamond-like Carbon Coatings on Carbon Steel via Laser Cladding

by
Ming Gong
1,†,
Haitao Li
2,†,
Mingzhong Wu
1,* and
Peng Lv
1,*
1
School of Materials Science and Engineering, Jiamusi University, Jiamusi 154007, China
2
School of Chemical Equipment, Shenyang University of Technology, Liaoyang 111003, China
*
Authors to whom correspondence should be addressed.
†
It represents Gong and Li are co-first author, and Jiamusi University and Shenyang University of Technology are co-first completed institution.
Coatings 2025, 15(10), 1121; https://doi.org/10.3390/coatings15101121
Submission received: 7 September 2025 / Revised: 17 September 2025 / Accepted: 19 September 2025 / Published: 26 September 2025
(This article belongs to the Section Corrosion, Wear and Erosion)
Browse Figures
Versions Notes

Abstract

A duplex coating system, consisting of a laser-cladded Fe-Cr-based interlayer and a silicon-doped diamond-like carbon (Si-DLC) top layer, was deposited on medium carbon steel substrate using laser cladding (LC) followed by plasma-enhanced chemical vapor deposition (PECVD). The LC interlayer (thickness of 1.5 mm, hardness of 455–620 HV0.3) was applied on both argon ion-etched and non-etched substrate surfaces. The microstructure and adhesion strength of the coatings were systematically investigated. The results show that the LC interlayer significantly enhanced the mechanical support for the Si-DLC coating, increasing adhesion strength by 4~5 times compared to direct deposition. Argon ion etching introduced micro-roughened surface features, increasing interfacial contact area and further boosting adhesion. A synergistic effect was observed between substrate hardness and ion etching in enhancing Si-DLC coating adhesion.

1. Introduction

Diamond-like carbon (DLC) coatings have attracted significant attention for surface enhancement of critical tribological components in the automotive, marine, and aerospace industries, owing to their exceptional hardness, low friction coefficient, and excellent corrosion resistance [1,2,3,4]. However, the inherent high residual stress and high modulus of DLC coatings often lead to poor mechanical compatibility with metallic substrates, particularly soft ones, resulting in weak adhesion and potential delamination under service conditions. These limitations severely restrict their full potential and broader engineering application [5,6].
Various coating design strategies have been extensively explored to ameliorate adhesion. Designing functional gradient interlayers represents a primary technical route. Nevertheless, for low-hardness metallic materials, the effectiveness of such interlayers is often limited due to the insufficient load-bearing capacity of the substrate, a phenomenon analogous to the “eggshell effect” [7,8,9]. Furthermore, hybrid surface techniques have also been demonstrated as viable solutions. For example, deposition of an electroless nickel interlayer, nitriding treatment, and high-velocity oxy-fuel (HVOF) spraying prior to coating deposition have been proposed in the literature. For instance, Farideh DAVOODI et al. [10] reported that the electroless nickel–phosphorous (Ni-P) interlayer thickness significantly influenced the load-bearing capacity of physical vapor deposition (PVD) coatings on aluminum alloys. Dalibon [11] showed that the duplex coatings prepared by nitriding and PACVD techniques exhibit better adhesion; Chen [12] demonstrated that duplex coatings reveal better wear resistance by HVOF/PVD. Furthermore, hybrid surface techniques, such as prior nitriding [11,13] or high-velocity oxy-fuel (HVOF) [12,14] spraying followed by DLC deposition, have also been demonstrated as viable solutions. Yet, these methods possess inherent drawbacks: nitriding can induce a brittle white layer, facilitating crack initiation; thermal spray coatings may contain pores or impurities that act as stress concentrators and corrosion channels, and their predominantly mechanical bonding with the substrate poses a risk of spallation under high loads [15,16].
In contrast, laser cladding (LC) technology offers a promising solution for creating an ideal interlayer on soft metallic substrates. It fabricates coatings that are metallurgically bonded to the substrate, with tunable composition, dense microstructure, and minimal porosity [17,18,19]. Medium carbon steel is widely used for manufacturing critical components like hydraulic parts and bearings due to its excellent comprehensive mechanical properties and notable cost-effectiveness [20,21]. Fabricating an Fe-Cr-based alloy cladding layer on medium carbon steel via laser cladding can effectively enhance the surface hardness and load-bearing capacity, thereby providing a superior supporting interface for subsequent DLC deposition.
Beyond the interlayer, the substrate surface state prior to deposition is another critical factor governing adhesion. Argon ion (Ar+) etching effectively removes surface contaminants and native oxides [22]. Moreover, it creates a micro-roughened morphology through preferential sputtering, which increases the effective interfacial contact area and enhances mechanical interlocking, potentially leading to further adhesion improvement [23,24].
Although both laser-clad interlayers and Ar+ etching technology individually show promise in enhancing coating adhesion, the combined effect and synergistic mechanism between the mechanical properties (especially hardness) of the Fe-Cr-based cladding layer and Ar+ etching surface modification on the ultimate adhesion strength of Si-DLC coatings remain inadequately studied and lack systematic reporting.
Therefore, this study employs laser cladding technology to fabricate Fe-Cr-based alloy cladding layers with three different hardness levels on medium carbon steel substrates serving as interlayers. The surface modification effects of Ar+ etching treatment on these specimens are systematically investigated. Subsequently, Si-DLC coatings are deposited using plasma-enhanced chemical vapor deposition (PECVD). This work aims to quantitatively evaluate the coating–substrate adhesion strength via scratch testing, focusing on elucidating the synergistic influence between the hardness of the Fe-Cr-based interlayer and the Ar+ etching process on the adhesion of the Si-DLC coating. The findings are expected to provide novel insights and a solid experimental basis for preparing high-performance, strongly adherent DLC composite coatings on soft steel substrates.

2. Materials and Methods

For the LC transition layer, the HWL-R6000W laser cladding (Wuhan Raycus Fiber Laser Technologies Co., Ltd., Wuhan, China) system was utilized to deposit three Fe-Cr-based coatings onto a medium carbon steel substrate (0.45% C, AISI 1045 equivalent). The chemical compositions of the three types of commercial powders are provided in Table 1. The powder particle size ranged from 53 to 150 μm. Before laser cladding, the substrate surfaces were mechanically abraded using 60-grit sandpaper. The laser cladding parameters were set as follows: laser power of 1500 W, powder feed rate of 33 g/min, scanning speed of 3 mm/s, laser beam diameter of 5 mm, an overlap ratio of 30%, and a single deposited layer. The resulting cladding layer exhibited a dilution rate of approximately 10%, a porosity below 0.5%.
For the Si-DLC coating, it was synthesized using a cage-type hollow cathode discharge technique. Figure 1 shows the schematic of the experimental setup. High-purity argon (99.99%) and acetylene (99.00%) served as working gases. Tetramethylsilane (TMS, purity > 99.9%), an organic liquid with a boiling point of 17 °C, was stored in a sealed stainless steel tank and vaporized using a water bath. All gas flows were regulated by mass flow controllers.
Three types of Fe-Cr-based coatings were progressively polished with 500–2000-mesh silicon carbide sandpaper and polished using 2.5 μm diamond spray to achieve a mirror-like finish, ultrasonically cleaned in anhydrous ethanol for 30 min, and dried. The cleaned specimens and single-sided-polished monocrystalline Si wafers were then mounted on a 150 mm × 100 mm specimen stage in the vacuum chamber. The stage was electrically isolated from the cage mesh, with a DC pulse power supply (−1350 V, 20 μs pulse width, 1000 Hz frequency) connected between the mesh and chamber wall. The base and working pressures were 3 × 10−3 Pa and 3.5 Pa, respectively.
To evaluate argon ion etching’s effect on Si-DLC adhesion, a −200 V substrate bias was applied for 30 min prior to deposition. The Si-DLC deposition parameters are listed in Table 2; Figure 2 schematically illustrates the LC/Si-DLC duplex coating. LC specimens prepared from commercial powders No. 1–No. 3 were labeled S1–S3, respectively, with the substrate designated S0. Specimens coated with Si-DLC without Ar+ etching were marked S1*–S3* and S0*, and those with post-etching were labeled S1e*–S3e* and S0e*.
The surface and cross-sectional morphology of the Si-DLC coating, along with its elemental composition, were examined using a JSM-780F (JEOL Ltd., Akishima, Tokyo, Japan) field emission scanning electron microscope (FESEM) equipped with an Energy-Dispersive Spectrometer (EDS). The deposition rate was calculated by dividing the coating thickness (measured from cross-sectional SEM images of the Si wafer) by the deposition time. The coating’s structure was analyzed using Via-Reflex laser confocal Raman spectroscopy (Renishaw Trading Co., LTD, Shanghai, China) with a needle tip. Raman spectra were acquired in the range of 800~2000 cm−1 with a 532 nm excitation laser.
Microhardness was measured using an HMV-2T Vickers hardness tester (Shimadzu Corporation, Kyoto, Japan) under a 300 gf load (15 s dwell time). Five indentations were made per sample, and the average value was recorded as the final hardness. Coating adhesion was assessed via scratch testing WS-2005 automated tester (Vishay Intertechnology, Inc., Malvern, PA, USA) with a linearly increasing load (0~50 N, at 50 N/min) over a 5 mm track at 25 °C. Each specimen was tested three times

3. Results

3.1. Raman Analysis

Figure 3 presents the Raman spectra of the Si-DLC coating in the 800–2000 cm−1 range. A characteristic peak at ~1500 cm−1 corresponds to the asymmetric stretching mode of amorphous hydrogenated DLC. The spectrum was deconvoluted using a double-Gaussian fit [25], revealing two distinct peaks at 1359 cm−1 (D-band) and 1573 cm−1. As shown in Figure 3b, the ID/IG values for Si-DLC coatings on all four specimen surfaces fall within a narrow range of 1.21–1.24, while the G-band FWHMG (full width at half maxima) values remain consistent (110.6–111.8 cm−1), indicating minimal structural variation. During the initial growth phase (<100 nm thickness), Si-DLC coating formation is strongly influenced by substrate properties such as surface chemical composition and roughness [26,27]. At depth exceeding the Raman probing limit (typically 200–400 nm for 532 nm excitation), the coating microstructure becomes primarily determined by PECVD parameters. Typically, the G-band of pure diamond-like carbon (DLC) coating is observed at approximately 1560 cm−1. For the Si-DLC coating, the incorporation of silicon releases internal stress, shifting the G-band position toward that of pristine graphene (1580 cm−1). The Si-DLC coating prepared in this experiment features silicon atoms that preferentially form Si-C bonds with carbon atoms. The addition of silicon reduces the sp3-C network and increases the proportion of graphitic (sp2) carbon, thereby promoting the formation of sp2-C. This graphitization reduces the deformation of the carbon network and contributes to a decrease in the internal stress of the coating.

3.2. Morphology Observation

Figure 4 shows the SEM images and corresponding EDS elemental maps: Figure 4a, S0, a Si-DLC coating deposited directly on a medium carbon steel substrate; and Figure 4c S1–S3, composite coatings with ≈1.5 mm LC layers. The LC layers exhibit dense microstructures and display sound metallurgical bonding to the substrates. The Si-DLC coating adheres well to the LC layer without interfacial cracking.
Figure 4 shows the magnified cross-sectional morphology of the LC/Si-DLC duplex coatings. As observed, the cross-section is free from defects such as cracks and pores. The thicknesses of the Si-DLC coatings prepared in this experiment were measured to be 3.22 μm, 3.10 μm, 3.15 μm, and 3.23 μm. Overall, the Si-DLC coating demonstrates favorable uniformity.
Figure 5 shows a cross-sectional SEM image of the Si-DLC coating deposited on a Si wafer, revealing its columnar upward growth. During deposition, the morphology of the Si-DLC coating is primarily governed by the migration of adsorbed atoms. In this study, the Si-DLC coatings were deposited using cage-shaped hollow cathode technology. Here, the limited potential difference (10–20 eV) [28] between the specimens and the surrounding plasma restricts adatom mobility, resulting in coarse columnar microstructures. As depicted in Figure 5, the coating thickness was approximately 3 μm after 30 min deposition, corresponding to a deposition rate of approximately 6 μm/h.

3.3. Ar+-Etched Surface

The cage-shaped hollow cathode technique used for Si-DLC deposition falls under the category of PECVD. In this process, specimens are immersed in a plasma generated by hollow cathode discharge. A bias voltage of −200 V (relative to the cage) accelerates argon ions to a kinetic energy of 200 eV, enabling effective sputter cleaning of the substrate surface. The ion current density at the specimen depends on both the hollow cathode discharge current and the substrate area. Based on the data model from previous research [29], the peak current density is estimated to be 60 mA/cm2.
Figure 6 shows the surface topography of specimens under three conditions: (1) untreated, (2) after Ar+ etching, and (3) following Si-DLC coating deposition. Initial observation reveals sandpaper-induced scratches (indicated by arrows in Figure 6a1–d1). After Ar+ etching, as shown in Figure 6a2–d2, these scratches are completely removed, and numerous island-like protrusions become clearly visible. The etching process involves two key stages: first, residual contaminants and minor scratches are eliminated, followed by preferential sputtering that modifies the local topography [30]. For medium carbon steel substrate (a dual-phase material consisting of ferrite and pearlite), the etching response varies between phases: the loosely packed ferrite phase, with its high sputtering yield, erodes rapidly, forming concave pits. In contrast, the hardened cementite phase, due to its low sputtering yield, resists etching and remains as convex protrusions.
Additionally, defects such as inclusions and microporosities undergo preferential sputtering, further enlarging the pits. Meanwhile, the LC specimen, with its fine-grained microstructure from rapid solidification, exhibits a surface dominated by sharp, fine protrusions and enhanced pit/protrusion contrast.
Figure 6a3–d3 and Figure 6a4–d4 present the surface topography of Si-DLC coatings deposited on unetched and Ar+-etched substrates, respectively. The morphology of the Si-DLC coating closely replicates that of the underlying substrate. This replication occurs because the amorphous Si-DLC coating grows conformally along the substrate surface, ultimately adopting a similar morphology 23.
Figure 7 shows the AFM morphology and roughness results of different specimens’ surfaces. As shown in Figure 7A(a1–d1), grinding marks by sandpaper can be observed on the S0–S3 specimens’ surface. The surface roughness values of S0 to S3 are 2.22 nm, 2.08 nm, 1.82 nm, and 1.41 nm, respectively. As shown in Figure 7A(a2–d2), after Ar+ etching with an applied bias voltage of −200 V, the surface grinding marks became relatively flat and smooth. Significant changes occurred on the substrate surface, with clearly visible nano-scale protrusions. The sandpaper grinding marks gradually disappeared. The surface roughness values for S0e to S3e are 5.72 nm, 4.67 nm, 3.21 nm, and 2.95 nm, respectively. As shown in Figure 7A(a3–d3,a4–d4), the surface roughness values of unetched Si-DLC coatings are 20.7 nm, 19.7 nm, 19.1 nm, and 18.2 nm, respectively. In contrast, the surface roughness values of Si-DLC coatings after Ar+ etching are 42.3 nm, 41.1 nm, 39.3 nm, and 38.2 nm, respectively. It can be concluded that the surface roughness of Si-DLC coatings after Ar+ etching is higher than that of unetched Si-DLC coatings. This replication occurs because the amorphous Si-DLC coating grows conformally along the substrate surface, ultimately adopting a similar morphology.

3.4. Hardness

Figure 8 and Figure 9 show the hardness of the LC layers and the indentation morphology of Si-DLC coatings, respectively. As shown in Figure 8, the hardness of specimens S0–S3 was measured as 220 HV0.3, 455 HV0.3, 571 HV0.3, and 620 HV0.3, respectively. S0 exhibits a coarse-grained microstructure consisting of white ferrite and gray pearlite. In contrast, the LC layers (S1–S3) are primarily composed of dendritic α-Fe (white regions), eutectic structures (gray α-Fe + Fe3C), and minor retained austenite. The volume fraction of the hardened eutectic structure (α-Fe + Fe3C) progressively increases from S1 to S3, significantly enhancing the layer hardness due to its high intrinsic hardness. Notably, the addition of boron in S1 and S3 promotes the formation of boron-containing cementite (Fe3(C,B)) with superior hardness [31,32]. As evidenced in Table 1, S3 demonstrates the highest hardness owing to (i) elevated C/B content increasing Fe3(C,B) phase fraction and (ii) the presence of 0.54 wt.% WC particles.
As shown in Figure 9, S0e* displayed the largest indentation diagonal (approximately 30 μm), corresponding to its lowest hardness value of 314 HV0.3. From S1e* to S3e*, the indentation size gradually decreased while the hardness consistently increased, reaching a peak value of 918 HV0.3 in S3e*. This trend mirrors the hardness variation in the substrate. The observed behavior can be attributed to the 300 gf test load exceeding the critical limit for the 3 μm thick Si-DLC coating, causing the indentation to penetrate entirely through the coating layer. As a result, the measured microhardness primarily reflects the substrate’s hardness variation.
Figure 10 shows the nanohardness and modulus curves. The maximum indentation depth (0.3 μm) is approximately one-tenth of the coating thickness, indicating that the measurement reflects the actual hardness of the coating. The nanohardness of the coating prepared in this experiment is 5.9 GPa, which is lower than the values reported in the literature [29]. This is because the potential difference between the workpiece and the surrounding plasma is only a few eV, resulting in low-energy ions reaching the workpiece surface, as illustrated in Figure 5 of Section 3.2.

3.5. Adhesion Strength

Figure 11 and Figure 12 show scratch morphologies of Si-DLC coatings on unetched and Ar+-etched specimens, respectively. The positions marked by the squares represent the flake fracture point (critical normal load Lc2 when the first arc-shaped spalling occurs) [33].
For the S0* specimen, arc-shaped cracks emerged along the scratch path at a 3 N ± 1.1 N, exposing the underlying steel substrate. In contrast, the Lc2 value for S1*, S2*, and S3* specimens reached 13 N ± 1.2 N, 14 N ± 1.1 N, and 17 N ± 1.3 N, respectively, which are 4–5 times higher than S0*. This disparity stems from S0 lacking an interlayer: substrate deformation occurred immediately upon indenter contact, causing deeper penetration and wider scratches under increasing load. The interlayer not only enhances the composite coating’s load-bearing capacity but also demonstrates that harder interlayers improve the top Si-DLC coating’s mechanical performance [34,35].
As shown in Figure 12, the Lc2 values for specimens S0e*, S1e*, S2e*, and S3e* were approximately 5 N ± 1.1 N, 17 N ± 1.3 N, 21 N ± 1.1 N, and 25 N ± 1.2 N, respectively. These values were 1.3 to 1.6 times greater than those of unetched specimens. Previous studies [23,24] have confirmed that Ar+ etching effectively removes surface contaminants and loose oxides while creating a micro-roughened surface morphology. This treatment expands the effective mechanical contact area at the Si-DLC/interlayer interface, thereby enhancing the mechanical interlocking effect and ultimately improving the adhesion strength of the Si-DLC coating.
To better understand how substrate hardness and Ar+ etching affect the scratch adhesion of Si-DLC coatings, Table 3 summarizes the relationship between substrate hardness, etching, and adhesion improvement. The Key findings are as follows.
For a medium carbon steel substrate, etching increases adhesion from 3 N to 5 N (a 66.7% improvement), but the absolute value remains low. This confirms that surface treatment alone cannot overcome the inherent limitations of soft substrates.
For Fe-Cr substrates with higher hardness (455–620 HV0.3, a 106.8–181.8% increase), adhesion strength rises dramatically (466.7–733.3%). Substrate hardening contributes 52.9–69.2% of this enhancement.
Ar+ etching further improves adhesion by 30.8–66.7%, but its effectiveness depends on substrate hardness. For example, the S3*/S3e* specimens show an 8 N increase, demonstrating that the etching effect is ultimately limited by the substrate’s load-bearing capacity.
These results highlight a synergistic effect between substrate hardening and ion etching in enhancing coating adhesion.

4. Conclusions

This study systematically investigated the structure and properties of Si-DLC coatings through Raman analysis, morphological observation, Ar+ etching treatment, hardness testing, and adhesion evaluation. Raman spectra revealed ID/IG ratios of 1.21–1.24 and G-band FWHM values of 110.6–111.8 cm−1, indicating high structural uniformity. The coatings exhibited columnar growth morphology at a deposition rate of 6 μm/h, with no structural defects observed. Ar+ etching effectively removed surface contaminants and generated a micro-roughened morphology, significantly enhancing mechanical interlocking at the coating–substrate interface. Hardness measurements demonstrated that the composite coating hardness (up to 918 HV0.3) was primarily governed by the substrate due to complete penetration of the indentation through the thin coating. Adhesion tests demonstrated that a synergistic improvement in adhesion strength through substrate hardening and Ar+ etching: Fe-Cr interlayers increased the critical load (Lc2) to 13–17 N (4–5 times higher than that of the medium carbon steel substrate), while Ar+ etching further improved Lc2 by 30.8% to 66.7% through mechanical activation, though its effectiveness was constrained by the substrate’s load-bearing capacity. These findings demonstrate a synergistic effect between substrate hardening and ion etching in enhancing adhesion.

Author Contributions

M.G.: Conceptualization, Methodology, Investigation, Data curation, Writing—Original Draft. H.L.: Investigation, Writing—Review and Editing. M.W.: Supervision, Conceptualization, Funding acquisition, Writing—Review and Editing. P.L.: Formal analysis, Validation. Writing—Review and Editing. All authors have read and agreed to the published version of the manuscript.

Funding

This research was funded by the project of Heilongjiang Provincial Department of Education and Liaoning Provincial Department of Education, China (2021-KYYWF-0554, LJ-212510142015).

Data Availability Statement

The original contributions presented in this study are included in the article. Further inquiries can be directed to the corresponding authors.

Acknowledgments

The authors gratefully acknowledge the financial support of this research from the project of Heilongjiang Provincial Department of Education and Liaoning Provincial Department of Education, China (2021-KYYWF-0554, LJ-212510142015).

Conflicts of Interest

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

References

  1. Liu, L.; Wu, Z.; Cui, S. Abrasion and erosion behavior of DLC-coated oil-well tubings in a heavy oil/sand environment. Surf. Coat. Technol. 2019, 357, 379–383. [Google Scholar] [CrossRef]
  2. Zhang, W.; Tanaka, A.; Xu, B.S.; Koga, Y. Study on the diamond-like carbon multilayer films for tribological application. Diam. Relat. Mater. 2005, 14, 1361–1367. [Google Scholar] [CrossRef]
  3. Wang, X.; Sui, X.; Zhang, S.; Yan, M.; Lu, Y.; Hao, J.; Liu, W. Impacts of the a-Si:H interlayer nanostructure on the adhesion of the thick DLC coatings prepared by PECVD. Appl. Surf. Sci. 2021, 565, 150539. [Google Scholar] [CrossRef]
  4. Beake, B.D.; McMaster, S.J.; Liskiewicz, T.W.; Neville, A. Influence of Si- and W- doping on micro-scale reciprocating wear and impact performance of DLC coatings on hardened steel. Tribol. Int. 2021, 160, 107063. [Google Scholar] [CrossRef]
  5. Hauert, R.; Müller, U. An overview on tailored tribological and biological behavior of diamond-like carbon. Diam. Relat. Mater. 2003, 12, 171–177. [Google Scholar] [CrossRef]
  6. Xiao, Y.; Shi, W.; Han, Z.; Luo, J.; Xu, L. Residual stress and its effect on failure in a DLC coating on a steel substrate with rough surfaces. Diam. Relat. Mater. 2016, 66, 23–35. [Google Scholar] [CrossRef]
  7. Pougoum, F.; Qian, J.; Laberge, M.; Martinu, L.; Klemberg-Sapieha, J.; Zhou, Z.; Li, K.Y.; Savoie, S.; Schulz, R. Investigation of Fe3Al-based PVD/HVOF duplex coatings to protect stainless steel from sliding wear against alumina. Surf. Coat. Technol. 2018, 350, 699–711. [Google Scholar] [CrossRef]
  8. Picas, J.A.; Menargues, S.; Martin, E.; Colominas, C.; Baile, M. Characterization of duplex coating system (HVOF+PVD) on light alloy substrates. Surf. Coat. Technol. 2017, 318, 326–331. [Google Scholar] [CrossRef]
  9. Li, W.; Tang, P.; Shang, L.; He, D.; Wang, L.; Zhang, G.; Jin, K. Tribological behaviors of CrN/Cr3C2-NiCr duplex coating at elevated temperatures. Surf. Coat. Technol. 2019, 378, 124926. [Google Scholar] [CrossRef]
  10. Davoodi, F.; Ashrafizadeh, F.; Atapour, M.; Rikhtehgaran, R. A novel approach for evaluation of load bearing capacity of duplex coatings on aluminum alloy using PLS and SVR models. Trans. Nonferrous Met. Soc. China 2022, 32, 1834–1851. [Google Scholar] [CrossRef]
  11. Dalibon, E.L.; Charadia, R.; Cabo, A.; Trava-Airoldi, V.; Brühl, S.P. Evaluation of the mechanical behaviour of a DLC film on plasma nitrided AISI 420 with different surface finishing. Surf. Coat. Technol. 2013, 235, 735–740. [Google Scholar] [CrossRef]
  12. Chen, W.; Mao, T.; Zhang, B.; Zhang, S.; Meng, X. Designs and preparation of advanced HVOF-PVD duplex coating by combination of HVOF and arc ion plating. Surf. Coat. Technol. 2016, 304, 125–133. [Google Scholar] [CrossRef]
  13. Jan, D.J.; Ai, C.F. Improvement of the adhesion of diamond-like carbon coatings induced by ion treatments. Mater. Chem. Phy. 2001, 72, 158–162. [Google Scholar] [CrossRef]
  14. Tillmann, W.; Stangier, D.; Hagen, L.; Schröder, P.; Krabiell, M. Influence of the WC grain size on the properties of PVD/HVOF duplex coatings. Surf. Coat. Technol. 2017, 328, 326–334. [Google Scholar] [CrossRef]
  15. Palanisamy, K.; Gangolu, S.; Mangalam Antony, J. Effects of HVOF spray parameters on porosity and hardness of 316L SS coated Mg AZ80 alloy. Surf. Coat. Technol. 2022, 448, 128898. [Google Scholar] [CrossRef]
  16. Yang, K.; Jiang, Z.; Chen, C.; Zhang, S.; Liu, X. Investigation on the microstructure, tribological performance and corrosion resistance of Ni–Mo coatings deposited by HVOF and APS methods. Vacuum 2022, 200, 111023. [Google Scholar] [CrossRef]
  17. Sexton, C.L.; Byrne, G.; Watkins, K.G. Alloy development by laser cladding: An overview. J. Laser Appl. 2001, 13, 2–11. [Google Scholar] [CrossRef]
  18. Zhang, D.; Zhang, X. Laser cladding of stainless steel with Ni–Cr3C2 and Ni–WC for improving erosive–corrosive wear performance. Surf. Coat. Technol. 2005, 190, 212–217. [Google Scholar] [CrossRef]
  19. Zhang, D.W.; Lei, T.C.; Li, F.J. Laser cladding of stainless steel with Ni–Cr3C2 for improved wear performance. Wear 2001, 251, 1372–1376. [Google Scholar] [CrossRef]
  20. Ge, H.; Ding, S.; Zhang, P.; Fang, H.; Hu, Y.; Yao, J. Influence of overlapping process on the distribution of Cr element in laser cladding 316L powder on 45# steel substrate. Surf. Coat. Technol. 2024, 493, 131249. [Google Scholar]
  21. Li, G.; Wang, Z.; Yao, L.; Xie, D.; Chen, G. Concentration mixing and melt pool solidification behavior during the magnetic field assisted laser cladding of Fe-Cr-based alloy on 45 steel surface. Surf. Coat. Technol. 2022, 445, 128732. [Google Scholar] [CrossRef]
  22. Lu, Y.; Wang, B.; Zhang, H.; Deng, L.; Song, H.; Yi, J.; Nishimura, K.; Jiang, N.; Zhou, P. Understanding of the adhesive strength enhancement mechanisms of bilayer diamond film at nanoscale. Diam. Relat. Mater. 2023, 137, 110133. [Google Scholar] [CrossRef]
  23. Morshed, M.M.; McNamara, B.P.; Cameron, D.C.; Hashmi, M.S.J. Effect of surface treatment on the adhesion of DLC film on 316L stainless steel. Surf. Coat. Technol. 2003, 163, 541–545. [Google Scholar] [CrossRef]
  24. Jones, B.J.; Anguilano, L.; Ojeda, J.J. Argon plasma treatment techniques on steel and effects on diamond-like carbon structure and delamination. Diam. Relat. Mater. 2011, 20, 1030–1035. [Google Scholar] [CrossRef]
  25. Cui, W.G.; Lai, Q.B.; Zhang, L.; Wang, F.M. Quantitative measurements of sp3 content in DLC films with Raman spectroscopy. Surf. Coat. Technol. 2010, 205, 1995–1999. [Google Scholar] [CrossRef]
  26. Robertson, J. Diamond-like amorphous carbon. Mat. Sci. Eng. R 2002, 37, 129–281. [Google Scholar] [CrossRef]
  27. Erdemir, A.; Donnet, C. Tribology of diamond-like carbon films: Recent progress and future prospects. J. Phys. D Appl. Phys. 2006, 39, R311. [Google Scholar] [CrossRef]
  28. Wei, R.H. Development of new technologies and practical applications of plasma immersion ion deposition (PIID). Surf. Coat. Technol. 2010, 204, 2869–2874. [Google Scholar] [CrossRef]
  29. Wu, M.Z. Study of bias voltage controlled cage type hollow cathode discharge characteristics and structure and properties of thick Si-DLC films. Harbin Inst. Technol. 2016. [Google Scholar]
  30. Barshilia, H.C.; Ananth, A.; Khan, J.; Srinivas, G. Ar+H2 plasma etching for improved adhesion of PVD coatings on steel substrates. Vacuum 2012, 86, 1165–1173. [Google Scholar] [CrossRef]
  31. Lentz, J.; Röttger, A.; Theisen, W. Hardness and modulus of Fe2B, Fe3(C,B), and Fe23(C,B)6 borides and carboborides in the Fe-C-B system. Mater. Charact. 2018, 135, 192–202. [Google Scholar] [CrossRef]
  32. Lentz, J.; Röttger, A.; Theisen, W. Mechanism of the Fe3(B,C) and Fe23(C,B)6 solid-state transformation in the hypoeutectic region of the Fe-C-B system. Acta Mater. 2016, 119, 80–91. [Google Scholar] [CrossRef]
  33. Li, X.; Bhushan, B. Micro/nanomechanical and tribological characterization of ultrathin amorphous carbon coatings. J. Mater. Res. 1999, 14, 2328–2337. [Google Scholar] [CrossRef]
  34. Liang, S.; He, D.; Shang, L.; Li, W.; Zhang, C.; Shao, L.; Seniuts, U.; Viktor, Z. Effect of cermet interlayer on the electrochemical behavior of Cr3C2-NiCr/DLC duplex coating. Surf. Coat. Technol. 2023, 469, 129813. [Google Scholar] [CrossRef]
  35. He, D.; Liang, R.; Wang, Q.; Shang, L. Impact damage behaviors of Cr3C2-NiCr/DLC duplex coatings. Tribol. Int. 2014, 200, 110086. [Google Scholar] [CrossRef]
Coatings 15 01121 g001
Figure 1. Schematic of the experimental setup.
Figure 1. Schematic of the experimental setup.
Coatings 15 01121 g001
Coatings 15 01121 g002
Figure 2. Schematic architecture of LC/Si-DLC duplex coating. (a) Unetched; (b) Ar+-etched.
Figure 2. Schematic architecture of LC/Si-DLC duplex coating. (a) Unetched; (b) Ar+-etched.
Coatings 15 01121 g002
Coatings 15 01121 g003
Figure 3. Structural characterization of the Si-DLC coating. (a) Raman spectra, (b) ID/IG ratio, and FWHM of G-band.
Figure 3. Structural characterization of the Si-DLC coating. (a) Raman spectra, (b) ID/IG ratio, and FWHM of G-band.
Coatings 15 01121 g003
Coatings 15 01121 g004
Figure 4. Cross-sectional SEM images and EDS elemental maps of the Si-DLC coating. (a) S0*; (b) S1*; (c) S2*; (d) S3*.
Figure 4. Cross-sectional SEM images and EDS elemental maps of the Si-DLC coating. (a) S0*; (b) S1*; (c) S2*; (d) S3*.
Coatings 15 01121 g004
Coatings 15 01121 g005
Figure 5. Cross-section image of the Si-DLC coating deposited on Si wafer.
Figure 5. Cross-section image of the Si-DLC coating deposited on Si wafer.
Coatings 15 01121 g005
Coatings 15 01121 g006
Figure 6. Surface topography of substrate before and after Ar+ etching and Si-DLC coatings. (a1–a4) S0 S0e S0* S0e*; (b1–b4) S1 S1e S1* S1e*; (c1–c4) S2 S2e S2* S2e*; (d1–d4) S3 S3e S3* S3e*.
Figure 6. Surface topography of substrate before and after Ar+ etching and Si-DLC coatings. (a1–a4) S0 S0e S0* S0e*; (b1–b4) S1 S1e S1* S1e*; (c1–c4) S2 S2e S2* S2e*; (d1–d4) S3 S3e S3* S3e*.
Coatings 15 01121 g006
Coatings 15 01121 g007
Figure 7. AFM surface morphology and roughness of different specimens. (A) AFM images; (B) roughness of different specimens.
Figure 7. AFM surface morphology and roughness of different specimens. (A) AFM images; (B) roughness of different specimens.
Coatings 15 01121 g007
Coatings 15 01121 g008
Figure 8. Surface microhardness and metallograph of substrate. (a) Surface microhardness; (b) metallograph.
Figure 8. Surface microhardness and metallograph of substrate. (a) Surface microhardness; (b) metallograph.
Coatings 15 01121 g008
Coatings 15 01121 g009
Figure 9. Indentation morphology of Si-DLC coatings. (a) S0e*; (b) S1e*; (c) S2e*; (d) S3e*.
Figure 9. Indentation morphology of Si-DLC coatings. (a) S0e*; (b) S1e*; (c) S2e*; (d) S3e*.
Coatings 15 01121 g009
Coatings 15 01121 g010
Figure 10. Nanohardness and modulus of Si-DLC. (a) Nanohardness; (b) modulus.
Figure 10. Nanohardness and modulus of Si-DLC. (a) Nanohardness; (b) modulus.
Coatings 15 01121 g010
Coatings 15 01121 g011
Figure 11. Scratch morphology of Si-DLC coatings deposited on unetched surface. (a,a1) S0*; (b,b1) S1*; (c,c1) S2*; (d,d1) S3*.
Figure 11. Scratch morphology of Si-DLC coatings deposited on unetched surface. (a,a1) S0*; (b,b1) S1*; (c,c1) S2*; (d,d1) S3*.
Coatings 15 01121 g011
Coatings 15 01121 g012
Figure 12. Scratch morphology of Si-DLC coatings deposited on Ar+-etched surface. (a,a1) S0e*; (b,b1) S1e*; (c,c1) S2e*; (d,d1) S3e*.
Figure 12. Scratch morphology of Si-DLC coatings deposited on Ar+-etched surface. (a,a1) S0e*; (b,b1) S1e*; (c,c1) S2e*; (d,d1) S3e*.
Coatings 15 01121 g012
Table 1. The chemical composition and content of the three types of commercial powders (wt.%).
Table 1. The chemical composition and content of the three types of commercial powders (wt.%).
ElementCOSBSiCrNiPMnMoWCFe
No. 10.090.03/0.831.1316.584.75/0.384.93/Bal
No. 20.170.020.01/0.7517.102.650.01/0.56/Bal
No. 30.18//0.840.9018.374.25/0.544.340.54Bal
Table 2. Process parameters for Si-DLC coating preparation.
Table 2. Process parameters for Si-DLC coating preparation.
SampleCraftArTMSC2H2Cage
Discharge
Parameters		Bias VoltagePressTime
(sccm)(V)(Pa)(min)
S0*
S1*
S2*
S3*		Pretreatment200//−1350 V/
20 µs/
1000 Hz		03.530
Si interlayer20020/03.510
Si-DLC701013003.530
S0e*
S1e*
S2e*
S3e*		Pretreatment200//−2003.530
Si interlayer20020/03.510
Si-DLC701013003.530
Table 3. Relationship between matrix hardness, etching, and adhesion enhancement.
Table 3. Relationship between matrix hardness, etching, and adhesion enhancement.
SampleSubstrateHardness
(HV0.3)		Improvement Rate of
Hardness (%)		Unetched Adhesion (N)Etched
Adhesion (N)		Improvement Rate of Adhesion (%) After EtchingOverall
Improvement Rate of
Adhesion (%)
S0*/S0e*substrate220-3 ± 1.15 ± 1.166.766.7
S1*/S1e*Fe-Cr455106.813 ± 1.217 ± 1.330.8466.7
S2*/S2e*Fe-Cr571159.514 ± 1.121 ± 1.150.0600.0
S3*/S3e*Fe-Cr620181.817 ± 1.325 ± 1.247.1733.3
Disclaimer/Publisher’s Note: The statements, opinions and data contained in all publications are solely those of the individual author(s) and contributor(s) and not of MDPI and/or the editor(s). MDPI and/or the editor(s) disclaim responsibility for any injury to people or property resulting from any ideas, methods, instructions or products referred to in the content.

Share and Cite

MDPI and ACS Style

Gong, M.; Li, H.; Wu, M.; Lv, P. Enhancing Adhesion of Si-Doped Diamond-like Carbon Coatings on Carbon Steel via Laser Cladding. Coatings 2025, 15, 1121. https://doi.org/10.3390/coatings15101121

AMA Style

Gong M, Li H, Wu M, Lv P. Enhancing Adhesion of Si-Doped Diamond-like Carbon Coatings on Carbon Steel via Laser Cladding. Coatings. 2025; 15(10):1121. https://doi.org/10.3390/coatings15101121

Chicago/Turabian Style

Gong, Ming, Haitao Li, Mingzhong Wu, and Peng Lv. 2025. "Enhancing Adhesion of Si-Doped Diamond-like Carbon Coatings on Carbon Steel via Laser Cladding" Coatings 15, no. 10: 1121. https://doi.org/10.3390/coatings15101121

APA Style

Gong, M., Li, H., Wu, M., & Lv, P. (2025). Enhancing Adhesion of Si-Doped Diamond-like Carbon Coatings on Carbon Steel via Laser Cladding. Coatings, 15(10), 1121. https://doi.org/10.3390/coatings15101121

Note that from the first issue of 2016, this journal uses article numbers instead of page numbers. See further details here.

Article Metrics

Back to TopTop