Coatings

18 pages, 3881 KB

Open AccessArticle

Study on the Effects of Micro-Groove Tools on Surface Quality and Chip Characteristics When Machining AISI 201

by Jinxing Wu, Wenhao Hu, Yi Zhang, Changcheng Wu and Zuode Yang

Coatings 2025, 15(10), 1124; https://doi.org/10.3390/coatings15101124 (registering DOI) - 28 Sep 2025

The excellent mechanical properties of AISI 201 make it well-suited for applications in industrial components, transportation, and household appliances. However, during machining, this material generates high cutting forces and temperatures, leading to rapid tool wear and high costs. To address this issue, micro-grooves [...] Read more.

The excellent mechanical properties of AISI 201 make it well-suited for applications in industrial components, transportation, and household appliances. However, during machining, this material generates high cutting forces and temperatures, leading to rapid tool wear and high costs. To address this issue, micro-grooves were designed on the rake face in areas prone to thermal and mechanical stress concentration. Through machining experiments focusing on workpiece surface quality, it was found that micro-grooved tools produced superior surface quality, specifically manifested in lower surface roughness, reduced work hardening, and shallower hardened layer depth. Experiments demonstrate that under identical conditions, increasing the cutting speed with tool M reduces the workpiece surface roughness by 0.096 μm to 0.236 μm compared to tool O. Under identical conditions, increasing the feed rate with tool M reduces the workpiece surface roughness by 0.070 μm to 0.236 μm compared to tool O. As cutting speed varies, the absolute surface hardness of workpieces machined by tool M decreases by approximately 39.85 HV, representing a hardness reduction of 14.5%. As feed rate varies, the surface hardness of workpieces machined with tool M is suppressed to a level 10.2%–14.2% lower than that of tool O. As cutting depth varies, the surface hardness of workpieces machined with tool M is suppressed to a level 10.0%–14.7% lower than that of tool O. Additionally, micro-grooved tools demonstrated superior chip curling and breaking performance. This tool design approach, optimized for tool durability and workpiece surface quality, establishes a research foundation for tool design targeting difficult-to-machine materials. Full article

(This article belongs to the Special Issue Alloy/Metal/Steel Surface: Fabrication, Structure, and Corrosion)

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23 pages, 5294 KB

Open AccessArticle

Analysis of Surface Material Design, Construction, and Optimization Measures of Qiang Zhuangfang Based on Physical Comforts

by Zhizheng Liu and Peng Tang

Coatings 2025, 15(10), 1123; https://doi.org/10.3390/coatings15101123 (registering DOI) - 27 Sep 2025

Abstract

This study evaluates the thermal comfort and energy performance of Qiang Zhuangfang manor houses in high-altitude regions, using Mao County’s Heihuzhai settlement as a representative case. Field surveys, tabulated data analysis, and computer simulations were conducted to measure wall surface temperature, ambient radiation [...] Read more.

This study evaluates the thermal comfort and energy performance of Qiang Zhuangfang manor houses in high-altitude regions, using Mao County’s Heihuzhai settlement as a representative case. Field surveys, tabulated data analysis, and computer simulations were conducted to measure wall surface temperature, ambient radiation temperature, air temperature, and relative humidity, comparing Zhuangfang buildings with brick Qiang houses. Results show that Zhuangfang walls have minor surface temperature differences, lower thermal conductivity, and superior insulation—retaining heat in winter, blocking heat in summer, and reducing solar gain. Optimization measures were tested through a model, revealing that lowering the main structure by 0.1 m and adding a surface material layer improved insulation while maintaining load-bearing capacity. The findings confirm that Zhuangfang houses are better suited to the local climate, offering ecological benefits in energy saving and heat preservation. Full article

(This article belongs to the Special Issue Advanced Technology in Surface Characterization and Conservation for Architectural and Archaeological Heritage)

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16 pages, 4066 KB

Open AccessArticle

Simplified Chemical Treatments for Improved Adhesive Bonding Durability and Corrosion Protection of High-Pressure Die-Cast Aluminum Alloy AlSi10MnMg

by Changfeng Fan, Bo Yang, Xue Wang, Xianghua Zhan, Xiaoli Yin, Jianmin Shi, Wei Wang, Yancong Liu and Klaus Dilger

Coatings 2025, 15(10), 1122; https://doi.org/10.3390/coatings15101122 (registering DOI) - 27 Sep 2025

Abstract

The adhesive bonding of high-pressure die-cast (HPDC) aluminum alloy AlSi10MnMg is extensively applied in the aerospace and automotive sectors. Surface pretreatment of HPDC aluminum prior to bonding is crucial for enhancing bonding strength and durability, as it regulates surface roughness, and chemical properties. [...] Read more.

The adhesive bonding of high-pressure die-cast (HPDC) aluminum alloy AlSi10MnMg is extensively applied in the aerospace and automotive sectors. Surface pretreatment of HPDC aluminum prior to bonding is crucial for enhancing bonding strength and durability, as it regulates surface roughness, and chemical properties. Traditional multi-step surface treatments including chromic acid anodizing for HPDC AlSi10MnMg are hazardous, complex, and often fail to balance adhesive bonding durability and corrosion protection, limiting their industrial applicability. This study examined the impact of various chemical treatments on the adhesive bonding performance of an AlSi10MnMg aluminum alloy. The treated surfaces were bonded using a structural adhesive, and bonding performance was evaluated via wedge tests under pristine conditions and after accelerated aging. A scanning electron microscope (SEM) was used to study the surface morphology, chemical composition, and corrosion characteristics of the treated surfaces. Energy dispersive spectroscopy (EDS), electrochemical impedance spectroscopy (EIS), and potentiodynamic polarization measurements were employed. Excellent adhesion characteristics, dominated by the cohesive failure of the adhesive, were observed in H₂O₂-treated samples. The H₂O₂-treated samples exhibited the shortest initial crack length, indicating a superior baseline bonding quality, and showed minimal crack propagation (only slight extension) after aging under extreme environmental conditions (70 °C and 100% relative humidity for 4 weeks). Electrochemical measurements revealed that the SG200-treated sample achieved the lowest corrosion current density (0.25 ± 0.03 μA/cm²) with an excellent corrosion resistance, while sol–gel-treated samples generally suffered from a poor adhesion, with interfacial failure. This study proposes a simplified, single-step chemical treatment using an H₂O₂ solution that effectively achieves both a strong adhesive bonding and an excellent corrosion resistance, without the drawbacks of conventional methods. It offers a viable alternative to conventional multi-step hazardous surface treatments. Full article

(This article belongs to the Special Issue Corrosion Resistance, Mechanical Properties and Characterization of Metallic Materials and Coatings, 2nd Edition)

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14 pages, 11190 KB

Open AccessArticle

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

by Ming Gong, Haitao Li, Mingzhong Wu and Peng Lv

Coatings 2025, 15(10), 1121; https://doi.org/10.3390/coatings15101121 - 26 Sep 2025

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, [...] Read more.

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. Full article

(This article belongs to the Section Corrosion, Wear and Erosion)

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20 pages, 5964 KB

Open AccessArticle

Synthesis and Characterization of Bioactive Coatings with Bone Regeneration Potential and Anti-Resorptive Effect

by Maxim V. Maximov, Lea Sleiman, Oana Cristina Maximov, Roxana Doina Trușcă, Ludmila Motelica, Angela Spoială, Denisa Ficai, Anton Ficai and Sorina Dinescu

Coatings 2025, 15(10), 1120; https://doi.org/10.3390/coatings15101120 - 26 Sep 2025

Abstract

Bioactive coatings are of great interest for orthopedic applications, as they combine mechanical stability with biological functionality. In this study, stainless steel discs were coated with 45S5 bioactive glass doped with 1.0 wt% samarium by spin coating, followed by surface functionalization with benfotiamine [...] Read more.

Bioactive coatings are of great interest for orthopedic applications, as they combine mechanical stability with biological functionality. In this study, stainless steel discs were coated with 45S5 bioactive glass doped with 1.0 wt% samarium by spin coating, followed by surface functionalization with benfotiamine through spraying. This strategy integrates three components: a metallic substrate as a stable and inexpensive support, a bioactive glass layer with well-known osteogenic potential, and a superficial organic layer of benfotiamine, a lipid-soluble analog of vitamin B1 with higher bioavailability. Samarium doping was selected based on previously reported antimicrobial potential against clinically relevant staphylococci, while the rationale for benfotiamine functionalization derives from literature describing vitamin B1 derivatives with anti-resorptive and osteogenic activity. The coatings were characterized by scanning electron microscopy (SEM) and Fourier-transform infrared (FTIR) microscopy. Bioactivity was assessed by immersion in simulated body fluid (SBF), where phosphate bands indicated the formation of calcium phosphate phases (CaPs). Wettability tests showed a reduced contact angle after benfotiamine functionalization. Cytocompatibility was evaluated by LDH and MTT assays with MC3T3-E1 cells, suggesting overall biocompatibility and enhanced cell viability after 7 days for the benfotiamine-functionalized coatings. The present findings support a simple and cost-effective route to multifunctional coatings with potential relevance for future orthopedic applications. Full article

(This article belongs to the Special Issue Films and Coatings with Biomedical Applications)

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13 pages, 4003 KB

Open AccessArticle

Research and Development of New Conductive Cement-Based Grouting Materials and Performance Studies

by Shen Zuo, Meisheng Shi, Junwei Bi, Menghan Zhang and Qingluan Li

Coatings 2025, 15(10), 1119; https://doi.org/10.3390/coatings15101119 - 25 Sep 2025

Abstract

In this study, cement, short-cut carbon fibers, and polymer water-absorbing resin were used as the main materials, with high-performance water-reducing polycarboxylic acid agent as the modified material. A new conductive cement-based grouting material was developed by incorporating functional additives. Its mix design was [...] Read more.

In this study, cement, short-cut carbon fibers, and polymer water-absorbing resin were used as the main materials, with high-performance water-reducing polycarboxylic acid agent as the modified material. A new conductive cement-based grouting material was developed by incorporating functional additives. Its mix design was optimized based on initial setting time, fluidity, bleeding rate, and compressive strength. The optimal ratio of the grouting material was determined as follows: 0.4 wt% of high water-absorbent resin, 0.25 wt% of high-efficiency water reducer, 0.8 wt% of short-cut carbon fibers, and a water–cement ratio of 0.8:1. The electrical conductivity of the grouting material was studied in depth under different dosages of short-cut carbon fibers, considering factors such as curing age, temperature, and pressure conditions. The results show that with the increase in curing age, the volume resistivity of the specimen gradually increases; the resistivity of the conductive cementitious grouting material decreases with the rise in temperature, showing a negative temperature coefficient effect; additionally, the doping of an appropriate amount of short-cut carbon fibers enables the conductive cementitious grouting specimen to exhibit good pressure-sensitive properties. Field test verification indicates that the new cementitious conductive grouting material has excellent conductive properties, and the grouting quality can be effectively evaluated via high-density electrical testing. Full article

(This article belongs to the Special Issue Advanced Functional Cement-Based Materials for Smart Applications)

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15 pages, 4158 KB

Open AccessArticle

Synthesis of Nanoscale Antimony Powder Using Aluminum as a Reducing Agent: Characterization and Sintering Microstructure

by Ehab AlShamaileh, Bashar Lahlouh, Ahmed N. AL-Masri and Iessa Sabbe Moosa

Coatings 2025, 15(10), 1118; https://doi.org/10.3390/coatings15101118 - 25 Sep 2025

Abstract

Antimony (Sb) is a key material in high-capacity potassium and sodium batteries, particularly in the fabrication of Sb–carbon composites. In this work, nanoscale Sb powder was synthesized directly from SbCl₃, using Al powder as a reducing agent. The reduction process was [...] Read more.

Antimony (Sb) is a key material in high-capacity potassium and sodium batteries, particularly in the fabrication of Sb–carbon composites. In this work, nanoscale Sb powder was synthesized directly from SbCl₃, using Al powder as a reducing agent. The reduction process was carried out by gradually adding Al powder to an SbCl₃—acetone solution under continuous cooling and stirring, owing to the highly exothermic nature of the reaction. Acetone was found to be an effective solvent, enabling the formation of Sb nanoparticles with an average particle size of 50 nm and a crystallite size of 25 nm. The purity of the produced powder was nearly 100%, as confirmed via SEM/EDS and XRD analyses. XRD patterns of both commercial and synthesized Sb powders displayed identical and ideal Sb reflections, while FTIR spectra further confirmed their structural similarity. Sintering studies revealed relative densities of 99% for pellets prepared from both commercial and synthesized powders. SEM/EDS examinations of the raw powders and sintered pellets provided complementary microstructural and compositional insights. Overall, this study demonstrates the feasibility of producing high-purity nanoscale Sb powder through a simple, single-step redox process that is both cost-effective and efficient. Full article

(This article belongs to the Section Surface Characterization, Deposition and Modification)

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16 pages, 3974 KB

Open AccessArticle

Optimizing FDM Printing Parameters via Orthogonal Experiments and Neural Networks for Enhanced Dimensional Accuracy and Efficiency

by Jinxing Wu, Yi Zhang, Wenhao Hu, Changcheng Wu, Zuode Yang and Guangyi Duan

Coatings 2025, 15(10), 1117; https://doi.org/10.3390/coatings15101117 - 24 Sep 2025

Viewed by 111

Abstract

Optimizing printing parameters is crucial for enhancing the efficiency, surface quality, and dimensional accuracy of Fused Deposition Modeling (FDM) processes. A review of numerous publications reveals that most scholars analyze factors such as nozzle diameter and printing speed, while few investigate the impact [...] Read more.

Optimizing printing parameters is crucial for enhancing the efficiency, surface quality, and dimensional accuracy of Fused Deposition Modeling (FDM) processes. A review of numerous publications reveals that most scholars analyze factors such as nozzle diameter and printing speed, while few investigate the impact of layer thickness, infill density, and shell layer count on print quality. Therefore, this study employed 3D slicing software to process the three-dimensional model and design printing process parameters. It systematically investigated the effects of layer thickness, infill density, and number of shells on printing time and geometric accuracy, quantifying the evaluation through volumetric error. Using an ABS connecting rod model, optimal parameters were determined within the defined range through orthogonal experimental design and signal-to-noise ratio (S/N) analysis. Subsequently, a backpropagation (BP) neural network was constructed to establish a predictive model for process optimization. Results indicate that parameter selection significantly impacts print duration and surface quality. Validation confirmed that the combination of 0.1 mm layer thickness, 40% infill density, and 5-layer shell configuration achieves the highest dimensional accuracy (minimum volumetric error and S/N value). Under this configuration, the volumetric error rate was 3.062%, with an S/N value of −9.719. Compared to other parameter combinations, this setup significantly reduced volumetric error, enhanced surface texture, and improved overall print precision. Statistical analysis indicates that the BP neural network model achieves a Mean Absolute Percentage Error (MAPE) of no more than 5.41% for volume error rate prediction and a MAPE of 5.58% for signal-to-noise ratio prediction. This validates the model’s high-precision predictive capability, with the established prediction model providing effective data support for FDM parameter optimization. Full article

(This article belongs to the Special Issue Technologies and Processes That Involve Surface Interaction or Successive Coating Processes for Additive Manufacturing)

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16 pages, 5948 KB

Open AccessArticle

Physicochemical, Microstructural and Biological Evaluation of Dressing Materials Made of Chitosan with Different Molecular Weights

by Zofia Płonkowska, Alicja Wójcik and Vladyslav Vivcharenko

Coatings 2025, 15(10), 1116; https://doi.org/10.3390/coatings15101116 - 24 Sep 2025

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Abstract

The use of advanced wound dressings can significantly support the skin healing process by maintaining optimal conditions for tissue regeneration. In this study, foam-like dressings composed of agarose and chitosan, enriched with vitamin C, were developed using a simple and cost-effective freeze-drying method. [...] Read more.

The use of advanced wound dressings can significantly support the skin healing process by maintaining optimal conditions for tissue regeneration. In this study, foam-like dressings composed of agarose and chitosan, enriched with vitamin C, were developed using a simple and cost-effective freeze-drying method. Three types of chitosan with varying molecular weights (low, medium, high) were used to investigate their impact on the biological, physicochemical, and mechanical properties of the resulting foams. All fabricated biomaterials were biocompatible, non-toxic, and did not promote cell adhesion to their surfaces. The foams exhibited highly porous, hydrophilic microstructures with excellent fluid absorption capacity (~20 mL/g) and sustained vitamin C release over the first 24 h. Chitosan molecular weight had no significant effect on biological properties, but influenced samples’ wettability and mechanical parameters. The hydrophilic character of samples was observed in all tested biomaterials, with the strongest enhancement of hydrophilicity noted for the low molecular weight variant. The highest tensile strength was observed in samples prepared with medium molecular weight chitosan. The results indicate that among the analyzed variants, agarose-chitosan foam biomaterials containing medium molecular weight chitosan exhibited the most favorable properties, making them the most promising candidates for the treatment of wounds with excessive exudate. Full article

(This article belongs to the Special Issue Advanced Biomaterials, Coatings and Techniques: Applications in Medicine and Dentistry, 2nd Edition)

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20 pages, 8912 KB

Open AccessArticle

Experimental Study on Tool Performance in the Machining of AISI 4130 Alloy Steel with Variations in Tool Angle and Cutting Parameters

by Jinxing Wu, Yi Zhang, Wenhao Hu, Changcheng Wu, Zuode Yang and Ruobing Yang

Coatings 2025, 15(10), 1115; https://doi.org/10.3390/coatings15101115 - 23 Sep 2025

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Abstract

The high hardness and toughness of AISI 4130 alloy present significant challenges during machining, including excessive cutting forces, rapid tool wear, and poor surface finish control. To address these issues, this study combines numerical simulation with turning experiments to systematically investigate the effects [...] Read more.

The high hardness and toughness of AISI 4130 alloy present significant challenges during machining, including excessive cutting forces, rapid tool wear, and poor surface finish control. To address these issues, this study combines numerical simulation with turning experiments to systematically investigate the effects of tool geometry and cutting parameters on cutting force, temperature, and surface roughness. Through Deform-3D finite element modeling, one-factor, and orthogonal simulation tests, it was found that the optimal tool geometric combination (λs = 2°, κ_r = 99°, γ₀ = 5°) reduces the cutting forces by 21.86% as compared to the baseline parameters. Experimental validation showed that the agreement between simulated and measured cutting forces was 86.73%–87.8%, with simulated values being 10%–13.27% higher due to idealized boundary conditions. Surface morphological analysis by Bruker Contour Elite K shows that the surface roughness of the workpiece decreases with an increasing cutting speed and increases with an increasing feed rate and depth of cut. The above studies provide a certain research basis for optimizing the tool angle and improving the cutting efficiency. Full article

(This article belongs to the Special Issue Alloy/Metal/Steel Surface: Fabrication, Structure, and Corrosion)

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19 pages, 6535 KB

Open AccessArticle

SEM/EDS and Roughness Analysis on Current Titanium Implant Decontamination Systems: In Vitro Study

by Marco Lattari, Andrea Butera, Simone Roatti, Maurizio Pascadopoli, Beatrice Alberti, Saverio Cosola, Mario Alovisi and Andrea Scribante

Coatings 2025, 15(10), 1114; https://doi.org/10.3390/coatings15101114 - 23 Sep 2025

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Abstract

The aim of this study was to evaluate the effects of different decontamination treatments on the surface roughness and elemental deposition of pristine dental implants using scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS). We divided 110 dental implants into 21 [...] Read more.

The aim of this study was to evaluate the effects of different decontamination treatments on the surface roughness and elemental deposition of pristine dental implants using scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS). We divided 110 dental implants into 21 groups based on the decontamination method used in vitro. One group was the untreated control. Roughness values (R_a) were analyzed with a profilometer, while elemental deposition was assessed through EDS. Results were obtained for each treatment and for macrogroups (control, ultrasound, curettes, powders, brushes, gels). Significantly lower R_a values were found in the neck zone with respect to the thread zone (p < 0.05). EDS analysis revealed a non-significant higher presence of carbon and calcium in certain treatments, denoting a certain deposition of the decontaminating products (p > 0.05). Although there were various significant differences among the groups, roughness values were low and no decontaminating methods macroscopically affected implant surfaces, so decontaminating procedures can be considered safe. Full article

(This article belongs to the Special Issue Surface Properties of Dental Materials and Instruments, 3rd Edition)

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Coatings, Volume 15, Issue 10 (October 2025) – 11 articles

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