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7 pages, 10330 KB

Open AccessProceeding Paper

Evaluation of the Corrosion Behavior of Low-Temperature Nitrided AISI 316L Austenitic Stainless Steel

by Francesca Borgioli

Eng. Proc. 2025, 105(1), 1; https://doi.org/10.3390/engproc2025105001 - 1 Aug 2025

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Nitriding of austenitic stainless steels at low temperatures hinders the precipitation of chromium nitrides and causes the formation of a supersaturated solid solution of nitrogen atoms in the austenite lattice, known as expanded austenite. In this study, the corrosion behavior of low-temperature nitrided [...] Read more.

Nitriding of austenitic stainless steels at low temperatures hinders the precipitation of chromium nitrides and causes the formation of a supersaturated solid solution of nitrogen atoms in the austenite lattice, known as expanded austenite. In this study, the corrosion behavior of low-temperature nitrided AISI 316L is investigated in a NaCl solution using different electrochemical techniques, electrochemical impedance spectroscopy, cyclic potentiodynamic polarization and galvanostatic tests, in order to assess the effect of test conditions. The nitrided layer has an enhanced resistance to localized corrosion, but its ability to repassivate depends on the damage extent caused by the different tests. Full article

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17 pages, 4404 KB

Open AccessProceeding Paper

Surface Roughness and Fractal Analysis of TiO₂ Thin Films by DC Sputtering

by Helena Cristina Vasconcelos, Telmo Eleutério and Maria Meirelles

Eng. Proc. 2025, 105(1), 2; https://doi.org/10.3390/engproc2025105002 - 4 Aug 2025

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Abstract

This study examines the effect of oxygen concentration and sputtering power on the surface morphology of TiO₂ thin films deposited by DC reactive magnetron sputtering. Surface roughness parameters were obtained using MountainsMap^® software(10.2) from SEM images, while fractal dimensions and texture [...] Read more.

This study examines the effect of oxygen concentration and sputtering power on the surface morphology of TiO₂ thin films deposited by DC reactive magnetron sputtering. Surface roughness parameters were obtained using MountainsMap^® software(10.2) from SEM images, while fractal dimensions and texture descriptors were extracted via Python-based image processing. Fractal dimension was calculated using the box-counting method applied to binarized images with multiple threshold levels, and texture analysis employed Gray-Level Co-occurrence Matrix (GLCM) statistics to capture local anisotropies and spatial heterogeneity. Four samples were analyzed, previously prepared with oxygen concentrations of 50% and 75%, and sputtering powers of 500 W and 1000 W. The results have shown that films deposited at higher oxygen levels and sputtering powers exhibited increased roughness, higher fractal dimensions, and stronger GLCM contrast, indicating more complex and heterogeneous surface structures. Conversely, films produced at lower oxygen and power settings showed smoother, more isotropic surfaces with lower complexity. This integrated analysis framework links deposition parameters with morphological characteristics, enhancing the understanding of surface evolution and enabling better control of TiO₂ thin film properties. Full article

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8 pages, 1944 KB

Open AccessProceeding Paper

Fabrication of Thin-Film Composite Nanofiltration Membrane Employing Polyelectrolyte and Metal–Organic Framework (MOF) via Spin-Spray-Assisted Layer-by-Layer Assembly

by Farid Fadhillah

Eng. Proc. 2025, 105(1), 3; https://doi.org/10.3390/engproc2025105003 - 11 Aug 2025

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Abstract

Spin-spray-assisted layer-by-layer (LbL) assembly is an innovative method for producing nanostructured thin films due to its rapid assembly and extensive coverage of substrates. In this study, a nanofiltration (NF) membrane consisting of multilayers of polyethyleneimine (PEI) and poly(sodium-4-styrene sulfonate) (PSS) was fabricated on [...] Read more.

Spin-spray-assisted layer-by-layer (LbL) assembly is an innovative method for producing nanostructured thin films due to its rapid assembly and extensive coverage of substrates. In this study, a nanofiltration (NF) membrane consisting of multilayers of polyethyleneimine (PEI) and poly(sodium-4-styrene sulfonate) (PSS) was fabricated on a polysulfone (PSF) support. The resulting membrane was further coated with a metal–organic framework (MOF303). The resulting (PEI/PSS)₅-MOF303 showed a rejection rate of 18.94 ± 1.58% and a permeability of 0.91 ± 0.13 L/(h·bar·m²)while also showing enhanced antifouling properties. This work explores the possibility of spin-spray-assisted LbL assembly as a promising method for fabricating membranes. Full article

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12 pages, 1331 KB

Open AccessProceeding Paper

Tailoring the Optical and Sensing Properties of Sol–Gel Niobia Coatings via Doping with Silica and Noble Metal Nanoparticles

by Tsvetanka Babeva, Venelin Pavlov, Georgi Zlatinov, Biliana Georgieva, Penka Terziyska, Gergana Alexieva, Katerina Lazarova and Rosen Georgiev

Eng. Proc. 2025, 105(1), 4; https://doi.org/10.3390/engproc2025105004 - 14 Aug 2025

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Abstract

Nb₂O₅ (niobia) coatings were prepared by spin coating of niobium sol, synthesized using niobium chloride as the precursor and ethanol and water as solvents, followed by high-temperature annealing. Doping of the films was achieved by incorporating commercially available SiO₂ [...] Read more.

Nb₂O₅ (niobia) coatings were prepared by spin coating of niobium sol, synthesized using niobium chloride as the precursor and ethanol and water as solvents, followed by high-temperature annealing. Doping of the films was achieved by incorporating commercially available SiO₂ (Ludox) and noble metal nanoparticles (NPs) into the sol prior to its deposition. Various sizes of Pt (5 and 30 nm), Ag (10, 20, and 40 nm), and Au (5, 10, and 20 nm) NPs were used to enhance sensing behavior of coatings. After annealing, films were subjected to chemical etching to remove the silica phase. This process generated porosity within the films, which in turn enabled the tailoring of both their optical and sensing properties. It was demonstrated that both the type and size of the incorporated nanoparticles significantly influenced the sensing behavior. The most effective enhancement was observed with the addition of 10 nm AuNPs. Optical characterization indicated that 10 nm AuNPs had a minimal effect on the optical properties. In contrast, doping with 20 nm AuNPs led to a reduction in the refractive index and an increase in Urbach energy. No significant alteration in the optical band gap due to doping was observed. Full article

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11 pages, 4000 KB

Open AccessProceeding Paper

Development of Biochar-Based Sustainable Corrosion-Resistant Coating

by Ganesh Zade and Malhari Kulkarni

Eng. Proc. 2025, 105(1), 5; https://doi.org/10.3390/engproc2025105005 - 27 Aug 2025

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Abstract

Conventional protective coatings based on petroleum raw materials have certain limitations in terms of their availability, environmental pollution, and sustainability. Therefore, this research successfully investigates the potential of sheep wool-derived biochar to develop a sustainable, high-performance protective coating. Two variants of biochar, namely [...] Read more.

Conventional protective coatings based on petroleum raw materials have certain limitations in terms of their availability, environmental pollution, and sustainability. Therefore, this research successfully investigates the potential of sheep wool-derived biochar to develop a sustainable, high-performance protective coating. Two variants of biochar, namely SW800 and SW1000, were developed by pyrolyzing sheep wool at 800 °C and at 1000 °C for 1 h, respectively. The prepared samples were characterized using FTIR, FESEM-EDX, and XRD analyses to confirm the structural and elemental differences between both biochar samples. Furthermore, biochar-based epoxy coatings were developed by varying the concentration of prepared biochar from 1% to 5%. The coating performance was evaluated for its aesthetic, mechanical, chemical resistance, and hydrophobicity. Crucially, this study demonstrated that biochar inclusion did not compromise critical mechanical and chemical properties like adhesion (5B), flexibility (7 mm), scratch hardness (3500 gms), pencil hardness (3H), acid-alkali resistance, and solvent rub test (rating 5). However, a key finding of this research is that the incorporation of biochar into an epoxy coating resulted in a significant improvement in hydrophobicity, which is measured using water contact angle. The incorporation of SW800 and SW1000 into coating formulations at varying concentrations resulted in an increase in water angle of approximately 18% and 20%, respectively. The outcomes of this project establish biochar-based coatings as a promising solution for eco-friendly and high-performance protective applications. Full article

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5 pages, 1366 KB

Open AccessProceeding Paper

Deposited Thin-Film Nanoelectrocatalysts of Non-Noble Metals for Co-Capture of CO₂ and Reduction of Nitrates

by Irina Kuznetsova, Marina Timina, Dmitry Kultin, Olga Lebedeva, Pavel Nesterenko and Leonid Kustov

Eng. Proc. 2025, 105(1), 6; https://doi.org/10.3390/engproc2025105006 - 4 Sep 2025

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Abstract

The co-electrolysis of nitrate and CO₂ can contribute to urea production with low carbon-oxide emission rate and at the same time reduce NO₃⁻ to extremely low permissible concentrations. It was found that Ag and Fe particles, as thin catalytic layers, [...] Read more.

The co-electrolysis of nitrate and CO₂ can contribute to urea production with low carbon-oxide emission rate and at the same time reduce NO₃⁻ to extremely low permissible concentrations. It was found that Ag and Fe particles, as thin catalytic layers, can potentially be used for the joint reduction of NO₃⁻ and CO₂ under benign ambient conditions. The linear voltammetry, chronoamperometry, electrochemical impedance spectroscopy, and electron scanning microscopy were used. The Fe/C electrocatalyst exhibits superior current density stability at −1.2 V vs. Ag/AgCl, whereas Ag/C electrocatalyst shows noticeable degradation over time. This reaction is necessary both for the removal of nitrates from wastewater and for the capture of carbon dioxide, which makes it one of the important applications of sustainable chemistry. Full article

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