Sürdürülebilir Kalkınma Amaçları
Yayınlar
- MakaleAçık Erişim2026Scopus SJRQ2Effects of Magnetic Abrasive Finishing Process Parameters on the Inner Surface Machining of AISI 304 Austenitic Stainless Steel Pipes
Sarıçiçek, İzel; Çaydaş, Alparslan Ulaş; Cihangir, Salih; Say, Yakup
In this study, the effects of SiC abrasive ratio, size of magnetic Fe particles and the machining time parameters on the surface roughness, material removal rate, roundness of the holes and corrosion resistance in magnetic abrasive inner surface finishing (MAF) of the AISI 304 austenitic stainless steel pipes were experimentally investigated. A Taguchi L9 orthogonal array was used for the experiments. The surface roughness and the characteristics of the machined surfaces were examined by using the3D surface topography method. The characteristics of the abrasive and magnetic powders before and after machining operations were investigated under scanning electron microscope (SEM) and x-ray diffraction analysis (XRD) techniques. The electrochemical corrosion measurements were performed in 3.5 wt.% NaCl solutions in a typical three-electrode electrochemical cell. An analysis of variance (ANOVA) method was also applied to the study in order to determine the statistical effects of each factor on the measured responses. Consequently, AISI 304 samples machined with MAF technique revealed better results for corrosion performance, surface quality, material removal rate and the hole dimensional tolerances.
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İncele - MakaleYalnız künye2026Scopus SJRQ1Electrochemically assisted leaching of rare earth carbonates in non-aqueous green solvents: Solvent design, characterization, and process optimization
Cihangir, Salih
This study presents a systematic approach to the design, characterization, and application of non-aqueous green solvents (NAGSs) for the leaching of rare earth carbonate hydrates (RECHs). Four NAGSs based on choline chloride, ethylene glycol, and various carboxylic acids were synthesized and evaluated for their physicochemical and electrochemical properties. Among the evaluated formulations, the choline chloride–ethylene glycol–Na₂EDTA·2H₂O mixture (N1) and the chloride–levulinic acid mixture (N2) were found were found suitable for both traditional and electrochemically assisted leaching due to their optimal viscosity, conductivity, and electrochemical stability. Electrochemical assistance significantly enhanced leaching efficiency, with improvements ranging from 22 % to over 300 % for certain elements compared to conventional methods. Mechanistic investigations revealed that the application of an oxidative potential facilitates the protonation and dissolution of RECHs, likely through the generation of localized acidic environments and the formation of intermediate species. The FTIR analysis confirmed the dissolution of carbonate phases and the formation of rare earth–ligand complexes, particularly in the N1 system, where new bands associated with carboxylate and amine coordination were observed. Importantly, the proposed electrochemically assisted method can be applied to different primary or secondary sources in both aqueous and non-aqueous solutions. The results demonstrate the advantages of combining non-aqueous green solvents with electrochemical assistance as an environmentally benign alternative to conventional acid-based leaching, especially for challenging carbonate forms of rare earth elements. This work provides important guidelines for the development of sustainable hydrometallurgical processes, with future directions including solvent recyclability, selective recovery, and environmental assessment.
AtıfScopus2WoS2İncele - MakaleAçık Erişim2025Scopus SJRQ1Y2O3-Doped BioGlass Coatings for Ti-6Al-4V Alloy: Insights into Degradation, Bioactivity, Ion Release, Adhesion, and Corrosion Behavior
Say, Yakup; Aslan, Naim; Cihangir, Salih; Murat, Oğuzkağan; Çaydaş, Ulaş
The Ti-6Al-4V alloy is particularly favored for orthopedic applications. However, important issues such as corrosion resistance, biocompatibility, and ion release need to be addressed. Therefore, this study aims to enhance the corrosion resistance and biocompatibility and reduce the ion release of the Ti-6Al-4V alloy by applying Y2O3-doped bioglass bioceramic coatings. The coatings were synthesized using the sol-gel method, including pure BioGlass and BioGlass with 1, 5, and 10 wt pct Y2O3. These coatings were then evaluated for their corrosion resistance, adhesion strength, degradation behavior, bioactivity, and ion release. The results showed that all coatings exhibited homogeneous, crack-free, and porous morphologies, which are favorable for osteointegration. The addition of 10 wt pct Y2O3 to the BioGlass coating resulted in a 52 pct increment in adhesion strength, which increased from 13.72 ± 2.80 MPa for single BioGlass coatings to 20.81 ± 2.53 MPa. All samples showed degradation values lower than 1 wt pct. Single BioGlass coatings significantly enhanced the bioactivity of Ti-6Al-4V alloy. However, the addition of Y2O3 negatively impacted BioGlass bioactivity, leading to a noticeable decrease as the Y2O3 content increased. Conversely, the presence of Y2O3 negatively impacted bioactivity and corrosion resistance while increasing the release of Ti ions. Specifically, the release of Ti ions increased from 79.5 ± 0.8 ppb in uncoated samples to 253.7 ± 15.3 ppb in BG-coated samples. For 1, 5, and 10 pct Y2O3-added samples, Ti releases were measured as 192.2 ± 33.6 ppb, 168.5 ± 62.4 ppb, and 194.3 ± 54.4 ppb, respectively. This research highlights the potential of tailored BioGlass coatings to improve the performance of Ti-6Al-4V alloys in orthopedic implant applications, particularly for enhancing bone integration and reducing implant failure.
AtıfScopus4WoS3OpenAlex5İncele - MakaleAçık Erişim2025Scopus SJRQ2Effects of ZrN and DLC coatings on morphostructural, corrosion, cell viability, and antibacterial properties of Ti6Al4V scaffolds
Aslan, Naim; Aksakal, Bünyamin; Cihangir, Salih; Fidan, Ferzan; Yilmazer, Yasemin
Lightweight and functional metallic materials are consistently favored and attract significant attention in the biomedical field. This study investigates the influence of ZrN and DLC coatings on Ti6Al4V scaffolds with varying porosities (40%, 50%, 60%) for biomedical applications. PVD-deposited coatings exhibited distinct growth mechanisms: High-resolution SEM-FIB analyses revealed columnar ZrN structures due to limited adatom mobility, while DLC formed conformal, amorphous layers via high-energy carbon species. Corrosion resistance decreased in 40% porous DLC and 60% porous ZrN-coated samples, likely due to coating defects and increased electrolyte access through open pores. ZrN coatings showed superior antibacterial activity and attributed to surface reactivity and potential ion release. In contrast, the uncoated 60% porous scaffolds demonstrated highest cell viability, suggesting that excessive coating on highly porous structures may hinder cell–material interactions. Furthermore, the cytotoxicity evaluations indicated that uncoated scaffolds exhibited the highest cell viability (77.51%) at 60% porosity after 48 hours, with ZrN coatings demonstrating better efficacy compared to DLC in the 50% and 60% porosity groups.
AtıfScopus3WoS3OpenAlex3İncele - MakaleAçık Erişim2025Scopus SJRQ2Investigation of anticorrosive and antibacterial properties of electrochemically modified AISI430 steel surfaces; [Elektrokimyasal yöntem ile modifiye edilmiş AISI430 çelik yüzeylerin antikorozif ve antibakteriyel özelliklerinin incelenmesi]
Açar, Gülistan; Cihangir, Salih; Omaç, Basri; Aydoğdu, Hacı Mehmet; Oflaz, Mücahit
Both pharmacological and material-based approaches aim to slow bacterial evolution toward resistance. In this context, imparting specific antibacterial properties to materials is essential. Traditionally, alloying was a method to equip entire metals with antibacterial features, such as incorporating small amounts of copper (Cu) and/or silver (Ag). However, due to the high cost and inherent limitations of alloying, surface modification processes have gained prominence. Recent antibacterial studies on copper have led to the application of Cu(Ag) electrochemical coatings on AISI430 steel surfaces. This study aims to combine copper’s antibacterial properties with enhanced corrosion resistance and surface hardness. The coatings were deposited using deep eutectic solvents, known for their environmentally friendly properties, followed by potentiodynamic analysis. Microstructural and phase distribution characteristics were examined through SEM-EDS analysis, while surface roughness was analyzed using profilometry. Transitioning from micro-disc electrodes to macro-scale AISI430 substrates, Cu(Ag) films containing 16% Ag demonstrated nanoscale roughness, approximately double the hardness, and superior corrosion resistance compared to conventional copper surfaces. Antibacterial tests compared the coated surfaces with untreated AISI430 steel. Results showed that Cu(Ag)-coated surfaces exhibited improved antibacterial properties. This study shows how Cu(Ag) electrochemical coatings can be used to make surfaces that are antibacterial, long-lasting, and resistant to corrosion.
- MakaleAçık Erişim2023Effect of Longer Waiting Time During OCP and Pre-Applied Cleaning Potential In Corrosion Analysis of Zinc Metal
Cihangir, Salih
Tafel analysis is a widely accepted technique for corrosion studies in electrochemistry. A general literature search for one of the electronegative metals, zinc, revealed serious deviations in corrosion results. In order to understand the reasons behind these deviations, zinc metal was investigated at macro and micro levels during and after the Tafel corrosion analysis. In-situ macro surface investigation during the OCP period and Tafel analysis were performed, and it was found that the zinc surface undergoes proceeding corrosion attack following the immersion in 3.5 wt.% NaCl solution. In-situ macro surface analysis exhibited that the pre-oxidation of the surface proceeds as nonuniform at local regions. SEM-EDS and XRD analysis proved that the particular crystal planes of the zinc form ZnO with increasing immersion time. A linear sweep voltammetry (LSV) technique was applied to detect the oxygen removal and starting hydrogen evolution potentials. Three identical Tafel experiments were performed on samples without any treatment, and another three consecutive Tafel experiments were performed on the samples which applied pre-reduction potential. Obtained results revealed that in-situ pre-applied reduction potential just before the Tafel analysis cleaned the surface and allowed uniform oxide formation, resulting in the lowest standard deviation of the calculated Tafel elements.
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İncele - MakaleAçık Erişim2023Scopus SJRQ1Greening Industrially Applied Toxic Cadmium Plating with γ-Ni2Zn11 Alloy in Deep Eutectic Solvents: Promising Electroplating Efficiency and Chemical Corrosion Resistance
Cihangir, Salih
Cadmium is an industrially applied plating metal used in aerospace applications, but electrodeposition of cadmium is toxic, and current production method will soon be banned. Therefore, electrodeposition of alternative alloys in environmentally friendly solutions is an attractive research area. An additive-free, nonaqueous, deep eutectic solvent (DES) containing Ni and Zn halide salts is developed in a greener environmental method. Gamma-phase nanocrystalline Ni2Zn11 is coated onto hot-rolled mild steel via pulse reverse current (PRC) in the developed nonaqueous solvent. The employed DES’ relatively low viscosity and sufficient conductivity enable the simultaneous reduction of Ni2+ and Zn2+ cations on microelectrode. Electrochemical quartz crystal microbalance (eQCM) analysis proves the absence of the commonly reported problem of electrode blocking during electrodeposition, revealing an efficiency of 86.07%. Appropriate PRC parameters are applied for scaled macroelectrode deposition. The plating profile exhibits 20 μm-thick alloy deposition without cracks around 3 h. Scanning electron microscopy–electron-dispersive spectroscopy and X-ray diffraction analyses reveal that 15.5 wt% Ni is in the nanograin phase, and all crystal planes belong to the γ-Ni2Zn11 phase, which is needed as an alternative to cadmium plating. Hardness and corrosion tests performed on the γ-Ni2Zn11 coating reveal better hardness and corrosion resistance with supporting morphological evidence.
AtıfScopus14WoS13OpenAlex16İncele - MakaleYalnız künye2023Scopus SJRQ2Replacement of Cu with One-Step Production of CuAg (Ag0.04Cu3.96): Superior Conductivity, Corrosion Resistance, and Hardness
Cihangir, Salih
Copper is the forefront of the fundamental metals used in various industries. It is utilized as bulk or electrodeposited on PCBs or interconnects. However, poor corrosion resistance and hardness reduce copper performance and limit its applicability in the fields that require mechanical strength, such as probing applications. Facile electrochemical deposition of Cu(Ag) films was examined in a deep eutectic solvent known for its green nature. SEM–EDS technique was applied for morphostructural and crsytal plane analysis. XRD analysis revealed Cu3.96Ag0.04 phase, and 2% Ag was identified in the Cu(Ag) film in EDS. Four-prope point resistivity analysis was performed via galvano-impedance spectroscopy. Obtained resistivity value of 5 µm thick Cu(Ag) coating was lower than the compliance limit of International Technology Roadmap for Semiconductors. Corrosion analysis was carried out via electrochemical impedance spectroscopy technique, and Cu(Ag) films demonstrated better resistance. Hardness tests also revealed that Cu(Ag) was approximately two times harder than Cu. Graphical Abstract: [Figure not available: see fulltext.]
AtıfScopus6WoS6OpenAlex6İncele - MakaleAçık Erişim2023Scopus SJRQ1Detailed investigation of zinc coating behaviours in various deep eutectic solvents
Cihangir, Salih; Ryder, Karl S.; Unal, Asuman
Determining the optimum conditions of a metal coating is significant for its possible applications in many fields. The present work described the electrodynamic process of zinc coating from six different deep eutectic solvents (DESs), especially type-III DES systems prepared with a quaternary ammonium salt and hydrogen bond type. Non-reversible processes without oxidation were found in DES systems prepared with choline chloride and zinc nitrate salts, and also, propylene glycol and zinc nitrate salts, termed as type-II and type-IV, respectively. The most attracted type-III DES prepared by a mixture of 1 molar choline chloride and 2 molar ethylene glycols, commercially known as Ethaline (E200), were examined for its electronucleation and possible reactions for zinc electrodeposition. For the first time, the Pt working electrode was investigated under high-resolution optical microscopy to visualize the in-situ morphology change during oxidation and reduction in E200. Furthermore, the morphological change during the anodic dissolution of zinc was also investigated in situ under a high-resolution microscope. It was found that insoluble species forming during anodic dissolution blocks the surface. Bulk electrolysis was performed in these solvents to investigate the formed zinc nucleates' morphological differences. XRD analysis was performed to differentiate the crystal planes of each deposition obtained from six DESs. It was found that the type-II and type-IV DESs consisting of zinc nitrates revealed zinc hydroxy nitrate dominated zinc deposition, which can be helpful in various applications.
AtıfScopus14WoS11OpenAlex15İncele - MakaleAçık Erişim2023Scopus SJRQ2ZrN and ta-C coatings on titanium for biomedical applications: Improved adhesion, corrosion, antibacterial activity, and cytotoxicity properties
Aslan, Naim; Aksakal, Bünyamin; Cihangir, Salih; Cetin, Fadime; Yilmazer, Yasemin
Commercially pure titanium (CP-Ti) is extensively used in biomedical applications. However, numerous qualities, including mechanical strength, corrosion resistance, and wear resistance, must be established for long-term performance as an implant material. This study investigates the enhancement of surface properties of CP-Ti through physical vapor deposition (PVD) with ZrN and ta-C (tetrahedral amorphous carbon). Among the coatings, ZrN revealed best overall results, such as adhesion, corrosion, microhardness, and wettability, excluding cell viability when compared to ta-C. E. coli and S. aureus were employed for antibacterial activity and MTS cell viability experiments. Compared to α-titanium, hardness tests revealed 91% increase in ZrN coating, and %22 increase in ta-C coating. Super-hydrophobicity and excellent antibacterial activity were found for ZrN coatings in comparison to ta-C. These findings emphasize the potential of ZrN and ta-C coatings to improve the surface properties of titanium, encouraging it to be used in biomedical devices. Graphical abstract: [Figure not available: see fulltext.].
AtıfScopus16WoS16OpenAlex19İncele - MakaleYalnız künye2022Scopus SJRQ2Microstructure and corrosion investigation of FeCoCrNiMo0,5(MnAl)0,3 high entropy alloy produced by 316 L stainless steel scrap
Cihangir, Salih; Say, Yakup; Ozkul, İskender; Guler, Omer; Guler, Seval Hale
FeCrCoNiMo0,5(MnAl)0.3 high-entropy alloy (HEA) was manufactured via arc melting process by adding the related metal powders into scrap of 316 L stainless steel for corrosion resistance tests under salt and acid conditions. Cyclic potentiodynamic polarization experiments performed under acidic conditions revealed pre-passivation due to abundance of network modifying metals in HEA composition which was further analyzed by electrochemical impedance spectroscopy. Elemental resolved analysis of leftover solutions was used to compare metal ions released during corrosion. X-ray diffraction analysis indicated the phase change in heat treated HEA samples. Non-heat treated HEA samples can be compared with stainless steel under moderate corrosion conditions and had better hardness results.
AtıfScopus20WoS17OpenAlex19İncele - MakaleAçık Erişim2021Scopus SJRQ1Highly Efficient Defluoridation of Water through Reusable poly(aniline-co-o-aminophenol) Copolymer Modified Electrode Using Electrochemical Quartz Crystal Microbalance
Unal, Asuman; Hillman, A. Robert; Ryder, Karl S.; Cihangir, Salih
Although the World Health Organization (WHO) recommends a limit of 1.5 mg l-1 fluoride ions in drinking water, this is not satisfied in many parts of the world. When this limit is exceeded, the electrochemically switched ion-exchange (ESIX) technique (mainly based on conductive polymers) has been identified as a promising method for removing the excess fluoride ions. The present study aimed to develop an efficient method based on the ESIX technique by using poly(aniline-co-o-aminophenol) copolymer to extract fluoride ions. Electrochemical quartz crystal microbalance (EQCM) and acoustic admittance data were utilized to assay the synthetic efficiency of copolymer deposition, and to evaluate the dependence of the defluoridation process on the proportions of the monomers in the copolymer matrix and on film thickness. The resulting films were characterised by Fourier transform infrared spectroscopy (FTIR) and scanning electrochemical microscopy (SEM) techniques. For optimized co-monomer ratio in the feedstock, poly(aniline-co-o-aminophenol) at an applied potential of 0.30 V showed excellent performance for fluoride removal from water at pH 6.6, to the extent of 20 (mg F-) (g polymer)-1. Comparison of the performance of ESIX using poly(aniline-co-o-aminophenol) with that of other techniques and materials reveal that it has significant potential for water defluoridation.
AtıfScopus9WoS8OpenAlex10İncele - MakaleAçık Erişim2021Scopus SJRQ1Electrogravimetric analysis of poly(aniline-co-o-toluidine) copolymer films in the presence of fluoride ions
Unal, Asuman; Robert Hillman, A.; Ryder, Karl S.; Cihangir, Salih
Polyaniline itself can be converted to its conductive form from its insulating form by applying an oxidising potential in which polyaniline is converted to its positive charge state. Anions in the target solution are driven into the positively charged polymer film by electrostatic force, and this process is reversed when a reduction potential is applied. Consequently, interfacial processes of polyaniline modified electrode make it viable to remove undesirable ions from the target solution. During this process, polyaniline operates as an ion-exchanger by directing specific ions at definite potentials, which is the principle of the electrochemically switched ion-exchange technique. Therefore, polyaniline can be employed as a convenient material to perform as a new ion-exchanger modified film in an acidic environment. On the other hand, an abrupt decrease in the electroactivity of polyaniline at elevated pH values restricts its use in such practical applications. To overcome this problem, copolymerization of aniline and o-toluidine is expedient as it will be able to enhance the electrochemical properties of polyaniline. Hence, several copolymers were synthesised in the presence of different aniline and o-toluidine feedstock ratios. It was found that the surface coverage value of a representative poly(aniline-co-o-toluidine) copolymer film was 139.7 nmol cm−2 compared with 76 nmol cm−2 for pure Pani under identical conditions. In addition, the redox cycling in monomer-free NaF solutions showed that the poly(aniline-co-o-toluidine) film exhibited excellent reversibility between redox reactions at pH 6.60. These outcomes clearly illustrate the contribution of o-toluidine to the electrochemical properties of polyaniline at raised pH medium.
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