Protection of Metals and Physical Chemistry of Surfaces最新文献

Aluminum oxide (Al₂O₃) exhibits robust self-healing properties and chemical stability, along with superior hydrogen resistance and corrosion resistance. Additionally, it can serve as a hard particulate component in various coatings. In this study, an amorphous Ni–P coating doped with Al₂O₃ nanoparticles was applied to a Q235 steel substrate using electrodeposition technique. The investigation focused on the influence of nano-Al₂O₃ dosage on the properties of the Ni–P composite plating. The findings indicate that the inclusion of Al₂O₃ nanoparticles significantly enhances the corrosion resistance, hydrogen resistance and wear resistance of the Ni–P coating. Specifically, for the Ni–P coating with the Al₂O₃ addition of 3 g/L (Ni–P–Al₂O₃-3 coating), the impedance value increased by 64.4%, while the corrosion current decreased by 58.7%. Furthermore, the Ni–P–Al₂O₃-3 coating demonstrated an extended hydrogen penetration time and a reduction in hydrogen diffusion coefficient by an order of magnitude compared with pure Ni–P coating.

In this study, the influence of boronizing on the high-temperature wear behavior of AISI 304 was examined experimentally and with FEA simulation. Boronizing, conducted at 950°C for 3 h using the powder-pack boronizing technique, showed an approximately 7-fold increase in hardness compared to untreated sample. Boride layer characterization was performed using XRD, SEM, and EDS line analyses. Wear tests were performed at ambient temperatures of 25, 250, and 500°C. While the wear rates of the untreated sample increased dramatically with increasing temperature, those of the boronized samples were significantly limited. FEA simulation using the Johnson–Cook fracture model demonstrated a high degree of consistency with the experimental wear profiles and this alignment enables reliable wear predictions. The oxide layer formation was observed on the worn surface of boronized samples during the tests at elevated temperatures, resulting in less plastic deformation.

The development of titanium–porcelain prosthetics has garnered significant attention due to their excellent biocompatibility and aesthetics. Unfortunately, the application of titanium–porcelain prosthetics has been restricted by their poor bonding strength. In this study, to enhance the bonding strength of the titanium surface, a ceramic coating was synthesized on the titanium surface using the micro arc oxidation method. Furthermore, the ceramic coating can substitute body porcelain in titanium–porcelain prostheses due to its color similarity to natural teeth. The morphologies and phase compositions of the coatings were analyzed using SEM and XRD techniques. The bonding strength, wettability, and colors were also investigated. The results show that the corresponding bonding strength between the titanium substrate and ceramic coating is higher than 30 MPa, which meets the requirements of porcelain-fused-to-metal restorations. The concentration of cerium oxide can be modulated by adjusting the cerium nitrate coating’s color distribution. Therefore, this method offers a practical and valuable approach to replacing opaque and body porcelain with ceramic coatings.

The goal of this work was to use graphene oxide (GO) to remove sulfur compounds from simulated fuel through an adsorption desulfurization process (ADP). Graphite powder was used to generate graphene oxide in order to modify its surface area and pore volume for use in the petroleum industry. Graphene oxide was produced from graphite via modification of the Hummer process. To investigate the activity of the prepared GO-nanoparticles, we adapted the recently developed digital baffle batch reactor (DBBR) and applied it to the adsorption desulfurization process (ADP). Using an N₂ adsorption/desorption isotherm, Fourier- transform infrared spectroscopy (FTIR), and a scanning electron microscope (SEM), the physicochemical characteristics of graphene oxide were characterized. Investigated were the effects of three operating conditions on the removal efficiency of sulfur compounds at constant pressure and temperature: adsorbent dosage (0.4–1.2 g), speed of impeller (150–350 rpm), and contact time (35–55 min). To assess the surface modifications of adsorbents in the current process, a removal efficiency study under various operating conditions was used. The largest sulfur removal efficiency and adsorption capacity were found in the sulfur removal experiments from model fuel, which had an initial sulfur concentration of 450 ppm. The adsorption capacity was found to be 83.30% of adsorbent. At a speed of impeller 350 rpm, a contact time of 55 min, and an adsorbent dosage of 1.2 g, the highest efficiency of sulfur removal was achieved.

We have analyzed the corrosion behavior of the AlSi10Cu(Fe) aluminum cast alloy of the surface in contact with sand during the casting, before and after polishing with and without perpendicular heterogeneous weak permanent magnetic field. The results obtained show that after immersion of non-polished sample generalized corrosion appears and the formation of hillocks on certain ridges of the microstructure were observed, and there is electrochemical noise only during 35 s of immersion of the sample; after that, fluctuations of stair steps take place. The polishing induces localized corrosion, pitting corrosion, and non-perfect-shape electrochemical noise until 24 h of immersion. It was observed that the application of a perpendicular homogeneous weak permanent magnetic field to the polished sample made the shape of the electrochemical noise perfect in the first 10 min, but after 24 h, the fluctuations took the form of stair steps.

In this study, a water-soluble with environmental friendly flame retardant (AEPBEA) containing B, N, and P elements was synthesized using erythritol, phosphoric acid, boric acid and urea. The synthesized AEPBEA was characterized by ¹H nuclear magnetic resonance (¹H NMR) and Fourier-transform infrared spectrum (FTIR). The synthesized AEPBEA was coated onto cotton fabrics to increase the flame retardancy of cotton fabrics. Cotton fabrics before and after treated by AEPBEA were characterized using Fourier-transform infrared (FTIR), Scanning electron microscopy—energy dispersive X-ray spectroscopy (SEM–EDX), X-ray diffraction (XRD). The thermal stability of the samples was researched by thermo-gravimetric (TG), and the char residue rate of the treated cotton fabrics could reach 47% in the nitrogen atmosphere. The combustion behavior of cotton fabrics was evaluated by cone calorimetry, and the peak of heat release rate (PHRR) and total heat release (THR) decreased by 90.7 and 60.58% after treated by AEPBEA. The limiting oxygen index (LOI) of cotton treated with 300 g/L AEPBEA reached 43.3% and the carbon length was 4.6 cm. After 50 laundering cycles (LCs), the LOI value could still reach 29.1%. In addition, the mechanical properties of the treated cotton only decreased slightly, and could match the practical usage.

The review summarizes the physicochemical properties, characteristics of selective, nonselective and multimodal hemosorbents and sorption systems approved for use in the Russian Federation in comparison with other materials used in medical practice. The main share of the materials studied for outside-body blood purification is occupied by sorbents based on carbon, natural and synthetic polymers. Research continues on expanding the types of materials for hemosorption, synthesis methods, improving their physical and chemical properties and structure, increasing adsorption characteristics, selectivity and biocompatibility. Among the methods for synthesizing new sorbents, methods of surface functionalization with various specific substances (ligands) of already known hemosorbents or newly developed matrices of various natures are distinguished. The review presents literary data on the creation of new materials for hemosorption over the past 5 years in Russia and abroad. The experience of successful application of outside-body blood purification methods using sorbents, both separately and in combination with other methods, for the treatment of patients with COVID-19 is shown.

A new 1,2,3-triazole compound namely 3-[4-(4-amino-phenyl)-[1,2,3]triazol-1-yl]-propyl}-phosphonic acid diethyl ester (APTP)), was synthesized under click chemistry regime and effectively tested as potential inhibitor for structural steel (S355) in 3.5% sodium chloride solution. The corrosion-inhibiting properties were examined through a combination of weight loss measurements and the electrochemical impedance spectroscopy (EIS). The results demonstrated that APTP significantly suppresses the structural steel corrosion, with an inhibition efficiency of 92.8% observed after 30 min of immersion. A blend of statistical analysis was employed to gain a comprehensive understanding of the corrosion parameters, providing a detailed insight into their effects and interactions. The maximum inhibition efficiency (IE %) of 93.06% was predicted by the full factorial design (FFD) with the conditions of 10 h of immersion time (A), an inhibitor concentration of 0.005 M (B), and a temperature of 25°C (C). The statistical model used to predict IE % proved to be advantageous, demonstrating strong accuracy and reliability in its prediction. DFT calculations and molecular dynamics simulations support the experimental finding.

The new study, focuses on dental titanium (cp-Ti) against corrosion with 2000 ppm α-pinene, citric acid (0.005 M; 0.01 M), and fluoride (1% NaF) in artificial oral conditions. The study performed by using electrochemical methods investigated with open-circuit (E_OCP-t(s) time) potential, impedance spectroscopy (EIS), current–potential (CP) and linear polarization (R_LPR) curves. The aim of this study is to prevent the corrosion of multi-Ti with more natural and accessible materials and to support it with the density functional theory (DFT). Electrochemical study results demonstrated that α-pinene acted as anodic inhibitor. It increased the corrosion resistance from 2.4 to 1450 kΩ cm² at 0.01 M citric concentration (99.8%). Also, ICP-MS analysis indicated that cp-Ti cations decreased from 246 to 14 ppb at this concentration. Additionally, the cations reduced significantly and covered on the surface thanks to the α-pinene at citric acid concentrations according to scanning electron microscopy (SEM/EDX) analysis. The results showed that DFT calculations and electrochemical are compatible with each other. Computational DFT study applied for α-pinene and fluoride on cp-Ti with Gaussian 09W, PBEPBE/6-311G(d,p) version.

Electric discharge machining (EDM) is a prominent machining process for machining hard to cut materials. This process is mainly used for fabrication of cooling holes, lubricating oil holes, and press tools and dies. In EDM process tool wear is inevitable and research on reduction of tool wear and increasing the accuracy gains an importance in manufacturing industries. This research, focus on coating of brass electrode with zinc and nickel through electrochemical method. The coated electrode is subjected in EDM performance analysis such as machining speed (MS), tool wear rate (TWR) and surface roughness (R_a). Artificial neural networks (ANN) with desirability function analysis (DFA) is used to analysis the EDM performance. The successful set of parameters determined were a gap voltage of 25 V, a current of 10.73 A, a pulse-on duration of 60 µs, and a pulse-off time of 10 µs. The application of the zinc- and nickel-coated electrodes attributed for the reduced TWR. The inclusion of ANN–DFA gives in accurate forecasts of the largely encouraging machining setting, providing a flexible structure for prospect EDM procedures.