This research investigates optimizing the properties of 2024 aluminum alloy using the Extreme Vertices Design (EVD) method and linear regression. It examines the oxidation behavior of the alloy during solubilization heat treatment, specifically focusing on the effect of magnesium addition leading to a dark oxide layer. The study employs a comprehensive experimental design and regression models to estimate the specific oxidation rate constant (k). Analysis of results reveals variations in oxidation behavior among alloys and the influence of aluminum, copper, and magnesium concentrations on the oxidation rate. The regression analysis yields a comprehensive equation: k = -0.01Al - 4.06Cu - 15.71Mg + 4.52Al·Cu + 17.01Al·Mg + 418.5Cu:Mg - 447.7Al·Cu·Mg, with statistically significant results (p < 0.05) for all terms. An increase in magnesium concentration was found to enhance the oxidation rate, implying a higher alloy susceptibility to oxidation. These findings underline the value of the EVD method and regression analysis in alloy property optimization, thus aiding in the design of aluminum alloys with improved oxidation resistance. 202 (EVD treatment layer k. . (k) copper equation 0.01Al 001Al Al 0 01Al 406Cu Cu 4 06Cu 1571Mg Mg 15 71Mg 452AlCu AlCu 52Al 1701AlMg AlMg 17 418.5CuMg 4185CuMg CuMg 418.5Cu 418 5Cu 4477AlCuMg AlCuMg 447 7Al 447.7Al·Cu·Mg p 0.05 005 05 terms optimization resistance 20 (k 1 5CuMg 4185Cu 41 44 0.0 00 2 0.

The surge in deep and ultra-deep water oil exploration in Brazil, particularly in the pre-salt layer, necessitates the advancement of materials and engineering components to meet sectoral challenges. To enhance the longevity and corrosion resistance of pipelines and structures, welded cladding of stainless alloys onto structural steels has been deployed. However, dissimilar welding often leads to the formation of Partially Diluted Zones (PDZ), marked by discontinuous, high-hardness regions at the interface. This study employs Electron Microscopy via Backscattered Electron Diffraction (EBSD) to characterize these zones, addressing limitations in conventional metallographic techniques. By cladding ASTM A36 steel test plates with AWS E 309L (309L stainless steel) through automated MIG welding, metallurgical-mechanical properties were assessed using Field Emission Scanning Electron Microscopy (FEG-SEM), EBSD, SEM-EDS, and Vickers Microhardness. The Heat-Affected Zone (HAZ) displayed low hardness, while the PDZ exhibited varied morphologies with significant concentrations of iron, chromium, and nickel, accompanied by elevated microhardness and a characteristic martensitic microstructure. In comparison between single and double-layer depositions, the latter substantially reduced hardness in the PDZ and HAZ. This study provides critical insights into the microstructural attributes of welded cladding, offering valuable guidance for optimizing materials in deepwater applications. ultradeep ultra Brazil presalt pre salt layer challenges structures deployed However PDZ, , (PDZ) discontinuous highhardness high interface EBSD (EBSD zones techniques A A3 L metallurgicalmechanical metallurgical mechanical FEGSEM, FEGSEM FEG SEM (FEG-SEM) SEMEDS, SEMEDS EDS, EDS SEM-EDS Microhardness HeatAffected Heat Affected HAZ (HAZ iron chromium nickel microstructure doublelayer double depositions applications (PDZ (FEG-SEM

A solution blow spinning (SBS) process was utilized to create nanofibers of TiO2/C and TiO2/C/N with potential applications in photocatalysis and dye adsorption. Polyvinylpyrrolidone was used as a carbon and nitrogen source. Their content in the TiO2 structure decreased as the temperature increased from 350 to 550 °C. Physical-chemical, morphological, and structural features were investigated. Adsorption and photodegradation experiments revealed that the material calcined at 400 °C had higher dye removal (98%) under dark settings, whereas the greater photodegradation efficiency under visible and UV light was 56% and 98%, respectively, for the sample calcined at 550 °C. The results suggest that the SBS has the potential to develop an efficient adsorbent and photocatalyst for use in treatments of contaminated water. (SBS TiO2C TiOC C TiO TiO2CN TiOCN N adsorption source 35 55 Physicalchemical, Physicalchemical Physical chemical, chemical Physical-chemical morphological investigated 40 98% 98 (98% settings 56 respectively water CN 3 5 4 9 (98 (9 (

Austenitic and lean duplex stainless steels, such as AISI 317L and SAF 2304, present high mechanical and corrosion resistance, which make them alternative materials for biodiesel plant equipment. Because there is not sufficient research about these stainless steel-specific applications, this work aims to evaluate AISI 317L and SAF 2304 stainless-steel pitting corrosion resistance in a chloride-containing acidified glycerin solution, collected directly from a biodiesel plant. The SAF 2304 presented a higher pitting potential than the AISI 317L, at room temperature and at service temperature, 337 K. However, the SAF 2304 passive layer was more reactive than the AISI 317L, showing a higher passive current density in the polarization and chronoamperimetric tests. Furthermore, the Mott–Schottky technique showed that the passive layer of the AISI 317L steel contained a lower concentration of defects than the passive layer of the SAF 2304, and the oxides of the passive layers are n-type semiconductors. steels L equipment steelspecific specific applications 230 stainlesssteel chloridecontaining chloride containing solution 33 K However tests Furthermore MottSchottky Mott Schottky ntype n type semiconductors 23 3 2

Research on eco-friendly methods led to the investigation of natural inhibitors and silane films modified with nanostructured mesoporous silica (SBA-15), a molecular sieve that can carry molecules with inhibitory properties. Combining natural extracts such as cocoa husk with SBA-15 aims to develop an enhanced silane-based pretreatment. This involves obtaining an alcoholic extract, and then mixing it with SBA-15 to modify the silane film. Different concentrations (1%, 2%, and 3%) of SBA-15 loaded with extract were prepared. Electrochemical tests, especially electrochemical impedance spectroscopy (EIS), in a 0.1 mol/L NaCl solution, revealed improved corrosion resistance with the tetraethylorthosilane (TEOS) film modified using 3% SBA-15 loaded with extract. Scanning electron microscopy showed the film and SBA-15 on the steel surface, while Fourier transform infrared spectroscopy identified functional groups characteristic of SBA-15, pure or loaded, and silane film. Therefore, it was possible to enhance the TEOS silane film by adding SBA-15 loaded with plant residue extract. ecofriendly eco friendly SBA15, SBA15 SBA 15 , (SBA-15) properties SBA-1 silanebased based pretreatment 1%, 1 (1% 2 2% 3 prepared tests EIS, EIS (EIS) 01 0 0. molL mol L solution (TEOS surface 15, Therefore SBA1 (SBA-15 SBA- 1% (1 (EIS (SBA-1 ( (SBA- (SBA

This study used an aqueous dispersion of silanized colloidal silica (SCS), whose particles’ surfaces were modified with an epoxysilane-based coupling agent, as the liquid medium and binder for MgO-Al2O3-containing suspensions. Fine calcined alumina and magnesia sinter particles were dispersed in SCS to form a 65 vol% solids suspension. Equivalent silica-free compositions containing calcium aluminate cement or unsilanized colloidal silica were tested as references. After mixing, the SCS-suspension showed low viscosity and suitable workability and, after curing, a thin protective coating of magnesium silicate hydrate (MSH) was formed, thus preventing MgO hydroxylation and improving bonding strength, generating green-dried structures of significant flexural strength (8 MPa). During initial heating, the decomposition of MSH and the softening of amorphous silica particles reduced the overall expansion of spinel (MgAl2O4) formation. After sintering at 1600ºC, the structure showed intense densification (total porosity of 8%) high flexural strength (73 MPa) and large spinel crystals surrounded by a thin layer of amorphous silica and magnesium silicates. SCS, , (SCS) epoxysilanebased epoxysilane based agent MgOAl2O3containing MgOAlOcontaining Al2O3 Al O suspensions 6 vol suspension silicafree free references mixing SCSsuspension curing (MSH formed greendried green dried 8 ( MPa. MPa . heating MgAl2O4 MgAlO MgAl (MgAl2O4 formation 1600ºC ºC total 8% 73 (7 silicates (SCS MgOAl AlO Al2O MgAl2O (MgAl2O 7

This study investigated the impact of adding graphene oxide (GO) and iron oxide (II) (Fe3O4) nanoparticles individually and in combination on the morphology, thermo-mechanical, and dielectric properties of a Polypropylene/High-Density Polyethylene (PP/HDPE) blend. By adding these nanoparticles separately or as a mixture, we can determine if both mechanisms have a synergistic effect and how they impact the dielectric constant values of their nanocomposites. The nanoparticle mixture was prepared in both an alkaline and a neutral medium. The mixture in the alkaline medium contained lower quantities of iron nanoparticles than in the neutral medium, and they were localized on the surface of GO. The nanocomposites showed significant differences in dynamic-mechanical and dielectric properties. The system with Fe3O4 exhibited a higher storage modulus, while the system with GO had a higher dielectric constant. However, no synergistic effect was observed in the nanoparticle mixtures. (GO II (II FeO Fe O (Fe3O4 morphology thermomechanical, thermomechanical thermo mechanical, mechanical thermo-mechanical Polypropylene/HighDensity PolypropyleneHighDensity Polypropylene/High Density Polypropylene High PP/HDPE PPHDPE PP HDPE (PP/HDPE blend dynamicmechanical dynamic Fe3O modulus However mixtures (Fe3O HighDensity PolypropyleneHigh

Blending finer powders of Ti, Zr, Ta, Sc, and Nb compounds as inoculants have been a promising strategy to modify precipitation-hardened aluminum alloys for laser-based powder bed fusion, promoting a crack-free equiaxed microstructure. However, there is still a lack of comprehensive understanding of the influence of these fine Al-Nb-B inoculant particles on the AA 2017 powder's physical characteristics and flowability during the process. The results indicate that blended powder has a similar PSD to AA 2017 powder. Furthermore, the circularity, smoothness, and morphology of the particles indicate that both inoculant and AA2017 powders do not exhibit high sphericity, but the blended powder showed slightly more agglomerated particles. Regarding rheological properties, it was observed that a higher flow energy was required to move the blended powder in unconfined conditions compared to the AA 2017 powder. Additionally, the blended powder exhibited higher compressibility and tendency to retain air in packed conditions during the deposition and spreading process. In conclusion, the physical characterization techniques combined with rheological tests have proven to be a rapid and reliable approach for assessing the impact of the finer inoculant particles' characteristics on the laser-based powder bed fusion. Ti Zr Ta Sc precipitationhardened precipitation hardened laserbased laser based fusion crackfree crack free microstructure However AlNbB Al B 201 s process Furthermore circularity smoothness AA201 sphericity properties Additionally conclusion 20 AA20 2 AA2

The use of fluorescent nanomaterials in various fields of study has become increasingly common. In this work, the use of carbon quantum dots as a corrosion marker in carbon steel is proposed. To produce the sensor, carbon quantum dots based on ethylenediamine and citric acid were used, dissolved in a polymeric matrix. The quantum dot used showed a quantum yield of 42.34%. The nanomodified coatings emitted blue light under ultraviolet radiation lamp. However, it was observed that there is a loss of photoluminescence in the coating on the carbon steel substrate compared to the coating on the polymeric substrate, which maintained photoluminescence activity after natural exposure. Thus, it is inferred that the loss of photoluminescence may be associated with the corrosion process. common work proposed sensor matrix 4234 42 34 42.34% lamp However exposure Thus process 423 4 3 42.34 42.3 42.

This work aims to determine the best substrate preparation and conversion coatings that may enhance the anti-corrosive performance of alumina film/stainless steel substrate systems in Ringer’s solution. Boehmite, silica, silica/boehmite, and boehmite/silica conversion coatings were deposited on sanded or sandblasted 304L stainless steel samples, and the best results were further covered with alumina film for a long-time exposure evaluation. The best anti-corrosive performances for each substrate preparation were observed for the sandblasted sample covered with silica/boehmite conversion coating (JSB500) and the sanded sample covered with silica (LS500), which showed the highest global resistance (Rg) values (828 Ω.cm2 and 1837 Ω.cm2, respectively) and the smallest values of global capacitance, Cg (2.19 X 10-6 F.cm-2 and 3.37 X 10-9 F.cm-2, respectively). After covering with the alumina film and evaluating for 216 h in the corrosive medium, it was noted an increase in the Rg values for both systems (JSBA500 and LSBA500), likely due to the presence of a corrosion products layer. The presence of iron oxides in these conversion coatings led to a more stable alumina film. Comparing the selected coating systems, the LSBA500 exhibited an improved performance, reaching an increase of 85% in Rg and a decrease of 94% in Cg. anticorrosive anti filmstainless Ringers Ringer s solution Boehmite silicaboehmite boehmite boehmitesilica L samples longtime long time evaluation JSB500 JSB (JSB500 LS500, LS500 LS , (LS500) (Rg 828 (82 Ωcm2 Ωcm Ω cm2 cm Ω.cm 183 respectively capacitance 2.19 219 2 19 (2.1 106 10 6 10- F.cm2 Fcm2 Fcm F.cm F F.cm- 337 3 37 3.3 109 9 F.cm2, 2, respectively. . 21 medium JSBA500 JSBA (JSBA50 LSBA500, LSBA LSBA500) layer LSBA50 85 94 JSB50 (JSB50 LS50 (LS500 82 (8 18 2.1 1 (2. 33 3. JSBA50 (JSBA5 LSBA5 8 JSB5 (JSB5 LS5 (LS50 ( 2. (2 JSBA5 (JSBA (JSB (LS5 (LS

A novel tungsten carbide (WC)-reinforced nickel (Ni)-based laser cladding layer was prepared through an in-situ synthesis process. The mechanism of the effect of scanning rates and laser power on the microstructures, wear and corrosion resistance of in-situ synthesized WC-reinforced Ni-based cladding layer were analyzed. The results revealed that the optimal in-situ synthesized WC laser cladding process entailed a scan rate of 3 mm/s and a laser power of 3000 W. The generation of WC phase has a significant strengthening effect on the cladding layer, which exhibits outstanding hardness (1261HV0.2). There is no clear linear relationship between scanning rate and abrasion resistance, and the coating abrasion resistance increased with increasing laser power. Furthermore, increasing the laser power improves the corrosion resistance of the cladding layer, while the scanning speed has a minimal effect on corrosion resistance. WCreinforced reinforced Nibased Ni based insitu in situ microstructures analyzed mms mm s 300 W 1261HV0.2. 1261HV02 HV 1261HV0.2 . 1261HV0 2 (1261HV0.2) Furthermore 30 1261HV0. 1261HV (1261HV0.2 (1261HV0. (1261HV0 (1261HV

For decades, lead-acid batteries have been supplying power to electrical systems through redox reactions involving Pb and PbO2. However, the energy supply capacity is inherently constrained by low energy density and challenges associated with charge/discharge cycles. Studies have indicated that additions of C to the composition of the active mass improve the electrochemical properties of batteries. This work aims to produce, characterize the microstructure and evaluate the electrochemical properties of Pb-Carbon composites, comparing different types of C (graphite, graphene and xerogel). The samples were produced through powder metallurgy, pressed at 550 MPa and sintered at 320°C-48 h. The microstructure was characterized by XRD, SEM/EDS, and Vickers microhardness. Electrochemical analyses were evaluated through OCP, polarization, and cyclic voltammetry (CV) measurements in a solution of 4.91 mol•L-1 of H2SO4. Microstructural characterizations revealed dispersions of C particles in the Pb matrix and an increase in the microhardness of the composites. Electrochemical analyses showed an increase in polarization resistance and a reduction in the corrosion rate compared to Pb. CV curves, demonstrated that C particles enhanced electrical conductivity for the formation of PbSO4 and PbO2, allowing greater absorption of electrical overpotentials when compared to Pb, thereby improving charge/discharge cycles in positive grids. decades leadacid lead acid PbO2 PbO However chargedischarge charge discharge produce PbCarbon Carbon composites graphite, graphite (graphite xerogel. xerogel . xerogel) metallurgy 55 320°C48 320C48 320°C 48 320 320°C-4 h XRD SEMEDS SEM EDS SEM/EDS OCP (CV 491 4 91 4.9 mol•L1 molL1 molL mol•L 1 mol L mol•L- H2SO4 HSO H SO curves PbSO grids 5 C48 320°C4 320C4 320C 32 320°C- 49 9 4. L1 H2SO C4 3

AISI 316L is a metallic biomaterial used in Unified Health System (SUS) due to low cost. However, corrosion in AISI 316L is a major cause of premature failure and toxic reactions to implants. Nanotubular or nanoporous anodized layers have proven to be good and affordable alternatives to create greater interaction and less damage to human tissue. Thus, the main of this study was to obtain a nanoporous layer by anodizing on AISI 316L, aiming to improve its corrosion resistance for use as a biomaterial. AISI 316L were anodized in 10M NaOH, 0.6mA/cm2 for 5 and 10min. Transients of current density and potential and oxide color were evaluated. Anodized layers were characterized by scanning electron microscopy, X-ray diffraction analysis and electrochemical assays. Nanoporous anodized layers with nanoplate arrangement were obtained. The 5min anodized sample showed better corrosion resistance than the original steel, being considered promising for use as a biomaterial. L SUS (SUS cost However implants tissue Thus M NaOH 06mAcm2 mAcm 0 6mA cm2 mA cm 0.6mA/cm 10min min evaluated microscopy Xray X ray assays obtained steel 06mAcm

In this study, we hypothesized that microtextured titanium (Ti) surfaces produced by laser metal fusion (LMF) 3D printing may play an important role in osteoblastic differentiation of mesenchymal stem cells (MSCs). For that, MSCs derived from mouse bone marrow were cultured on Ti discs produced in two different ways: microtextured produced by acid etched (Ti-Ac, control group) and microtextured produced by LMF 3D printing (Ti-3D-LMF, test group), in which it was evaluated: (1) cell proliferation, (2) alkaline phosphatase activity and (3) extracellular matrix mineralization. The results showed that both groups allowed cell proliferation over time (p<0.001). Additionally, there were no statistically significant differences between groups in the assessments of alkaline phosphatase activity (p=0.385) and extracellular matrix mineralization (p=0.234). Although both groups evaluated induce cell proliferation and osteoblastic differentiation similarly, the technology used in the Ti-3D-LMF group may prove advantageous as it produces specific dental implants for patients through customization. study (Ti (LMF D MSCs. . (MSCs) ways TiAc, TiAc Ac, Ac (Ti-Ac Ti3DLMF, Ti3DLMF TiDLMF LMF, (Ti-3D-LMF group, , 1 (1 2 (2 3 (3 p<0.001. p0001 p p<0.001 0 001 (p<0.001) Additionally p=0.385 p0385 385 (p=0.385 p=0.234. p0234 p=0.234 234 (p=0.234) similarly customization (MSCs DLMF ( p000 p<0.00 00 (p<0.001 p=0.38 p038 38 (p=0.38 p023 p=0.23 23 (p=0.234 p00 p<0.0 (p<0.00 p=0.3 p03 (p=0.3 p02 p=0.2 (p=0.23 p0 p<0. (p<0.0 p=0. (p=0. (p=0.2 p<0 (p<0. p=0 (p=0 p< (p<0 p= (p= (p< (p

Nitrocarburized coating by plasma electrolytic saturation, PEN/C coatings, have been proposed to increase the corrosion and wear resistance of steel by using a process of low-temperature hydrostatic plasma. The objective of this work is to analyse the wear and corrosion resistance of PEN/C coatings on SAE 1045 steel, using the electrochemical slurry erosion wear test (ESEWT). This test allows the evaluation of the simultaneous effect of erosion wear and electrochemical behaviour on this coating. Thus, it was possible to evaluate the erosive and corrosive effect and the synergy of these phenomena on the PEN/C coated SAE 1045 mass loss rates. ESEWT tests were performed at different times and under different electrochemical conditions: under cathodic protection and open circuit potential (OCP). The PEN/C coating increased the corrosion resistance of SAE 1045. Synergy between the erosive wear and corrosion was the main factor in the mass loss rates of both analysed systems. The synergistic mechanism of the substrate occurred by removing the corrosion product and by activating the surface generated by the erosive process of the particles. The synergistic mechanism of the PEN/C coating occurred with the removal of inherent surface irregularities through the erosive process, combined with localized corrosion. saturation PENC PEN C lowtemperature low temperature 104 ESEWT. . (ESEWT) Thus conditions OCP. OCP (OCP) systems particles 10 (ESEWT (OCP 1