Corrosion Resistance Of Materials Research Articles

Dense Al2O3 sealing inhibited high hydrostatic pressure corrosion of Cr/GLC coating

The corrosion failure of amorphous carbon (a-C) coatings is commonly ascribed to the existence of growth microdefects, which serve as pathways for corrosive fluids to permeate the substrate. Atomic layer deposition (ALD) is renowned for its ability to augment the corrosion resistance of metallic materials. Graphite-like carbon (GLC) is one of the amorphous carbon materials dominated by hybridized sp2-C bonds. In this study, an ALD-deposited Al2O3 layer is specially introduced on the Cr/GLC multilayer coating to solve the aforementioned corrosion risk of a-C by taking the sealing conception for defects. Compared to the as-deposited Cr/GLC coating, the coating encapsulated with Al2O3 layer depicts the reduction of corrosion current density over two orders of magnitude under a wide pressure range of 0.1 ~ 15 MPa. Particularly, the presence of released Crn+ and Fen+ in the corrosion solution is significantly diminished, accompanying with a small quantity of Aln+ generated in sealed coating during corrosion. Microstructural analysis and electrochemical results identified that both the dense Al2O3 layer offered strong safeguard for Cr elements released from multilayers, whilst amorphous carbon network inhibited the likelihood chloride penetration induced by partially infiltrated Al2O3, which made the synergistic contributions to the enhancement of corrosion resistance for Cr/GLC coating for deep-sea applications.

The Effects of Cl− and selected deoxidizers on the high temperature corrosion electrochemistry of alloy 690 in nuclear steam generator water

ABSTRACT The heat transfer tube in a steam generator serves as a critical heat exchange component in the primary and secondary loops of pressurized water reactor (PWR) nuclear power plants. The corrosion resistance of the heat transfer tube material directly influences the longevity of PWR nuclear power plants. This study investigated the electrochemical corrosion properties of 690 alloy (UNS N06690) in a simulated secondary water environment of PWR, focusing on different chloride ion concentrations and combinations of deoxidizers. The findings reveal a gradual decrease in the corrosion potential of 690 alloy, accompanied by an increase in self-corrosion current and a progressive reduction in the passivation range, ultimately leading to its disappearance as chloride ion concentration rises from 0 μg·L−1 to 500 μg·L−1. Moreover, the impedance value of the inner film exhibits a declining trend with increase of chloride ion concentration. Conversely, the resistance value of the outer film remains relatively stable while the size and spacing of oxide particles on the surface of the 690 alloy continuously increase. This observation suggests that chloride ions primarily influence the formation of the inner passivation film, which in turn determines the corrosion resistance of the 690 alloy. Notably, the performance of the 690 alloy is similar when the deoxidizer combination is ammonia(NH3)+erythorbic acid(ERA) or NH3+hydrazine(N2H4), demonstrating the ability to form a relatively complete passivation film and exhibit improved corrosion resistance compared to NH3+N-isopropyl hydroxylamine, additionally, when the deoxidizer combination is NH3+N2H4, the 690 alloy exhibits lower self-corrosion current density across different chloride ion concentrations, indicating enhanced corrosion resistance.

Material Research for Hypersonic Travel

The goal of travelling faster than five times the speed ofsound, or hypersonic travel, has enormous potential to transform global transportation, defence capabilities, and space access. However, materials and structures face severe obstacles because to harsh aerothermal conditions inherent in high Mach number trajectories. This work focuses on new approaches to do research for ceramics, composites, and refractory alloys that are essential for building hypersonic vehicles. Essential design concepts for primary structures, heat shielding, and propulsion systems are covered, highlighting the critical role that theory and computation play in comprehending the links between structure, property, and processing. The remarkable high-temperature capabilities, stiffness, strength, and corrosion resistance of ceramic materials are highlighted in the study as reasons for theirincreasing importance in aircraft applications. Based on their distinct features, titanium alloys, nickel aluminides, metal- matrix composites, carbon-carbon, and ceramic-matrix composites stand out as top choices for a high temperature. In pursuit of lightweight, high- performance materials for hypersonic travel, this paper summarises ongoing researchefforts, evaluates the state of the art, offers insights into technological hurdles, and identifies areas that require future improvement. To explore the complex field of hypersonicmaterials design and selection in this research, this paper hope to shed light on the critical role that materials science plays in pushing the boundaries of aerospace technology by investigating the special difficulties presented by hypersonic flight as well as the characteristics and potential of various material classes.

Microstructure evolution and corrosion behavior of TIG welded joint of a new Mg[sbnd]Gd[sbnd]Nd[sbnd]Zn[sbnd]Zr alloy during post-weld heat treatment

The corrosion behavior of the tungsten inert gas (TIG) welded Mg3Nd3Gd0.2Zn0.5Zr alloy with different post-weld heat treatments was systematically investigated. The results show that the corrosion resistance of the sand-cast base material (BM) was inferior to that of the fusion zone (FZ), which was attributed to the larger grain size and exacerbated galvanic corrosion caused by coarser Mg3(Nd, Gd) eutectic phases and numerous β precipitates. It is found that post-weld solid-solution (T4) treatment could significantly enhance the corrosion resistance of the joint due to the dissolution of the cathodic second phases and the denser protective film abundant in RE oxides generated in corrosive solution. The precipitation of nanosized phases and ZnZr clusters would slightly increase the susceptibility to localized corrosion of the peak-aged (T6) joint. As the main corrosion products, MgO and Mg(OH)2 are distributed throughout the whole corrosion film, while RE oxides and RE hydroxides are mainly distributed in the inner layer, which can be explained by inward oxidation and replacement reactions between RE elements and MgO/Mg(OH)2. Based on the composition and structure of the corrosion product film, a physical model has been proposed for depicting the microstructure evolution associated with the corresponding corrosion behavior of the joints. This work could promote the applications of welded MgRE alloy joint in some corrosion environments.

Study on seawater corrosion resistance of calcium sulfoaluminate cement-based novel grouting materials

Grouting materials play a critical role in anchoring structures of cross-sea tunnels by safeguarding the anchors against seawater corrosion and enhancing durability. In this paper, a novel grouting material comprising ferrite-rich sulfoaluminate cement (FCSA), ordinary Portland cement (OPC), anhydrite and limestone were prepared. Accelerated corrosion immersion tests were conducted to assess the corrosion resistance of the grouting material using artificial seawater solutions with varying salt concentrations. Pull-out tests were performed to verify the material's performance, while potentiometric titration and X-ray diffraction (XRD) analysis were employed to analyze free chloride ion concentration (Cf) and corrosion products at the anchorage interface. Results indicate that after 1.5 years of corrosion in seawater with different salt concentrations, the bond strength stabilized at 1.05 MPa. No rust was observed on the anchor surfaces and the Cf exhibited a linear increase with salt concentration. The content of Friedel's salt increases with salt concentration, demonstrating adequate chloride ion binding capacity. The test results validate the exceptional seawater corrosion resistance and long-term stability of the novel grouting material.

A dual-crosslinking strategy for waterborne polyurethane coatings to achieve outstanding anti-smudge and anti-corrosion properties

The inferior anti-smudge properties and compromised anti-corrosion performance of waterborne polyurethanes (WPUs) stem from the presence of abundant hydrophilic groups in their polymer networks. Despite various hydrophobic segments have been introduced in WPU skeleton to lower the impacts of hydrophilic groups, the limited migration capability of hydrophobic segments in waterborne matrix often result in unsatisfactory performance. Herein, we fabricate a multifunctional PDMS-modulated WPU coating employing sorbitan monooleate (SP), a renewable bio-derived polyol, as an internal crosslink agent, and hexamethoxymethylmelamine (HMMM) as a post-crosslink agent to fully eliminate the polar hydrophilic groups in the molecular linkages and further enhance the crosslink density of the coating. It is found that the coating exhibits exceptional anti-graffiti and self-cleaning effects when subjected to tests involving oil-based and water-based pens and inks, as well as common household liquids like milk, coffee, cooking oil, ethanol, n-hexadecane, etc. Such anti-smudge coating could readily remove carbon powder-like dust with water, ensuring a clean surface, and also possess a certain level of resistance to fingerprint smudges. Apart from excellent mechanical robustness and impressed durability after 500 cycles of writing erase tests, the coating also remains intact and has anti-smudge properties when folded or bent. For chemical resistance, the coating can resist at least 18 h of acid, alkali, and salt intrusion without being damaged. Moreover, the sufficient crosslink density imparts the coating with good thermal stability and outstanding anti-corrosion performance in extremely corrosive environments. This research presents a facile and effective approach for developing stain and corrosion-resistant PDMS-modulated waterborne polyurethane materials with high protective reliability and long lifespan through the dual-crosslinking strategy.

Medium-Entropy Monosilicates Deliver High Corrosion Resistance to Calcium-Magnesium Aluminosilicate Molten Salt.

For decreasing the global cost of corrosion, it is essential to understand the intricate mechanisms of corrosion and enhance the corrosion resistance of materials. However, the ambiguity surrounding the dominant mechanism of calcium-magnesium aluminosilicate (CMAS) molten salt corrosion in extreme environments hinders the mix-and-matching of the key rare earth elements for increasing the resistance of monosilicates against corrosion of CMAS. Herein, an approach based on correlated electron microscopy techniques combined with density functional theory calculations is presented to elucidate the complex interplay of competing mechanisms that control the corrosion of CMAS of monosilicates. These findings reveal a competition between thermodynamics and kinetics that relies on the temperatures and corrosion processes. Innovative medium-entropy monosilicates with exceptional corrosion resistance even at 1500°C are developed. This is achieved by precisely modulating the radii of rare earth ions in monosilicates to strike a delicate balance between the competition in thermodynamics and kinetics. After 50 and 100h of corrosion, the thinnest reactive layers are measured to be only 28.8 and 35.4µm, respectively.

Tribocorrosion behavior of GCr15 steel in water–glycol fire-resistant hydraulic fluids (HFC) containing seawater

With the development of deep-sea exploration technology, the technology of fire-retardant hydraulic fluid (HFC) has played an important role in the power transmission of exploration equipment. However, the mechanism of the influence of seawater content on the tribocorrosion behavior of HFC remains unclear. In this study, the effects of different seawater contents on the tribological and corrosive properties of HFC were systematically investigated. The results showed that when the seawater concentration exceeds 30 wt%, a soft Mg-containing reaction film is formed in the friction contact area owing to seawater corrosion, thus effectively improving the sintering load and wear resistance to some extent. By contrast, with increasing seawater concentration, the lubricity declines, the wear intensifies, and the extreme pressure characteristics decrease significantly. The comparative analysis shows that the composition of the wear and corrosion reaction films significantly differs under high-concentration seawater conditions, which is also a key factor affecting the friction and corrosion behavior of HFC. This study provides a direction for the research and development of wear- and corrosion-resistant materials and coatings on the surface of deep-sea exploration equipment.

Mechanical and Corrosion Tests for Magnesium-Zinc/Ti-6Al-4V Composites by Gravity Casting.

A new Mg-4Zn X Ti-6Al-4V (TC4, of 0, 1, and 3 wt.%) alloy was successfully fabricated by a simple and low-cost gravity casting method and heat treatment at 150 °C for 24 h. The composite was examined by XRD, uniaxial tests, FESEM/EDS, potentiostat/EIS, and immersion tests for the material's microstructures, mechanical properties, electrochemical characteristics, and corrosion resistance. Experimental results indicate that heat treatment enables the precipitation of Zn along the Mg grain boundaries and drives the co-precipitation of Al around the TC4 particles and nearby grain boundaries. Uniaxial tensile tests reveal that TC4 reinforces the Mg-Zn matrix material with higher elastic modulus, ultimate tensile stress, and toughness. The heat treatment further enhanced these mechanical properties. Electrochemical tests show that 1 wt.% TC4 composite exhibits the highest open circuit potential among all tested samples, which implies the 1 wt.% TC4-added Mg-Zn is better resistant to the oxidation of the essential metals Mg, Zn, and Al. The immersion tests in the HBSS solution further show that the 1 wt.% TC4 composite has the lowest rise of pH values after 14 days, and EDS for the corroded surface signifies that Mg is the main element vulnerable to oxidation by corrosion.

Mapping elemental solutes at sub-picogram levels during aqueous corrosion of Al alloys using diffusive gradients in thin films (DGT) with LA-ICP-MS.

A novel approach using diffusive gradients in thinfilms (DGT) with laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) for two-dimensional mapping of elemental solute release at sub-picogram levels during aqueous corrosion of Al alloys is presented. Evaluation of different DGT gels with mixed micro-sized binding phases (polyacrylamide-Chelex-Metsorb, polyurethane (PU)-Chelex-Metsorb, PU-Chelex-Zr(OH)4) demonstrated the superior performance of PU gels due to their tear-proof handling, low shrinkage, and compliance with green chemistry. DGT devices containing PU-Chelex-Zr(OH)4 gels, which have not been characterized for Al sampling before, showed quantitative uptake of Al, Zn, and Cu solutes over time (t = 4-48h) with higher Al capacity (ΓDGT = 6.25µgcm-2) than different gels. Application of PU-Chelex-Zr(OH)4 gels on a high-strength Al-Cu alloy (Al2219) exposed to NaCl (w = 1.5%, pH = 4.5, T = 21°C) for 15min in a novel piston-type configuration revealed reproducible patterns of Al and Zn co-solubilization with a spatial expansion ranging between 50 and 1000µm. This observation, together with complementary solid-state data from secondary electron microscopy with energy-dispersive X-ray spectroscopy, showed the presence of localized pitting corrosion at the material surface. Detection limits for total solute masses of Al, Zn, and Cu were ≤0.72pg, ≤8.38pg, and ≤0.12pg, respectively, for an area of 0.01 mm2, demonstrating the method's unique capability to localize and quantify corrosion processes at ultra-trace levels and high resolution. Our study advances the assessment of Al alloy degradation in aqueous environments, supporting the design of corrosion-resistant materials for fostering technological safety and sustainability.

Microstructure and mechanical properties of electron beam welded joints of GH3128 and CoCrFeNi high-entropy alloy

This study addresses the research gap in the field of fusion welding for high-entropy alloys and high-temperature alloys. The microstructure and mechanical properties of CoCrFeNi/GH3128 electron beam welded joints were investigated. Influenced by solidification rate and elemental composition, differences in grain crystallization modes and morphologies were observed on both sides of the weld, accompanied by a columnar-to-equiaxed transition in the weld center. Significant fluctuations in elemental concentrations across the weld indicated elemental segregation, with distinct segregation behaviors observed for Fe, Co, Cr, Ti, Al, W, and Mo elements between columnar and dendritic grains. XRD results revealed the presence of γ, γ', FeCrNi solid solution, and various intermetallic compounds such as Ni17W3, Cr4Ni15W, and Fe3Ni2 in the weld zone. Hardness testing showed a gradual increase in microhardness from CoCrFeNi to GH3128 within the weld. Tensile testing indicated a tensile strength of 532.5 MPa and an elongation of 40.4 %, suggesting a ductile fracture mechanism for the joint. Post-tensile testing, noticeable work hardening, tensile deformation in the weld zone, grain refinement, and increased hardness were observed, highlighting the joint's enhanced strain-hardening ability. However, the corrosion resistance of the CoCrFeNi base material decreased.

The metal anti-corrosion performance of light cured epoxy resin modified by zeolitic imidazolate frameworks (ZIF-8) with a core of polyaniline

In this paper, polyaniline (PANI) material was prepared by in-situ polymerization and mixed with zeolitic imidazolate frameworks (ZIF-8) to prepare PANI/ZIF-8 by surface modification. The light cured epoxy resin (RJ313) was modified by PANI/ZIF-8, and the PANI/ZIF-8/RJ313 anticorrosive coating was prepared. The chemical cross-linking of ZIF-8 with the epoxy resin can improve the cross-linking density and barrier property of the epoxy coating, thus improving the corrosion resistance of the coating. The encapsulation of PANI in ZIF-8 not only maintains the corrosion resistance of PANI, but also strengthens the dispersion of PANI under the action of ZIF-8 and improves the mechanical strength of the coating. A series of tests, such as the polarization test and electrochemical impedance test, proved that PANI/ZIF-8/RJ313 coating strongly affects 304SS acid corrosion resistance compared with RJ313, ZIF-8/RJ313 and PANI/RJ313. In 0.5 mol L−1 sulfuric acid solution, the corrosion current Icorr of this coating attached to 304SS was as low as 0.0308 μA·cm−2, and the impedance value can reach 37971.00 Ω·cm2. This provides a new idea for improving the dispersibility and corrosion resistance of other anti-corrosion materials.

Impact Strain Signal Characteristics of Al and Mg under Instrumented Charpy Test

Impact strain signal is used to examine strain signal patterns under various parameters. Impact is a complicated phenomenon that occurs within a millisecond timeframe. Material toughness is measured by the energy absorption recorded by the Charpy machine and closely related to the specimen fracture deformation. By utilizing the strain gauge and data acquisition, the impact strain signal provides additional data regarding impact duration, maximum strain value and the area under curve for a deeper understanding of the impact problem. A material with high toughness has great energy absorption and the capability to withstand high impact load. Although magnesium is lighter in weight compared to aluminium, aluminium is a better corrosion-resistant material and is stronger, which makes it more suitable to be fabricated as automotive structural components. Tensile test is typically used for investigating a material’s mechanical properties. In the automotive industry, materials are required to have good crashworthiness. This study investigates the relationship between the energy absorbed with the power spectral density and the area under strain–time graph for different materials, impact speeds, and material thicknesses. Furthermore, the relationship between the stress–strain curve and impact strain signal were examined. In this study, the behaviour of two materials, namely Aluminium 6061-T6 and Magnesium AM60, was investigated using instrumented Charpy test, by referring to the impact strain signal pattern result. For the experiment, strain gauge attached to the Charpy machine striker was employed and linked to the data acquisition system. Charpy impact specimen has three different thicknesses; 10 mm, 7.5 mm and 5 mm. Impact speed is at 3.35 m/s and 5.18 m/s. Results show a correlation between energy absorbed with strain energy. Strain energy obtained is directly proportional to the energy absorbed. Aluminium 6061-T6 has the highest energy absorption, maximum strain, and strain energy under power spectral density graph compared to Magnesium AM60. Relation of strain signal from Charpy test and stress–strain curve from tensile test shows a significant finding where the material deforms and fracture points are identified through the signal pattern and curve. Thus, the strain signal pattern can be used to predict material behaviour.

Al2O3 Fiber-Reinforced MAX Phase Ceramic Matrix Composite

In the aerospace industry, lightweight can reduce the weight of the engine and improve the thrust-weight ratio of the engine. Ceramic matrix composites have attracted widespread attention in the industry due to their much lower density compared to high-temperature alloys and excellent high-temperature performance. SiC fiber-reinforced SiC ceramic matrix composites are the most outstanding representatives, but their long manufacturing cycle and high manufacturing costs limit their widespread use. Ti2AlC is a new type of ceramic material with the characteristics of low density, high melting point, high-temperature resistance, oxidation resistance, and corrosion resistance of ceramic materials, as well as the conductivity and machinability of metals. However, its mechanical properties are slightly inadequate. The use of chopped fibers for toughening can compensate for these deficiencies to a certain extent and improve mechanical properties. This article first explored the influence of various process parameters on the mechanical properties of pure-phase Ti2AlC ceramic materials in SPS preparation technology and then prepared Ti2AlC composites reinforced with 10vol.%, 20vol.%, and 30vol.% Al2O3 chopped fibers. The results showed that the samples prepared at 1300°C, 40 MPa, and 10 min had a flexural strength of 697 MPa and a fracture toughness of 9.83 MPa·m1/2 when the volume ratio of the reinforcement phase was only 10vol.%, which was the same as that of the continuously fiber-reinforced SiCf/SiC composites. This study showed that the MAX phase matrix composites reinforced with chopped fibers have the potential to become high-temperature structural materials by adjusting the composite composition and optimizing the preparation process.

Effect of Al content on the corrosion behavior and mechanism of AlxCoCrFeNi high-entropy alloys

Al addition is known to improve the tensile strength and high-temperature oxidation behavior of the AlxCoCrFeNi high-entropy alloy (HEA). However, the corrosion behavior and mechanisms associated with these HEAs remain unclear. The corrosion resistance of structural materials is as important as their mechanical properties. In this study, AlxCoCrFeNi HEAs with different molar ratios of Al (x = 0.0, 0.5, 1.0, and 1.5) and various crystal structures (FCC, FCC+BCC, and BCC phases) were prepared, and their corrosion behavior and mechanisms were studied, which revealed a competitive relationship between the Al and Cr passivation films. The thickness of the Al passivation film increased with increasing Al content, which was found to be the main reason for the decrease in the corrosion resistance of the AlxCoCrFeNi HEAs. The corrosion type of the AlxCoCrFeNi HEA changed from pitting corrosion to selective corrosion with increasing Al content, and the corroded elements changed from (Co, Cr, Fe, and Ni) to (Al and Ni) and then (Al, Ni, and Co). Accordingly, the corrosion mechanisms associated with the AlxCoCrFeNi HEAs were elucidated.

Perspective on “An Electrochemical Approach to Predicting Long-Term Localized Corrosion of Corrosion-Resistant High-Level Waste Container Materials,” D.S. Dunn, G.A. Cragnolino, and N. Sridhar, Corrosion 56, 1 (2000): p. 90-104

Perspective on “An Electrochemical Approach to Predicting Long-Term Localized Corrosion of Corrosion-Resistant High-Level Waste Container Materials,” D.S. Dunn, G.A. Cragnolino, and N. Sridhar, <i>Corrosion</i> 56, 1 (2000): p. 90-104

Computational study of fluorinated defective h-BN sheet controlling corrosion in the marine environment

Chloride ions are responsible for triggering severe corrosion in the marine environment. Hence, there is a need to deploy corrosion resistant materials such as hexagonal boron nitride (h-BN) sheet to protect mechanical components operating under such harsh conditions. In this work, a first-principles approach was employed to investigate the effect of fluorine modification on the thermodynamic and kinetic behaviors of oxygen on different kinds of vacancy-defective hexagonal boron nitride (h-BN) in a Cl-containing marine environment. Geometrical and electronic structures were systematically analyzed along with adsorption and diffusion behaviors. The existence of a low energy barrier implies that there is a relatively attenuated ability to inhibit O diffusion for double vacancy VBN-h-BN sheet compared to single vacancy VB-h-BN and VN-h-BN sheets. Interestingly, the fluorine functionalization for three defective h-BN sheet is found to cause an increased energy barrier of O diffusion. The F@Cl@VN-h-BN sheet possesses the highest diffusion energy barrier, indicating a superior anti-oxidation property in the marine environment. This study provides some fundamental guidelines for realizing high-performance h-BN sheets for protecting equipment and components used in marine applications.

Effects of strain induced martensite on high temperature electrochemical performance of 321 stainless steel in the simulated PWR first circuit environment

The electrochemical properties of 321 stainless steel with different cold strains in simulated PWR first circuit environment were studied mainly by electrochemical impedance spectroscopy (EIS). The results show that with the increase of strain (0, 20%), the charge transfer resistance increases and the film resistance decreases. By combining the electrochemical experiments and microscopic characterization results of different specimens, including solution annealed, cold worked and hot worked, it is found that the charge transfer resistance increases with the increase of deformation degree, the increase of strain induced martensite content enriches Cr in the oxide layer, but with the decreased material corrosion resistance.

Influence of Al addition on microstructure and electrochemical behaviour of CrMnFeCoNi high-entropy alloy

To develop new corrosion-resistant materials for structural applications, CrMnFeCoNiAlx high-entropy alloys (HEAs) are produced via semi-industrial induction casting. The study aimed to investigate the influence of Al content (x=0-0.3) on both microstructure evolution and corrosion properties of the alloys. X-ray diffraction and scanning electron microscopy (SEM) analysis revealed that all the alloys exhibited a single-phase face-centered cubic structure, with dendritic (Fe, Co, Cr-rich) and interdendritic (Mn, Ni, Al-rich) regions distinguished by elemental segregations. Furthermore, the incorporation of Al atoms into the solid solution led to an increase in the lattice parameter, indicating alloy strengthening. The corrosion resistance of the CrMnFeCoNiAlx alloy improved with higher Al addition. Electrochemical polarisation tests demonstrated a slight increase in the corrosion potential (Ecorr) and a significant decrease in the corrosion current density (Icorr) upon Al addition. Additionally, slower kinetics for pit nucleation (higher E’corr) were observed, particularly notable for x=0.3. Analysis of the corroded surfaces revealed a mixed degradation mechanism, involving pitting corrosion and selective dissolution of the interdendritic zone, which decreased as the Al content of the HEA increased. These findings underscore the effectiveness of Al addition in not only enhancing the mechanical properties of the Cantor alloy through solid solution strengthening but also improving its corrosion resistance.

Evaluation of antibacterial activity and biocompatibility of nano-titanium dioxide coatings prepared by atomic layer deposition for dental titanium abutments

To reduce the adhered bacteria on the dental titanium (Ti) abutments and the risk of peri‑implantitis, an antibacterial nanometer titanium dioxide (nano-TiO2) coating was developed by atomic layer deposition (ALD). The effects of the nano-TiO2 coatings on surface characteristics, antibacterial efficacy, biocompatibility, and corrosion resistance of Ti abutment materials were investigated. Specifically, the colors of Ti samples were changed from silver-gray to blue, yellow, and purple corresponding to the coating thicknesses were 50 nm, 100 nm, and 150 nm, respectively. Moreover, these coatings with different thicknesses all presented uniform morphologies with anatase TiO2 phases and hydrophobic characteristics. Simultaneously, the prepared coatings exhibited strong antibacterial effects against Staphylococcus aureus (S. aureus), Streptococcus mutans (S. mutans), and Porphyromonas gingivalis (P. gingivalis), which were independent of coating thicknesses. Additionally, Ti substrates coated with 100 nm nano-TiO2 demonstrated exceptional cell compatibility and corrosion resistance. In conclusion, these antibacterial and biocompatible nano-TiO2 coatings prepared by ALD possess great potential in dental aesthetic restorative materials.