Glass Corrosion Research Articles

FeCrMoWCBY metallic glass with high corrosion resistance in molten lead–bismuth eutectic alloy

The FeCrMoWCBY metallic glass exhibited excellent corrosion resistance in oxygen-saturated lead-bismuth eutectic (LBE) at 500 °C. The corrosion resistance could be enhanced by adding an appropriate amount of W element, while excessive W deteriorated the corrosion resistance of the metallic glass. The surface of the Fe-based metallic glass was composed of an inner amorphous transition layer and outer FeCr2O4 oxide nanocrystal layer. The continuous amorphous transition layer acted as a diffusion barrier layer to prevent further corrosion of the metallic glass.

Corrosion of ternary borosilicate glass in acidic solution studied in operando by fluid-cell Raman spectroscopy

Fluid-cell Raman spectroscopy is a space and time-resolving application allowing in operando studies of dynamic processes during solution–solid interactions. A currently heavily debated example is the corrosion mechanism of borosilicate glasses, which are the favoured material for the immobilization of high-level nuclear waste. With an upgraded fluid-cell lid design made entirely from the glass sample itself, we present the polymerization of the surface alteration layer over time in an initially acidic environment, including the differentiation between pore and surface-adsorbed water within it. Our results support an interface-coupled dissolution-precipitation model, which opposes traditional ion-exchange models for the corrosion mechanism. A sound description of the corrosion mechanism is essential for reliable numerical models to predict the corrosion rate of nuclear waste glasses during long-term storage in a geological repository.

Ion-exchange mechanisms and interfacial reaction kinetics during aqueous corrosion of sodium silicate glasses

The ion-exchange and associated interfacial reaction mechanisms of silicate glasses are critical in elucidating their aqueous corrosion behaviors, surface modification and property changes, hence have potential impact on both science and technology. This work reports findings of the atomic and nanoscale details of the glass–water interfacial reactions revealed by applying reactive force field (ReaxFF) based molecular dynamics (MD) simulations, from which the key mechanisms of the ion exchange, as well as the kinetics of associated interfacial reactions, are elucidated. It was found that the Na+ and H+ ion exchange can happen between two oxygen ions on a single silicon oxygen tetrahedron or adjacent tetrahedra. In addition, the clustered reaction of two non-bridging oxygens mediated by an adjacent water molecule was also identified. The latter reaction might be the main mechanism of water transport after initial surface reactions that consume the non-bridging oxygen species on the surface. Water molecules thus can play two roles: as an intermediate during the proton transfer processes and as a terminator of the clustered reactions. Statistical analyses were performed to obtain reaction kinetics and the results show that silanol formation is a more favored process than the silanol re-formation within the first 3 ns of interfacial reactions. The results obtained thus shed lights on the complex ion-exchange mechanisms during glass hydration and enable more detailed understanding of the corrosion and glass–water interactions of silicate glasses.

Predicting zeolites’ stability during the corrosion of nuclear waste immobilization glasses: Comparison with glass corrosion experiments

During the long-term corrosion of nuclear waste glasses under nuclear waste disposal conditions, the precipitation of zeolitic phases has been linked to a delayed acceleration in glass corrosion (known as “Stage III”). Hence, predicting the thermodynamic propensity for zeolites to form upon the dissolution of nuclear waste glasses is key to ensure their long-term performance. Here, we compile a unified, internally-consistent thermodynamic database “clay20” to estimate the stability of clay and feldspar phases relevant to nuclear waste immobilization glasses, including beidellite(Mg, Ca, Na, K), kaolinite, montmorillonite(Mg, Ca, Na, K), nontronite(Mg, Ca, Na, K), saponite(Ca, Na, K), and albite. Based on this, we report a geochemical modeling method allowing us to predict the stability of secondary phases (including zeolites, calcium–silicate–hydrate gels, and clays) upon the dissolution of nuclear waste immobilization glasses. We show that this approach offers a realistic description of the stability of the secondary phases forming during the dissolution of two archetypical model nuclear glasses (namely, the International Simple Glass, ISG, and WVUTh-203) under conditions relevant to nuclear waste disposal (T = 90 °C, p = 1 bar) as a function of pH. We find that the formation of silica and clay secondary phases is thermodynamically favored at low pH (pH < 10), whereas, in contrast, zeolite (analcime) and calcium–silicate–hydrate phases are favored at high pH (pH > 10.5). This suggests that thermodynamics (i.e., not solely kinetics) might play a key role in determining the range of solution pH wherein stage III corrosion may occur, i.e., when zeolite formation is favored.

A state of art review on the graphene and carbon nanotube reinforced nanocomposites: A molecular dynamics approach

In the present time, need of high-performance composites have been increased greatly due to their high-performance mechanical, electrical and electronic properties, low weight, reduced cost. Presently, composites are used in various industries such as aerospace, automobiles, space, defence, sports and medicals. Various properties of the composites such as strength, stiffness, fatigue, thermal conductivity, glass transition temperature, thermal stiffness, corrosion and wear resistance may be improved by reinforcing the materials which have superior properties than the composite base material. In this context, graphene (Gr) and carbon nanotube (CNT) are the two different forms of carbon which have exceptional mechanical and electrical electronics properties. Both Gr and CNT are known to have superior electrical conductivity, tensile strength and excellent molecular arrangement. In last couple of decades numerous researchers from different research areas have tried to exploit the exceptional properties of Gr and CNT by reinforcing them into different base materials such as polymer, metals glass etc. to improve their mechanical, thermal and electrical properties. In the present work, the authors have attempted to present a state of art literature review on the reinforcement of Gr and CNT into different materials such as polymer, ceramics & metals using the molecular dynamics and investigated the different properties such as strength, stiffness, fatigue, thermal conductivity, glass transition temperature, thermal stiffness, corrosion and wear resistance.

Effect of pH and NaF addition on corrosion of Zr-based bulk metallic glass in Na2SO4-containing solution

In order to expand the application of Zr-based bulk metallic glasses (BMGs) in the field of biomaterials, it is vital to investigate their corrosion behaviour in different solution environments. However, until now, the corrosion behaviour of Zr-based BMGs in F−-containing solution has been rarely studied, and the corrosion mechanism is not fully understood. In this study, the effect of pH and NaF addition on the corrosion behaviour of Zr52Al10Ni6Cu32 BMG in Na2SO4-containing solution has been investigated by employing the standard electrochemical methods. The relationship between the critical pF value and pH has been subsequently obtained, which provides a criterion for judging the state of corrosion of Zr-based BMGs in F−-containing solution. The cathodic reaction mainly involves the reduction of the dissolved oxygen in the solution, and the kinetic mechanism is similar to that of pure Zr. An oxidation peak appearing during the upward polarization scanning is attributed to the active dissolution of Cu caused by SO42− and F−. During upward polarization, different pH values and addition of NaF are observed to result in consequent film breakdown behaviour. For 0.1 M NaF and pH = 8.0, the protective ZrO2 passive film is noted to be replaced by the corrosion product of the Zr–F compound. However, at pH = 4.0 with 0.001 M NaF, the F− concentration is not sufficient to form the Zr–F corrosion products, and the dissolution rate of the passive film is enhanced due to the reduced pH. This study provides a deeper understanding of the corrosion mechanism of Zr-based BMGs alloys in F−-containing solution.

Multiscale Investigation of the Mechanisms Controlling the Corrosion of Borosilicate Glasses in Hyper-Alkaline Media

The overarching goal of the present multiscale investigation is to unearth the kinetics and mechanisms of corrosion of borosilicate glasses in hyper-alkaline (pH = 13) environments as a function of...

Insights into the mechanisms controlling the residual corrosion rate of borosilicate glasses

Borosilicate glasses are widely used to confine high-level radioactive wastes. The lifetime of these materials could reach hundreds of thousands of years if leaching of the glass into groundwater enables the formation of a passivating gel layer. Even in this regime, the glass will never stop corroding as thermodynamic equilibrium between glass and solution cannot be achieved. Therefore, accurate predictions of glass durability including passivation, require a deep understanding of the mechanisms controlling the so-called residual rate. However, despite tremendous efforts, these mechanisms remain poorly understood. Here, focusing on the behavior of the soluble elements of the International Simple Glass (B, Na, and Ca), we show that the residual rate is controlled by the behavior of B, a glass former supposed to dissolve instantaneously when in contact with water and thus widely considered as an ideal tracer. We then demonstrate that B release is controlled by multiple processes highly dependent on the pH. At the beginning of the passivating layer formation, the hydrolysis of B-O-Si linkages is rate-limiting and has an activation energy of ∼60 kJ mol−1, a value slightly lower than that for breaking Si-O-Si linkages. Once the fraction of closed pores resulting from gel restructuring is high enough, then diffusion of both reactants (water molecules) and some products (mainly Baq, Caaq) through the growing gel layer becomes rate-limiting. Consequently, B and Ca accumulate in an inner layer referred to as the active zone, with potential feedback on the B-O-Si hydrolysis. A new paradigm, including B as a key element of the system, is proposed to develop a comprehensive model for the corrosion of borosilicate glass.

Patchy particle model of hydrated amorphous silica

Glasses corroded in static aqueous conditions typically reach a slow, residual rate of dissolution as a result of the complex interplay between multiple processes. While intrinsically suited to address this problem, Monte Carlo (MC) models developed to date have relied on lattices to describe the amorphous structure of glass and are thus unable to reproduce the residual rate of glass corrosion. A recently developed MC approach based on amorphous structures derived from molecular dynamics simulations offers a solution [Kerisit and Du J. Non-Cryst. Solids 522 (2019) 119601], but it requires a simple model that can rapidly relax the glass-water interface upon each dissolution/condensation event to retain the ability of MC simulations to reach large spatial and temporal scales. To this end, a patchy particle model of hydrated amorphous silica was developed and evaluated against atomistic simulations in this work. Models of water and amorphous silica were first developed separately, and cross terms were then defined to enable simulations of hydrated amorphous silica structures with varying water content. While the nature of its interaction potential prevents the patchy particle model from reproducing simultaneously the structure and dynamics of the systems of interest with a single set of parameters, it described well the connectivity of hydrated amorphous silica structures and the local coordination geometry of individual species. Therefore, this model opens the door to MC simulations of the residual rate of glass corrosion and offers an alternative to atomistic models to investigate the evolution of silica gels over large spatial and temporal scales.

A New General Paradigm for Understanding and Preventing Li Metal Penetration through Solid Electrolytes

Summary The use of lithium (Li) or sodium (Na) metal anodes together with highly ion-conductive solid electrolytes (SEs) could provide batteries with a step improvement in volumetric and gravimetric energy densities. Unfortunately, these SEs face significant technical challenges, in large part because Li and Na dendrites can penetrate through SEs, leading to short circuits. The ability of such a soft material (Li or Na metal) to penetrate through ceramic is surprising from the point of view of models widely used in the Li-battery field. We introduce a concept, new to the battery field, for preventing penetration of lithium dendrites through SEs by putting the SE surfaces into a state of residual compressive stress. For a sufficiently high compressive stress, cracks have difficulty forming, and cracks that do form are forced to close, inhibiting dendrite penetration. This approach is widely used to solve commercially important stress corrosion cracking problems in metals and static fatigue problems in ceramics and glasses (e.g., Gorilla Glass). However, the technique will not be useful for SEs if the Li-ion transport rate through a SE is substantially reduced when the SE is under compression. Our molecular dynamics calculations for Li-ion transport through a common SE demonstrate that the introduction of even very high residual compressive stresses (∼10 GPa) has only a modest effect on Li-ion transport kinetics, suggesting that this approach is viable and capable of providing a new paradigm for developing high-performance and mechanically stable SEs.

Effects of Alloying Additions on the Glass Forming Ability and Corrosion Resistance of Bulk Zr-Based Amorphous Alloys

By using the real-place Recursion method,the effects of alloying additions (Nb, Ta, Y, La) on glass forming ability(GFA) and corrosion resistance of bulk Zr-based amorphous alloys are studied. An atomic group model in the Zr2Ni primary crystalline phase centered to Ni atom are constructed by computer programming. We have calculated the total bond order integral (£BOI) between Ni atom and its neighbor elements (Nb, Ta, Y, La), also calculated the Fermi energy level of alloying elements. The calculation results show that the XBOI and the glass forming ability are greatly enhanced after Y substitution. Nb, Ta, La decrease the GFA and La has little influence on the GFA of the alloys.Nb, Y, La enable Zr-based amorphous easy to passive and increase corrosion resistance. Therefore, Y and La are most effective on glass forming ability and corrosion resistance of Zr-based amorphous alloys. By addition of minor Y and La can produce the new bulk amorphous alloys with good corrosion resistance.

Atomic and micro‐structure features of nanoporous aluminosilicate glasses from reactive molecular dynamics simulations

AbstractLong‐term chemical durability of borosilicate glasses that makes them a widely accepted form of nuclear waste disposal is achieved through the formation of a porous aluminosilicate gel layer that provides passivity and limits the transport of water to the reaction front. Detailed understanding of the porous silicate gel layer is thus critical in elucidating the corrosion mechanism of these glasses and to design of new glass composition for waste immobilization and other applications. In this paper, we use the diffuse charge reactive potential to generate porous aluminosilicate glass structures with compositions equivalent to the gel layers formed at the glass‐water interface with an aim to understand the processing condition on the microstructure and atomic structure of these systems. We demonstrate the use of the charge scaling techniques is an effective approach to generate these porous structures with controllable pore mophologies. After initial validation of the potentials and calcium aluminosilicate glass structures using neutron diffraction, we created gel structures with compositions similar to well‐known model nuclear waste borosilicate glasses. The porosities and the pore size distribution bear a strong correlation to the processing temperature, as well as to the local atomic structure. Thus, by controlling the processing parameters, the generated porous structures can be customized to closely resemble gel structures due to borosilicate glass corrosion. These results provide insights of the micro‐ and atomic structure features of the porous aluminosilicate glasses and on the optimal procedure to generate porous structures that can be comparable to experimentally observed gel layer structures thus to elaborate on the correlations between the structure and phenomena in glass‐water interactions.

Ab Initio Study of Hydrolysis Effects in Single and Ion-Exchanged Alkali Aluminosilicate Glasses

Hydrolysis in alkali-doped aluminosilicate glasses is one of the most complicated mechanisms in glass science. There remain many fundamental and unresolved issues with implications on their potential applications. Herein, we address this challenge by carrying out detailed calculations on the structure and properties of both anhydrate (dry) and hydrated alkali aluminosilicate glasses on carefully constructed models. Specifically, the Na-, (Na + K)- and K-doped aluminosilicate glasses with compositions (SiO2)0.6 (Al2O3)0.2 (Na2O)0.2-x (K2O)x (x = 0, 0.10 and 0.20) are simulated using ab initio molecular dynamics (AIMD). The local short- and intermediate-range order in these glasses are analyzed in terms of atomic pair distribution, coordination number, bond length and bond angle distributions to delineate the subtle variations due to different alkali size and hydrolysis. The electronic structure, interatomic bonding, mechanical and optical properties for these models are calculated and validated with available experimental data. We use the novel concept of total bond order density (TBOD), the quantum mechanically derived metric, to characterize the internal cohesion and strength in the simulated glasses. Detailed analysis of the hydrolysis mechanism enables us to provide information on the complex interplay of various participating elements and their interactions at the atomic level. Such detailed information provides new platform of knowledge which is crucial for understanding the issues related to glass corrosion and durability and ways and means for their special applications in commercial glass products. Both un-dissociated molecular water and dissociated water in the form of hydroxyl group exist in the hydrated models in the presence of alkali ions. For the first time, we observed the opposite mixed alkali effect in the Poisson's ratio for anhydrate and hydrated glasses.

Effects of nanoscale chemical heterogeneity on the wear, corrosion, and tribocorrosion resistance of Zr-based thin film metallic glasses

The effects of nanoscale chemical heterogeneity on the wear, corrosion, and tribocorrosion resistance of ZrCuNiAl thin film metallic glasses were investigated by examining samples of similar global composition but with either homogenous or heterogeneous local composition. Unlike the homogenous sample, the heterogeneous sample exhibited local compositional fluctuations of Zr-rich (~52.8 at.%) and Zr-lean (~51.7 at.%) regions separated by ~413.0 ± 64.7 nm. Dry scratch wear study showed that the homogenous samples exhibited lower wear rates and friction coefficients than their heterogenous counterparts due to their higher hardness and lower stiffness, as measured from nanoindentation tests. Corrosion resistance of both samples was studied through potentiodynamic polarization and Mott-Schottky analysis in 0.6 M NaCl aqueous solution under room temperature. It was found that the heterogeneous samples exhibited higher pitting resistance than their homogenous counterparts by forming a protective passive layer with lower defect density. Finally, the effects of chemical heterogeneity on the tribocorrosion rate and repassivation kinetics of both samples were discussed based on their differences in mechanical and electrochemical properties measured.

Effect of pH Cycling Frequency on Glass-Ceramic Corrosion.

The effect of pH changes on the chemical durability of dental glass–ceramic materials was evaluated using weight loss and ion release levels. The hypothesis that increased pH changes will exhibit greater corrosion was investigated. The ion concentration was analyzed using inductively coupled plasma atomic emission spectrometer (ICP). The surface compositions were investigated using X-ray photoelectron spectroscopy (XPS). The surface morphologies were examined using scanning electron microscopy (SEM). Dental glass–ceramics were tested in constant immersion, 3-day cycling, and 1-day cycling with pH 10, pH 2, and pH 7 for 3, 15, and 30 days. The 1-d cycling group demonstrated the highest levels of weight loss compared with 3-d cycling and constant immersion. For the ion release, Si4+ and Ca2+ had the highest rates of release in 1-d cycling, whereas the Al3+ release rate with constant pH 2 was highest. The alteration/passivation layer that was formed on the surface of disks possibly prevented further dissolution of pH 10 corroded disks. XPS analysis demonstrated different surface compositions of corroded disks in pH 10 and pH 2. Si4+, K+, Na+, Al3+, and Ca2+ were detected on the surface of corroded pH 10 disks, whereas a Si4+ and P5+-rich surface formed on corroded pH 2 disks. SEM results demonstrated rougher surfaces for corroded disks in cycling conditions and pH 2 constant immersion. In conclusion, increased pH changes significantly promote the corrosion of dental glass–ceramic materials.

Stability against the aqueous corrosion and nanofilamentation of chalcogenide glass

Chalcogenide photonic devices are widely used in the detection of harmful substances in solutions; thus, their stability in aqueous solutions is very critical. In this work, the aqueous corrosion behaviors of commonly used chalcogenide glasses (ChGs) were studied at different temperatures and duration. Optical transmission spectra show that the durability of ChGs is greatly affected by glass composition corrosion, solution temperature, and corrosion time. In addition, Se-based glasses are less stable in aqueous solution and will form nanoparticles of pure Se component on the outer surface of samples, which will contribute to the loss of optical transparency. However, Se-nanostructured materials, such as nanowires, can be obtained by carefully controlling the corrosion process and used for the self-assembly of multi-scale devices. The results show that water is a good solvent for the growth of Se nanowires in the liquid phase. This study provides a new way for the production of Se nanowires.

Remedial insight on ageing of glass through the study of ancient man‐made artefacts

Ancient man‐made glass artefacts provide vital information about the physical and chemical processes occurring over the long‐term period of weathering conditions. Despite the obvious complications associated with purity, non‐optimal conditions of synthesis and unknown thermal prehistory, the studies are important in the context of surface chemical degradation and structural relaxation theories. The soda‐lime‐silica glass from the sixth‐century bce period of Eastern Europe are studied in this paper by X‐ray photoelectron spectroscopy, differential scanning calorimetry and electron microscopy techniques. The dense, amorphous, about 43 μm‐thick SiO2 layer was detected on the surface of all artefacts; it formed a sharp boundary with the rest of the bulk. Thermal studies show that the ancient soda‐lime‐silica glass did not lose much enthalpy during about 2600 years of natural storage. The results suggest important modifications to a general glass corrosion theory and favour the existence of a terminal temperature for glass relaxation, below which the enthalpy of a macrosystem remains stable. Although the applied methods are rarely used in archaeology, the developed approach allows the value of recovered glass artefacts to be expanded beyond just their cultural or historical significance.

Raman spectroscopy study of glass corrosion

Binary sodium silicate and potassium silicate glasses with different alkali content were exposed to the corrosion environment of 35 % hydrochloric acid (HCl). Glass samples were measured by Raman spectroscopy and the spectra were compared with Raman spectra of original pristine glasses in order to observe structural changes induced by corrosion within the surface layer. The usage of confocal Raman spectroscope enabled the measurement of Raman spectra from the depths of few micrometres to document the range of structural changes. The results suggest the depolymerisation of silicate structure due to the growth of the corrosion layer on the surface. The decrease of D2 peak points at the decomposition of three-membered rings. In addition, it is assumed that the Si-O-Si angle changes within the surface layer.

Near-field corrosion interactions between glass and corrosion resistant alloys

This study explores the corrosion interactions between model nuclear waste glass materials and corrosion resistant alloys, under accelerated conditions that simulate the near field of a nuclear waste repository. The interactions between the corrosion of stainless steel (SS) 316, alloy G30, or alloy 625, and international simple glass or soda-lime silica glass are systematically studied. The dissimilar materials were exposed in close proximity to each other in different electrolytes at 90 °C. After exposure, the glass surface exposed near metals showed different regimes of corrosion, with distinct surface morphologies and chemistries that were likely affected by the local environment created by the localized corrosion of metals. Surface and solution analyses showed that the corrosion rate of glass was enhanced by the presence of metals. Infrared spectroscopy data suggested the local build-up of stresses in the contact area of glass, which may lead to the mechanical instability of the glass alteration layer. On the other hand, the effect of glass on metal corrosion is strongly dependent on the leaching solution. In electrolytes containing abundant aggressive anions such as Cl−, glass seems to suppress the localized corrosion of SS by the precipitation of a Si-rich surface film that protects the SS substrate from solutions. However, in less aggressive electrolytes, the corrosion rate of SS was increased by the presence of glass corrosion products. Overall, our study showed that the hidden and localized damage on glass in contact with metals may enhance the release rate of glass components compared to typical uniform glass corrosion.

Tomographic mapping of the nanoscale water-filled pore structure in corroded borosilicate glass

Cryo-based atom probe tomography has been applied to directly reveal the water-solid interface and hydrated corrosion layers making up the nanoscale porous structure of a corroded borosilicate glass in its native aqueous environment. The analysis includes morphology and compositional mapping of the inner gel/glass interface, isolation of a tomographic sub-volume of the tortuous water-filled gel, and comparison of the gel structure with simulations. The nanoscale porous structure is qualitatively consistent with that of the molecular dynamics simulation, enabling in greater confidence in both interrogations. Comparison of the gel/glass interface between desiccated and cryogenically preserved samples reveals consistently abrupt B dissolution behavior and quantitative differences in the apparent H ingress into the glass. These comparisons give some guidance to future experimental approaches to understanding glass corrosion behavior. More broadly, the cryogenic preservation and 3D visualization of the native water/solid structure in 3D at the nanoscale has direct relevance to a wide range of materials systems beyond glass science.