Anticorrosive nanoparticle composition

Abstract

An anticorrosion nanoparticle composition includes a carrier and a plurality of non-ionic metal nanoparticles. The metal nanoparticles can be spherical and / or coral-like metal nanoparticles. The nanoparticles are selected to be located at the grain boundaries of a metal or metal alloy when the anticorrosion composition is applied to the metal or metal alloy, thereby reducing or preventing intergranular corrosion of the metal or metal alloy.

Description

Technical Field

[0001] This article discloses nanoparticle compositions and methods for preventing corrosion of metals and metal alloys. Background Technology

[0002] The microstructure of metals and metal alloys consists of grains separated by grain boundaries. Under certain conditions, these grain interfaces can be very active, leading to localized corrosion at and in regions adjacent to the grain boundaries. This intergranular corrosion can cause harmful weakening or damage to metals and alloys, and even to other metals and alloys that are relatively corrosion-resistant in other respects.

[0003] Intergranular corrosion is often a result of increased impurities and / or segregation effects at grain boundaries, leading to areas of reduced corrosion resistance. In many cases, grain boundaries on the surface of a metal or metal alloy can become anodic and possess a potential relative to adjacent portions of the metal or alloy surface. This effect adversely leads to corrosion along the grain boundaries, affecting the mechanical properties of the material at both the microscopic and ultimately bulk levels, and can even result in material loss as entire grains detach due to boundary deterioration.

[0004] Methods to minimize this type of corrosion typically require additional heating and quenching steps during raw material preparation, or the introduction of stabilizing elements or strong carbide-forming agents into the metal or metal alloy prior to material formation and / or processing. While these methods can be beneficial, they are unsuitable in many cases, requiring the addition of extra materials during manufacturing, and / or additional manufacturing steps and associated costs.

[0005] Coatings, such as paints, can sometimes provide effective corrosion resistance, but especially in industrial environments, they are often impractical, too expensive, or unnecessary. For example, in closed-loop heat exchange systems, coatings can impede the flow of heat from one part of the exchanger to another. Additionally, the application of paints or other coatings is impractical for many pipes or other internal surfaces.

[0006] In some cases, especially in closed-loop systems, large amounts (typically around 2,000 ppm) of reducing agents (such as nitrite (NO2)) are present. - Hydrogen ions (H+) are added to water to minimize its oxidizing power and to attempt to maintain the water's pH at approximately pH 11 to help reduce the amount of hydrogen ions (H+) present in the water. + The amount of hydrogen is reduced, thereby inhibiting or at least minimizing hydrogen propagation, which is another cause of corrosion on metal surfaces.

[0007] In piping setups where materials flow through pipes (as opposed to closed-loop systems), the use of reducing agents is not applicable. Therefore, other applications in piping setups include the use of more expensive and imported alloys or difficult and costly surface treatments for internal piping.

[0008] Therefore, there has been a persistent need to find corrosion-resistant compositions and methods to prevent the corrosion of metals and metal alloys. Such compositions and methods should reliably limit the corrosive effects of intergranular corrosion without requiring excessive manufacturing steps or pre-forming material additions. Summary of the Invention

[0009] This article discloses nanoparticle compositions and application methods for providing corrosion-resistant properties to metals and alloys. The corrosion-resistant nanoparticle compositions can be applied to the surface of a metal or metal alloy to limit intergranular corrosion on the metal or alloy surface.

[0010] The corrosion-resistant nanoparticle composition may include metallic nanoparticles, such as spherical nanoparticles and / or coral-like nanoparticles, which, when applied to a metal or metal alloy surface, align with the grain boundaries of the metal or metal alloy to reduce or eliminate intergranular corrosion at and near the grain boundaries. In some embodiments, the corrosion-resistant nanoparticle composition includes both spherical and coral-like nanoparticles.

[0011] As used herein, nanoparticles are defined as very small particles with a size between about 1 nm and 100 nm. However, in some cases, particles with a size slightly larger than 100 nm can also be used as a unit cell and thus conform to the general definition of nanoparticles in some implementations.

[0012] In some embodiments, the corrosion-resistant nanoparticle composition includes: (1) a carrier configured to be applied to a metal or metal alloy; and (2) a plurality of nonionic metal nanoparticles suspended in the carrier, the size and shape of which are selected to be positioned along the grain boundaries of the metal or alloy surface and / or within the grain boundaries of the metal or alloy surface.

[0013] In some embodiments, the corrosion-resistant nanoparticle composition includes: (1) a carrier configured to be applied to a surface of a metal or metal alloy; (2) an electrolytic modifier; and (3) a plurality of nonionic metal nanoparticles suspended in the carrier, the size and shape of which are selected to be positioned along the grain boundaries of the metal or alloy surface and / or within the grain boundaries of the metal or alloy surface.

[0014] In some embodiments, the electrolytic modifier may be a reducing agent, such as one or more of nitrites, sulfites, or phosphites. The reducing agent may be included to work in conjunction with (e.g., synergistically) the metal nanoparticles to further provide corrosion inhibition. The effective concentration of the reducing agent can vary depending on the type and / or composition of the metal surface being treated. In some embodiments, the reducing agent is included at a concentration of about 50-200 ppm; higher concentrations remain effective, but the aforementioned lower concentrations advantageously provide similar results without increasing cost.

[0015] The effective concentration of metal nanoparticles can vary slightly depending on the composition of the nanoparticles used and the metal surface being treated, but typically a minimum concentration of about 0.5 ppm to 15 ppm, or about 0.5 ppm to 5 ppm, is preferred, with a range between about 0.5 ppm and 3 ppm, and even more preferred, a minimum concentration between about 1 ppm and 2 ppm. Higher concentrations (e.g., above about 5 ppm or above about 15 ppm) also remain effective, but the aforementioned lower concentrations advantageously provide effective results without increasing costs.

[0016] The application of anti-corrosion compositions involves adhering or otherwise attaching nanoparticles to a metal surface. This can be accomplished through a variety of methods, including simply exposing or immersing the surface in the anti-corrosion composition for a sufficient time to allow the nanoparticles to adhere to the metal surface. In one embodiment, the metal surface is heated, and the anti-corrosion composition is sprayed onto the surface. The liquid carrier of the anti-corrosion composition is allowed to evaporate, leaving the nanoparticles attached to the surface. In some embodiments, electrostatic charges are introduced into the metal surface to more easily attract the metal nanoparticles of the anti-corrosion composition to the metal surface.

[0017] Once the nanoparticles have been effectively attached to the metal surface, continuous treatment of the metal surface can be achieved by maintaining at least an effective concentration of an electrolyte modifier (e.g., a reducing agent) in the environment of the treated metal surface. After the initial treatment, as the nanoparticles align at the grain boundaries of the metal surface, subsequent treatments can advantageously have a significantly reduced amount of nanoparticles while maintaining the same corrosion resistance.

[0018] In some embodiments, the method of applying the anti-corrosion nanoparticle composition includes: (1) applying a nanoparticle composition comprising a carrier and a plurality of nonionic metal nanoparticles to a surface of a metal or metal alloy, and (2) removing the liquid carrier to produce a nanoparticle-treated surface, wherein at least a portion of the nonionic metal nanoparticles are positioned along and / or within the grain boundaries of the metal or metal alloy to provide corrosion resistance to the metal or alloy.

[0019] In some embodiments, a method for manufacturing a corrosion-resistant metal or metal alloy includes: (1) obtaining the metal or metal alloy, (2) applying a nanoparticle composition comprising a liquid carrier and a plurality of nonionic metal nanoparticles to the surface of the metal or alloy, and (3) removing the liquid carrier to produce a nanoparticle-treated surface, wherein at least a portion of the nonionic metal nanoparticles are positioned along and / or within the grain boundaries of the metal or alloy to provide corrosion resistance to the metal or alloy.

[0020] In some embodiments, the metal nanoparticles may comprise spherical metal nanoparticles and / or coral-like metal nanoparticles. In some embodiments, coral-like metal nanoparticles may be used in conjunction with spherical metal nanoparticles to aid in the transport and / or potentiate of the spherical metal nanoparticles.

[0021] In some embodiments, the nanoparticle composition (including spherical, coral-like, or multi-component nanoparticle compositions) includes a carrier capable of holding the nanoparticles in solution while still maintaining their functionality.

[0022] In a preferred embodiment, the metal nanoparticles are formed from elements or alloys that are not easily corroded in the environment in which they will be used. In some embodiments, at least a portion of the metal nanoparticles are antimony (Sb) nanoparticles, which function to prevent hydrogen propagation, thereby further suppressing mechanisms known to be part of the corrosion process.

[0023] These and other advantages and features of the invention will be set forth in part in the description which follows, and in part will become apparent to those skilled in the art upon examination thereafter, or may be learned by practice of the invention. Attached Figure Description

[0024] Figure 1A The images are scanning transmission electron microscope (STEM) images of exemplary spherical gold nanoparticles having a substantially uniform size of about 14 nm, a narrow particle size distribution, and no particle aggregation, and the nanoparticles are intended for use in preparing corrosion-resistant nanoparticle compositions.

[0025] Figure 1B and 1C The image shows a scanning transmission electron microscope (STEM) image of exemplary spherical gold nanoparticles on a carbon lattice structure. The nanoparticles have a generally uniform size of about 14 nm, a narrow particle size distribution, and do not show particle aggregation. The nanoparticles are intended for use in the manufacture of corrosion-resistant nanoparticle compositions.

[0026] Figure 2AThe image is a scanning transmission electron microscope (STEM) image of an exemplary coral-like gold nanoparticle with a length of about 25 nm, showing no right angles or facets and having smooth curves at all intersections, the nanoparticle having the use of manufacturing corrosion-resistant nanoparticle compositions.

[0027] Figure 2B and 2C These are scanning transmission electron microscope (STEM) images showing magnified views of exemplary coral-like gold nanoparticles with a length of approximately 25 nm. No right angles or facets are shown, and smooth curves are present at all intersections. The atomic structure at the edges differs from that at the center of the particle, showing shorter bond lengths to achieve the exhibited smoothness. These nanoparticles are intended for use in the manufacture of corrosion-resistant nanoparticle compositions.

[0028] Figure 3 The surface of a metal or metal alloy with intergranular spaces is schematically shown;

[0029] Figure 4 schematically shown Figure 3 A close-up view of a portion of the surface of the metal or metal alloy shown; and

[0030] Figure 5 This schematically illustrates the effect after applying the anti-corrosion composition. Figure 4 The portion shown contains multiple nanoparticles located at grain boundaries to reduce or prevent intergranular corrosion. Detailed Implementation

[0031] This document discloses nanoparticle compositions for providing corrosion-resistant properties to metals and / or metal alloys. It also discloses methods for applying corrosion-resistant nanoparticle compositions to metals or metal alloys to provide corrosion resistance, and methods for manufacturing metals or alloys with corrosion-resistant surfaces.

[0032] Surprisingly, it has now been found that by selecting nanoparticles with appropriate size distribution and / or surface properties and suspending the nanoparticles in a suitable carrier to form an anti-corrosion nanoparticle composition, applying the composition to a metal or metal alloy results in enhanced corrosion resistance of the metal or alloy.

[0033] Nanoparticle configuration

[0034] In some embodiments, the metal nanoparticles may comprise nonionic ground-state metal nanoparticles or consist substantially of nonionic ground-state metal nanoparticles. Examples include spherical metal nanoparticles, coral-like metal nanoparticles, or blends / combinations of spherical and coral-like metal nanoparticles.

[0035] In some embodiments, the metal nanoparticles used to prepare nanoparticle compositions comprise spherical nanoparticles, preferably solid-core spherical metal nanoparticles. The term "spherical metal nanoparticle" refers to nanoparticles made of one or more metals, preferably nonionic ground-state metals, which have only internal bond angles and no external edges or bond angles. In this way, spherical nanoparticles exhibit strong ionization resistance, high stability, and high anti-agglomeration properties. Such nanoparticles can exhibit high absolute zeta potentials (positive or negative), which allows spherical nanoparticles to remain dispersed in polar solvents without the use of surfactants—a surprising and unexpected result.

[0036] In some embodiments, the spherical metal nanoparticles may have a diameter of about 40 nm or less, about 35 nm or less, about 30 nm or less, about 25 nm or less, about 20 nm or less, about 15 nm or less, about 10 nm or less, about 7.5 nm or less, or about 5 nm or less. In some embodiments, the nanoparticles are not less than about 1 nm.

[0037] In some embodiments, the spherical nanoparticles may have a particle size distribution such that at least 99% of the nanoparticles have a diameter within 30% of the average nanoparticle diameter, or within 20% of the average diameter, or within 10% of the average diameter. In some embodiments, the spherical nanoparticles may have an average particle size, and at least 99% of the nanoparticles have a particle size within ±3 nm, ±2 nm, or ±1 nm of the average diameter. In some embodiments, the spherical nanoparticles may have an absolute zeta potential (positive or negative) of at least 10 mV, preferably at least about 15 mV, more preferably at least about 20 mV, even more preferably at least about 25 mV, and most preferably at least about 30 mV.

[0038] Examples of methods and systems for manufacturing spherical nanoparticles are disclosed in US Patent Publication No. 2013 / 0001833 by William Niedermeyer, which is incorporated herein by reference. Figure 1A-1C This image shows a scanning transmission electron microscope (STEM) image of exemplary spherical nanoparticles prepared using the methods and systems described in U.S. Patent Publication No. 2013 / 0001833. The nanoparticles shown are spherical gold nanoparticles with a substantially uniform size, an average diameter of about 14 nm, and a narrow particle size distribution. In some embodiments, the spherical nanoparticles may be hollow rather than solid, as is typically the case with conventional metallic nanoparticles formed on the surface of non-metallic seed nanoparticles (e.g., silica) (where the seed nanoparticles are subsequently removed to produce hollow nanospheres).

[0039] In some embodiments, the nonionic metal nanoparticles used to prepare the nanoparticle compositions may also comprise coral-like nanoparticles. The term "coral-like metal nanoparticles" refers to nanoparticles made of one or more metals, preferably nonionic ground-state metals, having a non-uniform cross-section and a spherical structure formed by multiple nonlinear chains linked together without right angles. Similar to spherical nanoparticles, coral-like nanoparticles may have only internal bond angles and no external edges or bond angles. In this way, coral-like nanoparticles can exhibit high ionization resistance, are highly stable, and have high anti-agglomeration properties. Such coral-like nanoparticles can exhibit high absolute zeta potentials (positive or negative), which allows coral-like spherical nanoparticles to remain dispersed in polar solvents without the use of surfactants—a surprising and expected result.

[0040] In some embodiments, the coral-like nanoparticles may have a length of about 15 nm to about 100 nm, or about 25 nm to about 95 nm, or about 40 nm to about 90 nm, or about 60 nm to about 85 nm, or about 70 nm to about 80 nm. In some embodiments, the coral-like nanoparticles may have a particle size distribution such that at least 99% of the nanoparticles have a length within 30% of the average length, or within 20% of the average length, or within 10% of the average length. In some embodiments, the coral-like nanoparticles may have an absolute zeta potential (positive or negative) of at least 10 mV, preferably at least about 15 mV, more preferably at least about 20 mV, even more preferably at least about 25 mV, and most preferably at least about 30 mV.

[0041] Examples of methods and systems for manufacturing coral-like nanoparticles are disclosed in US Patent Publication No. 2016 / 0082514 by William Niedermeyer, which is incorporated herein by reference. Figure 2A-2C These are scanning transmission electron microscopy (STEM) images of exemplary coral-like metallic nanoparticles fabricated using the methods and systems applied for by Niedermeyer. The nanoparticles shown are coral-like gold nanoparticles with a length of approximately 25 nm and exhibit no right angles or facets, displaying smooth curves at all intersections. Specifically, as... Figure 2B and 2C As shown, the nanoparticles exhibit a different atomic structure at the edges compared to the center of the particle, with shorter bond lengths at the edges, thus providing the smoothness of the particles.

[0042] Metal nanoparticles, including spherical and coral-like nanoparticles, may comprise any desired metal, metal mixture, or metal alloy, including at least one of silver, gold, platinum, palladium, rhodium, osmium, ruthenium, rhenium, molybdenum, copper, iron, nickel, tin, beryllium, cobalt, antimony, chromium, manganese, zirconium, tin, zinc, tungsten, titanium, vanadium, lanthanum, cerium, heterogeneous mixtures thereof, or alloys thereof.

[0043] In a preferred embodiment, the nanoparticles comprise noble metals such as gold, silver, platinum, and palladium. In some embodiments, the nanoparticles will be made of an alloy of a noble metal combined with antimony, bismuth, lead, or other elements with the ability to prevent or inhibit hydrogen propagation. In some embodiments, the nanoparticles are made of stainless steel, austenitic nickel-chromium alloys (e.g., by trade name...). (sold) and / or nickel-based alloys (e.g., nickel-copper-iron-manganese alloys, for example, under trade names) Those being sold).

[0044] Multi-component nanoparticle composition

[0045] In some embodiments, coral-like metal nanoparticles may be used in combination with spherical metal nanoparticles. Typically, spherical metal nanoparticles can be smaller than coral-like metal nanoparticles, and in this way can provide a very high surface area for catalyzing desired reactions or providing other desired benefits. On the other hand, coral-like nanoparticles, which are typically larger, can exhibit a higher surface area per unit mass compared to spherical nanoparticles because they have internal space and surface rather than a solid core and only an external surface. In some cases, providing a nanoparticle composition containing spherical and coral-like nanoparticles can provide synergistic results. For example, in addition to providing their own unique advantages, coral-like nanoparticles can also help transport and / or enhance the activity of spherical nanoparticles.

[0046] In some embodiments, the nanoparticle composition may include both spherical and coral-like nanoparticles. In some embodiments, the mass ratio of spherical nanoparticles to coral-like nanoparticles in the nanoparticle composition may be in the range of about 1:1 to about 50:1, or about 2.5:1 to about 25:1, or about 5:1 to about 20:1, or about 7.5:1 to about 15:1, or about 9:1 to about 11:1, or about 10:1. The particle number ratio of spherical nanoparticles to coral-like nanoparticles in the nanoparticle composition may be in the range of about 10:1 to about 500:1, or about 25:1 to about 250:1, or about 50:1 to about 200:1, or about 75:1 to about 150:1, or about 90:1 to about 110:1, or about 100:1.

[0047] In some embodiments, the composition will comprise at least one spherical nanoparticle component and at least one larger coral-like nanoparticle component. In these embodiments, the at least one selected spherical nanoparticle component will be present in solution at a concentration ranging from about 1 ppm to about 15 ppm (e.g., at least 1 ppm and at most 15 ppm), and more particularly at a concentration ranging from about 1 ppm to about 5 ppm (e.g., at least 1 ppm and at most 5 ppm). Furthermore, in some embodiments, the larger coral-like nanoparticles will be present in solution at a concentration ranging from about 1 ppm to about 5 ppm (e.g., at least 1 ppm and at most 5 ppm), and more particularly at a concentration ranging from about 1 ppm to about 3 ppm (e.g., at least 1 ppm and at most 3 ppm). It should be understood that the upper concentration limit is not limited by efficacy but rather by the formulation cost of the product. Therefore, in other embodiments, the spherical nanoparticle component may be present at a concentration higher than 5 ppm and / or the coral-like nanoparticle component may be present at a concentration higher than 3 ppm.

[0048] Some implementations may include stabilizers. For example, there may be multiple instances where it is desirable to have nanoparticles of different specific sizes in the same solution to utilize each different property and effect of the particles. Therefore, stabilizers may be included to enhance the overall long-term stability of these particles, thereby balancing or reducing the effects of unequal forces applied to the individual particles, thus minimizing or preventing particle aggregation. Aggregation effects may become more pronounced when the solution is heated or cooled to conditions significantly above or below standard room temperature.

[0049] Stabilizers themselves can be advantageous for use in corrosion-preserving applications. Examples of stabilizers include alcohols (e.g., ethanol, propanol, butanol, etc.), as alcohols have been observed to effectively retain nanoparticles of different sizes and shapes within a given solution. Additionally, amine compounds such as monoethanolamine, diethanolamine, and triethanolamine can be used as stabilizers or as a component thereof. Stabilizers can also be used as a carrier (and vice versa), as described in more detail below, or can be added as a separate component (e.g., in addition to a carrier) to the nanoparticle composition.

[0050] Corrosion resistance

[0051] Figure 3 The diagram schematically illustrates the surface of a metal or metal alloy with multiple intergranular connections. These grain boundaries of the metal or metal alloy are subject to corrosion, leading to localized corrosion between the metal or alloy grains. Figure 4 schematically shown Figure 3 A close-up view of the grain boundaries of the surface shown. Figure 4 The grain surface 410 and intergranular space 420 between adjacent grains located at the grain boundary are shown.

[0052] As mentioned above, when local impurities or segregation effects lead to the formation of galvanic couples at grain boundaries, intergranular corrosion occurs, resulting in unfavorable oxidation, hydrogen propagation, and other unwanted corrosive effects. For example... Figure 5 As shown, when the anti-corrosion composition of the present invention is applied to a metal or alloy, the nanoparticles 430 contained in the composition may be located at grain boundaries, including between grains 410 in the intergranular space 420.

[0053] Surprisingly, it has been found that applying the anti-corrosion composition of the present invention provides corrosion resistance to the treated metal or alloy. Unbound from any particular theory, theoretically, when the nanoparticles 430 are located at grain boundaries, the local electrical coupling driving intergranular corrosion is disrupted and / or the local potential at or near the grain boundaries is balanced.

[0054] carrier

[0055] The anti-corrosion composition may further include a carrier for delivering metal nanoparticles to the metal or metal alloy to be treated for corrosion resistance. The carrier may be a liquid, gel, or solid. The nanoparticles can be readily incorporated into any number of carriers, which can then serve as the basis for a variety of products, including, for example, sprays, coatings, dry fog solutions, soaking solutions, and wipe solutions.

[0056] Depending on the metal or alloy to be treated and / or the desired application method, some supports may be more suitable than others. For example, the volatility of the support can be selected to allow for rapid evaporation of the support and relatively rapid deposition of nanoparticles onto the metal or alloy to be treated.

[0057] Alternatively, the liquid carrier can be selected to provide the desired surface tension when applied to a metal or metal alloy surface in order to provide the desired wetting effect. For example, the liquid carrier can be selected to provide high wetting when applied to a metal or alloy surface, such as a carrier forming a contact angle between about 0 degrees and about 90 degrees, or between about 0 degrees and about 60 degrees, or between about 0 degrees and about 45 degrees when applied to the surface to be treated. In some embodiments, such a carrier may comprise an alcohol or an alcohol / water mixture.

[0058] In addition to those disclosed herein or as alternatives, other examples of carriers that can be used to formulate anti-corrosion compositions include, but are not limited to, alcohols (e.g., methanol, ethanol, isopropanol, glycols, other lower alcohols), ketones, esters, ethers, and other organic solvents.

[0059] Gels known in the art can be used as carriers, such as gels containing one or more of the aforementioned liquid components and known gelling agents. Anti-corrosion compositions having a gel or gel-like carrier can be applied more easily in certain situations compared to liquid carriers. For example, when the surface of the metal or metal alloy to be treated is not in a suitable location for liquid application, or when the liquid carrier cannot provide the desired application coverage (e.g., when the target surface to be treated is facing downwards and the liquid carrier lacks viscosity to maintain contact with the surface for a sufficient duration).

[0060] Additional components can be added to the corrosion-resistant nanoparticle composition. These additives can be selected to provide the composition with additional desired properties and / or enhance or modify the properties of the carrier. For example, additives can be added to change surface tension or viscosity to improve the stability of the composition and / or protect against ultraviolet radiation. Additives may also include thickeners, emulsifiers, viscous agents, etc.

[0061] Electrolytic modifiers and reducing agents

[0062] In some embodiments, an electrolytic modifier may be added to the composition to alter the electrolytic environment in which the nanoparticles are present and / or to act as a reducing agent to help prevent oxidation of the metal surface on which the composition is applied. In some embodiments, such an electrolytic modifier may be added to alter the adsorption and / or adhesion of the nanoparticles to the grain boundaries of the metal or alloy to which the anticorrosion composition is applied. In a preferred embodiment, an electrolytic modifier is added to increase the adsorption and / or adhesion of the nanoparticles along or within the grain boundaries of the metal or alloy, such that a higher proportion of the nanoparticles in the anticorrosion composition are located in these regions and / or remain at a higher proportion in these regions after application.

[0063] In some embodiments, electrolytic modifiers can be used to modify the surface properties of nanoparticles, thereby altering the interaction between the nanoparticles and the surface environment of the metal or alloy when applied to a metal or alloy. For example, one or more electrolytic modifiers can be added to increase the amount and / or strength of regional electronic coupling between the nanoparticles and the surface of the metal or alloy along and / or within the grain boundaries.

[0064] Electrolytic modifiers may include, for example, electrolytes and polyelectrolytes. For instance, one or more salts may be added to the anti-corrosion composition. Non-limiting examples of salts include cations such as sodium (Na₂O₃). + ), potassium (K) + ), magnesium (Mg) +2 ), calcium (Ca +2 ), ammonium (NH4) +), iron (e.g., ferrous Fe(II) or ferric Fe(III)), copper (e.g., cuprous Cu(I) or divalent copper Cu(II)), zinc, nickel, etc., and may include anions such as nitrite (NO2–) and phosphate (PO42–). –3 ), sulfate (SO4– 2 ), carbonate (CO3) –2 ), nitrate (NO3) – ), chloride ions (Cl) – Suitable polyelectrolytes include, for example, polystyrene sulfonates, polymethacrylic acid, polyallylamine, sodium polyacrylate, polyethyleneamine, polyethylimide, polyphosphates, and other polyelectrolytes and polyampholytes.

[0065] Electrolytic modifiers may also include acids (such as hydrochloric acid, nitric acid, acetic acid, sulfuric acid, citric acid, carbonic acid, phosphoric acid, oxalic acid, etc.) or bases (such as sodium hydroxide, sodium bicarbonate, calcium hydroxide, potassium hydroxide, ammonia, etc.).

[0066] In some preferred embodiments, one or more electrolytic modifiers can act as reducing agents to help prevent oxidation of the metal surface on which the composition is applied. For example, one or more of nitrites, sulfites, phosphites, or polyphosphates can be added in the range of about 50 ppm to 200 ppm. While higher concentrations are also effective, the aforementioned concentration range has been shown to be effective and beneficial in providing effective results without the need for additional higher concentrations. A suitable example of a polyphosphate is sodium hexametaphosphate.

[0067] In implementations that include a reducing agent (e.g., to provide the desired synergistic anti-corrosion effect with the nanoparticles), the anti-corrosion effect can be maintained even when subsequent treatments can reduce the concentration of the applied nanoparticles. For example, in a closed-loop system such as an evaporative cooling tower system, the fresh makeup water added to the system can still contain a reducing agent between 50 ppm and 200 ppm, but the concentration of nanoparticles can be reduced to less than 0.5 ppm or less than 0.1 ppm, or even eliminated entirely, while still maintaining the same level of anti-corrosion activity.

[0068] In another example, in piping applications, once the inner surface of the pipe has been treated to allow nanoparticles to adhere to it, maintenance of the inner pipe surface can be accomplished with limited or no additional application of nanoparticles. In some cases, an effective concentration of reducing agent can be maintained in the aqueous phase of the material flowing through the pipe.

[0069] In another example, in a captured water system (where corrosion is caused by stagnant or otherwise evaporated water, such as bilge water in the hull of a ship), a sufficient concentration of nanoparticles (and optional reducing agents) can be added to the captured water to form an anti-corrosion composition, and typically no further addition of nanoparticles is required.

[0070] parameter

[0071] Various parameters of the corrosion-resistant nanoparticle composition can vary depending on the desired corrosion-resistant application. Parameters include, for example, nanoparticle configuration (e.g., particle shape, particle size and size distribution, particle type and mixing ratio), nanoparticle concentration, and carrier characteristics (e.g., viscosity, volatility, pH, conductivity, presence of additives, and presence of electrolytic modifiers such as reducing agents). Each of these parameters and sub-parameters can vary based on the selected application of the corrosion-resistant composition. Influencing factors may include, for example, the type of metal or alloy to be treated, the desired application method (e.g., spraying, coating, immersion), and / or the level of intergranular corrosion exhibited by the material to be treated.

[0072] For example, the anti-corrosion composition can be formulated at least in part based on the size and / or shape of the measured or anticipated intergranular spacing. In such embodiments, the nanoparticle size can be selected such that when the anti-corrosion composition is applied to a metal or metal alloy, the nanoparticles fit between the grains of the material and more effectively disrupt the electrical couplings that drive intergranular corrosion or put the material at risk of intergranular corrosion.

[0073] In another example, the anti-corrosion composition can be formulated at least in part based on a comparison of the measured or expected surface properties of the nanoparticles with the measured or expected surface properties of the target grain boundaries (e.g., the average potential across the grain boundaries). In such embodiments, the nanoparticles and / or electrolytic modifiers can be selected to provide surface properties to the nanoparticles that enable greater electronic coupling at the grain boundaries and / or between the grains of the material to be treated.

[0074] In some embodiments, the nanoparticle composition can be formulated such that the concentration of the metal nanoparticles contained therein is such that, when applied to a surface of a metal or metal alloy, a measured amount of the nanoparticle composition will provide a predetermined concentration or amount of metal nanoparticles and / or will provide sustained anti-corrosion efficacy over an extended period of time. The nanoparticle composition can have a high concentration of nanoparticles, for example, when mixed with other liquids applied to the treated surface, the nanoparticles become diluted. Depending on the metal or alloy surface being treated, the nature of the added nanoparticles, and the type of carrier used, the nanoparticle composition can contain about 0.5 ppm to about 100 ppm of metal nanoparticles by weight, or about 1 ppm to about 50 ppm by weight, or about 2 ppm to about 25 ppm, or about 3 ppm to about 20 ppm of metal nanoparticles by weight. In other embodiments, the nanoparticle composition can contain about 0.5 ppm and 15 ppm, or about 0.5 ppm and 5 ppm, more preferably in the range between about 0.5 ppm and 3 ppm, and even more preferably in the range between about 1 ppm and 2 ppm.

[0075] Application method

[0076] In some embodiments, methods for applying the anti-corrosion composition include immersing, spraying, or otherwise exposing the metal surface for a sufficient time to allow the nanoparticles to adhere to the surface. It has been observed that, under typical temperature conditions (e.g., approximately room temperature), nanoparticle adhesion can be completed in approximately 4 hours or less.

[0077] In some embodiments, the adhesion of nanoparticles to a metal surface is accelerated and / or enhanced by the following steps: heating the metal surface (e.g., to a temperature of 120-160°F) and applying an anti-corrosion composition sufficiently to the surface (e.g., as a spray or mist) to thoroughly wet the surface, and then allowing the liquid of the anti-corrosion composition to evaporate rapidly, thereby leaving the nanoparticles attached to the surface.

[0078] In some implementations, the adhesion of nanoparticles to a metal surface can be accelerated and / or enhanced by introducing electrostatic charges. For example, it has been observed that, under typical temperature conditions, the adhesion of nanoparticles to a metal surface using electrostatic charges can be completed in as little as approximately 30 minutes or less.

[0079] In some embodiments, the method of applying the anti-corrosion nanoparticle composition includes: (1) applying the nanoparticle composition comprising a carrier and a plurality of nonionic metal nanoparticles to a surface of a metal or alloy, and (2) removing the liquid carrier to produce a nanoparticle-treated surface, wherein at least a portion of the nonionic metal nanoparticles are positioned along and / or within the grain boundaries of the metal or alloy to provide corrosion resistance to the metal or alloy. Removal of the liquid carrier may include removal as a liquid or vapor.

[0080] In some embodiments, the corrosion-resistant nanoparticle compositions of this disclosure may be applied to metals and / or alloys. For example, the corrosion-resistant compositions may be applied to metals and / or alloys known to have a risk of intergranular corrosion, or metals and / or alloys expected to undergo intergranular corrosion based on factors such as material type, previous manufacturing process (e.g., extrusion and / or intensive processing), and / or the metal or alloy intended to be used.

[0081] In some embodiments, the anti-corrosion composition can be applied to austenitic stainless steel containing chromium or to nickel alloys in which chromium has been added. Such steels / alloys are often susceptible to intergranular corrosion due to chromium loss at grain boundaries caused by the precipitation of chromium carbide. High-carbon steels can also benefit from the anti-corrosion composition because the grain boundaries can be altered by carbon. The anti-corrosion composition can also be applied to metals or alloys known to be susceptible to knife-line corrosion, such as 347 stainless steel and other stainless steels including niobium.

[0082] The corrosion-resistant composition disclosed herein can also be applied to aluminum or titanium metals and aluminum- and titanium-based alloys. For example, the corrosion-resistant composition can be applied to aluminum-based and titanium-based materials whose grain boundaries are susceptible to intergranular corrosion due to iron impurity segregation and concentration at the grain boundaries. Other embodiments include applying the corrosion-resistant composition to aluminum alloys having a copper content capable of promoting the formation of localized galvanic couples at the grain boundaries of the alloy. Other embodiments include applying the corrosion-resistant composition to brass, such as brass having an increased zinc content at or near the grain boundaries.

[0083] The corrosion-resistant composition can also be applied to closed-loop applications, such as heat exchangers and evaporative coolers, to open-loop applications such as pipelines, and to stagnant fluid applications such as bilge areas.

[0084] In some implementations, the anti-corrosion treatment is repeated once or multiple times, or different treatments or combinations of treatments are subsequently applied.

[0085] Manufacturing method

[0086] In some embodiments, a method for manufacturing a corrosion-resistant metal or alloy includes: (1) obtaining a metal or metal alloy, (2) applying a nanoparticle composition comprising a liquid carrier and a plurality of nonionic metal nanoparticles to a surface of the metal or metal alloy, and (3) removing the liquid carrier to produce a nanoparticle-treated surface, wherein at least a portion of the nonionic metal nanoparticles are positioned along and / or within the grain boundaries of the metal or alloy to provide corrosion resistance to the metal or alloy.

[0087] In some embodiments, a method for manufacturing a corrosion-resistant metal or alloy includes: (1) obtaining a metal or metal alloy, (2) obtaining a nanoparticle composition comprising a liquid carrier and a plurality of nonionic metal nanoparticles having the metal or alloy, and (3) integrating the nanoparticle composition and the metal or alloy before or during the metal or alloy manufacturing process such that at least a portion of the nonionic metal nanoparticles are positioned along and / or within the grain boundaries of the metal or alloy to provide corrosion resistance to the metal or alloy.

[0088] The invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. The described embodiments are to be considered in all respects merely illustrative and not restrictive. Therefore, the scope of the invention is defined by the appended claims rather than the foregoing description. All variations falling within the meaning and scope of the equivalents of the claims are to be included within their scope.

[0089] Example

[0090] Example 1

[0091] A corrosion-inhibiting composition is provided, comprising distilled deionized water adjusted to pH 6.0 with sulfuric acid, 100 ppm sodium nitrite, and 1 ppm Ag nanoparticles prepared by laser ablation (wherein the average size of the Ag nanoparticles is approximately 10 nm). A low-carbon steel sample (coupon) was placed in the composition. No corrosion measurable by weight loss or visible corrosion was observed within 3 years.

[0092] Example 2

[0093] A corrosion-inhibiting composition is provided, comprising distilled deionized water adjusted to pH 6.0 with sulfuric acid, 100 ppm sodium nitrite, and 1 ppm Au nanoparticles (with an average size of approximately 40-60 nm) prepared by laser ablation. A low-carbon steel sample was placed in the composition. No corrosion measurable by weight loss or visible corrosion was observed within 3 years.

[0094] Example 3

[0095] A corrosion-inhibiting composition is provided, comprising distilled deionized water adjusted to pH 6.0 with sulfuric acid, 100 ppm sodium nitrite, and 0.5 ppm Ag nanoparticles prepared by laser ablation (wherein the average size of the Ag nanoparticles is about 10 nm) and 0.5 ppm Au nanoparticles prepared by laser ablation (wherein the average size of the Au nanoparticles is about 40-60 nm) (total nanoparticle concentration of 1.0 ppm). A low-carbon steel sample was placed in said composition. No corrosion measurable by weight loss or visible corrosion was observed within 3 years.

[0096] Example 4

[0097] A corrosion-inhibiting composition is provided, comprising distilled deionized water adjusted to pH 3.0 with acetic acid, 100 ppm sodium nitrite, and 2.0 ppm AgSb alloy nanoparticles (with an average nanoparticle size of about 20-25 nm) prepared by laser ablation. A low-carbon steel sample was placed in the composition. No corrosion measurable by weight loss or visible corrosion was observed within one month.

[0098] Example 5

[0099] A corrosion-inhibiting composition is provided, comprising distilled deionized water adjusted to pH 6.0 with sulfuric acid, 50 ppm sodium nitrite, and 2.0 ppm AgSb alloy nanoparticles (with an average nanoparticle size of about 20-25 nm) prepared by laser ablation. A low-carbon steel sample was placed in the composition. No corrosion measurable by weight loss or visible corrosion was observed within 6 months.

[0100] Example 6

[0101] A corrosion-inhibiting composition is provided, comprising distilled deionized water adjusted to pH 6.0 with sulfuric acid, 100 ppm sodium nitrite, and 1 ppm Au nanoparticles prepared by laser ablation (wherein the average size of the Au nanoparticles is approximately 40-60 nm). A copper sample is placed in the composition. No corrosion measurable by weight loss or visible corrosion was observed within 3 years.

[0102] Example 7

[0103] A corrosion-inhibiting composition is provided, comprising distilled deionized water adjusted to pH 6.0 with sulfuric acid, 100 ppm sodium nitrite, and 1 ppm Au nanoparticles prepared by laser ablation (wherein the average size of the Au nanoparticles is approximately 40-60 nm). A naval brass sample was placed in the composition. No corrosion measurable by weight loss or visible corrosion was observed within 3 years.

[0104] Although the foregoing has been described in detail by way of illustration and examples for clarity and understanding, those skilled in the art will understand that many and various modifications can be made. Therefore, it should be clearly understood that the form disclosed herein is merely illustrative and is not intended to limit the scope of this disclosure.

Claims

1. A corrosion-resistant composition comprising the following: The carrier includes a volatile organic solvent that is readily applied to a metal or metal alloy and whose volatility allows it to evaporate when applied to the metal or metal alloy. Electrolytic modifier comprising a reducing agent, wherein the reducing agent comprises one or more of nitrite, sulfite, phosphite, or polyphosphate; and Multiple spherical nonionic metal nanoparticles are suspended in a carrier and have a diameter of 1 nm-40 nm, wherein the spherical nonionic metal nanoparticles have an average diameter, and wherein at least 99% of the metal nanoparticles have a diameter within 30% of the average diameter. The spherical nonionic metal nanoparticles are sized and shaped such that they are located at the grain boundaries of the metal or metal alloy when the carrier is applied to the metal or metal alloy. The nonionic metal nanoparticles comprise at least one metal selected from the group consisting of gold, silver, platinum, palladium, stainless steel, austenitic nickel-chromium alloys, and nickel-copper alloys, or The nonionic metal nanoparticles comprise a metal selected from the group consisting of gold, silver, platinum, and palladium, which forms an alloy with a metal selected from the group consisting of antimony, bismuth, and lead. The anti-corrosion composition is applied to the metal or metal alloy, causing the volatile organic solvent to evaporate, thereby leaving only the metal nanoparticles and electrolytic modifiers on the metal or metal alloy to provide anti-corrosion protection.

2. The anti-corrosion composition according to claim 1, wherein the concentration of the reducing agent contained therein is from 50 ppm to 200 ppm.

3. The anti-corrosion composition according to claim 1, wherein the electrolytic modifier is configured to change the adsorption amount or adsorption strength of the nanoparticles at the grain boundaries.

4. The anti-corrosion composition according to any one of claims 1 to 3, wherein the nonionic metal nanoparticles have a ξ potential with an absolute value of at least 10 mV.

5. The anti-corrosion composition according to any one of claims 1 to 3, wherein the spherical nanoparticles have an average diameter, and wherein at least 99% of the spherical nanoparticles have a diameter within ±3 nm of the average diameter.

6. The anti-corrosion composition according to any one of claims 1 to 3, wherein the volatility of the carrier allows the carrier to evaporate rapidly and the nanoparticles to be deposited rapidly on the surface of the metal or metal alloy.

7. The anti-corrosion composition according to any one of claims 1 to 3, wherein the viscosity of the carrier allows for adequate coating of the surface of the metal or metal alloy.

8. A method for treating a metal or metal alloy to have improved corrosion resistance, the method comprising: An anti-corrosion composition is applied to a metal or metal alloy such that at least a portion of the nonionic metal nanoparticles are located at the grain boundaries of the metal or metal alloy to provide corrosion protection on the metal or metal alloy, said anti-corrosion composition comprising: A carrier that is readily applied to the metal or metal alloy, the carrier comprising a volatile organic solvent whose volatility allows for evaporation; Electrolytic modifier, wherein the electrolytic modifier is a reducing agent comprising one or more of nitrite, sulfite, phosphite, or polyphosphate; and Multiple nonionic metal nanoparticles are suspended in a support, and their size and shape are chosen so that they are located at the grain boundaries of the metal or metal alloy when the support is applied to the metal or metal alloy. The nonionic metal nanoparticles described herein have an average diameter or average length, wherein at least 99% of the metal nanoparticles have a diameter or length within 30% of the average diameter or average length. The nonionic metal nanoparticles described herein have a ξ potential with an absolute value of at least 10 mV, and The nonionic metal nanoparticles comprise at least one metal selected from the group consisting of gold, platinum, palladium, stainless steel, austenitic nickel-chromium alloys, and nickel-copper alloys, or... The nonionic metal nanoparticles comprise a metal selected from the group consisting of gold, silver, platinum, and palladium, and the metal forms an alloy with a metal selected from the group consisting of antimony, bismuth, and lead; and The anti-corrosion composition is applied to the metal or metal alloy, causing the volatile organic solvent to evaporate, thereby leaving only the metal nanoparticles and electrolytic modifiers on the surface of the metal or metal alloy to provide anti-corrosion protection.

9. The method of claim 8, wherein the anti-corrosion composition is applied to the metal or metal alloy by immersing the metal or metal alloy in the anti-corrosion composition for at least four hours.

10. The method according to claim 8 or 9, wherein the anti-corrosion composition is applied to the metal or metal alloy by the following steps: heating the metal or metal alloy, applying the anti-corrosion composition to the surface of the metal or metal alloy, and causing the carrier to evaporate from the surface, thereby leaving only metal nanoparticles and electrolytic modifiers on the metal or metal alloy.

11. The method of claim 8, wherein the anti-corrosion composition is applied to the metal or metal alloy by applying an electrostatic charge to the surface of the metal or metal alloy to enhance the bonding between the nanoparticles and the surface of the nanoparticles.

12. The method of claim 11, wherein the surface of the metal or metal alloy is in contact with the anti-corrosion composition for at least 30 minutes.

13. A corrosion-resistant metal or metal alloy, prepared by a method comprising the following steps: An anti-corrosion composition is applied to a metal or metal alloy such that at least a portion of the nonionic metal nanoparticles are located at the grain boundaries of the metal or metal alloy to provide anti-corrosion protection on the surface of the metal or metal alloy, said anti-corrosion composition comprising: A carrier that is readily applied to the metal or metal alloy, the carrier comprising a volatile organic solvent whose volatility allows for evaporation; An electrolytic modifier comprising a reducing agent at a concentration of 50 ppm to 200 ppm, wherein the reducing agent comprises one or more of nitrite, sulfite, phosphite, or polyphosphate; and Multiple nonionic metal nanoparticles are suspended in a support, and their size and shape are chosen so that they are located at the grain boundaries of the metal or metal alloy when the support is applied to the metal or metal alloy. The nonionic metal nanoparticles comprise at least one metal selected from the group consisting of gold, platinum, palladium, stainless steel, austenitic nickel-chromium alloys, and nickel-copper alloys, or The nonionic metal nanoparticles comprise a metal selected from the group consisting of gold, silver, platinum, and palladium, and the metal forms an alloy with a metal selected from the group consisting of antimony, bismuth, and lead; and The anti-corrosion composition is applied to the metal or metal alloy, causing the volatile organic solvent to evaporate, thereby leaving only the metal nanoparticles and electrolytic modifiers on the surface of the metal or metal alloy to provide anti-corrosion protection.

14. The corrosion-resistant metal or metal alloy according to claim 13, wherein the following steps are performed to... The anti-corrosion composition is applied to the metal or metal alloy: the metal or metal alloy is heated. The anti-corrosion composition is applied to the surface of the metal or metal alloy, and the carrier is allowed to evaporate from the surface. This leaves only metal nanoparticles and electrolytic modifiers on the metal or metal alloy.

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