Aqueous treatment medium and method for treating glass articles therewith

Abstract

The aqueous treatment medium may include water; an acid selected from the group consisting of HCl, HBr, HNO3, H2SO4, H2SO3, H3PO4, H3PO2, HOAc, citric acid, tartaric acid, ascorbic acid, EDTA, methanesulfonic acid, toluenesulfonic acid, and combinations thereof, having a concentration in the aqueous treatment medium of 0.5M to 1.5M; a salt having a concentration in the aqueous treatment medium of greater than 0M to 2M; a fluoride-containing compound selected from the group consisting of HF, NaF, NH4HF2, and combinations thereof, having a concentration in the aqueous treatment medium of 0.026M to 0.26M; and silica saturating the aqueous treatment medium.

Description

Description of Related Applications

[0001] This application claims the benefit of priority under 35 U.S.C. § 119 of U.S. Provisional Patent Application No. 63 / 400,846, filed August 25, 2022, the contents of which are relied upon and incorporated herein by reference in its entirety. [Technical Field]

[0002] This specification relates generally to aqueous media, and more particularly to aqueous media for etching glass articles. [Background technology]

[0003] Creating a roughened surface on a glass article can increase the surface area of ​​the glass article and improve the adhesion of coatings to the glass article. Various coatings can protect the glass article from damage caused by frictional contact. Methods for increasing the surface area of ​​silica-containing glass articles can be limited by their ability to consistently leach silica from the surface of the glass article. On a laboratory scale, mineral acid solutions, including hydrofluoric acid and boric acid, can be used to leach silica from the glass surface. However, the use of these acids may not be suitable for manufacturing-scale operations due to high capital costs and environmental concerns. Summary of the Invention [Problem to be solved by the invention]

[0004] Therefore, there remains a need for alternative methods of producing a textured surface on glass articles that are more environmentally friendly and suitable for use in manufacturing scale operations. [Means for solving the problem]

[0005] According to a first aspect of the present disclosure, the aqueous treatment medium may include water; an acid selected from the group consisting of HCl, HBr, HNO3, H2SO4, H2SO3, H3PO4, H3PO2, HOAc, citric acid, tartaric acid, ascorbic acid, EDTA, methanesulfonic acid, toluenesulfonic acid, and combinations thereof, wherein the acid has a concentration in the aqueous treatment medium of 0.5 M to 1.5 M; a salt having a concentration in the aqueous treatment medium of greater than 0 M to 2 M; a fluoride-containing compound selected from the group consisting of HF, NaF, NH4HF2, and combinations thereof, wherein the fluoride-containing compound has a concentration in the aqueous treatment medium of 0.026 M to 0.26 M; and silica saturating the aqueous treatment medium.

[0006] A second aspect of the disclosure may include the first aspect, wherein the acid comprises citric acid.

[0007] A third aspect of the disclosure may include either the first or second aspect, wherein the salt comprises an alkali salt.

[0008] A fourth aspect of the present disclosure may include any of the first to third aspects, wherein the salt comprises sodium chloride.

[0009] A fifth aspect of the present disclosure may include any of the first to fourth aspects, wherein the salt comprises aluminum chloride.

[0010] A sixth aspect of the present disclosure may include any of the first to fifth aspects, wherein the salt comprises sodium chloride and aluminum chloride.

[0011] A seventh aspect of the present disclosure may include the sixth aspect, wherein the ratio of aluminum to sodium is from 1:1 to 3:1.

[0012] An eighth aspect of the present disclosure may include any of the first through seventh aspects, wherein the fluoride-containing compound comprises NH 4 HF 2 .

[0013] A ninth aspect of the present disclosure may include any of the first through eighth aspects, wherein the acid comprises citric acid, the salt comprises sodium chloride, aluminum chloride or a combination thereof, and the fluoride-containing compound comprises NH4HF2.

[0014] According to a tenth aspect of the present disclosure, a method for treating a glass article may include contacting a surface of the glass article with an aqueous treatment medium to form a treated surface of the glass article. The glass article contains silica. The aqueous treatment medium includes water; an acid selected from the group consisting of HCl, HBr, HNO3, H2SO4, H2SO3, H3PO4, H3PO2, HOAc, citric acid, tartaric acid, ascorbic acid, EDTA, methanesulfonic acid, toluenesulfonic acid, and combinations thereof, at a concentration of 0.5M to 1.5M in the aqueous treatment medium; a salt at a concentration of greater than 0M to 2M in the aqueous treatment medium; a fluoride-containing compound selected from the group consisting of HF, NaF, NH4HF2, and combinations thereof, at a concentration of 0.026M to 0.26M in the aqueous treatment medium; and silica saturating the aqueous treatment medium. The aqueous treatment medium etches silica from the surface of the glass article and deposits silica on the surface of the glass article.

[0015] An eleventh aspect of the present disclosure may include the tenth aspect, wherein the glass article is formed from Type I Class A or Type I Class B glass according to ASTM Standard E438-92.

[0016] A twelfth aspect of the present disclosure may include either the tenth or eleventh aspects, wherein the glass article is formed from borosilicate glass.

[0017] A thirteenth aspect of the present disclosure may include any of the tenth to twelfth aspects, wherein the glass article is an ion-exchange strengthened glass article having a surface compressive stress layer.

[0018] A fourteenth aspect of the present disclosure may include any of the tenth to thirteenth aspects, wherein the glass article is a glass container with a sidewall at least partially enclosing an interior volume, the sidewall having an exterior surface.

[0019] A fifteenth aspect of the present disclosure may include the fourteenth aspect, wherein the aqueous treatment medium contacts an exterior surface of the sidewall.

[0020] A sixteenth aspect of the present disclosure may include any of the tenth to fifteenth aspects, wherein contacting the glass article with the aqueous treatment medium occurs for a period of time from 5 minutes to 72 hours.

[0021] A seventeenth aspect of the present disclosure may include any of the tenth to sixteenth aspects, wherein the step of contacting the glass article with the aqueous treatment medium occurs at a temperature from ambient temperature to 50°C.

[0022] An eighteenth aspect of the present disclosure may include any of the tenth to seventeenth aspects, wherein the method further includes rinsing at least the treated surface of the glass article with deionized water.

[0023] A nineteenth aspect of the present disclosure may include any of the tenth to eighteenth aspects, wherein the treated surface of the glass article comprises silica deposits, the silica deposits having a height of greater than 0 nm to 20 nm and a diameter of greater than 0 nm to 50 nm.

[0024] A twentieth aspect of the present disclosure may include any of the tenth to eighteenth aspects, wherein the method further includes applying a low-friction coating to the treated surface of the glass article.

[0025] According to a twenty-first aspect of the present disclosure, a method of producing an aqueous treatment medium includes heating a mixture comprising water; an acid selected from the group consisting of HCl, HBr, HNO3, H2SO4, H2SO3, H3PO4, H3PO2, HOAc, citric acid, tartaric acid, ascorbic acid, EDTA, methanesulfonic acid, toluenesulfonic acid, and combinations thereof; a fluoride-containing compound selected from the group consisting of HF, NaF, NH4HF2, and combinations thereof; and silica powder to a temperature of 25°C to 95°C; cooling the mixture to ambient temperature; filtering the undissolved silica powder from the mixture; and adding one or more salts to the mixture to form the aqueous treatment medium.

[0026] A twenty-second aspect of the present disclosure may include the twenty-first aspect, wherein the water is deionized water.

[0027] A twenty-third aspect of the present disclosure may include either the twenty-first or twenty-second aspect, wherein the acid comprises citric acid.

[0028] A twenty-fourth aspect of the present disclosure may include any of the twenty-first to twenty-third aspects, wherein the salt comprises an alkali salt.

[0029] A twenty-fifth aspect of the present disclosure may include any of the twenty-first to twenty-fourth aspects, wherein the salt comprises sodium chloride.

[0030] A twenty-sixth aspect of the present disclosure may include any of the twenty-first to twenty-fifth aspects, wherein the salt comprises aluminum chloride.

[0031] A twenty-seventh aspect of the present disclosure may include any of the twenty-first to twenty-sixth aspects, wherein the salt comprises sodium chloride and aluminum chloride.

[0032] A twenty-eighth embodiment of the present disclosure may include the twenty-seventh embodiment, wherein the ratio of aluminum to sodium is from 1:1 to 3:1.

[0033] A twenty-ninth aspect of the present disclosure can include any of the twenty-first through twenty-eighth aspects, wherein the fluoride-containing compound comprises NH 4 HF 2 .

[0034] A thirtieth aspect of the present disclosure may include any of the twenty-first to twenty-ninth aspects, wherein the silica powder comprises silica particles having a particle size of 100 nm to 1000 nm.

[0035] A thirty-first aspect of the present disclosure can include any of the twenty-first to thirtieth aspects, wherein the acid comprises citric acid, the salt comprises sodium chloride, aluminum chloride, or a combination thereof, and the fluoride-containing compound comprises NH4HF2.

[0036] A thirty-second aspect of the present disclosure can include any of the twenty-first to thirty-first aspects, wherein the concentration of the acid in the aqueous treatment medium is from 0.5M to 1.5M.

[0037] A thirty-third aspect of the present disclosure may include any of the twenty-first to thirty-second aspects, wherein the concentration of salt in the aqueous treatment medium is from greater than 0M to 2M.

[0038] A thirty-fourth aspect of the present disclosure can include any of the twenty-first to thirty-third aspects, wherein the concentration of the fluoride-containing compound in the aqueous treatment medium is 0.026M to 0.26M.

[0039] A thirty-fifth aspect of the present disclosure can include any of the twenty-first through thirty-fourth aspects, wherein the aqueous treatment medium is saturated with silica.

[0040] Additional features and advantages will be set forth in the following detailed description, and in part will become readily apparent to those skilled in the art from that description, or may be learned by practicing the embodiments described herein, including the following detailed description, claims, and accompanying drawings.

[0041] It should be understood that both the foregoing general description and the following detailed description describe various embodiments and are intended to provide an overview or framework for understanding the nature and character of the claimed subject matter. The accompanying drawings are included to provide a further understanding of the various embodiments, and are incorporated into and constitute a part of this specification. The drawings illustrate various embodiments described herein, and together with the description, serve to explain the principles and operation of the claimed subject matter. [Brief explanation of the drawings]

[0042] [Figure 1] 1 is a schematic diagram of a glass container according to one or more embodiments described herein. [Figure 2] Scanning electron microscope (SEM) image of the surface of a vial etched with sample 1 of aqueous treatment medium according to an embodiment of Example 2. [Figure 3] SEM image of the surface of a vial etched with sample 9 of aqueous treatment medium according to an embodiment of Example 2 [Figure 4] SEM image of the surface of a vial etched with sample 18 of aqueous treatment medium according to an embodiment of Example 2 [Figure 5] SEM image of the surface of a vial etched with sample 19 of aqueous treatment medium according to an embodiment of Example 2 [Figure 6] Confocal image of the surface of a vial etched with sample 1 of aqueous treatment medium according to an embodiment of Example 2 [Figure 7] Confocal image of the surface of a vial etched with sample 9 of aqueous treatment medium according to an embodiment of Example 2 [Figure 8] Confocal image of the surface of a vial etched with a sample 17 of aqueous treatment medium according to an embodiment of Example 2 [Figure 9] Confocal image of the surface of a vial etched with a sample 24 of aqueous treatment medium according to an embodiment of Example 2 [Figure 10]Atomic force microscope (AFM) image of the surface of a vial etched with sample 1 of aqueous treatment medium according to an embodiment of Example 2. [Figure 11] AFM image of the surface of a vial etched with sample 5 of aqueous treatment medium according to an embodiment of Example 2 [Figure 12] AFM image of the surface of a vial etched with a sample 11 of aqueous treatment medium according to an embodiment of Example 2. [Figure 13] Graph showing coefficient of friction data for coated vials according to an embodiment of Example 3. DETAILED DESCRIPTION OF THE INVENTION

[0043] Reference will now be made in detail to various embodiments of aqueous treatment media for treating glass articles. Whenever possible, the same reference numbers are used throughout the drawings to refer to the same or similar parts. In embodiments, the aqueous treatment medium may include water, an acid, a salt, a fluoride-containing compound, and silica. Embodiments of the aqueous treatment medium may be used in methods of treating glass articles, the methods including contacting a surface of the glass article with the aqueous treatment medium to form a treated surface of the glass article. Embodiments of the aqueous treatment medium and methods of making and using the same are described in further detail herein.

[0044] Ranges may be expressed herein as from "about" one particular value, and / or to "about" another particular value. When such a range is expressed, another embodiment includes from the one particular value and / or to the other particular value. Similarly, when values ​​are expressed as approximations, by use of the antecedent "about," it will be understood that the particular value forms another embodiment. It will be further understood that the endpoints of each of the ranges are significant both in relation to the other endpoint, and independently of the other endpoint.

[0045] As used herein, nouns include plural referents unless the context clearly indicates otherwise. Thus, for example, reference to an element includes references having two or more of such elements unless the context clearly indicates otherwise.

[0046] Glass articles, including glass containers, can be coated to protect them from damage, including damage caused by frictional contact between glass articles. Creating a textured surface on a glass article can improve the adhesion of a coating to the surface of the glass article. Traditional methods for texturing the surface of a glass article can include leaching silica from the surface of the glass article. At the laboratory scale, mineral acid solutions, such as solutions containing hydrofluoric acid or boric acid, can be used to leach silica from the glass surface. However, the use of such solutions may not be suitable for producing a textured surface on glass articles in manufacturing-scale operations due to high capital costs and environmental concerns. Therefore, there remains a need for alternative methods for forming textured surfaces on glass articles that are more environmentally friendly and suitable for use in manufacturing-scale operations. Embodiments of the aqueous treatment medium described herein may be suitable for use in manufacturing-scale operations and may be more environmentally friendly than conventional etching solutions. Without intending to be bound by theory, embodiments of the aqueous treatment medium described herein may be more environmentally friendly and suitable for manufacturing scale operations due to their relatively low fluoride content.

[0047] In embodiments, the aqueous treatment medium may include water. For example, without limitation, the water may include one or more of deionized water, tap water, distilled water, or fresh water. In embodiments, one or more components of the aqueous treatment medium may be dissolved in the water.

[0048] The aqueous treatment medium may include an acid. The acid may be selected from the group consisting of HCl, HBr, HNO3, H2SO4, H2SO3, H3PO4, H3PO2, HOAc, citric acid, tartaric acid, ascorbic acid, EDTA, methanesulfonic acid, toluenesulfonic acid, and combinations thereof. In embodiments, the aqueous treatment medium may include multiple acids. For example, the aqueous treatment medium may include two, three, four, five, or more acids. In embodiments, the acid may include citric acid. In embodiments, the acid may consist essentially of, or consist of, citric acid.

[0049] In embodiments, the concentration of the acid in the aqueous treatment medium can be from 0.5 molar (M) to 1.5 M. For example, without limitation, the concentration of the acid in the aqueous treatment medium can be from 0.5 M to 1.5 M, 0.7 M to 1.5 M, 0.9 M to 1.5 M, 1.1 M to 1.5 M, 1.3 M to 1.5 M, 0.5 M to 1.3 M, 0.5 M to 1.1 M, 0.5 M to 0.9 M, 0.5 M to 0.7 M, or any combination or subset of these ranges.

[0050] Without intending to be bound by theory, when the acid comprises one or more of HCl, HBr, HNO, HSO, HSO, HPO, HPO, HOAc, citric acid, tartaric acid, ascorbic acid, EDTA, methanesulfonic acid, and toluenesulfonic acid, and the acid has a concentration of 0.5 M to 1.5 M, the acid can act to dissolve silica from portions of the surface of the glass article without removing silica from other portions of the surface of the glass article, thereby imparting texture to the surface of the glass article that comes into contact with the aqueous treatment medium without damaging the structure of the glass article.

[0051] The aqueous treatment medium may include a salt. In embodiments, the concentration of the salt in the aqueous treatment medium may be from greater than 0 M to 2.0 M. For example, the concentration of the salt in the aqueous treatment medium may be from greater than 0 M to 2.0 M, from greater than 0 M to 1.8 M, from greater than 0 M to 1.6 M, from greater than 0 M to 1.4 M, from greater than 0 M to 1.2 M, from greater than 0 M to 1.0 M, from greater than 0 M to 0.8 M, from greater than 0 M to 0.6 M, from greater than 0 M to 0.4 M, from greater than 0 M to 0.2 M, 0.2 M to 2.0 M, 0.4 M to 2.0 M, 0.6 M to 2.0 M, 0.8 M to 2.0 M, 1.0 M to 2.0 M, 1.2 M to 2.0 M, 1.4 M to 2.0 M, 1.6 M to 2.0 M, 1.8 M to 2.0 M, or any combination or subset of ranges thereof.

[0052] In embodiments, the salt may include an alkali salt. As used herein, "alkali salt" includes alkali metals that are Group 1 metals under the IUPAC nomenclature, including lithium (Li), sodium (Na), potassium (K), rubidium (Rb), cesium (Cs), and francium (Fr). For example, without limitation, the salt may include sodium chloride or potassium chloride. In embodiments, the salt may include sodium chloride. In embodiments, the salt may include other metal salts, such as aluminum chloride, in addition to the alkali salt. In embodiments, the aqueous treatment medium may include multiple salts. For example, without limitation, the aqueous treatment medium may include two, three, four, five, or more salts. In embodiments, the aqueous treatment medium may include sodium chloride and aluminum chloride. In such embodiments, the molar ratio of aluminum to sodium may be 1:1 to 3:1. For example, without limitation, the molar ratio of aluminum to sodium can be from 1:1 to 3:1, from 1.5:1 to 3:1, from 2:1 to 3:1, from 2.5:1 to 3:1, from 1:1 to 2.5:1, from 1:1 to 2:1, from 1:1 to 1.5:1, or any combination or subset of ranges. Without intending to be bound by theory, the inclusion of salts in the aqueous treatment medium can alter the etch rate of glass articles treated with the medium.

[0053] Without intending to be bound by theory, the concentration of salt in the aqueous treatment medium affects the degree to which the surface area of ​​a glass article in contact with the aqueous treatment medium is textured. For example, as the concentration of acid in the aqueous treatment medium increases, the density and size of silica deposits on the surface of a glass article treated with the aqueous treatment medium increases.

[0054] The aqueous treatment medium may further include a fluoride-containing compound. The fluoride-containing compound may be selected from the group consisting of HF, NaF, NH4HF2, and combinations thereof. In embodiments, the aqueous treatment medium may include multiple fluoride-containing compounds. For example, without limitation, the aqueous treatment medium may include two or three fluoride-containing compounds. In embodiments, the fluoride-containing compound may include NH4HF2. In embodiments, the fluoride-containing compound may consist essentially of or consist of NH4HF2. Without intending to be bound by theory, the fluoride-containing compound may dissociate in the aqueous treatment medium and serve as a source of fluoride ions in the aqueous treatment medium.

[0055] In embodiments, the concentration of the fluoride-containing compound in the aqueous treatment medium is from 0.026 M to 0.26 M. For example, without limitation, the concentration of the fluoride-containing compound in the aqueous treatment medium can be from 0.026 M to 0.26 M, 0.05 M to 0.26 M, 0.10 M to 0.26 M, 0.15 M to 0.26 M, 0.20 M to 0.26 M, 0.026 M to 0.20 M, 0.026 M to 0.15 M, 0.026 M to 0.10 M, 0.026 M to 0.05 M, or any combination or subset of these ranges.

[0056] Without intending to be bound by theory, the concentration of the fluoride-containing compound affects the degree to which the surface area of ​​the glass article in contact with the aqueous treatment medium is textured. For example, as the concentration of the fluoride-containing compound in the aqueous treatment medium increases, the density and size of silica deposits on the surface of the glass article in contact with the aqueous treatment medium will increase.

[0057] The aqueous treatment medium further comprises silica (SiO2). In embodiments, the aqueous treatment medium may be saturated with silica. As described herein, the aqueous treatment medium will be saturated with silica when no more silica can be dissolved in the aqueous treatment medium. The amount of silica required to saturate the aqueous treatment medium may vary depending on the temperature of the aqueous treatment medium, the pressure at which the aqueous treatment medium is maintained, and the concentrations of acids, salts, and fluoride-containing compounds in the aqueous treatment medium.

[0058] Without intending to be bound by theory, an aqueous treatment medium saturated with silica can cause silica to dissolve from the surface of the glass article in the aqueous treatment medium and deposit from the aqueous treatment medium onto the surface of the glass article, thereby imparting texture to the surface of the glass article. This effect can occur because local undersaturation of silica in the aqueous treatment medium can dissolve a portion of the surface of the glass article, while local supersaturation of silica in the aqueous treatment medium can deposit silica from the aqueous treatment medium onto the surface of the glass article. Dissolution of silica from the surface of the glass article can leave depressions in the surface of the glass article, and deposition of silica on the surface of the glass article can create protrusions on the surface of the glass article. Thus, glass articles containing silica can be textured by exposing the glass article to an aqueous treatment medium saturated with silica.

[0059] This description now turns to a method of producing an aqueous treatment medium. In embodiments, the method of producing an aqueous treatment medium can include heating a mixture including water, acid, and silica powder to a temperature of 25° C. to 95° C. For example, the mixture can be heated to a temperature of 25° C. to 95° C., 35° C. to 95° C., 45° C. to 95° C., 55° C. to 95° C., 65° C. to 95° C., 75° C. to 95° C., 85° C. to 95° C., 25° C. to 85° C., 25° C. to 75° C., 25° C. to 65° C., 25° C. to 55° C., 25° C. to 45° C., 25° C. to 35° C., or any combination or subset of these ranges. Without intending to be bound by theory, heating the mixture can increase the solubility of silica in the mixture and the rate of dissolution of silica powder in the mixture.

[0060] The water may be any of those previously described with respect to the aqueous treatment medium. In embodiments, the water may be deionized water. As previously described, the acid may be selected from the group consisting of HCl, HBr, HNO3, H2SO4, H2SO3, H3PO4, H3PO2, HOAc, citric acid, tartaric acid, ascorbic acid, EDTA, methanesulfonic acid, toluenesulfonic acid, and combinations thereof.

[0061] In embodiments, the silica powder may include silica particles having an average particle size of 100 nm to 1000 nm. For example, without limitation, the silica particles may have an average particle size of 100 nm to 1000 nm, 300 nm to 1000 nm, 500 nm to 1000 nm, 700 nm to 1000 nm, 900 nm to 1000 nm, 100 nm to 800 nm, 100 nm to 600 nm, 100 nm to 400 nm, 100 nm to 200 nm, or any combination or subset of these ranges. Without intending to be bound by theory, when the silica particles have an average particle size of 100 nm to 1000 nm, the silica can be readily dissolved in the aqueous treatment medium, and once the aqueous treatment medium is saturated with silica, the undissolved particles can be filtered from the aqueous treatment medium.

[0062] The method for producing an aqueous treatment medium may include a step of cooling the mixture to ambient temperature after heating. Cooling may be accomplished by any suitable means, including, but not limited to, active cooling and passive cooling. In embodiments, the mixture is passively cooled to ambient temperature. Without intending to be bound by theory, as the mixture cools, the solubility of silica in the mixture decreases. Dissolving silica in the mixture at an elevated temperature and subsequently cooling the mixture can facilitate the production of a silica-saturated mixture at a lower temperature. It should be noted that silica may precipitate from the mixture during the cooling step.

[0063] In an embodiment, the method for producing the aqueous treatment medium may include filtering the insoluble silica powder from the mixture. The insoluble silica powder may be filtered using any filtering means capable of removing insoluble silica particles having an average particle size of 100 nm to 1000 nm. For example, without limitation, suitable filtering means include filter paper and cheesecloth, depending on the size of the particles to be removed from the aqueous treatment medium. Without intending to be bound by theory, unfiltered silica particles may come into contact with the glass surface and cause visible defects on the glass surface. Filtering excess silica particles from the aqueous treatment medium can prevent contact between the silica particles and the glass surface in contact with the aqueous treatment medium.

[0064] The method of producing the aqueous treatment medium may include adding one or more salts to the mixture to form the aqueous treatment medium. The salt may be any salt described above with respect to the composition of the aqueous treatment medium. In embodiments, the salt may include sodium chloride, aluminum chloride, or a combination thereof. It should be understood that embodiments of the aqueous treatment medium formed by the methods described herein may have a composition as described above in this specification.

[0065] The description now turns to methods of treating a glass article with an aqueous treatment medium. In embodiments, the method of treating a glass article may include contacting a surface of the glass article with an aqueous treatment medium, as described above. In embodiments, the glass article includes silica. The aqueous treatment medium may etch silica from the surface of the glass article and deposit silica on the surface of the glass article to impart texture to the treated surface of the glass article.

[0066] In embodiments, the glass article can be formed from a glass composition that meets the criteria for Type I, Class A (Type IA) or Type I, Class B (Type IB) glass under ASTM Standard E438-92 (2011), entitled "Standard Specification for Glasses in Laboratory Apparatus." In embodiments, the glass can be a borosilicate glass that meets these criteria, or an aluminosilicate glass that meets the same criteria (except for composition). Borosilicate glasses meet Type I (A or B) criteria and are routinely used in pharmaceutical packaging. Examples of borosilicate glasses include, without limitation, Corning® Pyrex® 7740, 7800, Wheaton 180, 200, and 400, Schott Duran®, Shott Fiolax®, KIMAX® N-51A, Gerresheimer GX-51 Flint, and the like. Exemplary aluminosilicate glasses include Valor® from Corning Incorporated. It should be understood that the methods described herein may be used with other glass compositions, including borosilicate and aluminosilicate glasses that do not meet the criteria set forth above.

[0067] In embodiments, the glass article may be an ion-exchange strengthened glass article having a surface compressive stress layer. In embodiments, the ion-exchange strengthened glass article may have a compressive stress of about 250 MPa or more, 300 MPa or more, or even about 350 MPa or more at the surface of the ion-exchange strengthened glass article. In embodiments, the compressive stress may be about 400 MPa or more, or even about 450 MPa or more at the surface of the glass. In some embodiments, the compressive stress may be about 500 MPa or more, or even about 550 MPa or more at the surface of the glass. In still other embodiments, the compressive stress may be about 650 MPa or more, or even about 750 MPa or more at the surface of the glass. The compressive stress in the ion-exchange strengthened glass article generally extends to a depth of layer (DOL) of at least about 10 μm. In some embodiments, the ion-exchange strengthened glass article may have a depth of layer greater than about 25 μm, or even greater than about 50 μm. In some other embodiments, the layer depth may be up to about 75 μm, or even up to about 100 μm. This ion exchange strengthening may be performed in a molten salt bath maintained at a temperature of about 350° C. to about 600° C. To achieve the desired compressive stress, the glass article may be immersed in the salt bath for less than about 30 hours, or even less than about 20 hours. In embodiments, the glass article may be immersed for less than about 15 hours, or even less than about 12 hours. In other embodiments, the glass article may be immersed for less than about 10 hours. For example, in one embodiment, to achieve the desired layer depth and compressive stress, the glass article is immersed in a 100% KNO salt bath at about 450° C. for about 5 to about 8 hours.

[0068] In embodiments, the glass article may be a glass container including a glass body at least partially enclosing an interior volume, with a sidewall having an exterior surface. Referring to FIG. 1 , by way of example, a glass container, such as a glass container for storing a pharmaceutical composition, is shown schematically in cross section. The glass container 100 generally includes a glass article having a glass body 102. The glass body 102 extends between an interior surface 104 and an exterior surface 106 and generally encloses an interior volume 108. In the embodiment of the glass container 100 shown in FIG. 1 , the glass body 102 generally includes a wall portion 110 and a floor portion 112. The wall portion 110 and the floor portion 112 may generally have thicknesses ranging from about 0.5 mm to about 3.0 mm. The wall portion 110 transitions to the floor portion 112 through a heel portion 114. Although the glass container 100 is shown in FIG. 1 as having a particular shape (i.e., a vial), it should be understood that the glass container 100 may have other shapes, including, without limitation, a Vacutainer®, a cartridge, a syringe, a syringe barrel, an ampoule, a bottle, a flask, a vial, a tube, a beaker, and the like.

[0069] In embodiments, the aqueous treatment medium may contact the exterior surface 106 of the glass body 102. In embodiments, the aqueous treatment medium may be prevented from contacting the interior surface 104 of the glass article. This may be done by plugging or otherwise closing the opening of the glass container to prevent the aqueous treatment medium from entering the interior volume 118 of the glass container 100.

[0070] In embodiments, the step of contacting the glass article with the aqueous treatment medium may be carried out for a period of time from 5 minutes to 72 hours. For example, without limitation, the step of contacting the glass article with the aqueous treatment medium may be carried out for a period of time from 5 minutes to 72 hours, 30 minutes to 72 hours, 1 hour to 72 hours, 6 hours to 72 hours, 12 hours to 72 hours, 24 hours to 72 hours, 48 ​​hours to 72 hours, 5 minutes to 48 hours, 5 minutes to 24 hours, 5 minutes to 12 hours, 5 minutes to 6 hours, 5 minutes to 1 hour, 5 minutes to 30 minutes, or any combination or subset of these ranges.

[0071] In embodiments, contacting the glass article with the aqueous treatment medium may occur at a temperature between ambient temperature and 50°C. For example, without limitation, contacting the glass article with the aqueous treatment medium may occur at a temperature between ambient temperature and 50°C, between 20°C and 50°C, between 25°C and 50°C, between 30°C and 50°C, between 35°C and 50°C, between 35°C and 50°C, between 40°C and 50°C, between 45°C and 50°C, between 20°C and 45°C, between 20°C and 40°C, between 20°C and 35°C, between 20°C and 30°C, between 20°C and 25°C, or any combination or subset of these ranges. As used herein, "ambient temperature" refers to the temperature of the environment at a particular location. For example, without limitation, the ambient temperature may be about 20°C. Without intending to be bound by theory, the temperature and time that the glass article is contacted with the aqueous treatment medium to achieve a desired level of surface roughening may be inversely proportional. For example, as the temperature at which the glass article and the aqueous treatment medium are in contact increases, the time that the glass article and the aqueous treatment medium are in contact will decrease to achieve a desired level of surface roughening.

[0072] In embodiments, the method of treating a glass article may further include rinsing at least the treated surface of the glass article with water, which in some embodiments may be deionized water. Rinsing the surface of the glass article may remove the aqueous treatment medium from the treated surface of the glass article and stop etching of silica from or deposition of silica on the treated surface of the glass article.

[0073] In embodiments, the treated surface of the glass article may include silica deposits. The silica deposits may be dome-shaped in one or more embodiments. The silica deposits may have a height of greater than 0 nm to 20 nm. For example, without limitation, the silica deposits may have a height of greater than 0 nm to 20 nm, 5 nm to 20 nm, 10 nm to 20 nm, 15 nm to 20 nm, 0 nm to 15 nm, 0 nm to 10 nm, 0 nm to 5 nm, or any combination or subset of these ranges. The height of the silica deposits may be measured by atomic force microscopy. The height of the silica deposits may be relative to the base surface of the glass article. In embodiments, the silica deposits may have a diameter of greater than 0 nm to 50 nm. For example, without limitation, the silica deposits may have a diameter of greater than 0 nm to 50 nm, 10 nm to 50 nm, 20 nm to 50 nm, 30 nm to 50 nm, 40 nm to 50 nm, greater than 0 nm to 40 nm, greater than 0 nm to 30 nm, greater than 0 nm to 20 nm, greater than 0 nm to 10 nm, or any combination or subset of these ranges. The diameter of the silica deposits may be measured by atomic force microscopy. Without intending to be bound by theory, the silica deposits on the treated glass surface may be bonded to the treated glass surface by a combination of van der Waals forces, hydrogen bonding, and capillary forces.

[0074] The method for treating the surface of a glass article may further include applying a low-friction coating to the treated surface of the glass article. The low-friction coating may be applied to the treated surface by any suitable means, such as spraying the low-friction coating onto the treated surface. The low-friction coating reduces the coefficient of friction of the portion of the body at which it is coated, thereby reducing the occurrence of wear and surface damage on the exterior surface of the glass body. Essentially, the coating allows the container to "slide" relative to another object (or container), thereby reducing the likelihood of surface damage on the glass. Furthermore, the low-friction coating also cushions the impact of the glass container against the body, thereby reducing the impact of blunt impact damage to the glass container. Suitable coatings are disclosed in U.S. Patent Application Nos. 13 / 780,754, filed February 28, 2013, and 14 / 075,630, filed November 8, 2013, each of which is incorporated herein by reference in its entirety. However, it should be understood that other types of coatings may be applied to the treated surface of the glass article.

[0075] As previously mentioned, coatings can have a low coefficient of friction. The coefficient of friction (μ) of a portion of a glass container coated with a low-friction coating can be lower than the coefficient of friction of the surface of an uncoated glass container formed from the same glass composition. The coefficient of friction (μ) is a quantitative measure of friction between two surfaces and is a function of the mechanical and chemical properties of the first and second surfaces, including surface roughness and environmental conditions such as temperature and humidity. As used herein, a measured coefficient of friction for a coated glass container is reported as the coefficient of friction between the exterior surface of a first glass container and the exterior surface of a second glass container identical to the first glass container, where the first and second glass containers have the same body and coating composition (if applied) and are exposed to the same environment before, during, and after manufacture. Unless otherwise specified, the coefficient of friction refers to the maximum coefficient of friction measured with a 30 N normal load measured on a vial-on-vial test fixture. However, it should be understood that a coated glass container that exhibits a maximum coefficient of friction at a particular applied load will also exhibit the same or better (i.e., lower) maximum coefficient of friction at lower loads. For example, if a coated glass container exhibits a maximum coefficient of friction of 0.5 or less under an applied load of 50 N, the coated glass container will also exhibit a maximum coefficient of friction of 0.5 or less under an applied load of 25 N.

[0076] In the embodiments described herein, the coefficient of friction of glass containers (both coated and uncoated) is measured with a vial-on-vial test fixture. This measurement technique and corresponding instrumentation are described in U.S. Patent Application No. 13 / 780,754, filed February 28, 2013, which is incorporated herein by reference in its entirety.

[0077] In embodiments described herein, the portion of glass container coated with the low-friction coating has a coefficient of friction of about 0.7 or less against a similarly coated glass container, as determined in a vial-on-vial test fixture. In other embodiments, the coefficient of friction may be about 0.6 or less, or even 0.5 or less. In some embodiments, the portion of glass container coated with the low-friction coating has a coefficient of friction of about 0.4 or less, or even about 0.3 or less. Coated glass containers having a coefficient of friction of about 0.7 or less generally have improved resistance to frictional damage and, as a result, improved mechanical properties. For example, conventional glass containers (without a low-friction coating) may have a coefficient of friction greater than 0.7.

[0078] In some embodiments described herein, the coefficient of friction of a portion of a glass container coated with a low-friction coating is at least 20% lower than the coefficient of friction of the surface of an uncoated glass container formed from the same glass composition. For example, the coefficient of friction of a portion of a glass container coated with a low-friction coating may be at least 20% lower, at least 25% lower, at least 30% lower, at least 40% lower, or even at least 50% lower than the coefficient of friction of the surface of an uncoated glass container formed from the same glass composition. [Example]

[0079] The embodiments described herein will be further clarified by the following examples.

[0080] Example 1 - Samples of aqueous treatment media Aqueous treatment medium samples were prepared by heating a mixture of citric acid, ammonium bifluoride (NH4HF2), and fine silica powder in deionized water at 45°C for 24 hours. Each sample was saturated with silica (SiO2). The mixture was cooled to room temperature and filtered to remove undissolved silica. Varying amounts of aluminum chloride (AlCl3) and sodium chloride (NaCl) were added to the mixture to form the aqueous treatment medium samples. The concentrations of citric acid, sodium chloride, aluminum chloride, and ammonium bifluoride in each aqueous treatment medium sample are given in Table 1.

[0081] [Table 1]

[0082] Example 2 - Etching of Glass Articles with Samples of Aqueous Treatment Media Ion-exchanged "Valor" glass pharmaceutical vials from Corning Incorporated were contacted with each sample of aqueous treatment medium listed in Table 1. Each vial was etched in a bath of the aqueous treatment medium sample for 24 hours at room temperature. Each vial was then rinsed with deionized water and stored in deionized water.

[0083] The surface morphology of each vial was characterized using images of the vial captured under top-down illumination. The relative intensity of light scattered from each vial was measured based on the grayscale intensity of the vial image. The relative intensity of light scattered from each vial is included in Table 2.

[0084] [Table 2]

[0085] Vials etched in samples of aqueous treatment media containing no salt or aluminum chloride (Samples 1–3 and 10–18) appeared smooth and comparable to reference vials not exposed to the aqueous treatment media. Vials etched in samples of aqueous treatment media containing sodium chloride (Samples 4–9) contained heterogeneous macroscopic deposits on the vial surfaces that had come into contact with the aqueous treatment media. As the ammonium bifluoride concentration increased, the density and size of these deposits increased. For example, vials etched with Sample 6 contained larger deposits on the vial surface than vials etched with Sample 4. Vials etched with samples of mixed salt aqueous treatment media containing 0.26 M ammonium bifluoride (Samples 21 and 24) showed macroscopic deposits; however, when the ammonium bifluoride concentration was 0.13 M or 0.026 M (Samples 19–20 and 22–23), the vial surfaces appeared smooth.

[0086] The surface morphology of the vials etched with the aqueous treatment medium samples was observed by scanning electron microscopy (SEM). Figure 2 shows an SEM image of the surface of a vial etched with aqueous treatment medium Sample 1. Figure 3 shows an SEM image of the surface of a vial etched with aqueous treatment medium Sample 9. Figure 4 shows an SEM image of the surface of a vial etched with aqueous treatment medium Sample 18, and Figure 5 shows an SEM image of the surface of a vial etched with aqueous treatment medium Sample 19. The macroscopic deposits observed on the vial etched with aqueous treatment medium Sample 9 were identified as crystalline formations with a composition similar to the base glass. The vial etched with the mixed salt solution of Sample 19 had unevenly distributed depressions on the treated surface of the vial, representing the removal of glass material from the glass surface.

[0087] The surface morphology of vials etched with the aqueous treatment medium samples was quantified by confocal imaging. Figure 6 shows a confocal image of the surface of a vial etched with aqueous treatment medium Sample 1. Figure 7 shows a confocal image of the surface of a vial etched with aqueous treatment medium Sample 9. Figure 8 shows a confocal image of the surface of a vial etched with aqueous treatment medium Sample 17, and Figure 9 shows a confocal image of the surface of a vial etched with aqueous treatment medium Sample 24. Statistical analysis of the surface roughness revealed a high sensitivity of the vial surface to the interaction between the concentration of ammonium bifluoride and the ratio of aluminum chloride to sodium chloride salts in the aqueous treatment medium.

[0088] The surfaces of vials treated with aqueous treatment media samples were analyzed by atomic force microscopy (AFM). Typically, AFM can characterize feature sizes with a spatial resolution of approximately 10 nm. Figure 10 shows an AFM image of the surface of a vial etched with aqueous treatment media Sample 1. Figure 11 shows an AFM image of the surface of a vial etched with aqueous treatment media Sample 5. Figure 12 shows an AFM image of the surface of a vial etched with aqueous treatment media Sample 11. In addition, Figure 12 shows a plot of the height and depth of silica deposits and pits on the surface of a vial etched with Sample 11. In vials etched with salt-free aqueous treatment media samples (Samples 1–3), the thickness of the deposited particulates was approximately 10 nm. Vials etched with aluminum-containing aqueous treatment media samples (Samples 10–24) developed pits approximately 10 nm deep.

[0089] Example 3 - Coating of glass articles treated with samples of aqueous treatment media Ion-exchanged "Valor" glass pharmaceutical vials were etched for 24 hours at room temperature in aqueous treatment medium samples 1, 25, and 26. Aqueous treatment medium samples 25 and 26 were prepared by the procedure described in Example 1. The compositions of aqueous treatment medium samples 1, 25, and 26 are included in Table 3.

[0090] [Table 3]

[0091] The etched vials were dip-coated in a 3 wt. % solution of CP1™ polyimide from Nexolve™. CP1 is a colorless fluorinated polyimide that is soluble in its fully imidized form. Additionally, the etched vials were dip-coated in a coating containing 3 wt. % of CP1 and silica nanoparticles. The silica nanoparticles had a diameter of approximately 20 nm and were added at 5 wt. % of the CP1. Additionally, a reference vial that had not been etched with the aqueous treatment medium was coated with a 3 wt. % solution of CP1 and a 3 wt. % solution of CP1 and silica nanoparticles. The coated vials were cured at a temperature of 360°C for 15 minutes.

[0092] The coefficient of friction of the coated vials was determined under 10 x 10 N scratch test conditions. Specifically, two vials were mounted perpendicular to each other. One vial was traversed at 45° with a specific normal force applied to the other vial, and the coefficient of friction was measured. The coefficient of friction was measured at 50% relative humidity and ambient temperature. The normal force was 10 N over 10 repeated scratches. The coefficient of friction data for each of the vials is shown in Figure 13. Additionally, the average coefficient of friction for each vial is listed in Table 4. The vials etched with the aqueous treatment medium had a lower coefficient of friction than the reference vial.

[0093] [Table 4]

[0094] The present disclosure relates to various embodiments of an aqueous treatment medium, a method for making the aqueous treatment medium, and a method for using the aqueous treatment medium. In embodiments, the aqueous treatment medium includes water, an acid, a salt, a fluoride-containing compound, and silica, and the aqueous treatment medium is saturated with silica. The aqueous treatment medium can function to impart texture to the surface of a glass article treated with the aqueous treatment medium. The texture can improve adhesion of a coating to the glass article, thereby reducing the coefficient of friction of the glass article.

[0095] It will be apparent to those skilled in the art that various modifications and variations can be made to the embodiments described herein without departing from the spirit and scope of the claimed subject matter. Thus, it is intended that this specification cover modifications and variations of the various embodiments described herein, provided such modifications and variations come within the scope of the appended claims and their equivalents.

[0096] Preferred embodiments of the present invention will be described below in detail.

[0097] Embodiment 1 In the aqueous treatment medium, water, an acid selected from the group consisting of HCl, HBr, HNO3, H2SO4, H2SO3, H3PO4, H3PO2, HOAc, citric acid, tartaric acid, ascorbic acid, EDTA, methanesulfonic acid, toluenesulfonic acid, and combinations thereof, wherein the acid has a concentration in the aqueous treatment medium of 0.5M to 1.5M; a salt having a concentration in the aqueous treatment medium of greater than 0M to 2M; a fluoride-containing compound selected from the group consisting of HF, NaF, NH4HF2, and combinations thereof, wherein the fluoride-containing compound has a concentration in the aqueous treatment medium of 0.026M to 0.26M; and silica saturating said aqueous treatment medium; An aqueous treatment medium comprising:

[0098] Embodiment 2 2. The aqueous treatment medium of embodiment 1, wherein the acid comprises citric acid.

[0099] Embodiment 3 2. The aqueous treatment medium of embodiment 1, wherein the salt comprises an alkali salt.

[0100] Embodiment 4 2. The aqueous treatment medium of embodiment 1, wherein the salt comprises sodium chloride.

[0101] Embodiment 5 2. The aqueous treatment medium of embodiment 1, wherein the salt comprises aluminum chloride.

[0102] Embodiment 6 2. The aqueous treatment medium of embodiment 1, wherein the salts comprise sodium chloride and aluminum chloride.

[0103] Embodiment 7 7. The aqueous treatment medium of embodiment 6, wherein the ratio of aluminum to sodium is from 1:1 to 3:1.

[0104] Embodiment 8 2. The aqueous treatment medium of embodiment 1, wherein the fluoride-containing compound comprises NH4HF2.

[0105] Embodiment 9 2. The aqueous treatment medium of embodiment 1, wherein the acid comprises citric acid, the salt comprises sodium chloride, aluminum chloride, or a combination thereof, and the fluoride-containing compound comprises NH4HF2.

[0106] Embodiment 10 A method of treating a glass article, comprising contacting a surface of the glass article with an aqueous treatment medium to form a treated surface of the glass article; the glass article comprises silica; The aqueous treatment medium is water, an acid selected from the group consisting of HCl, HBr, HNO3, H2SO4, H2SO3, H3PO4, H3PO2, HOAc, citric acid, tartaric acid, ascorbic acid, EDTA, methanesulfonic acid, toluenesulfonic acid, and combinations thereof, wherein the acid has a concentration in the aqueous treatment medium of 0.5M to 1.5M; a salt having a concentration in the aqueous treatment medium of greater than 0M to 2M; a fluoride-containing compound selected from the group consisting of HF, NaF, NH4HF2, and combinations thereof, wherein the fluoride-containing compound has a concentration in the aqueous treatment medium of 0.026M to 0.26M; and silica saturating said aqueous treatment medium; Including, The method of claim 1, wherein the aqueous treatment medium etches silica from the surface of the glass article and deposits the silica on the surface of the glass article.

[0107] Embodiment 11 11. The method of claim 10, wherein the glass article is formed from Type I Class A or Type 1 Class B glass according to ASTM standard E438-92.

[0108] Embodiment 12 11. The method of claim 10, wherein the glass article is formed from borosilicate glass.

[0109] Embodiment 13 11. The method of claim 10, wherein the glass article is an ion-exchange strengthened glass article having a surface compressive stress layer.

[0110] Embodiment 14 11. The method of claim 10, wherein the glass article is a glass container having a sidewall at least partially enclosing an interior volume, the sidewall having an exterior surface.

[0111] Embodiment 15 15. The method of embodiment 14, wherein the aqueous treatment medium contacts the exterior surface of the sidewall.

[0112] Embodiment 16 11. The method of claim 10, wherein contacting the glass article with an aqueous treatment medium occurs for a period of time from 5 minutes to 72 hours.

[0113] Embodiment 17 11. The method of claim 10, wherein contacting the glass article with an aqueous treatment medium occurs at a temperature from ambient temperature to 50°C.

[0114] Embodiment 18 11. The method of claim 10, wherein the method further comprises rinsing at least the treated surface of the glass article with deionized water.

[0115] Embodiment 19 11. The method of claim 10, wherein the treated surface of the glass article comprises silica deposits, the silica deposits having a height of from greater than 0 nm to 20 nm and a diameter of from greater than 0 nm to 50 nm.

[0116] Embodiment 20 11. The method of claim 10, wherein the method further comprises applying a low-friction coating to the treated surface of the glass article.

[0117] Embodiment 21 1. A method for producing an aqueous treatment medium, comprising: heating a mixture comprising water; an acid selected from the group consisting of HCl, HBr, HNO3, H2SO4, H2SO3, H3PO4, H3PO2, HOAc, citric acid, tartaric acid, ascorbic acid, EDTA, methanesulfonic acid, toluenesulfonic acid, and combinations thereof; a fluoride-containing compound selected from the group consisting of HF, NaF, NH4HF2, and combinations thereof; and silica powder to a temperature of 25°C to 95°C; cooling the mixture to ambient temperature; filtering the undissolved silica powder from the mixture; and adding one or more salts to said mixture to form said aqueous treatment medium; A method comprising:

[0118] Embodiment 22 22. The method of embodiment 21, wherein the water is deionized water.

[0119] Embodiment 23 22. The method of embodiment 21, wherein the acid comprises citric acid.

[0120] Embodiment 24 22. The method of embodiment 21, wherein the salt comprises an alkali salt.

[0121] Embodiment 25 22. The method of embodiment 21, wherein the salt comprises sodium chloride.

[0122] Embodiment 26 22. The method of embodiment 21, wherein the salt comprises aluminum chloride.

[0123] Embodiment 27 22. The method of embodiment 21, wherein the salts comprise sodium chloride and aluminum chloride.

[0124] Embodiment 28 28. The method of embodiment 27, wherein the ratio of aluminum to sodium is 1:1 to 3:1.

[0125] Embodiment 29 22. The method of embodiment 21, wherein the fluoride-containing compound comprises NH4HF2.

[0126] Embodiment 30 22. The method of claim 21, wherein the silica powder comprises silica particles having a particle size of 100 nm to 1000 nm.

[0127] Embodiment 31 22. The method of embodiment 21, wherein the acid comprises citric acid, the salt comprises sodium chloride, aluminum chloride, or a combination thereof, and the fluoride-containing compound comprises NH4HF2.

[0128] Embodiment 32 22. The method of embodiment 21, wherein the concentration of the acid in the aqueous treatment medium is 0.5M to 1.5M.

[0129] Embodiment 33 22. The method of embodiment 21, wherein the concentration of said salt in said aqueous treatment medium is from greater than 0M to 2M.

[0130] Embodiment 34 22. The method of embodiment 21, wherein the concentration of the fluoride-containing compound in the aqueous treatment medium is 0.026M to 0.26M.

[0131] Embodiment 35 22. The method of embodiment 21, wherein the aqueous treatment medium is saturated with silica. [Explanation of symbols]

[0132] 100 glass containers 102 Glass body 104 Interior 106 Exterior 108 internal volume 110 Wall section 112 Floor part 114 Heel part

Claims

1. In the aqueous treatment medium, water, HCl, HBr, HNO ３ , H ２ SO ４ , H ２ SO ３ , H ３ P.O. ４ , H ３ P.O. ２ an acid selected from the group consisting of HOAc, citric acid, tartaric acid, ascorbic acid, EDTA, methanesulfonic acid, toluenesulfonic acid, and combinations thereof, wherein the acid has a concentration in the aqueous treatment medium of 0.5M to 1.5M; a salt having a concentration in the aqueous treatment medium of greater than 0 M to 2 M; HF, NaF, NH ４ HF ２ and combinations thereof, wherein the fluoride-containing compound has a concentration in the aqueous treatment medium of 0.026M to 0.26M; and silica saturating said aqueous treatment medium; An aqueous treatment medium comprising:

2. The aqueous treatment medium of claim 1 , wherein the acid comprises citric acid.

3. 2. The aqueous treatment medium of claim 1, wherein said salt comprises an alkali salt.

4. 2. The aqueous treatment medium of claim 1, wherein said salt comprises sodium chloride.

5. 2. The aqueous treatment medium of claim 1, wherein said salt comprises aluminum chloride.

6. 2. The aqueous treatment medium of claim 1, wherein said salts comprise sodium chloride and aluminum chloride.

7. 7. The aqueous treatment medium of claim 6, wherein the ratio of aluminum to sodium is from 1:1 to 3:

1.

8. The fluoride-containing compound is NH ４ HF ２ 2. The aqueous treatment medium of embodiment 1, comprising:

9. The acid comprises citric acid, the salt comprises sodium chloride, aluminum chloride, or a combination thereof, and the fluoride-containing compound is NH ４ HF ２ 2. The aqueous treatment medium of embodiment 1, comprising:

10. A method of treating a glass article, comprising contacting a surface of the glass article with an aqueous treatment medium to form a treated surface of the glass article; the glass article comprises silica; The aqueous treatment medium is water, HCl, HBr, HNO ３ , H ２ SO ４ , H ２ SO ３ , H ３ P.O. ４ , H ３ P.O. ２ an acid selected from the group consisting of HOAc, citric acid, tartaric acid, ascorbic acid, EDTA, methanesulfonic acid, toluenesulfonic acid, and combinations thereof, wherein the acid has a concentration in the aqueous treatment medium of 0.5M to 1.5M; a salt having a concentration in the aqueous treatment medium of greater than 0 M to 2 M; HF, NaF, NH ４ HF ２ and combinations thereof, wherein the fluoride-containing compound has a concentration in the aqueous treatment medium of 0.026M to 0.26M; and silica saturating said aqueous treatment medium; Including, The method of claim 1, wherein the aqueous treatment medium etches silica from the surface of the glass article and deposits the silica on the surface of the glass article.

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