MXPA99010527A - Lithium and vanadium containing sealing composition and process therewith - Google Patents

Abstract

The corrosion resistance of an article having a surface with a primary inorganic coating, such as a conversion coating, over a metal substrate can be improved by treatment of the primary coating with an aqueous liquid sealing composition comprising lithium cations and vanadate anions. This treatment is particularly advantageous for primary coatings formed on aluminum alloys by treating them with a conversion coating forming aqueous composition made by reacting cobalt(II) cations, acetate ions, hydroxyalkyl amines, and peroxides in aqueous solution.

Description

COMPOSITION OF SEAL CONTAINING LITHIUM AND VANADIUM AND ITS PROCESS FIELD OF THE INVENTION This invention relates to compositions and processes for improving the corrosion protection offered by a pre-existing primary coating on a metal surface, particularly a zinc, aluminum and / or surface. or zinc and / or aluminum alloy, more particularly an aluminum and / or aluminum alloy surface. BACKGROUND OF THE INVENTION AND RELATED TECHNIQUE A process of the type known as the "sealing" process because, in some cases, the effect of the process has been theoretically ascribed to sealing pores that exist in the primary coating. The evidence of such pores is generally considered to be very strong in the case of coatings formed by aluminum anodization, for example, but the term "sealing" is now applied to any liquid composition that may be in contact with a pre-existing coating, particularly a conversion coating, on a metal surface in order to improve the corrosion resistance of the object including the metal surface and all its protective coatings and to any process that thereby improves the corrosion resistance, regardless of whether the pores in The primary coating is actually sealed or even existed at the time of treatment. Alternative names for what is known here as "stamp" in this sense include "passivation," "final rinse," "after-rinse," and the like. A seal treatment in accordance with the present invention is especially useful in the case of surfaces that are not intended to receive any coating based on additional organic protective substances such as paint or the like, but is also useful in the case of substrates which will be additionally protected in this way.

Various seal compositions are known for several primary coatings in the prior art, but, particularly in the case of aluminum substrates which are not intended to receive a substantial protective coating of paint or a similar material containing an organic binder, it is desired to achieve Still further improvements in terms of corrosion resistance. Accordingly, a principal object of this invention is to offer seal compositions and processes which, in combination with known primary coatings, produce an improved corrosion resistance, especially in the absence of organic protective coatings. Other _alter_natives or concurrent objects are the minimization of the adverse environmental impact in comparison with the previously used related sealants, which frequently contain hexavalent chromium or other materials capable of easily damaging the environment, and provide more economical treatments without diminishing the protection against the corrosion. Other objects will be apparent from the following description. Except in the claims and in the examples of operation, or when expressly indicated otherwise, all the numerical quantities in this description that refer to quantities of material or conditions of reaction and / or use will be understood as modified by the word " approximately "when describing the broader scope of the invention. However, practice is preferred within established numerical limits. Also, in the description, unless otherwise expressly stated, percentage, "parts of", and proportion values are understood by weight or mass; the term "polymer" includes "oligomers", "copolymers", "terpolymers" and the like. The description of a group or class of suitable or preferred materials for a given purpose in relation to the invention implies that mixtures of two or more of the members of this group or class are equally suitable or preferred; a description of constituents in chemical terms refers to the constituents at the time of addition to any combination specified in the description or generated in situ within the composition by chemical reaction (s) indicated in the specification between one or several newly added constituents and one or more constituents already present in the composition when the other constituents are added, and does not necessarily exclude chemical interactions between the constituents of a mixture once mixed; the specification of constituents in ionic form further implies the presence of a sufficient number of counterions to produce electrical neutrality for the composition, overall, and for any substance added to the composition; counterions specified implicitly in this way are preferably selected from among other constituents specified explicitly in ionic form, as far as possible; otherwise, such counterions may be freely selected, except in the sense of avoiding counterions that act negatively on an object of the invention; the word "mol" refers to "gram molecule", and the word itself and all its grammatical variations can be used for any chemical species defined by all the types and numbers of atoms present in it, regardless of whether the species is ionic, neutral, unstable, hypothetical, or in fact a neutral substance with well-defined molecules; and the terms "solution", "soluble", "homogeneous", and the like are understood as including not only solutions in true equilibrium or homogeneity but also dispersions that show no visually detectable tendency towards phase separation in an observation period. of at least 100, or preferably at least 1000 hours during which the material is in a mechanically undisturbed condition and the temperature of the material is maintained within a range of 18 to 25 ° C. BRIEF COMPENDIUM OF THE INVENTION A seal composition in accordance with this invention is a homogeneous liquid composition comprising, which preferably consists essentially of, or more preferably, consisting of water, lithium cations, and vanadate anions, particularly decavanadate anions , which will be understood below as including not only ions with the chemical formula V? o028 ~ 6 which are present in decavanadate salts, but also protonated derivatives thereof having the formula V? 0O (28-i) (OH) _. ' - (6-1) where i represents an integer from one to four, which are believed to be the predominant species present in aqueous solutions with a pH of 2 to 6. See F.A. Cotton and G. Wilkinson, Advanced Inorganic Chemistry, 4th. Edition, (John Wiley &Sons, New York, 1980), page 712. Optionally, a seal composition in accordance with the present invention may also contain one or more surfactants, pH adjusting components, and fluoride ions. This seal composition, either as such or after dilution with water, is suitable for sealing any primary coating layer containing metal and oxygen atoms, especially cobalt and aluminum oxides. If it is immediately suitable for use, a composition according to the present invention can be known as a "working composition"; if it is preferably used only after dilution with water, a composition according to the present invention can be called a "concentrate", "concentrated composition", or "concentrate composition", these three terms are considered interchangeable in this document . Many compositions according to the present invention can obviously be suitable for use either as such, or after dilution with water, and can therefore be known as either working compositions or concentrated compositions. according to the present invention comprises, at least, a step of contacting a composition according to the present invention defined herein with a primary coating layer for a sufficient time at a sufficient temperature such that, after the suspension of contact and drying, optionally with intermediate rinse or other water treatment of the primary coating layer after its formation but before coming into contact with the seal composition, additional rinsing after contact with the seal composition, and / or additional coating treatments after drying, the treated object has a better corrosion resistance measurable in at least one accelerated corrosion test or at least one type of use real that an otherwise identical object treated identically, except insofar as deionized water or at least equally well purified water is replaced by the seal composition according to the present invention employed in a process in accordance with the invention. Additional process steps, including those that are conventional in themselves, may also be part of a process in accordance with the present invention. It is preferable that none of these additional steps include contacting the surfaces with a composition containing more than, preferably increasing in the order indicated, 1.0, 0.35, 0.10, 0.08, 0.04, 0.02, 0.01, 0.003, 0.001, or 0.0002% hexavalent chromium, except that a final protective coating system that includes an organic binder, more particularly those that include a first coating, may include hexavalent chromium as a constituent. Said hexavalent chromium in the protective coating is generally suitably limited by the organic binder in order to avoid an adverse impact on the environment. Objects treated by a process according to this invention are also within the scope of the invention. BRIEF DESCRIPTION OF THE DRAWINGS Not applicable. DETAILED DESCRIPTION OF THE INVENTION For various reasons, it is preferred that compositions according to the present invention as defined above are substantially free of many ingredients employed from compositions for similar purposes in the prior art. Specifically, it is increasingly preferred in the given order, independently of each preferably minimized component that appears in the following list, that the seal compositions in accordance with this invention, when in direct contact with a primary coating on metal in a process according to this invention, preferably contain, preferably increasing in the given order, no more than 1.0, 0.35, 0.10, 0.08, 0.04, 0.02, 0.01, 0.001, or 0.0002% of each of the following constituents : hexavalent chromium, cyanide, nitrite ions, and coordinated complexing agents that stabilize cobalt (II) cations, rather than cobalt (III) cations. Independently, seal compositions in accordance with the present invention preferably contain, preferably increasing in the given order, no more than 0.033, 0.030, 0.027, 0.024, 0.021, 0.018, 0.015, 0.012, 0.009, 0.006, 0.003, 0.001, or 0.0003 moles of tungsten in any anionic form per kilogram of total composition. (The concentration unit of moles of constituent per kilogram of total composition can then be used for any other constituent as well as for tungsten in anionic form and is usually abbreviated below as "M / kg".) The lithium ions required in the composition in accordance with the present invention they can be supplied by any sufficiently soluble salt, hydroxide or lithium oxide, or even by reaction with lithium metal, even if the latter is rarely preferred due to the expense and the required safety precautions. In general terms, for economic reasons, the least expensive source will be selected, and in the United States, at least, this usually means lithium hydroxide. Whatever the source, the concentration of dissolved lithium cations in a working composition according to the present invention is preferably at least, preferably increasing in the given order, 0.0040, 0.0070, 0.010, 0.020, 0.030, 0.040. , 0.050, 0.060, 0.065, 0.070, or 0.072 M / kg and independently of preference, is not more than, with increasing preference in the given order, 0.75, 0.50, 0.30, 0.20, 0.130, 0.115, 0.105, 0.095, 0.085, 0.080, 0.077, or 0.074 M / kg.

Vanadates of any degree of aggregation can also be employed to supply the required dissolved vanadium atoms in a composition according to the invention, but decavanadates are most preferred; sodium ammonium decavanadate with the chemical formula Na2 (NH4) 4? 0O28 is currently the most preferred because it is the least expensive commercially available source of decavanadate ions. If other vanadates are used, the counterions are preferably selected from the group consisting of alkali metal and ammonium cations, since most other vanadates are insufficiently soluble in water. The concentration of vanadium atoms present in vanadate ions in a stamp composition according to this invention is preferably at least, preferably increasing in the given order, 0.00050, 0.0010, 0.0020, 0.0030, 0.0040, 0.0050, 0.0060, 0.0070, 0.0080, 0.0085, 0.0090, or 0.0092 M / kg and it is independently preferred that it is not greater than, preferably increasing in the given order, 0.15, 0.10, 0.080, 0.060, 0.040, 0.030, 0.025, 0.020, 0.017, 0.014, 0.011, or 0.0095 M / kg. In addition, regardless of their actual concentrations, the ratio between the concentration of vanadium atoms in M / kg and the concentration of lithium cations in M / kg in a composition according to the present invention is preferably at least, preferably each time greater in the given order, 0.010: 1.0, 0.030: 1.0, 0.050: 1.0, 0.070: 1.0, 0.080: 1.0, 0.090: 1.0, 0.100: 1.0, 0.110: 1.0, 0.120: 1.0 or 0.125: 1.0 and it is preferred independently that is not greater than, with increasing preference in the given order, 1.0: 1.0, 0.8: 1.0, 0.60: 1.0, 0.50: 1.0, 0.40: 1.0, 0.30: 1.0, 0.25: 1.0, 0.20: 1.0, 0.18: 1.0 , 0.16: 1.0, 0.140: 1.0, or 0.130: 1.0. Typically, a seal composition according to the present invention preferably contains anions which include fluorine atoms, said anions can be simple fluoride anions with the chemical formula F ~, acid fluoride ions with the chemical formula HF2 ~, fluoroborate ions with the formula BF4 ~, fluoro-ethanolate ions according to the general formula MF6 ~ 2 where M represents Si, Tiz, Zr, Sn, Sb, or Hf, or fluorometalate ions according to the general formula M'F6 ~ 3 , where M 'represents Al or Fe. Simple fluoride ions are generally preferred for reasons of economy but for other reasons.Anions including fluorine atoms can be derived from any salt or acid as known to those skilled in the art. already indicated, the cations in the normally used salts must be selected between cations of alkali metals and ammonium, in order to minimize the danger of precipitation of a large part of the holding vanadate. When present, the concentration of fluorine atoms in anionic form in a working composition according to the present invention is preferably at least 0.005, 0.007, 0.009, 0.012, 0.016, 0.020, 0.030, 0.040, 0.045, 0.050, or 0.054 M / kg and preferably independently is not greater than, preferably increasing in the given order, 0.50, 0.40, 0.30, 0.20, 0.10, 0.080, 0.070, 0.065, 0.060, or 0.056 M / kg. Independently, the ratio between the concentration in M / kg of fluorine atoms in an anionic form in a composition according to the present invention and the concentration of M / kg of lithium cations in the same composition is preferably at least, preferably each time greater in the given order, 0.02: 1.0, 0.05: 1.0, 0.10: 1.0, 0.20: 1.0, 0.30: 1.0, 0.40: 1.0, 0.50: 1.0, 0.55: 1.0, 0.60: 1.0, 0.65: 1.0, 0.70: 1.0, or 0.74: 1.0 and preferably independently is not more than, preferably increasing in the given order, 10: 1.0, 5: 1.0, 3.0: 1.0, 2.0": 1.0, 1.7": 1.0, 1.5: 1.0, 1.3: 1.0, 1.1: 1.0, 0.97: 1.0, 0.93: 1.0, 0.89: 1.0, 0.85: 1.0, 0.81: 1.0, or 0.76: 1.0. The inclusion of a surfactant in a composition according to the present invention is usually preferred, in order to improve the ability of the composition to wet the primary coating surfaces in contact with it uniformly. Any surfactant that achieves this purpose can be employed, and the surfactant can also be omitted, but a cationic surfactant, particularly a predominantly tertiary amine surfactant, whose molecules are formed according to the following general formula: ~ (CH2CH20) xH is preferred. - / "NR \ (CH2CH20) yH where each of x and y in an individual molecule represents a nonnegative whole number and R represents a hydrophobic group.In a surfactant in which the molecules conform to this formula, the average value of the sum of x and y is preferably at least, preferably increasing in the given order, 2, 5, 7, 8, 10, 11 or 12 and independently, preferably, is not more than, preferably increasing in order given, 27, 22, 17, 15, 14, or 12, and, independently for each established preference: at least with increasing preference in the given order, 50, 60, 70, 80, 83, 86, or 89% of the R portions are saturated alkyl groups, at least 50, 60, 70, 80, 85, 90, or 95% of the R portions are straight chain alkyl groups, and the average number of carbon atoms per portion R is at least, preferably increasing in the given order, 8.0, 9.0, 10.0, 11.0, or 12.0 and is independently preferred other than more than, preferably more and more in the given order, 22, 20, 18.0, 17.0, 16.0, 15.0, 14.0, or 13.0. A mixture of hydrophobic portions R derived from fatty acids produced by the saponification of natural coconut oil is most preferred. If a surfactant is used, its concentration in a composition according to the present invention is preferably at least, preferably increasing in the given order, 0.00010, 0.00030, 0.00050, 0.00070, 0.00080, 0.00090, 0.0010, or 0.0012 parts of the surfactant per thousand parts of the total composition (one unit of concentration which may then be used for any other constituent as well as for the surfactant and which is usually abbreviated below as "ppt") and is independently preferred not to be greater that, with increasing preference in the given order, 0.010, 0.008, 0.006, 0.004, 0.0030, 0.0025, 0.0020, 0.0017, or 0.0014 ppt. The components of a composition according to the present invention as specified above can nourish some microbes that can be introduced therein from the ambient atmosphere. In order to avoid difficulties of such a source, an optional preservative can be incorporated into a composition in accordance with the present invention. Any conservator who does not object to the subject (s) of the invention may be employed, in an amount generally known in the art. Preservatives for use in this invention are preferably organic molecules containing at least one of the following: isothiazolin-3-one moieties; halogen, preferably bromine atoms, more preferably at least two per molecule; and cyano portions, preferably at least two per molecule. Particularly suitable preservatives include preservatives sold under the trademark KATHON® "by Rohm and Haas Co., For example KATHON® 886 MW, which according to its supplier contains from 10 to 12% of 5-chloro-2-methyl-isothiazolin-3. -one and 3 to 5% of 2-methyl-isothiazolin-3-one as preservative active ingredients together with 14-18% magnesium nitrate and 8-10% magnesium chloride, all in solutions with water, water constituting the remainder, and those sold under the trade name TTEKTAMER® by Calgon Corp., for example, TEKTAMER® 38LV, which according to its supplier, consists of 25% of 1,2-dibromo-2,4-dicyanobutane dispersed in water. In order to avoid the cost of transporting large quantities of water, it is usually preferred in practice to formulate a seal composition in accordance with this invention in a concentrated composition rather than offering a working composition. concentrated contains preferably the same s components as indicated above for the work compositions, but in a concentration for each ingredient, except water, which is at least, preferably increasing in the given order, 2, 4, 6, 8, 10, 20, 30, 40 or 50 times greater than the concentration specified above for a working composition. The pH value of a working seal composition according to the invention is preferably, preferably increasing in the given order, 2.0, 3.0, 4.0, 4.5, 4.8, 5.1, 5.3, or 5.5 and preferably independently is nothing more than, preferably increasing in the given order, 8.0, 7.5, 7.0, 6.7, 6.4, 6.2, or 6.0. if the pH is too high, the underlying metal may be subject to attack, whereas if the pH is too low, the primary coating may dissolve instead of being sealed. If lithium hydroxide is used as the main source of lithium and other necessary and optional ingredients as described above are present in preferred amounts, an acidic pH adjusting component will normally be required to bring the pH at least in its range. favorite. In order to provide a buffering effect within a preferred range of pH, a weakly ionizing acid is usually preferred, and acetic acid, which is inexpensive and does not pose a risk of precipitation of other normal ingredients of a compliance seal composition. with this invention, it has been found highly suitable. The temperature of a seal composition in accordance with the present invention during contact with the metal substrate previously treated primarily and optionally treated in an intermediate manner as briefly described above and in greater detail below is, preferably in increasing order in the order given, of at least 15, 20, 22.0, 23.0, 24.0, 25.0, 26.0 or 26.5 ° C and, independently, primarily for reasons of economy, it is preferably, with increasing preference in the given order, no more than 90, 80, 70, 60, 50, 45, 40, 35, 30, or 28 ° C. At a temperature of 26.7 ° C, the contact time between said stamp composition according to this invention and the metal substrate previously treated primarily and optionally treated in an intermediate manner is, preferably increasingly, in the order given, not more than 0.5, 1.0, 2.0, 2.5, 3.0, 3.5, 4.0, 4.3, 4.6, or 4.9 min and is preferably independently, with increasing preference in the given order, primarily for reasons of economy, not greater than 60 , 30, 15, 12, 10, 8, 7.0, 6.5, 6.0, 5.7, 5.4, or 5.1 minutes. In the case of other temperatures during the treatment with a seal composition of this type, shorter times are preferred at higher temperatures and longer times at lower temperatures. After a sealing process according to the present invention, the sealed surfaces are again preferably rinsed with water, preferably with deionized water or with at least equally purified water, before drying or before allowing to dry. If heat is used to accelerate the drying, the temperature of the metal during drying preferably does not exceed, preferably increasing in the given order, 100, 85, 75, 66, or 60 ° C, in order to avoid damage to the protective quality of the coating formed by the process according to the invention. A process according to the present invention is more preferably applied to a surface on which a pre-existing primary treatment has been formed by contacting a metal surface, preferably a surface of cleaned and deoxidized aluminum alloy with a first treatment composition made by reaction in an aqueous solution comprising, preferably consisting essentially of, or more preferably consisting of water and the following single components: (A) cobalt (II) cations; (B) carboxylate anions; (C) chemical species, excluding carboxylate anions, which form more stable coordination bonds with cobalt (III) cations than with cobalt (II) cations; and (D) an oxidizing agent; and optionally, one or more of the following components: (E) nitrate ions; (F) a component selected from the group consisting of alkali metal cations and alkaline earth metal cations; and (G) complex fluoride and fluoride anions, wherein the ratio between the number of moles of component (B) and the number of moles of component (A) in an aqueous solution before the reaction is 0.10 to 6.8. The contact of an "active" metal substrate with such a primary treatment composition results in the formation on the metal substrate surface of an adherent conversion coating containing at least cobalt and oxygen atoms and also some carbon atoms. metal from the treated substrate. (Any metal that reacts in this way is considered an "active metal" within the meaning of this term below). The concentration of the component (A) which reacted is preferably such that, in a preferred primary composition used to form a primary coating prior to a seal process according to the invention, the concentration of cobalt atoms is, preferably each time greater in the given order, not less than 0.001, 0.002, 0.004, 0.008, 0.016, 0.032, 0.040, 0.045, 0.050, 0.055, 0.060, 0.063, 0.066, 0.069, 0.072, 0.074, or 0.076 M and is preferably independently , preferably increasing in the given order, not greater than 0.8, 0.6, 0.4, 0.2, 0.17, 0.14, 0.11, 0.90, 0.85, 0.080, or 0.078 M. The particular contraion (s) (is ) in the salt (s) in the form in which the cobalt (II) cations are usually added to the aqueous solution in which they react they are not strictly restricted, but all the counterions that are so stably bound to the cobalt (II) in such a way that they prevent its oxidation in cobalt (III) during reaction with the other components should be avoided. However, in order to minimize the prospects of unwanted interference with the desired reactions, the counterions for cobalt when added to the aqueous solution in which it reacts are preferably selected within the group consisting of nitrate ions, which have a tendency to relatively low to complex formation, and carboxylate ions that are part of component (B). The component (B) is preferably selected from the anions of unsubstituted carboxylic acids containing from 1 to 6 carbon atoms, and more preferably, preferably increasing in the given order, no more than 5, 4, 3 or well 2 carbon atoms, per molecule. Acetate ions are most preferred, largely because they are less expensive than most other carboxylates. Independently, the ratio between the number of moles of component (B) and the number of moles of component (A) in solution before a reaction between them is preferably, preferably increasing in the given order, of at least 0.1 : 1.0, 0.2: 1.0, 0.4: 1.0, 0.8: 1.0, 1.2: 1.0, 1.5: 1.0, 1.8: 1.0, 2.0: 1.0, 2.2: 1.0, 2.3: 1.0, 2.4: 1.0, 2.5: 1.0 or 2.6: 1.0 and independently, it is preferably with increasing preference in the given order, not greater than 6.5: 1.0, 6.0: 1.0, 5.5: 1.0, 5.0: 1.0, 4.5: 1.0, 4.0: 1.0, 3.7: 1.0, 3.4: 1.0, 3.1: 1.0, 3.0: 1.0, 2.9: 1.0, 2.8: 1.0, or 2.7: 1.0. "The more preferred concentrations of carboxylate ions are therefore higher than those which can be supplied by the cobalt (II) carboxylates themselves, and for the alternative cations which serve as counterions for this carboxylate" excess ", metal cations are preferred. ferrous alkalines, particularly magnesium and calcium, especially magnesium, on alkali metal cations, although the latter may also be used.The use of carboxylic acids to supply the required amounts of carboxylate ions, although it is also possible within the scope of the present invention, it is not preferred, because such use tends to depress the pH value of a composition according to the invention below the most preferred values presented below. Component (c) is preferably selected from organic compounds containing at least one nitrogen atom with an electron pair not shared per molecule of compound. The hydroxyalkylamines, more particularly triethianolamine, are the most preferred class of materials for component (C). Independently, the ratio of the molar concentration of nitrogen atoms each carrying an unshared pair of electrons and the molar concentration of component (A) present in solution before any reaction between them is preferably, preferably increasing in the given order, not less than 0.03: 1, 0.06: 1.0, 0.13: 1.0, 0.20: 1.0, 0.24: 1.0, 0.26: 1.0, 0.28: 1.0, 0.30: 1.0, 0.32: 1.0, 0.34: 1.0, 0.35: 1.0, or 0.36: 1.0, and is preferably, independently, with increasing preference in the given order, not greater than 2.0: 1.0, 1.75: 1.0, 1.50: 1.0, 1.25: 1.0, 1.00: 1.0, 0.75: 1.0, 0.60: 1.0, 0.50: 1.0, 0.45: 1.0, 0.41: 1.0, 0.39: 1.0, or 0.38: 1.0. The amount and strength of oxidation of the component (D) used must be sufficient to cause a color change and / or an increase in ultraviolet adsorption at a wavelength within a range of 160-450 nanometers (abbreviated below "nm ") of a precursor solution containing only water, components (A), (B), and (C), and any possible reaction product between these constituents, after the addition of component (D) to the mixed solution of precursors . Ordinary ambient air or any other source of gaseous oxygen is suitable as the oxidizing agent but, for ease of preparation, convenience and easy control to the process, soluble compounds including a portion of peroxide and / or superoxide are preferred, especially peroxide, and preferably optimum hydrogen peroxide (because it is usually the least expensive peroxide available commercially), as at least part of the component (D). The ratio between the molar concentration of peroxide moieties present in the solution before the reaction and the molar concentration of cobalt atoms present in the solution is preferably, preferably increasing in the given order, of at least 0.05: 1.0, 0.10: 1.0, 0.20: 1.0, 0.30: 1.0, 0.40: 1.0, 0.45: 1.0, 0.50: 1.0, 0.55: 1.0, 0.60: 1.0, 0.65: 1.0, 0.68: 1.0, 0.71: 1.0, or 0.73: 1.0 and is preferably, independently, with increasing preference in the given order, not greater than 10: 1.0, 7: 1.0, 5: 1.0, 3: 1.0, 2: 1.0, 1.5: 1.0, 1.0: 1.0, 0.95: 1.0 , 0.90: 1.0, 0.85: 1.0, 0.80: 1.0, 0.77: 1.0, or 0.74: 1.0. Although the peroxide is used in the preparation of a preferred primary composition used to form a primary coating prior to seal processing in accordance with the present invention, it is preferable to keep the primary composition well profiled during use, by employing (i) ) of spraying to contact the solution, with the metal to be treated, (ii) a separate spray theater for aeration purposes and a process line through which the preferred primary composition used to form the primary coating before a seal process according to the present invention circulates during use, and / or (iii) spraying with air and / or oxygen gas in a container for the primary composition in such a process line, said container can conveniently be the tank of immersion if immersion processing is used. The presence, particularly from the beginning of the reaction, of nitrate ions in the mixture reacting to prepare a preferred primary composition used to form a primary coating prior to a sealing process in accordance with this invention is generally preferred because it has been observed that In these cases, more uniform primary coatings on aluminum are achieved. Therefore, the ratio between the molar concentration of nitrate ions before the reaction and the molar concentration of cobalt atoms in the aqueous compositions which reacted to make the preferred compositions employed to form a primary coating prior to a sealing process in accordance with this invention is preferably, preferably increasing in the given order, not less than 0.05: 1.0, 0.1: 1.0, 0.2: 1.0, 0.4: 1.0, 0.6: 1.0, 0.8: 1.0, 1.0: 1.0, 1.2: 1.0, 1.4: 1.0, 1.6: 1.9: 1.0, 1.9: 1.0, or 1.95: 1.0 and preferably, independently, with increasing preference in the given order, not greater than 20: 1.0, 15: 1.0, 10: 1.0 , 5: 1.0, 4: 1.0, 3.5: 1.0, 3.0: 1.0, 2.8: 1.0, 2.6: 1.0, 2.4: 1.0, 2.2: 1.0, 2.1: 1.0, or 2.05: 1.0. The pH value of preferred primary compositions employed to form a primary coating before a seal process in accordance with this invention is preferably, preferably increasing in the given order, of at least 3, 4, 4.5, 5.0, 5.5, 6.0, 6.2, 6.3, 6.4, 6.5, "6.6, 6.7, or 6.8 and, independently, preferably, with increasing preference in the given order, not greater than 10, 9, 8.5, 8.2, 8.0 , 7.9, 7.8, 7.7, 7.6, 7.5, 7.4, 7.3, or 7.2, pH values within these preferred ranges will generally result from the use of the preferred components mentioned above for the preparation of the preferred compositions employed to form a primary coating before a seal process according to the invention, but the pH value can be adjusted as necessary by minor additions of other acidic or basic components as is generally known in the art. Preferred alternatives offered above frequently result in the rapid formation of cobalt-containing precipitates, thus rendering the compositions unsuitable for their intended use, while pH values below the preferred lower limits provided above will likely destabilize cobalt (III) sufficiently to affect the desired performance of the compositions. In the preparation of the preferred compositions employed to form a primary coating prior to a seal process according to the invention, the components (A) and (B) are preferably mixed together in aqueous solution first in the absence of other constituents, except the counterions of components (A) and (B) and optionally component (E) if employed, and component (C) added later to this mixture. Only after complete mixing of components (A), (B), and (C) in solution should component (D) be added (except for air in equilibrium with the aqueous solution). Even though the temperature during mixing is not strictly restricted, so that any temperature between the freezing point and the boiling point of the solution can be used, all these additions are made with greater preference while the solution is at approximately the normal ambient temperature, that is, between 20 and 25 ° C. Usually, before the treatment to form a primary coating to be sealed according to the invention, preferably a metal substrate must be cleaned, and if the substrate is one of the metals such as aluminum and magnesium which have a tendency to spontaneously form Thick layers of oxide on its surfaces, must also be deoxidized by some process known per se in the prior art or by some other suitable process. Preferred deoxidation processes are described in the working examples presented below. The preferred primary compositions employed to form a primary coating prior to a seal process in accordance with the present invention can be employed over a substantial range of temperatures, with the formation of protective coatings generally at a slightly higher rate at the higher temperatures within the range . In general, the temperature during a primary coating forming process when one of the aforementioned preferred compositions is employed is preferably, preferably increasing in the given order, of at least 20, 25, 28, 30, 32, 34, 35, 36, or 37 ° C and, if the rapid formation of a suitable coating is more important than the maximum possible resistance to corrosion, said temperature is preferably, preferably increasing in the given order, at least 40, 43, 45, 47, or 49 ° C. Independently, as a generalization, the temperature during a primary coating forming process when one of the preferred compositions indicated above is employed is preferably, preferably increasing in the given order, not greater than 90, 85, 80, 75, 72, 69, 67, 65, 63, 62, 61, or 60 ° C; and, if a maximum possible resistance to corrosion is desired, particularly when the metal substrates treated in accordance with this invention should be employed without application of paint or protective coating based on similar organic substances, it is preferably, with increasing preference in the given order, not greater than 55, 50, 45, 40, 39, or 38 ° C. The contact between a preferred primary composition used to form a primary coating prior to a sealing process in accordance with this invention and the metal substrate treated in a primary coating formation process can be achieved by any convenient method or combinations of methods. Immersion and spraying, for example, can both offer totally satisfactory results. In general, the spray achieves desired coating weights slightly faster than the immersion, perhaps due to the mixing effect of the portion of the liquid primary composition in close proximity to the surface to be treated with most of the liquid primary composition and / or the greatest opportunity is provided by spraying for atmospheric oxygen to participate in the coating formation reaction. Whatever the real reason, at a temperature of 60 ° C for spraying, the contact time is preferably, preferably increasing in the given order, not less than 5, 10, 20, 30, 40, 50, 60, 65, 70, 75, 80, 85, or 90 seconds (usually abbreviated hereinafter as "sec") and is preferably independently, preferably increasing in the given order, not greater than 30, 15, 12 , 10, 8, 6, 5, 4, 3, 2.5, 2. 2, 2.0, 1.7, 1.6 or 1.55 minutes (usually abbreviated below as "min"). For immersion at 60 ° C, the contact time is preferably, preferably increasing in the given order, of at least 0.2, 0.5, 0.8, 1.0, 1.5, 2.0, 2.5, 2.8, 3.2, 3.6, or 3.9 min and is preferably, independently, with increasing preference in the given order, no greater than 30, 25, 20, 15, 12, 9, 8, 7, 6, or 5 minutes. For immersion at a temperature of 38 ° C, the contact time is preferably, preferably increasing in the given order, of at least 2, 5, 8, 10, 11, 12, 13, or 14 min and it is preferably independently, preferably increasing in the given order, primarily for reasons of economy, not greater than 60, 40, 30, 25, 20, 18, 17 or 16 min. At other temperatures, contact times should preferably be longer at lower temperatures and may be shorter at higher temperatures. After the formation of a primary coating, the treated metal surface, which now carries a primary coating, is preferably rinsed with water before being dried or allowed to dry. In many cases, including cases in which the primary coating contains cobalt, oxygen and aluminum, even if the primary coating is not formed by the use of a preferred composition in accordance with that described above, but can be formed, for example, in accordance with the teachings of WO94 / 00619, it is advantageous, in addition to an ordinary rinse or instead of an ordinary rinse that would normally take place in a minute or less, to maintain contact between the water and the treated surface with the treatment primary according to what is written above for a longer period of time. The total time for this intermediate treatment is preferably, preferably increasing in the given order, of at least 1.0, 2.0, 3.0 / 3.3 ', 4.0, 4.3, 4.6, or 4.9 min and is preferably, independently, with increasing preference in the given order, primarily for reasons of economy, not greater than 60, 30, 20, 10, 8, 7.0, 6.5, 5.7, 5.4, or 5.1 min. Usually, the intermediate treatment is preferably achieved by immersion, because spraying during such relatively long periods will likely result in higher volumes of wastewater and / or water loss by evaporation. Usually, a single dive during the total desired time is satisfactory and is preferred because it is more economical, but the total immersion period can also be achieved through two or more dives with a removal interval of the treated substrate from contact with water between each dive and the next immersion, if it exists. The use of an intermediate treatment is especially preferred if it is to be followed by a vanadium-containing seal treatment together with higher than preferred amounts of anionic tungsten. As previously observed, purified water is usually preferred for this intermediate treatment, but an oxidizing agent such as for example nitrite ions, conveniently added in the form of sodium nitrite, can be included together with the water if desired. The temperature is not strictly restricted, but usually room temperature is preferred or temperatures slightly higher than room temperature within a range of 20 to 30, or better to 26 to 28 ° C. Preferably, any sealed primary coating with a seal treatment in accordance with that described above contains at least 5, or, preferably increasing in the given order, at least 10, 15, 20, or 25 atomic percent. in total of selected metals within the group consisting of aluminum, cerium, cobalt, molybdenum, titanium, tungsten, banadium, zinc and zirconium, most preferably within the group consisting of aluminum and cobalt. Independently, these sealed primary coatings with a seal treatment in accordance with that described above contain at least 5, or, preferably increasingly in the order given, at least 10, 15, 20 or 25 atomic percent oxygen. After primary coating, intermediate treatments if desired, sealing according to the present invention and drying, a metallic substrate is well suited as a base for paint application or another protective coating based on similar organic substance, which can be applied in any way known per se in the art. With the most preferred primary coatings, intermediate treatments, and seal treatments in accordance with this invention, aluminum substrates often have superior corrosion resistance even without a protective coating based on organic substances. A seal composition in accordance with the present invention is also suitable for sealing primary coatings formed by the treatment of metal surfaces with compositions and processes in accordance with that described in any of the following North American Patents and co-pending US Patent Application, all of which , insofar as they are not inconsistent with an explicit statement contained herein, are incorporated herein by reference: Patents 5,098,064 of February 18, 1992 of Reghi; 5,268,042 of December 7, 1993 and 5,281,282 of January 25, 1994 of Dolan; 5,342,456 of August 30, 1994 and 5,356,490 of October 18, 1994 of Dolan et al., "5,411,606 of May 2, 1995 and 5,415,687 of May 16, 1995 of Schriever, 5,427,632 of June 27, 1995 and 5,449,414 and 5,449,415 of September 12, 1995 of Dolan, 5,472,984 of 5 December 1995 and 5,487,949 of January 30, 1996 of Schriever, 5,534,082 of July 9, 1996 of Dollman et al, 5,541,994 of September 3, 1996 of Schriever, and International Application No. PCT / US94 / 13273 appointing the States United States of America and presented on November 23, 1994. In addition, even in cases in which the claims of these patents and applications may be restricted to coatings formed by drying in place, coatings formed by treatment with the compositions taught and Subsequent rinsing are also preferred primary coatings for seal with a seal and process composition in accordance with this invention The invention will be better understood by taking the following examples into account of non-limiting work and comparison as well as the results of tests. A primary working coating composition was prepared as follows: 1063 grams of an aqueous solution of cobalt (II) nitrate containing 13% cobalt and 670 grams of magnesium acetate tetrahydrate were added to approximately 15 liters of water deionized. After complete mixing of these ingredients at room temperature, aeration of the liquid mixture began; then 131 grams of triethanolamine with a purity of 99% were added, and after complete mixing of these ingredients, 168 grams of an aqueous solution of hydrogen peroxide containing 35% H202 was added. This liquid mixture was then diluted to a total volume of 30.3 liters with additional deionized water, in order to produce a liquid solution which, when diluted 10 times its initial volume with deionized water, produced a primary coating formation liquid with a Absorbance of UV light at 362 nm wavelength, in a 1 cm long transmission path, within the range of 4 to 40%. The heating of the liquid solution diluted in this way began, and aeration was continued until the temperature of the mixture rose to 54 ± 1 ° C, the selected working temperature, which was maintained during the use of this composition. of primary coating formation in accordance with what is described below. Rectangular aluminum alloy panels of type 2024-T3 of 7.6x25.4 centimeters were the substrates used. These substrates were subjected to the following processing steps, in which all the products identified by the "®" symbol are available from Henkel Surface Technologies Division of Henkel Corp., Madison Heights, Michigan: 1. to clean by immersion for 5 minutes at a temperature of 60 ° C in an aqueous solution containing 15 g / L of alkaline cleaner inhibited by RIDOLINE® 53 silicate. 2. rinse with hot water. 3. deoxidizing by immersion for 5 minutes at a temperature of 21 ° C in an aqueous solution of DEOXIDIZER® 6-16 concentrate prepared in accordance with the manufacturer's instructions. 4. rinse with cold water. 5. Immerse in the primary working coating formation composition described above at the temperature also indicated above for 4 to 10 minutes, according to the thickness of the desired primary coating. 6. Remove from contact with the primary coating coating composition and rinse with cold water. 7. immerse for 5 minutes at a temperature of 60 ± 1 ° C in a sealing composition according to the present invention or a comparison in accordance with that described below. 8. Remove from contact with the seal composition and rinse. with cold water. 9. Dry by applying blown air and / or in an oven at a temperature of 32 to 66 ° C. The seal composition 1 according to the present invention contained the following ingredients, which were added to approximately 900 parts of deionized water in the order illustrated: 4.54 parts of glacial acetic acid; 3.08 parts of lithium hydroxide monohydrate; 1.00 parts of ammonium sodium decavanadate (commercially supplied as SAVAN® by Kerr-McGee Chemical); CHEMEEN® C-12 surfactant, commercially supplied by Chemax and reported by the supplier as being 100% cocaine PEG-12; 3.2 parts of anhydrous potassium fluoride; and a sufficient amount of deionized water to bring the total parts to 1000. The seal composition 2, not in accordance with the present invention, contained the same ingredients as the seal composition 1 except that it did not have sodium decavanadate ammonium. The seal composition 3, neither in accordance with the present invention, was a solution of 7.5 grams per liter of sodium ammonium decavanadate in deionized water only. Aluminum panels treated in accordance with the above described were tested in salt spray at an angle of 6 ° relative to the horizontal level, with reported results as the number of holes per panel after at least one particular exposure time, in Table 1 below. Table 1 Cobalt grams number of holes per panel after per square meter salt spray composition during: seal coating 168 hours 336 hours primary used 0.214 1 none 0.243 2 no. too much not measured from holes to count them 0.121 3 10-25 not measured 0.122 1 no It is clear from the results of Table 1 that the corrosion resistance of the panels treated in accordance with the present invention is far superior to the corrosion resistance of the panels treated with any of the comparison compositions.

Claims (2)

CLAIMS A homogeneous liquid composition of material suitable either as such or after dilution with water to seal a primary coating on a metal substrate by contacting it, said composition comprising water and: (A ') lithium cations; and (B ") decavanadate anions A composition according to claim 1, comprising water and: (A") a concentration of at least about 0.0040 M / kg of lithium cations; (B ") a concentration of at least about 0.00050 M / kg of vanadium atoms in decavanadate anions, said concentration of vanadium atoms in decavanadate anions in M / kg has a ratio relative to the concentration in M / kg of lithium cations in the same composition that is from about 0.01: 1.0 to about 1.0: 1.0, and (C) a concentration of fluorine-containing anions that corresponds stoichiometrically to a concentration of fluorine atoms that: (i) is at least about 0.005 M / kg and (ii) has a ratio in relation to the concentration, also measured in M / kg, of lithium cations in the same solution which is from about 0.02: 1.0 to about 10: 1.0. A composition according to claim 2 , which comprises water and: (A ") a concentration of at least about 0.020 M / kg of lithium cations; (B ") a concentration of at least about 0.0030
1. M / kg of vanadium atoms in decavanadate anions, said concentration of vanadium atoms in decavanadate anions in M / kg has a ratio in relation to the concentration in M / kg of lithium cations in the same composition which is approximately 0.050: 1.0 at approximately 0.60: 1.0; (C) a concentration of fluorine-containing anions corresponding stoichiometrically to a concentration ^ of fluorine atoms that: (i) is at least about 0. 005 M / kg and (ii) has a ratio in relation to the concentration, also measured in M / kg, of lithium cations which is from about 0.20: 1.0 to about
2. 2. 0: 1.0; and (D ') at least 0.00030 ppt of surfactant. A composition according to claim 3, comprising water and: (A ') a concentration of at least about 0.60 M / kg of lithium cations; (B ") a concentration of at least about 0.080 M / kg of vanadium atoms in decavanadate anions, said concentration of vanadium atoms in decavanadate anions in M / kg has a ratio in relation to the concentration in M / kg of lithium cations in the same composition that is from about 0.10: 1.0 to about 0.18: 1.0; (C) a concentration of fluorine-containing anions that corresponds stoichiometrically to a concentration of fluorine atoms that: (i) is at least about 0.04 M / kg and (ii) has a ratio in relation to the concentration, also measured in M / kg, of lithium cations in the same solution that is from about 0.55: 1.0 to about 1.1: 1.0, and (D ") to" minus 0.010". ppt of a component of surfactant molecules corresponding to the general formula: (CH2CH20) xH / NR \ (CH2CH20) and H where each of "x" and "y" represents a non-negative whole number and R represents a hydrophobic group of portion n saturated alkyl, the average value in all molecules in the surfactant molecule component for the sum of "x" and "y" is 10 to 14 and for the number of carbon atoms in the R portions it is 9.0 to 14.0. A homogeneous liquid composition of suitable material either as such or after dilution with water to seal a primary coating on a metal substrate by contact with it, said composition was made by dissolving it in pure water, or in a liquid that it comprises both water and at least one other dissolved material, stably dispersed or both dissolved and stably dispersed there, the following component or the following components: (A ") an amount of one or more sources of lithium cations; and, at least if said source or said sources of lithium cations is not / are also a source of decavanadate anions, (B ") an amount of one or more sources of decavanadate anions. to prepare the composition, dissolve in said pure water, or in said liquid comprising both water and at least one other dissolved material, stably dispersed, or both dissolved and stably dispersed therein, the following component or the following components: (A) ) an amount of the lithium cation source (s) containing a quantity of lithium cations corresponding to a concentration of at least about 0.0040 M / kg of lithium cations in said composition; and, unless said amount of the source (s) of dissolved lithium cations also supplied to the composition when a source of decavanadate anions was dissolved in an amount corresponding to a concentration of vanadium atoms in decavanadate anions in said composition that: (i) was at least about 0.00050 M / kg and (ii) had a ratio relative to the concentration in M / kg of lithium cations supplied to the same composition from about 0.01: 1.0 to about 1.0: 1.0, (B ") an amount of the decavanadate anion source (s) which, together with the decavanadate anions supplied to the composition by the lithium cation source (s), gave said composition a concentration of atoms of vanadium in decavanadate anions that: (i) was at least less than 0.0030 M / kg and (ii) had, when measured in M / kg, a ratio in relation to the concentration in M / kg of lithium cations supplied to the my ma composition that was from about 0.050: 1.0 to about 0.60: 1.0; and, unless the source (s) of lithium cations and dissolved vanadate anions also supplied to the composition when an amount of fluorine-containing anions was dissolved which corresponds stoichiometrically to a concentration of fluorine atoms that: ) was at least about 0.005 M / kg and (ii) had a ratio in relation to the concentration, also measured in M / kg, of lithium cations supplied to the same solution which was from about 0.02: 1.0 to about 10: 1.0 , (C ") an amount of an anion source containing fluorine which, together with fluorine-containing cations that were supplied by the source (s) of lithium cations and decavanadate anions, corresponded stoichiometrically to a concentration of atoms of fluorine in said composition that: (i) was at least about 0.005 M / kg and (ii) had a ratio in relation to the concentration, also measured in M / kg, of lithium cations supplied to the same solution that was from about 0.02: 1.0 to about 10: 1.0. A composition according to claim 6, wherein in order to make the composition dissolved, stably dispersed, or dissolved and stably dispersed the following component or the following components: (A ") an amount of the (s) lithium cation source (s) containing a quantity of lithium cations corresponding to a concentration in the composition of at least about 0.020 M / kg of lithium cations, and, unless the source (s) of lithium cations which were dissolved also supplied to the composition when decavanadate anions were dissolved in an amount corresponding to a concentration of vanadium atoms in decavanadate anions which: (i) was at least about 0.0030 M / kg and (ii) when measured at M / kg had a ratio in relation to the concentration in M / kg of lithium cations supplied to the same composition that was soluble in water and / or could be dispersed again in water in the same manner. spontaneous ratio from about 0.050: 1.0 to about 0.60: 1.0,(B ") an amount of the decavanadate anion source (s) which, together with the decavanadate anions supplied to the composition by the lithium cation source (s), supplied an anion concentration to said composition decavanadate that: (i) was at least about 0.0030 M / kg and (ii) when measured in M / kg presented a ratio relative to the concentration in M / kg of lithium cations supplied to the same composition that was soluble in water and / or spontaneously redispersible in water of about 0.050: 1.0 to about 0.60: 1.0; and, unless the source (s) of dissolved lithium cations and decavanadate anions also supplied the composition when an amount was dissolved. of fluorine-containing anions corresponding stoichiometrically to a fluorine atom concentration that: (i) was at least about 0.005 M / kg and (ii) had a ratio in relation to the concentration, also measured in M / kg of lithium cations supplied to the same solution that was from about 0.20: 1.0 to about 2.0: 1.0, (C ") an amount of a source of fluorine-containing anions that, together with fluorine-containing anions that were supplied by the (s) source (s) of lithium cations and cavanadate anions corresponded stoichiometrically to a concentration of fluorine-containing anions that: (i) was at least about 0.005 M / kg and (ii) had a ratio in relation to the concentration, measured also in M / kg, of lithium cations supplied to the same solution that was found within a range from about 0.20: 1.0 to about 2.0: 1.0; and, unless the source (s) of lithium cations, decavanadate anions, and fluorine-containing anions supplied together said composition an amount of at least 0.00030 ppt of surfactants, (D ") an amount of surfactant that, together with the surfactants supplied to said composition by the source (s) of lithium cations, decavanadate anions, and fluorine-containing anions, it supplied to said composition at least 0.00030 ppt of surfactant A composition in accordance with the claim 7, where in order to make the composition, the following component or the following components were dissolved: (A ") an amount of the lithium cation source (s) containing a quantity of lithium cations corresponding to a concentration in the composition of at least about 0.60 M / kg of lithium cations; and, unless the source (s) of lithium cations that were dissolved will also supply the composition when a decavanadate anion source was dissolved in an amount corresponding to a decavanadate anion concentration which was: (i) less than about 0.080 M / kg and (ii) had a ratio relative to the concentration in M / kg of lithium cations supplied to the same composition that was from about 0.10: 1.0 to about 0.18: 1.0, (B ") an amount of the source (s) of decavanadate anions, which, together with the decavanadate anions supplied to the composition by the lithium cation source (s), supplied to said composition a concentration of decavanadate anions which: (i) was at least about 0.080 M / kg and (ii) had a ratio relative to the concentration in M / kg of lithium cations in the same composition that was from about 0.10: 1.0 to about 0.18: 1.0, and, unless the (s) fu lithium cation and dissolved decavanadate anions (s) also supplied to the composition when an amount of fluorine-containing anions was dissolved which corresponded stoichiometrically to a concentration of fluorine atoms which: (i) was at least about 0.04 M / kg and (ii) had a ratio in relation to the concentration, also measured in M / kg, of lithium cations supplied to the same solution which was from about 0.55: 1.0 to about 1.1: 1.0, (C ") an amount of one Anion source containing fluorine, which, together with fluorine-containing anions supplied by the source (s) of lithium cations and decavanadate anions, supplied to said composition a concentration of fluorine-containing anions which corresponded stoichiometrically to a concentration of fluorine atoms which: (i) was at least about 0.04 M / kg and (ii) had a ratio in relation to the concentration, also measured in M / kg of lithium cations supplied to the same solution which is from about 0.55: 1.0 to about 1.1: 1.0; and, unless the source (s) of lithium cations, decavanadate anions, and fluorine-containing anions that were dissolved would also supply the composition when at least 0.010 ppt of a component of surfactant molecules corresponding to The general formula: (CH2CH20) xH N-R \ (CH2CH2O) yH where each of "x" and "y" represents a nonnegative integer and R represents a hydrophobic group of alkyl portion, the average value in all molecules of the component of surfactant molecules for the sum of "x" and "y" "is from 10 to 14 and for the number of carbon atoms in the portions R is from 9.0 to 14.0; (D ") a source of at least 0.010 ppt of surfactant molecules corresponding to the general formula: (CH2CH2O) xH N-R \ (CH2CH2O) and H where each of "x" and "y" represents a non-negative integer and R represents a hydrophobic group of saturated alkyl moiety, the average value in all the molecules in the component of surfactant molecules for the sum of "x" and "y" is from 10 to 14, and for the number of carbon atoms in the portions R is from 9.0 to 14.0.