TW201831736A - Dark colored electroceramic coatings for magnesium - Google Patents

Abstract

This invention relates to articles having magnesium-containing metal surfaces with a black, brown or bronze electroceramic coating, chemically bonded directly to the magnesium metal surfaces, the coating having an outer darkly colored layer and an underlying interfacial layer. Articles having a composite coating comprising first sectors of the electroceramic coating and second sectors comprising organic and/or inorganic components different from the electroceramic coating are also provided. The invention further relates to processes of making and using the articles.

Description

Dark electronic ceramic coating for magnesium

The invention relates to an article having a metallic surface with magnesium, which has been provided with a dark electronic ceramic coating chemically bonded to the metal surfaces, preferably a black, brown or bronze electronic ceramic coating. As used herein, "dark" means black, brown, bronze or gray. The article has a composite coating that includes a first partition of an electronic ceramic coating and also provides a second partition that includes an organic and / or inorganic component different from the electronic ceramic coating. The invention further relates to a method of making and using the article.

Compared to ferrous metals, the light weight and strength of magnesium and alloys (density of about 1.74 gm / cm ³ ) make products made from them highly ideal for manufacturing parts, such as electronic devices, including handheld electronic devices; motor vehicles ; Aircraft and other low and medium density products that are beneficial. One of the most significant disadvantages of magnesium or magnesium alloys is the susceptibility to corrosion, which is usually generated on Mg in the presence of oxygen, moisture, and other environmental factors such as human fingerprint components. Various coating products have been used on magnesium or magnesium alloy surfaces to give them the desired dark color and attempts have been made to improve corrosion resistance, but none have met the need for both corrosion resistance and dark color. One method to improve the corrosion resistance of metal surfaces is anodization, in which the metal (M) surface is electro-oxidized to form a metal oxide (MOx) layer from molecules on the metal surface, see, for example, U.S. Patent No. 4,978,432 and U.S. Patent No. 5,264,113. Anodization of magnesium or magnesium alloys provides some protection against corrosion, but US Patent No. 5,683,522 indicates that conventional anodization often fails to form a protective layer on the entire surface of complex workpieces and may contain cracks at sharp corners. To a metal surface. This lack of coverage adversely affects corrosion and also fails to provide a uniformly colored surface. Plasma electrolytic oxidation (PEO), also known as micro-arc oxidation (MAO), spark anodization, and micro-plasma oxidation (collectively referred to herein as "PEO"), is a method in which the application to The high voltage alternating current of the metal parts in the tank converts the surface of specific metals (such as aluminum and magnesium) into oxide coatings. PEO is characterized by a strong spark caused by micro-arc discharge, which decomposes the oxide layer originally deposited. The discharge leaves "pits" on the surface of the growing coating, with an average diameter of more than one micrometer after 1 minute and more than two micrometers after 30 minutes. Surface roughness also increases as the thickness of the PEO coating increases, which is generally undesirable. PEO treatment of magnesium or magnesium alloys results in a crystalline oxide (60-80 vol.%) Coating with a small amount of silicate and / or phosphate, depending on the composition of the PEO bath. The PEO method has disadvantages, including a lack of uniformity in the coating structure between crystalline and amorphous pit regions, and thicker and thinner coating regions can adversely affect color uniformity, making it unsuitable for display surfaces . In addition, PEO creates a brittle sublayer with a porosity of more than 15%, which is removed by an additional polishing step. Polishing has the following disadvantages: extra processing and often manual labor, and loss of dimensional integrity of the articles, and uniform polishing of complex articles or their articles with uneven coatings are challenging due to the travel capability limitations of PEO. More importantly, by removing a color-containing coating, the coloring characteristics of the coating may be adversely affected (e.g., causing unevenness). The disadvantage of magnesium-coated display surfaces (e.g., housings for electronic devices) is the susceptibility of the surface to stains, corrosion, and (especially for dark surfaces) fingerprint marks, which is reduced by reducing stains, corrosion, and fingerprints. The effort to leave marks (usually with more layers of coating) increases manufacturing costs. It is desirable to provide a method for uniformly coating an Mg alloy with a dark coating, and the coated Mg alloy article has a dark coating that provides improved corrosion resistance.

The invention described herein reduces at least some of the disadvantages described above. It is an object of the present invention to provide an article having a metal surface of at least one magnesium or magnesium alloy, the metal surface having an inorganic, preferably electrolytically deposited coating, which is directly chemically bonded to the at least one metal surface and exhibits blackness to the human eye , Brown, bronze or gray appearance. The inorganic coating may have additional layers deposited thereon to form a composite coating including the inorganic coating and the first coating distributed throughout the inorganic coating or in contact with at least a portion of the inorganic coating. Two components; and / or the coating on the surface of the magnesium or magnesium alloy may include a reaction product of an inorganic coating and the second component. The object of the present invention is also to provide a method for depositing a dark-colored coating for improving the corrosion resistance of a magnesium or magnesium alloy metal substrate, the method comprising: A) providing an alkaline electrolyte, which may be a solution or dispersion, including water, An organic amine, a phosphorus source, and one or more additional components selected from the group consisting of a water-soluble transition metal oxide, a water-soluble transition metal salt, and a mixture thereof; and the cathode is in contact with the alkaline electrolyte; B) Contacting an article with at least one bare metal magnesium or magnesium alloy surface with the electrolyte and electrically connecting it so that the surface acts as an anode; C) passing an electric current between the anode and the cathode via an electrolyte solution for a certain period of time to effectively produce direct chemistry The first layer of an inorganic coating that is bonded to the surface of a bare metal. The first layer is black, brown, bronze or gray to the human eye; D) removing the first layer of the inorganic coating from the electrolyte And, if necessary, dry it; E) optionally, at least the first layer of the inorganic coating is processed by: 1) the first layer of the inorganic coating is different from the inorganic coating Contacting the treatment composition, the post-treatment composition may react with the inorganic coating as appropriate; and / or 2) if it exists, applying the polymer composition to the first layer of the inorganic coating after step 1), This results in a second layer with a layer thickness of 0.1 micrometers to 15 micrometers containing organic polymer chains and / or inorganic polymer polymers; and F) optionally applying an additional protective layer, such as a quick-drying paint, after the post-treatment step ,paint. The object of the present invention is to provide a method, wherein the post-treatment step E) exists as the following steps: contacting the first layer of the inorganic-based coating layer with a second component different from the inorganic-based coating layer; Distributed in at least a portion (especially pores) of the first layer; and depositing and attaching a second layer different from the inorganic-based coating to at least the outer surface of the inorganic-based coating. An object of the present invention is to provide a method in which step E) i) is present and includes the step of introducing at least one composition containing Ti, Zr, Hf or a combination thereof as a second component into a second inorganic coating layer. A sub-layer that contacts at least the outer surface and desirably at least some of the inner surface with a second sub-layer, wherein the second component forms a thin inorganic coating that is in contact with the outer surface of the inorganic coating and is lined with an inorganic coating At least a portion of the holes. The object of the present invention is to provide a method, wherein step E) 1) comprises reacting the composition with the elements of the inorganic coating to form a part of the second component, which is different from the inorganic coating and composition. It is an object of the present invention to provide a method wherein step E) ii) is present and comprises contacting a first layer of an inorganic coating with a polymer composition, thereby forming an organic polymer chain and / or an inorganic polymer chain. A second layer; and optionally a paint layer after the post-treatment step. Another object of the present invention is to provide a method without any step prior to step B), which makes elemental silicon (e.g. silicate) and / or fluorine (e.g. metal fluoride, non-metal fluoride, fluorine Metallization) material is deposited on the metal surface. In some embodiments, except for trace amounts from the metal substrate and electrolyte raw materials, neither Si nor F is present in the electrolyte or coating. The object of the present invention is to provide a method comprising controlling the temperature and concentration of the electrolyte and the time and waveform of the current in step C) so that the thickness of the inorganic coating is 1-50 microns, preferably 1-20 microns, It also contains carbon, oxygen, phosphorus, one or more transition metals and magnesium. Another object of the present invention is to provide a method in which the first layer in step C) is formed using less than 10 kWh per square meter, and is measured in square meters of the total coated metal surface. An object of the present invention is to provide a method, further comprising performing at least one step selected from the group consisting of cleaning, etching, deoxidizing, decontaminating, and a combination thereof before contacting the magnesium-containing article with an alkaline electrolyte, so that Before the first layer, 0.05 to 50 g / m ^{2 of} metal is removed from the surface of the bare metal magnesium or magnesium alloy. The object of the present invention is to provide a method, further comprising the step of: covering a part of the magnesium-containing article before contacting the surface of at least one metal magnesium or magnesium alloy metal with an alkaline electrolyte. The object of the present invention is to provide a method in which after step C), not more than 10 mg / m ^{2 of the} inorganic coating is removed. An object of the present invention is to provide a method, wherein the current is a pulsed DC current having an average voltage in a range of 50 to 700 volts. An object of the present invention is to provide a composition suitable as a substance for an electrolytic solution in a plasma electrolytic deposition bath. The electrolytic solution may be an alkaline electrolytic solution, which may be a solution or a dispersion, which contains; it should consist essentially of each of the following; or, as appropriate, of the following: water, an organic amine, a phosphorus source, and at least one transition metal At least one water-soluble source, such as one or more additional components selected from water-soluble transition metal oxides, water-soluble transition metal salts, and mixtures thereof. In one embodiment, the organic amine is monoethanolamine and the at least one transition metal element comprises one or more of iron, vanadium, and tungsten. In one embodiment, the alkaline electrolyte contains less than 100 ppm silicon or aluminum and is substantially free of fluorine and tertiary amines. In one embodiment, the organic amine is a primary monoamine in which an acyclic amine is present, and at least one transition metal element is composed of iron or vanadium or tungsten. In one embodiment, the organic amine is monoethanolamine, the phosphorus source is phosphoric acid and at least one transition metal element includes iron and vanadium, and the pH of the alkaline electrolyte is at least 10.2. In one embodiment, the organic amine is monoethanolamine, the phosphorus source is phosphoric acid, and at least one transition metal element includes tungsten. In one embodiment, the alkaline electrolyte does not contain vanadium, the organic amine is monoethanolamine, the phosphorus source is phosphoric acid, and at least one transition metal element includes iron and optionally a second transition metal element other than vanadium. In one embodiment, the organic amine is a primary monoamine in the presence of an acyclic amine, and at least one water-soluble or dispersible source of the at least one transition metal element comprises iron citrate. The composition can be provided as a storage-stable dual-encapsulation system, where part A contains water; phosphorus sources, such as phosphoric acid, phosphorous acid, pyrophosphoric acid, and phosphonates; water-soluble salts of one or more transition metals, such as iron, vanadium, and tungsten And the like; wherein the mass ratio of phosphorus to the total amount of the transition metal is 4: 1 to 1: 1; and part B contains organic amine, preferably monoethanolamine, part A and part B so that part A is more than part B Mass ratios are provided in quantities ranging from 1: 1 to 2: 1. It is an object of the present invention to provide an article comprising at least one magnesium or magnesium alloy metal surface coated according to the method disclosed herein. The object of the present invention is to provide an article comprising at least one metal magnesium or magnesium alloy surface coated with a first layer of a dark inorganic coating, the coating being directly chemically bonded to the at least one metal magnesium or magnesium alloy surface Wherein the inorganic coating has a double-layer structure, and includes: a first sub-layer directly bonded to the surface of metallic magnesium or a magnesium alloy at a first interface, the first sub-layer comprising Mg, O, C, P, and at least one transition Metal element; a second sublayer integrally connected to the first sublayer at the second interface, the second sublayer including a surface outside the outer boundary of the inorganic-based coating, and optionally the inorganic substance in the second sublayer The inner surface defined by the pores that are within the outer boundary of the coating-like layer and communicate with the outer boundary. The second sub-layer includes Mg, O, C, P and at least one transition metal element; wherein the weight percentage of C in the second sub-layer More than the weight percentage of C of the first sublayer. In one embodiment, the weight percentage of C in the second sub-layer exhibits an increasing concentration gradient from the second interface to the outer surface of the inorganic-based coating. An object of the present invention is to provide an article having at least one metal magnesium or magnesium alloy surface, and a composite coating layer deposited thereon, the composite coating layer comprising: directly chemically bonding to the first layer through an inorganic coating layer; A matrix formed on the surface of at least one metallic magnesium or magnesium alloy, the matrix having pores and an inner surface defined by the pores, at least some of the pores communicating with the outer surface of the first layer and forming openings therein; and different The second component of the inorganic coating is applied to at least a part of the pore-containing substrate, and the second component is in contact with at least some of the inner surface and the outer surface. In one embodiment, the article further comprises a second layer different from the inorganic-based coating and attached to at least an outer surface of the inorganic-based coating. It is an object of the present invention to provide an article having at least a magnesium or magnesium alloy surface having an electronic ceramic coating chemically bonded thereto, and with or without post-treatment, the electronic ceramic coating having a surface attached thereto. Spray deposited anti-fingerprint coating. The anti-fingerprint coating contains uncoalesced spray droplets, which form a series of flat, cured spheres that form a cured refractive surface. In one embodiment of the present invention, an article having an inorganic coating is provided, the coating comprising magnesium metal bonded directly to a bare (meaning no pure surface with a coating applied thereto) at a first interface. Or a first sub-layer on the surface of a magnesium alloy, the first sub-layer comprising Mg, O, C, P and at least one transition metal; a second sub-layer at the second interface and integrally connected to the first sub-layer, the second The sub-layer includes an outer surface outside the outer boundary of the inorganic coating and an inner surface defined by holes in the second sub-layer that are within the outer boundary of the inorganic coating and communicate with the outer boundary. The second sub-layer includes Mg , O, C, P, and at least one transition metal, and the second sublayer has a composition such that O exhibits a concentration gradient, wherein O is the largest at the second interface and is reduced to approximately 30-50 wt.% Near the outer surface. ; And wherein Mg, P, and C each exhibit a concentration gradient in the second sublayer, so that the concentration of each element in the second sublayer is largest near the outer surface and close to the second interface, and is reduced to its level in the second sublayer. The lowest concentration. For the purpose of the present invention, the term "inorganic coating" means that the electronic ceramic coating contains a large amount of inorganic compounds and / or inorganic glass, and the inorganic coating may additionally include some sources derived from raw materials, in situ or similar sources. organic material. Organic materials should be understood as describing molecules consisting of at least one carbon atom and one or more hydrogens bound to it. The carbon atoms can form a chain or ring structure and optionally include additional atoms and functional groups (such as oxygen, silicon, etc.) attached. , Phosphorus and nitrogen). In general, inorganic coatings can contain less than 50, 40, 30, 20, 10, 8, 6, 4, 2, 1 wt.%, More preferably the unit is one thousandth, the best one millionth The amount of organic material. The term "paint" includes all similar materials that may be specified by more specific terms such as quick-drying lacquers, enamels, varnishes, shellacs, topcoats, and the like; and unless explicitly stated otherwise or necessarily implied by context. The single term "metal" or "metallic" should be understood by those skilled in the art to mean a material made of atoms of a metal element (such as magnesium), whether it is an article or a surface, the metal element is at least (of which preferred The increasing order is given) 55, 65, 75, 85, or 95 atomic%, and the single term "magnesium" includes pure magnesium and its containing 55, 65, 75, 85 or 95 atomic% of their alloys. Except where indicated in the operating examples or otherwise, all numbers expressing the number of ingredients, reaction conditions, or defining ingredient parameters used herein should be understood to be modified in all cases by the term "about". Throughout this specification, unless expressly stated to the contrary:%, "parts" and ratios are by weight or mass; groups or categories describing materials are intended to be suitable or better for a given purpose related to the present invention. Means that a mixture of any two or more of the members of a group or category is equally suitable or preferred; the description of a component in chemical terms refers to the group when added to any combination specified in this specification Or a group produced in situ within a composition from one or more newly added components and one or more chemical reactions between one or more components already present in the composition when other components are added Specifying the component in ionic form additionally means that there are sufficient relative ions to be electrically neutral to the overall composition and to any substance added to the composition; to the extent possible, any relative ions are implicitly specified by this It is preferably selected from other components explicitly designated in the form of ions; otherwise, in addition to avoiding adverse effects on the opposite ions of the object of the present invention, such relative ions can be freely selected; molecular weight (Mw) is the weight average The word "Mole" means "gongkemor", and the word itself and all its grammatical variations can be used for any chemical substance defined by all types and values of the atoms present in it, regardless of whether the species is ionic, Neutral, unstable, hypothetical or stable neutral substance with clearly defined molecules; and the term "storage stable" should be understood to include exhibiting no visual inspection during an observation period of at least 100 hours, or preferably at least 1000 hours Detected solutions and dispersions of phase separation trends during which the material is not subject to mechanical interference and the material temperature is maintained at ambient room temperature (18 to 25 ° C).

The applicant has unexpectedly discovered a method for manufacturing electronic ceramic coatings, which have a uniform dark surface on magnesium, preferably without subsequent smoothing of the coated surface. Articles according to the invention include magnesium-containing articles with a coating, which may be an electrolytic deposition coating chemically bonded to one or more metal surfaces of the article, the coating having a dark appearance to the human eye, such as black, Brown, bronze, gray and the like. Desirably, the coating exhibits L * a * b * measurements in the following ranges: For black L = 0 to 30, and L * a * b * values corresponding to brown, bronze, or gray should be familiar with this technique It is understood as defined by the Commission Internationale de l'Eclairage (CIE) L * a * b * color space (1976), where L * indicates brightness, a * is red / green coordinates and b * is yellow / Blue coordinates. Such articles are suitable for use as parts of, for example, electric vehicles, aircraft and electronic devices (including handheld electronic devices) and other products where the lightweight and strength of magnesium is desired. Articles generally have at least one metal surface that includes magnesium or a magnesium alloy and an inorganic-based coating is directly chemically bonded to the metal surface. In some embodiments, the inorganic-based coating is post-treated and / or painted. At least a part of the article has a metal surface containing not less than 50% by weight, more preferably not less than 70% by weight magnesium or a magnesium alloy. As used in the specification and the scope of patent applications, the term "magnesium-containing article" means an article having at least one surface that may be wholly or partially metallic magnesium or a magnesium alloy. The body of the article may be formed of metallic magnesium or a magnesium alloy, or may be formed of other materials, such as metals other than magnesium, polymeric materials, refractory materials such as ceramics, which have magnesium or magnesium alloys on at least one surface. Floor. The other materials may be other metals, non-metallic materials, or a combination thereof other than magnesium, such as composite materials or aggregates. The article may include at least one surface of metallic magnesium or a magnesium alloy, the surface comprising (in order of increasing preference) at least about 51, 60, 65, 70, 75, 80, 85, 86, 87, 88, 89, 90, 91 , 92, 93, 94, 95, 96, 97, 98, or 99 wt.% Magnesium. The coated metal surface has a different appearance than the uncoated metal surface. Desirably, the coated metal surface may have a black, brown, bronze, or gray appearance, and is generally darker than bare metal surfaces and MOx-coated surfaces, where M is a magnesium or magnesium alloy element. The coating may have a uniform thickness or may be selectively deposited (e.g., using a sealed chamber to limit the electrolyte to only contact, cover, and the like with the selected surface) such that the coating thickness is higher in the selected metal surface area. A first layer comprising an inorganic coating is chemically bonded to at least one metal surface of the article. Inorganic coatings may include some organic materials, but contain inorganic materials of higher quality than organic molecules. Inorganic materials can serve as a matrix in which any organic component can be distributed. In some embodiments, no organic molecules may be present. In some embodiments, carbon is present in the coating and no organic molecules are detected. Desirably, the inorganic-based coating can be applied by an electrolytic deposition method as described herein. In one embodiment, the inorganic-based coating contains carbon, oxygen, phosphorus, one or more transition metals, and magnesium. In one embodiment, the inorganic-based coating contains oxygen, at least one alloy element from a metal substrate and at least one element from a bath, in addition to at least one of magnesium or a magnesium alloy. In another embodiment, the inorganic coating comprises two or more transition metals and magnesium, such as carbon, oxygen, and phosphorus. The foregoing can be evaluated based on glow discharge light emission spectroscopy (GDOES), which is a spectroscopic method known in the art for the qualitative and quantitative analysis of metallic and non-metallic solid materials. In some embodiments, the inorganic-based coating may include carbon even if no organic or other carbon-containing components are added to the electrolyte. Both carbon and alloying elements (if present) can be dispersed in the ceramic layer. Even when carbon and alloy elements are included in the inorganic coating, a uniform thickness that provides uniform paint coating and adhesion and corrosion resistance can be produced, which is improved compared to the bare surface of a magnesium-containing substrate. This feature of the present invention is beneficial to reduce the rejection rate, in which the substrate and the inorganic coating deposited thereon obtain good coating quality even in the presence of carbon and alloy elements in the inorganic coating. Surprisingly, it has been found that the corrosion performance remains substantially the same in the presence of carbon, which is often seen as a contaminant indicating poor cleaning of metal substrates. In one embodiment, the inorganic coating includes C, O, P, Al, Mg and at least one transition metal. As shown in FIGS. 1 and 2, the inorganic-based coating layer may have a double-layered morphology. FIG. 1 is a diagram showing an element depth distribution obtained by using the glow discharge light emission spectroscopy (GDOES) for an inorganic coating according to the present invention. The amount of each element is displayed as a percentage by weight at a specific distance from the metal surface. Figure 1 shows that the first and second sublayers differ in morphology and elemental composition. FIG. 2 shows a cross-section of a magnesium alloy plate coated according to Example 1 before applying post-treatment. Despite being deposited in a single processing step, the inorganic-based coating 100 has a two-layer structure: a first sub-layer120 Bind directly toMagnesium items 200 Interface with metal surface110 (First interface 110); and a second sublayer140 , Which is in direct contact with the first sub-layer and is spaced from the metal surface by the first sub-layer in between. The second sublayer is at the interface with the first sublayer130 (Second Interface) is directly combined with the first sublayer. The second sublayer of the inorganic coating contains pores160 And has an inner surface 170 And outer surface150 . The inner surface 170 is defined by a hole 160 in the second sub-layer and within the outer boundary of the inorganic-based coating, which contains the outer surface 150 of the second sub-layer. The outer surface of the second sub-layer is at the boundary between the inorganic-type coating and the external environment or the second layer applied to the external boundary, and does not directly contact the metal surface of the magnesium-containing article. The first sublayer may have few or no pores and have a more dense composition than the second sublayer. Any holes present in the first sub-layer should not be continuous between the metal surface of the article and the outer surface of the inorganic coating, and may be smaller than the holes in the second sub-layer as the case may be. Some holes of the second sub-layer are openings communicating with the outer surface. In some embodiments, the second sub-layer may include open-cell and closed-cell structures. The pore size can be in the range of about 0.1 microns to 5 microns and can account for up to 50% or more of the volume of the deposited coating. The surface area of the electrolytically-coated inorganic coating can be about 75-150X of the surface of the uncoated substrate. At least a part of the inorganic coating layer has an amorphous structure. The physical form of the inorganic coating may include an amorphous compound of magnesium and one or more elements. In one embodiment, the inorganic-based coating exhibits an amorphous structure by X-ray crystallography (XRD). Desirably, the inorganic-based coating may be a hard (hardness 5-6 Moh) amorphous coating containing a non-stoichiometric magnesium compound. There may be non-stoichiometric glass of Mg and transition metals with or without oxygen as disclosed herein. In one embodiment, the inorganic coating is an inorganic composition comprising Mg, O, and Fe, which includes stoichiometric and non-stoichiometric compounds of these elements and each other. In another embodiment, the inorganic composition includes crystalline and non-crystalline compounds containing magnesium, and more than 50 atomic% of the composition includes non-crystalline compounds. The coating thickness of the inorganic electrolytic deposition coating can be in the range of 0.1 micrometer to about 50 micrometers, and it is preferably 1-20 micrometers depending on the intended use of the coated article. The coating thickness of the inorganic electrolytic deposition coating should be at least (in increasing order of preference) 0.5, 1, 3, 5, 7, 9, 10, or 11 microns, and if it is not more than (for economic reasons only) Ascending order of preference) 50, 30, 25, 20, 15, 14, 13, or 12 microns thickness. As a decorative layer, the coating can be in the range of 2-5 microns. In one embodiment, the coating thickness is in the range of 3 to 10 microns. The examples show that the electrolytically coated inorganic coatings according to the present invention perform better in unpainted and painted corrosion tests than commercially available conversion coatings for magnesium, and are comparable to those commonly used in the automotive industry Compared to PEO coatings on magnesium alloys such as magnesium cast alloys and wrought alloys, they provide improved corrosion resistance. Compared to commercially available conversion coatings for magnesium, electrolytically coated inorganic coatings perform better in unpainted and painted corrosion tests, and are comparable to magnesium alloys commonly used in the automotive industry (e.g. Compared with PEO coatings on magnesium cast alloys and wrought alloys, it provides improved corrosion resistance. In one embodiment, the magnesium-containing article may have a composite coating, where an inorganic-based coating may serve as a matrix. This embodiment may include a coating comprising: A) a first substrate of an inorganic coating, which is directly chemically bonded to a magnesium-containing surface, and B) is different from an inorganic coating and is distributed in at least a portion of the substrate Of the second component. In another embodiment, an article containing a coating on magnesium may include: A) a first layer of an inorganic coating, which is directly chemically bonded to the magnesium-containing surface, and B) different from an inorganic coating that is cut on an inorganic coating A second component distributed in at least a portion of the coating, such as Ti, Zr or Hf or similar post-treatment, and C) a second layer that is different from the inorganic coating and adheres to at least the outer surface of the inorganic coating, in In one embodiment of the present invention, the second component may have the same composition as the second layer. In another embodiment of the invention, the second component may be different from both A) and C). In one embodiment, the second component and / or the second layer may form reaction products with elements in the inorganic coating. In one embodiment, the inorganic-based coating has a paint layer deposited thereon, which may include a second layer or may be added to the second layer. For a number of reasons, as defined above, the inorganic coatings and aqueous compositions for depositing inorganic coatings according to the present invention may preferably be substantially free of many compositions used for similar purposes in the prior art. ingredient. Specifically, for each of the preferably minimized ingredients listed below, they are given in order of increasing preference, and when the aqueous composition according to the present invention is in direct contact with the metal in the method according to the present invention, it contains Each of the following components in excess of 1.0, 0.5, 0.35, 0.10, 0.08, 0.04, 0.02, 0.01, 0.001, or 0.0002%, more preferably in gram / liter: chromium, cyanide, nitrite ion, Organic surfactants, formaldehyde, formamidine, urea, hydroxylamine, ammonia, tertiary amines, cyclic amines, such as hexamethylenetetramine; silicon, such as siloxane, organosiloxane, silane, silicate; Rare earth metals; alkali metals, such as sodium, potassium; sulfur, such as sulfate; permanganic acid; perchlorate; boron, such as borax, borate; strontium, fluorine, such as free or bound fluoride ions; and / or free Chloride. Also for each of the preferred minimizing ingredients listed below in order of increasing preference, the inorganic coating and inorganic second layer deposited according to the present invention contain no more than 1.0, 0.5, 0.35, 0.10, 0.08 , 0.04, 0.02, 0.01, 0.001 or 0.0002%, more preferably each of these values in units of one thousandth (ppt): chromium, cyanide ion, nitrite ion, organic surfactant, formaldehyde , Formamidine, urea, hydroxylamine, ammonia, and hexamethylenetetramine; silicon, such as siloxane, organosiloxane, silane, silicate; rare earth metals; alkali metals, such as sodium, potassium; sulfur, such as Sulfate; permanganic acid; perchlorate; boron, such as borax, borate; strontium, fluorine, such as free or bonded fluoride ions; and / or free chloride ions. Inorganic coatings can be made by a variety of methods that can produce a hard amorphous coating that is chemically bonded to a magnesium-containing metal. In one embodiment, an inorganic-based coating can be formed using electrolytic deposition according to the method of the invention described herein. For post-treatment, several commercially available options may be suitable, including conversion coating composites including fluorometallates such as Ti, Zr, Hf, or combinations thereof. It has been found that suitable compositions for forming a second layer comprising organic polymer chains and / or inorganic polymer chains include, as non-limiting examples, aqueous compositions comprising (A) dissolved fluorine containing one or more metal and metalloid elements Acid substitution components selected from the group of elements consisting of: titanium, zirconium, hafnium, boron, aluminum, germanium, and tin; and / or (B) one or more of the following components (i ) Finely pulverized form of dissolved or dispersed metal and metalloid elements selected from the group of elements consisting of titanium, zirconium, hafnium, boron, yttrium, lithium, aluminum, germanium, and tin, and (ii) oxides, hydroxides and carbonates of such metals and metalloids; plus (C) any one of the following components (i) water-soluble or dispersible polymers and / or copolymers, preferably From the group consisting of: (i.1) one or more x- (N--R¹ --N--R² -Aminomethyl) -4-hydroxy-styrene polymers and copolymers, where x = 2, 4, 5, or 6, R¹ Represents an alkyl group containing 1 to 4 carbon atoms, preferably methyl, and R² -Indicates conforming to the general formula H (CHOH)_n CH₂ --- substituents, where n is an integer of 1 to 7, preferably 3 to 5, (i.2) epoxy resin, especially the polymer of diglycidyl ether of bisphenol A, non-polymerizable groups can be used as appropriate End-capped and / or have some epoxy groups that hydrolyze to hydroxyl groups; (i.3) polymers and copolymers of acrylic acid and methacrylic acid and their salts; and (i.4) polymers and copolymers containing silicon Materials, which may be organic and / or inorganic polymers. The treatment may consist of any of the following: coating the surface of the first layer of the inorganic coating with a liquid film of the composition and then drying the liquid film in situ on the surface of the first layer, or applying only the inorganic coating The first layer of the layer is in contact with the composition for a sufficient time to produce an improvement in the resistance of the coated article to corrosion, and is subsequently rinsed before drying. Such contact can be achieved by spray coating, immersion, and the like known per se in this technology. Depending on the surface conditions of the magnesium-containing surface to be coated, the method may include the following steps, as appropriate: the intervention steps of cleaning, etching, deoxidizing and decontaminating, with or without rinsing with water. In the case of use, the flushing water can be counter-currently flown into the aforementioned bath. Before contacting the magnesium-containing article with the electrolyte, the following step 5) may be performed: covering or closing a part of the article to restrict or prevent contact with the electrolyte. For example, a cover may be applied to a magnesium-containing portion that is not desired to be coated, or a cover may be applied to protect a component or surface that may be damaged by the electrolyte. Similarly, a hollow portion of an article (such as the inner cavity of a pipe) may be covered by Seal or plug to prevent electrolyte from coming into contact with internal surfaces. Desirably, the inorganic-based coating is not physically or chemically removed or etched between the step of removing the coated article from the electrolyte and the post-processing step. Specifically, inorganic coatings not exceeding 1000, 500, 100, 50, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1 or 0.5 mg / m2 can be removed from the article. The inorganic coating is preferably removed without any deposition. As discussed above, there are no specific restrictions on the items to be subjected to the treatment according to the present invention, and the limitation is that the surface to be electrolytically coated has sufficient magnesium metal or other light metal combined with magnesium that is preferably in a zero oxidation state, in order to The coating is allowed to develop and non-magnesium-containing surfaces are not adversely affected by the treatment. Covering the selected surface to prevent contact with the electrolyte can be achieved by methods known in the art. Electrolytic treatment is advantageously applied to magnesium-based alloys containing one or more other elements such as Al, Zn, Mn, Zr, Si, and rare earth metals. If electrolytic deposition is used, the magnesium-containing surface to be coated is contacted with an alkaline electrolyte as described herein. The pH of the electrolyte can be 10 or more, preferably higher than 10, 10.1, 10.2, 10.3, 10.4, 10.5, 10.6, 10.7, 10.8, 10.9, 11, 11.1, 11.2, 11.3, 11.4, 11.5, 11.6, 11.7, 11.8, 11.9, 12, 12.1, 12.2, 12.3, 12.4, 12.5, 12.6, 12.7, 12.8, 12.9, or 13. In performing the electrolytic deposition, an electrolytic solution that can be maintained at a temperature between about 5 ° C and about 90 ° C, preferably about 20 to about 45 ° C, is used. The electrolyte is an alkaline solution or dispersion, which contains; preferably consists of each of the following; or, as appropriate, of the following: water, an organic amine, a phosphorus source, and at least one water-soluble source of at least one transition metal, For example one or more additional components selected from the group consisting of water-soluble transition metal oxides, water-soluble transition metal salts, and mixtures thereof. Organic amines are soluble or dispersible in the electrolyte. The organic amine may be a primary amine, preferably a monoamine, such as monoethanolamine as a non-limiting example. The organic amine present should preferably be free of cyclic or tertiary amines. Primary monoamines are preferred; secondary amines or diamines may be present, the limitation being that they do not interfere with the deposition or corrosion resistance of the coating. Sources of organic amines are usually present in the following (in increasing order of preference): about 50, 60, 70, 80, 90, 100, 105, 110, 115, 120, 125, 130 or 140 g / l, and at most (In increasing order of preference) about 500, 400, 350, 300, 275, 250, 225, 200, 190, 180, 170, 160, 150, 145, 143 or 141 g / l. Suitable phosphorus sources include water-soluble acids and their salts, preferably oxo acids. The source is inorganic or organic. Non-limiting examples include phosphoric acid, phosphite, phosphonic acid, phosphate, pyrophosphate, phosphonate, and combinations thereof. Phosphorus sources are usually present in the following order (in increasing order of preference): about 10, 15, 17, 19, 20, 21, 22, 23, 24, 25, 26, 28, 30, 32, 34, 36, 38 Or 40 g / l and at most (in increasing order of preference) about 85, 80, 75, 70, 65, 60, 55, 50, 45, 44, 43, 42, or 41 g / l, which starts at PO_x Calculation. Water-soluble sources of at least one transition metal include transition metal sources such as transition metal oxides, acids and salts of metal oxides; unoxidized transition metal salts, and mixtures thereof. The salt may be inorganic or may include an organic counter ion. Examples of suitable sources include metal oxides, such as oxides of vanadium and their oxide salts, acids and salts of metal oxides, including, for example, tungstic acid and ammonium metatungstate; and unoxidized transition metal salts, such as iron citrate, Iron acetate, iron acetopyruvate, and the like; and combinations thereof. As used herein, "water soluble" includes sources of transition metals, which may be insoluble in H₂ O or only slightly soluble in H₂ O, but soluble in alkaline electrolyte as described herein. Preferred transition metals include iron, tungsten, vanadium and mixtures thereof. Suitable iron sources are water-soluble or alkali-soluble salts of iron, such as non-limiting examples of iron nitrate, iron sulfate, ferric ammonium citrate, ferric citrate, ferric ammonium sulfate, ferric acetate, acetamylpyruvate Iron and similar. Iron acetate and iron citrate are preferred. The transition metal source exists as ions dissolved in the electrolyte, and the amount used in the electrolyte depends on the transition metal selected and the desired color. For black, each transition metal may be present in an amount up to the solubility limit of the transition metal ions, the limitation being that the amount present does not interfere with the deposition of the coating, corrosion resistance, or bath maintenance. Desirably, iron ions may be present in the following order (in increasing order of preference): about 0.40, 0.45, 0.50, 0.55, 0.60, 0.65, 0.70, 0.75, 0.80, 0.85, 0.90, 0.95, 1.00, 1.1, 1.2, 1.3, 1.4 g / l and at most (in increasing order of preference) about 5.0, 4.0, 3.5, 3.0, 2.5, 2.4, 2.3, 2.2, 2.1, 2.0, 1.9, 1.8, 1.7, 1.6 or 1.5 g / l. Desirably, vanadium may be present (in increasing order of preference): about 0.50, 0.55, 0.60, 0.65, 0.70, 0.75, 0.80, 0.85, 0.90, 0.95, 1.00, 1.1, 1.2, 1.3, 1.45, 1.5 , 1.55, 1.6, 1.65, 1.7, 1.75, 1.8, or 1.85 g / l and at most (in increasing order of preference) about 10, 9, 8, 7, 6, 5.5, 5.0, 4.5, 4.25, 4.0, 3.9, 3.8, 3.7, 3.6, 3.5, 3.4, 3.3, 3.2, 3.1, 3.0, 2.9, 2.8, 2.7, 2.6, 2.5, 2.4, 2.3, 2.2, 2.15, 2.1, 2.05, 2.0, 1.95, 1.9, or 1.875 g / l . It is expected that, in terms of tungstic acid, tungsten may exist in the following amounts (in increasing order of preference): about 0.5, 1, 2, 3, 4, 5, 6, 7, 8, 9.00, 9.1, 9.2, 9.3, 9.4 , 9.5, 9.6, 9.7, 9.8, 9.9, 10.00, 10.1, 10.2, 10.3, 10.45 g / l and at most (in increasing order of preference) about 20, 19, 18, 17, 16, 15, 14, 14, 13, 12, 12.5, 12.4, 12.3, 12.2, 12.1, 12.0, 11.9, 11.8, 11.7, 11.6, 11.5, 11.4, 11.3, 11.2, 11.1, 11.0, 10.9, 10.8, 10.7, 10.6 or 10.5 g / l. Optionally, the electrolyte may contain at least one additive, such as a ligand, a chelating agent, or the like capable of forming a coordination complex with a transition metal in the electrolyte bath, such as acetamidoacetone. In one embodiment, the organic amine is monoethanolamine and the at least one transition metal element comprises one or more of iron, vanadium, and tungsten. In one embodiment, the alkaline electrolyte contains less than 100 ppm silicon or aluminum and is substantially free of fluorine and tertiary amines. In one embodiment, the organic amine is a primary monoamine in which an acyclic amine is present, and at least one transition metal element is composed of iron or vanadium or tungsten. In one embodiment, the organic amine is monoethanolamine, the phosphorus source is phosphoric acid and at least one transition metal element includes iron and vanadium, and the pH of the alkaline electrolyte is at least 10.2. In one embodiment, the organic amine is monoethanolamine, the phosphorus source is phosphoric acid, and at least one transition metal element includes tungsten. In one embodiment, the alkaline electrolyte does not contain vanadium, the organic amine is monoethanolamine, the phosphorus source is phosphoric acid, and at least one transition metal element includes iron and optionally a second transition metal element other than vanadium. In one embodiment, the organic amine is a primary monoamine in the presence of an acyclic amine, and at least one water-soluble or dispersible source of the at least one transition metal element comprises iron citrate. The composition can be provided as a storage-stable dual-encapsulation system, where part A contains water; phosphorus sources, such as phosphoric acid, phosphorous acid, pyrophosphoric acid, and phosphonates; water-soluble salts of one or more transition metals, such as iron, vanadium, and tungsten And the like; wherein the mass ratio of phosphorus to the total amount of the transition metal is 4: 1 to 1: 1; and part B contains organic amine, preferably monoethanolamine, part A and part B so that part A is more than part B Mass ratios are provided in quantities ranging from 1: 1 to 2: 1. In one embodiment, a method is provided in which the surface of a magnesium or magnesium alloy is contacted with an aqueous electrolyte (preferably immersed therein) and electrolyzed as an anode in a circuit. One such method involves immersing at least a portion of the article in an electrolyte, which is preferably contained in a bath, tank, or other such container. The second item is the cathode opposite the anode, which is also placed in the electrolyte. Alternatively, the electrolyte is placed in a container which is itself a cathode with respect to the item (anode). Applying a voltage across the anode and cathode for a time sufficient to form an inorganic electrolytic coating. The time required to produce a coating in the electrolytic method according to the present invention can vary in the range of about 30, 60, 90, 120 seconds, up to about 150, 180, 210, 240, 300 seconds. Longer deposition times can be used, but are considered to be commercially undesirable. The electrolytic treatment time can be varied to maximize efficiency and control coating weight by reducing the time to Vmax. Alternating current, direct current, or a combination may be used to apply a desired voltage, such as a linear DC, pulsed DC, AC waveform, or a combination thereof. In one embodiment, a pulsed DC current is used. The following time periods should be used: at least 0.1, 0.5, 1.0, 3.0, 5.0, 7.0, 9.0, or 10 milliseconds and no more than 50, 45, 40, 35, 30, 25, 20, or 15 milliseconds, the time period Can remain constant or can change during immersion. The waveform may be rectangular, including square; sine; triangular; sawtooth; and combinations thereof, such as a modified rectangle as a non-limiting example, having at least one vertical segment that is not perpendicular to the horizontal portion of the rectangular wave. The peak voltage potential should preferably be (in increasing order of preference) up to about 800, 700, 600, 500, 400 volts, and should preferably be at least (in increasing order of preference) 200, 250, 300, 350, 375 or 395 volts. Lower voltages result in thinner films, which are usually lighter in color, which may be acceptable for gray or to obtain brown. The average voltage may be (in increasing order of preference) at least 300, 310, 320, 330, 350, or 375 volts, and independently preferably may be less than 600, 550, 500, 450, 425, or 400 volts. In one embodiment, the average voltage may be in the range of about 300-450 volts. In another embodiment, the average voltage may be selected to be in the higher range of 400-550 volts. A voltage is applied across the electrodes until a coating of a desired thickness is formed on the surface of the article. Generally, higher voltages increase the total coating thickness. Higher voltages can be used within the scope of the invention, with the limitation that the substrate is not damaged and the coating formation is not adversely affected. Prior to electrolytic coating, the magnesium-containing surface may undergo one or more of the cleaning, etching, deoxidizing, and decontaminating steps, with or without a rinse step. The cleaning may be an alkaline cleaning and a cleaner may be used to etch the surface. A suitable cleaner for this purpose is Parco Cleaner 305, which is an alkaline cleaner available from Henkel. Desirably, the magnesium-containing surface can be etched (in increasing order of preference) by at least 1, 3, 5, 7, 10, or 15 g / m2, and independently for economic reasons, it is preferably at least not Over 20, 25, 30, 35, 40, 45 or 50 g / m2. Etching can be achieved using commercially available etchants and / or deoxidizers for magnesium. Depending on the magnesium or magnesium alloy composition and cleanliness, a decontamination step may also be included in the treatment. Suitable detergents include acids, such as carboxylic acids, such as glycolic acid, alone or in combination with chelating agents and nitrates. If any of the above steps are used, washing the magnesium-containing surface is usually the final step to reduce the introduction of chemicals from the previous step into the electrolyte. Additional processing steps may be used after depositing the inorganic coating, such as water, alkaline solution, acid solution rinse, and a combination of such steps. In some embodiments, the method may include the step of applying at least one post-treatment, which may be dispersed in the inorganic coating, may form reaction products therewith, and / or may form additional layers and combinations thereof. The additional layer may be an inorganic layer, an organic layer, or a layer containing inorganic and organic components. Advantageously, any post-treatments (including, for example, additional layers described herein) are permanently bonded to the inorganic coating; at the same time other removable layers can be applied, which are used to cover during manufacture or to Ship after shipment. The porous structure of the inorganic coating that is electrolytically deposited on magnesium-containing articles is a particular challenge for post-processing. Due to the significant surface area present on the inner surface of the inorganic coating, the post-processing does not close the pores. By BET measurement, the surface area of the inorganic coating according to the present invention is usually 75 to 100 times the original metal surface. Such surface areas are usually not found in conventional conversion coatings. Surprisingly it has been found in the method according to the invention that, although other post-treatments that can be used to anodize the layer have little or no positive effect on the corrosion resistance, the above-mentioned post-treatment steps containing Ti, Zr and the like are introduced Suitable method for a second component for additional corrosion protection. For example, conventional post-treatments (including nickel and lithium salts) used to anodize magnesium have been found to provide insufficient unpainted corrosion resistance. In contrast, post-treatment with an inorganic coating of a fluorinated metal compound composition provides improved corrosion resistance. A post-processing step using a fluorine-containing metal compound immediately after the deposition of the inorganic-based coating may be performed, and the coating may be dried. Preferably, at least one post-treatment composition is introduced into the second sub-layer of the inorganic coating, and is in contact with at least some of the outer surface and preferably with its inner surface. The second component may include a post-treatment composition and / or may include a reaction product of the post-treatment composition and an element of the inorganic coating. In one embodiment, the post-treatment composition reacts with the elements of the inorganic coating to form a second component, which is different from the inorganic coating at least in that the second component contains a metal or polymer from the post-treatment. The second component may form a thin inorganic coating that contacts the outer surface of the inorganic coating and is lined with at least a portion of the pores in the inorganic coating. In some embodiments, the post-treatment composition may also contact the inner surface of the inorganic coating and / or react with elements on the inner surface, making the inorganic coating more resistant to the corrosion-producing factors that reach the magnesium-containing surface. The depth at which the second component penetrates into the inorganic coating substrate may include up to 70%, 65%, 60%, 55%, or 50% of the total thickness of the porous second sublayer of the inorganic coating. Measure from the second interface to the surface outside the inorganic coating. In some embodiments, the post-treatment composition may react with elements in the inorganic coating. Contacting the inorganic coating with the post-treatment composition provides improved corrosion resistance and does not cover holes in the outer surface of the inorganic coating. This is beneficial if a subsequent paint step is used because the holes provide anchor anchor points for the paint to adhere to the surface. Another post-treatment step that can be used is to deposit an additional layer containing the polymer, which is preferably performed using a thermosetting resin, which may or may not react with the inorganic coating. As measured from the outer surface of the inorganic coating to the outer surface of the second layer, the average thickness of the polymerized second layer can be in the following range: (in order of increasing preference) at least about 0.1, 0.25, 0.5, 0.75, 1, 2, 3, 4 or 5 microns and (in order of increasing preference) no more than about 14, 12, 10, 8 or 6 microns. In comparison, a typical paint thickness is at least 25 microns thick. The use of either a thin polymer layer or paint as described above usually covers holes in the outer surface of the inorganic coating, which holes provide improved adhesion of the polymer or paint and unexpectedly a uniform surface. Desirably, the polymer forming the second layer may include organic polymer chains or inorganic polymer chains. Examples of polymers suitable for the additional layer include, as non-limiting examples, polysiloxanes, epoxy resins, phenols, acrylics, polyurethanes, polyesters, and polyimides. In one embodiment, an organic polymer selected from the group consisting of epoxy resin, phenols and polyimide is used. Preferred polymers for forming additional layers include phenol-formaldehyde polymers and copolymers produced from, for example, novolac resins, the copolymer having a molar ratio of formaldehyde to phenol of less than one, and soluble formaldehyde of phenolic resins The molar ratio of phenol is greater than one. Such polyphenol polymers can be made known in the art, for example according to US Patent No. 5,891,952. Novolac resins are preferably used in combination with a crosslinking agent to promote curing. In one embodiment, a soluble phenolic resin having a molar ratio of formaldehyde to phenol of about 1.5 is used to form an additional polymer layer on the inorganic coating. The phenolic resin suitable for forming the polymer layer preferably has a molecular weight of about 1,000 to about 5000 g / mole, preferably 2000 to 4000 g / mole. It is desirable to introduce at least one of the above resins into the first layer of the inorganic coating, contact and crosslink at least its outer surface, so as to form a polymer layer on the outer surface of the inorganic coating. This polymeric second layer is different from and adheres to an inorganic coating. In some embodiments, the resin may also contact the inner surface of the inorganic coating and form a polymeric second component upon curing, which is different from the inorganic coating and is distributed in at least a portion of the inorganic coating. Analysis of an inorganic coating according to the present invention that has been in contact with a soluble phenolic resin (whose formaldehyde to phenol has a molar ratio of 1.5) shows that the polymeric component is present in the inorganic coating matrix, thereby forming a composite coating Floor. The depth at which the polymeric second component penetrates into the inorganic coating substrate can be in the following ranges: (in increasing order of preference) 1, 2, 5, 10, 15, 20, or 25% and (in increasing order of preference) ) May not exceed 70, 65, 60, 55 or 50, 45, 40 or 35% of the total thickness of the inorganic coating, and the total thickness is measured from the first interface to the outer surface of the inorganic coating. In some embodiments, the resin may include a functional group capable of reacting with the inorganic coating layer, which may form a bond between the resin and the inorganic coating layer. For example, uncured novolac resins and soluble phenolic resins contain OH functional groups that can react with metals in inorganic-based coatings, thereby connecting polymers to the inorganic-based coatings. The coated substrate according to the present invention can be used in motor vehicles; aircraft and electronic devices, in which the combination of an inorganic coating and a post-treatment layer can provide more corrosion protection than paint or anodization alone, and the combined ceramic-type hardness imparts The outer layer is extra tough because sharp objects are more difficult to deform harder substrate undercoats than magnesium, and magnesium is relatively softer than ceramic. The coating according to the present invention can also be beneficial in maintaining the gloss and color readings of the topcoat relatively constant by providing a relatively uniform paint base. The method and coated articles of the present invention provide a more uniform dark surface on magnesium and magnesium alloys. Non-limiting examples of magnesium and magnesium alloys are AZ-31B, AZ-91B, AZ-91D, AM-60, AM -50, AM-20, AS-41, AS-21, AE-42, LZ-91, WS-82 and AM-lite® (exclusive Mg-Zn-Al alloy). Uniformity facilitates the adhesion of any subsequently applied layers which provide improved corrosion resistance. Examples For examples, commercially available magnesium or magnesium alloy test panels were used. The AZ-31 Mg alloy plate is about 93-97 wt.% Mg, and the rest is composed of Al, Zn, Mn and other metal and metal-like impurities less than 0.5 wt.%. AZ-91 Mg alloy plate has less magnesium, about 87-91 wt.%, And the rest is composed of Al, Zn, Mn and other metal and metalloid impurities less than 1.2 wt.%.Cleaning steps : Place all AZ-31 boards in 5% BONDERITE^® C-AK 305 (alkaline cleaner available from Henkel Corp.) was cleaned at 60 ° C for 3 minutes; rinsed with deionized water; 3% BONDERITE^® Deoxidation in C-IC HX-357 at 20-22 ° C for 90 seconds, which is about 30 g / m² Of etching rate. Turco for all AZ-91 boards^® 6849 alkaline cleaner for one minute; rinse with deionized water; deoxidize with a commercially available phosphate-based deoxidizer at 20-22 ° C for 60 seconds; decontaminate with a 25,000 KHz ultrasonic bath with 1 gram per liter of citric acid .Coating conditions Unless otherwise stated, the conditions of the electrolytic coating method used in the examples were: the bath temperature was maintained between 20-25 ° C, the plate was immersed in the electrolyte as the anode and steel was the cathode. After coating and removal from the electrolyte, the coated plate was rinsed with deionized water. The coated boards are dried and not baked, kiln fired, calcined or otherwise heat treated at temperatures above 100 ° C.Examples 1 : On magnesium Black electronic ceramic coating The AZ-31 Mg alloy plate was immersed in an electrolyte bath containing: Table 1 The pH of the electrolyte was measured at 10.55. At a peak voltage of 350 volts, the plate was electrolytically coated as an anode for 30 seconds using a square DC waveform with 25 ms on and 9 ms off to produce an inorganic coating covering the edges. The coated plate was removed from the electrolyte bath and rinsed with deionized water for 300 seconds. The resulting coating was uniformly black to the human eye. The color was measured with a Minolta Cr 300 color meter: the L, a, and b color values of the coating were: 29.93, -2.14, and +2.33 respectively. Inorganic coatings have uniform texture and surface appearance. The thickness of the coating was measured and the thickness was 10.01 microns. The coating was corrosion tested under e-coat paint and passed the B-117 ASTM NSS test for 504 hours.Examples 2 : On magnesium Black electronic ceramic coating The AZ-31 Mg alloy plate was immersed in an electrolyte bath as described below, and coated under the same conditions as in Example 1: Table 2 The resulting coating was uniformly black to the human eye. The coating is measured with a Minolta Cr color meter and L, a, and b are: 28.18, -2.68, and +2.33 respectively. The inorganic coating has a uniform texture and surface appearance, and the measured coating thickness is 10.22 microns.Examples 3 : On magnesium Black electronic ceramic coating The AZ-31 Mg alloy plate was immersed in an electrolyte bath as described below, and coated under the same conditions as in Example 1: Table 3 The pH of the bath was measured at 10.26. The resulting coating was uniformly black to the human eye. The obtained coating was measured with a Minolta Cr color meter and L, a, and b were: 28.87, -2.66, and +2.70, respectively. The inorganic coating has a uniform texture and surface appearance, and has a thickness of 9.29 microns.Examples 4 : Black Electronic Ceramic Coating on Magnesium The AZ-31 Mg alloy plate was immersed in an electrolyte bath as described below, and coated under the same conditions as in Example 1: Table 4 The pH of the bath was measured at 10.30. The resulting coating was uniformly black to the human eye. The coating was measured with a Minolta Cr color meter and L, a, and b were: 32.59, -1.62, and +6.13 respectively. The inorganic coating has a uniform texture and surface appearance, and has a thickness of 10.06 microns.Examples 5 : Brown Electronic Ceramic Coating on Magnesium The AZ-31 Mg alloy plate was immersed in an electrolyte bath as described below, and coated under the same conditions as in Example 1: Table 5 The pH of the bath was measured at 10.33. The resulting coating was uniformly brown to the human eye. The coating was measured with a Minolta Cr color meter and L, a, and b were: 42.19, -1.89, and +11.90 respectively. The inorganic coating has a uniform texture and surface appearance, and has a thickness of 15.76 microns.Examples 6 : Black Electronic Ceramic Coating on Magnesium An AZ-31 Mg alloy plate was immersed in the electrolyte bath according to Example 3, and was coated under the same conditions as in Example 1 except that a higher peak voltage of 420 volts was used. The obtained coating was measured with a Minolta Cr color meter and L, a, and b were: 25.21, -2.75, and +1.55, respectively. The inorganic coating is uniform and has a thickness of 14.98 microns.Examples 7 : Comparative Example 1 The AZ-31 Mg alloy plate was cleaned with the same cleaning used in Example 1. Thereafter, the plate was immersed in an electrolyte bath and subjected to ammonium metavanadate (NH₄ VO₃ Plasma electrolytic oxidation (PEO) coating in high concentration phosphate electrolyte. : Table 6 The plate is treated under the same conditions (including pH, conductivity, composition, and electrical input) as bath B in Table 1, such as "Effect Of Ammonium Metavanadate On Surface Characteristics Of An Oxide Layer Formed On Mg Alloy Via Plasma Electrolytic Oxidation"Surface & Coatings Technology , Vol. 236, December 15, 2013, pages 70-74. Although treated according to the example of the publication identified above, no coating was observed on 90% of the test panels. No measurable coating was found on the partially exposed and shiny parts of the test board.Examples 8 : Gray electronic ceramic coating on magnesium The AZ-31 Mg alloy plate was immersed in an electrolyte bath as described below, and coated under the same conditions as in Example 1: Table 7 The resulting coating was uniform gray. The thickness of the inorganic coating is 10.2 microns. The obtained coating was measured with a Minolta Cr color meter, and L = 53.83, a = -3.45, and b = +6.72.Examples 10 : On magnesium Black electronic ceramic coating The AZ-31 Mg alloy plate was immersed in an electrolyte bath as described below, and coated under the same conditions as in Example 1: Table 10 The pH of the electrolyte was measured at 10.51. The obtained coating was measured with a Minolta Cr color meter, and L = 28.69, a = -2.60, and b = +2.30. The inorganic coating is extremely uniform and has a thickness of 8.48 microns. This coating has an emissivity of 0.77 (on a scale of 0 to 1), making it useful for heat sinks and heat dissipation applications, such as in electronic devices where a lightweight and uniform visual appearance is desired. GDOES depth distribution is performed for this example. The GDOES results are shown in Figure 1, which tends to show that the chemical composition in the outermost 0.5 micron electronic ceramic coating contributes significantly to giving the coating the desired color.Examples 11 : Comparative example 2 , 3 and 4 Three comparative examples (Comparative Example 2, Comparative Example 2, and Example 6) were performed on magnesium plates using an electrolytic solution similar to "Illustrative Example 1", "Illustrative Example 4", and "Illustrative Example 6" of U.S. Patent Publication No. 2015/0083598 3 and 4). The electrolytic solution was prepared using deionized water as a solvent, and the obtained pHs were 5.7, 9.9, and 6.6, respectively. The pH of these electrolytes was chosen to cross the pH range disclosed in the '598 publication to test how the' 598 electrolyte operates on magnesium, which is claimed but not exemplified in this publication.Process Standard commercial cleaning and deoxygenation processes were used to prepare the AZ31 board, and its board and preparation were the same as the examples according to the present invention. Measured as one of 1 inch by 2 inch (2.54 cm by 5.08 cm) immersed in one of the electrolytes, and electrolyzed at 20 amps, 350 volts with a square DC waveform of 25 milliseconds on and 9 milliseconds off second. The amperage and voltage are within the parameters disclosed in the '598 publication and the time is selected to be similar to the example according to the invention. The AZ31 plate was removed from the electrolyte, allowed to dry and tested. The board shows etching of magnesium but without coating. The other AZ31 plates were exposed for a longer period of time in the electrolyte and also only etched magnesium plates were produced. The photos of the boards treated as described above are shown in Figures 3a and 3b. The bright silver appearance clearly shows that the samples were not deposited with a black coating or any visible coating. The process parameters were adjusted, that is, similar to the electrolytic solution of pH 6.1 of Exemplary Example 1 by adding another 17 grams of hexamethylenetetramine to match the electrolytic solution of Exemplary Example 1. Similar to "Exemplary Example 1" and "Exemplary Example 4", the bath was repeated for 10 minutes, each using the same voltage and waveform as the example according to the present invention and other aspects from the method described above in the "598 publication" parameter. None of the baths produced a dark or black coating. Photographs of the boards after 10 minutes of treatment at pH 6.1 and pH 9.9 as described above are shown separately in 3c and 3d; none of the samples had a black coating deposited on the board. Discoloration of turbid and uneven white appearance was seen on the part of the board. These tests tend to show that the process disclosed in the '598 publication does not provide a uniform black, brown, bronze or gray coating on magnesium. The foregoing invention is described in accordance with the relevant legal standards, so this description is illustrative and not restrictive in nature. Variations and modifications of the disclosed embodiments may be apparent to those skilled in the art and are indeed within the scope of the invention. Therefore, the scope of legal protection granted to the present invention can only be determined by studying the scope of the following patent applications.

100‧‧‧ inorganic coating

110‧‧‧ interface / first interface

120‧‧‧ the first sub-layer

130‧‧‧ interface / second interface

140‧‧‧second sublayer

150‧‧‧ outer surface

160‧‧‧hole

170‧‧‧Inner surface

200‧‧‧ Magnesium Items

Figure 1 is a diagram of the elemental composition of the inorganic electrolytic deposition coating according to the present invention measured by GDOS in weight percent, showing the different chemical composition of the coating of the present invention, which varies with the distance from the surface of the magnesium alloy And change. FIG. 2 is a cross-sectional view of an AZ-31 plate coated according to Example 1 before post-treatment, showing an inorganic coating and its sublayers. FIG. 3 shows photographs of Comparative Examples 2, 3, and 4. Figure 3a shows a photo of an AZ-31 Mg alloy plate treated for 45 seconds at pH 5.7, and Figure 3b shows a photo of an AZ-31 Mg alloy plate treated for 45 seconds at pH 6.6. Both panels are bright and shiny in appearance Metal, without a deposited coating. Figure 3c shows a photo of an AZ-31 Mg alloy plate treated for 10 minutes at pH 6.1, showing etching but without coating. Figure 3d shows a photo of an AZ-31 Mg alloy plate treated for 10 minutes at pH 9.9, showing etching but without coating.

Claims (19)

A method for depositing a dark coating on a magnesium or magnesium alloy metal surface, the method comprising: A) providing an alkaline electrolyte and a cathode in contact with the alkaline electrolyte; the alkaline electrolyte may be a solution or a dispersion Comprising at least one water-soluble or water-dispersible source of water, organic amine, phosphorus source and at least one transition metal element; B) placing an article having at least one metal magnesium or magnesium alloy surface in contact with the electrolyte and electrically contacting it with the electrolyte Connected so that the surface acts as an anode; C) transferring an electric current between the anode and the cathode via the electrolyte solution for a certain period of time to effectively produce a first inorganic-based coating that is directly chemically bonded to the magnesium or magnesium alloy metal surface One layer, the first layer is black, brown, bronze or gray to the human eye; D) the article having the surface of the at least one metal magnesium or magnesium alloy coated with the first layer of the inorganic coating is The alkaline electrolyte is removed, and the item is rinsed and dried as appropriate; E) The at least the first layer of the inorganic-based coating is post-treated by the following operations as appropriate: 1) The inorganic-based coating is applied The first layer is in contact with a post-treatment composition different from the inorganic-based coating, and the post-treatment composition may react with the inorganic-based coating as appropriate; and / or 2) after step 1) if present, polymerizes The composition is applied to the first layer of the inorganic-based coating, thereby forming a second layer containing organic polymer chains and / or inorganic polymer chains and having a layer thickness of 0.1 to 15 microns; and F) In this case, a paint layer is applied after this post-treatment step. The method of claim 1, wherein the method is performed before step B) without any step of depositing a silicon and / or fluorine-containing material on the magnesium surface. The method of claim 1 or 2, wherein the organic amine is monoethanolamine and the at least one transition metal element comprises one or more of iron, vanadium and tungsten. The method of any one of claims 1 to 3, wherein the alkaline electrolyte contains less than 100 ppm silicon or aluminum and is substantially free of fluorine and tertiary amines. The method according to any one of claims 1 to 4, wherein the organic amine is a first-order monoamine in which an acyclic amine exists, and the at least one transition metal element is composed of iron, vanadium, or tungsten. The method according to any one of claims 1 to 5, wherein the organic amine is monoethanolamine, the phosphorus source is phosphoric acid, the at least one transition metal element comprises iron and vanadium and the pH of the alkaline electrolyte is at least 10.2. The method according to any one of claims 1 to 6, wherein the organic amine is monoethanolamine, the phosphorus source is phosphoric acid, and the at least one transition metal element comprises tungsten. The method according to any one of claims 1 to 7, wherein the alkaline electrolyte does not contain vanadium, the organic amine is monoethanolamine, the phosphorus source is phosphoric acid, and the at least one transition metal element contains iron and optionally vanadium Other than the second transition metal element. The method of any one of claims 1 to 8, wherein the organic amine is a primary monoamine in which an acyclic amine is present, and the at least one water-soluble or dispersible source of at least one transition metal element comprises iron citrate. The method of any one of claims 1 to 9, further comprising performing at least one step selected from the group consisting of cleaning, etching, deoxidizing, and decontaminating before placing the magnesium-containing article in contact with the alkaline electrolyte. And their combination, so that 0.05 to 50 g / m ² metal is removed from the surface of the bare metal magnesium or magnesium alloy before the first layer is produced. The method according to any one of claims 1 to 10, further comprising the step of covering a part of the magnesium-containing article before placing the surface of the at least one metallic magnesium or magnesium alloy metal in contact with the alkaline electrolyte. The method of any one of claims 1 to 11, comprising controlling the temperature and concentration of the alkaline electrolyte and providing a selected waveform of the current in step E) for a sufficient time, thereby producing a thickness of 1 to The inorganic coating of 40 microns and the coated metal surface per square meter below 10 kWh are used to form the first layer in step E). The method according to any one of claims 1 to 12, wherein after step E), the inorganic-based coating not exceeding 10 mg / m ^{2 is} removed. The method of any one of claims 1 to 13, wherein the current is a pulsed direct current having an average voltage in a range of 50 to 700 volts. An article comprising at least one coated magnesium or magnesium alloy metal surface as claimed in any one of claims 1 to 14. An article comprising at least one metallic magnesium or magnesium alloy surface, the surface being coated with a dark first layer of an inorganic coating that is chemically bonded directly to the surface of the at least one metallic magnesium or magnesium alloy, wherein the inorganic coating Has a double-layer structure, including: a. A first sub-layer directly bonded to the surface of the metal magnesium or magnesium alloy at a first interface, the first sub-layer comprising Mg, O, C, P and at least one transition metal element B. A second sub-layer integrally connected to the first sub-layer at a second interface, the second sub-layer comprising an outer surface at an outer boundary of the inorganic coating, and optionally by the second sub-layer An inner surface of the layer that is within the outer boundary of the inorganic coating and is defined by pores in communication therewith; the second sublayer includes Mg, O, C, P and at least one transition metal element; wherein in the second sublayer The weight percentage of C is greater than the weight percentage of C of the first sublayer. The article of claim 16, wherein the weight percentage of C in the second sub-layer exhibits an increasing concentration gradient from the second interface to the outer surface of the inorganic coating. An article having at least one metal magnesium or magnesium alloy surface and a composite coating deposited thereon, the composite coating comprising: a. An inorganic coating that is directly chemically bonded to the surface of the at least one metal magnesium or magnesium alloy A matrix formed by a first layer of the matrix, the matrix having holes and an inner surface defined by the holes, at least some of the holes communicating with the outer surface of the first layer and forming openings therein; and b. Different A second component of the inorganic-based coating is applied to at least a portion of the substrate including the pores, and the second component is in contact with at least some of the inner and outer surfaces. The article of any one of claims 15 to 18, further comprising a second layer different from the inorganic-based coating and attached to at least an outer surface of the inorganic-based coating.