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EP0492487A1 - Means of temporary protection of bare silver and copper surfaces against tarnishing and method of using it - Google Patents

Means of temporary protection of bare silver and copper surfaces against tarnishing and method of using it Download PDF

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Publication number
EP0492487A1
EP0492487A1 EP19910121903 EP91121903A EP0492487A1 EP 0492487 A1 EP0492487 A1 EP 0492487A1 EP 19910121903 EP19910121903 EP 19910121903 EP 91121903 A EP91121903 A EP 91121903A EP 0492487 A1 EP0492487 A1 EP 0492487A1
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EP
European Patent Office
Prior art keywords
inhibitor
agent according
silver
water
emulsifier
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
EP19910121903
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German (de)
French (fr)
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EP0492487B1 (en
Inventor
Hermann Dr. Dipl.-Chem. Grossmann
Erwin Marka
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Doduco Contacts and Refining GmbH
Original Assignee
Doduco GmbH and Co KG Dr Eugen Duerrwaechter
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Priority claimed from DE19904041596 external-priority patent/DE4041596A1/en
Application filed by Doduco GmbH and Co KG Dr Eugen Duerrwaechter filed Critical Doduco GmbH and Co KG Dr Eugen Duerrwaechter
Publication of EP0492487A1 publication Critical patent/EP0492487A1/en
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Publication of EP0492487B1 publication Critical patent/EP0492487B1/en
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Classifications

    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23F—NON-MECHANICAL REMOVAL OF METALLIC MATERIAL FROM SURFACE; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL; MULTI-STEP PROCESSES FOR SURFACE TREATMENT OF METALLIC MATERIAL INVOLVING AT LEAST ONE PROCESS PROVIDED FOR IN CLASS C23 AND AT LEAST ONE PROCESS COVERED BY SUBCLASS C21D OR C22F OR CLASS C25
    • C23F11/00—Inhibiting corrosion of metallic material by applying inhibitors to the surface in danger of corrosion or adding them to the corrosive agent
    • C23F11/08—Inhibiting corrosion of metallic material by applying inhibitors to the surface in danger of corrosion or adding them to the corrosive agent in other liquids
    • C23F11/10—Inhibiting corrosion of metallic material by applying inhibitors to the surface in danger of corrosion or adding them to the corrosive agent in other liquids using organic inhibitors
    • C23F11/16—Sulfur-containing compounds
    • C23F11/161—Mercaptans

Definitions

  • the invention is based on an agent for protecting bare silver surfaces against tarnishing, which contains, as a hydrophobic inhibitor, a long-chain aliphatic mercapto compound with at least 12 carbon atoms in the chain and water.
  • Silverware and silver-plated parts tarnish in an atmosphere containing hydrogen sulfide and turn brown to black due to the formation of silver sulfide.
  • an inorganic cover layer for example with rhodium or with silver chromate, which are applied by electrolytic processes.
  • silver surfaces by means of transparent lacquers or waxes, which are applied by dipping, spraying or vapor deposition.
  • a major disadvantage of these coatings is that they do change the external appearance of the silver, which is particularly disadvantageous for decorative objects.
  • passivating coatings are not desirable because they greatly increase the electrical contact resistance.
  • a transparent, colorless, ideally monomolecular protective layer remains on the silver surface, which at least adheres to the goods until they are processed further or reach the consumer.
  • the disadvantage here is that the inhibitors are dissolved in halogenated hydrocarbons, which are harmful to the environment.
  • the inhibitors which in turn are long-chain aliphatic compounds with SH group, namely mercapto compounds with 12 to 25 carbon atoms, in organic solvents such as glycols and / or Solve glycol ethers with a total of 4 or 5 carbon atoms and treat the silver surfaces to be protected with this solution.
  • organic solvents such as glycols and / or Solve glycol ethers with a total of 4 or 5 carbon atoms and treat the silver surfaces to be protected with this solution.
  • Glycols and glycol ethers have the advantage of being less harmful to the environment than halogenated hydrocarbons.
  • they have the disadvantage that they are flammable and that the vapors escaping from the treatment solution can form an explosive mixture, so that special precautions must be taken when working with such solutions.
  • DE-OS 39 05 850 In order to counteract the formation of flammable or explosive gas mixtures, it is already known from DE-OS 39 05 850 not to dry the treated surfaces by letting the solvent evaporate. Rather, the solvent is removed from the treated surfaces by rinsing with aqueous solvents or with warm water with detergents. To reduce the evaporation rates, it is also known from DE-OS 39 05 850 to add water to the solution of the inhibitor in glycol or glycol ether. The glycol and the glycol ether dissolve in the water and are thereby diluted. However, care is taken to ensure that with this dilution the solubility limit of the inhibitor in the glycol or glycol ether is not exceeded so that there is no clouding or precipitation. The addition of water reduces the dangerousness of the glycol or the glycol ether, but does not eliminate it.
  • Another, particularly significant disadvantage of thiocarboxylic acids is that water can accumulate on their hydrophilic carboxyl group, which ultimately enables the hydrogen sulfide from which the silver surface is to be protected to attack the silver surface, so that there is no protective layer which is impermeable to hydrogen sulfide receives.
  • the agent which is intended to protect against tarnishing of the surface, should be applied to decorative silverware as a film that is so uniform that the gloss of the surface is retained.
  • the present invention has for its object to provide a means for the temporary protection of bare silver surfaces, which can be handled comfortably and safely, even in immersion baths, and is environmentally compatible.
  • This object is achieved by an agent with the composition specified in claim 1.
  • a particularly suitable method for using this agent is the subject of claim 11.
  • Advantageous developments of the invention are the subject of the subclaims.
  • the agent according to the invention contains a hydrophobic aliphatic thio compound with at least 12 C atoms in the chain from the group of thio alcohols and their esterification products without hydrophilic carboxyl groups, the thio alcohols being particularly preferred.
  • they are not dissolved in an organic solvent, but used in the form of an aqueous emulsion.
  • the emulsifier which is inevitably required to bring the selected inhibitors into an emulsion is incorporated only in a negligible amount in the inhibitor film which forms on the silver surface which has been treated with the emulsion.
  • the emulsifier can be easily washed off by rinsing with water, while the passivating film of the inhibitor substance remains on the treated silver surface.
  • the silver surface in the emulsion is treated at a temperature which is above the melting point of the inhibitor substance.
  • the inhibitor substance is particularly readily distributed evenly and thinly on the surface to be passivated.
  • the subsequent rinsing of the surface is then best carried out at a temperature below the melting point of the inhibitor substance, which has the advantage that it then adheres particularly firmly to the passivated surface.
  • the agent according to the invention is easy to handle. It contains neither an environmentally hazardous nor a flammable solvent, but only water as the carrier substance of the emulsion.
  • the sub-substances contained in the water, the inhibitor and the emulsifier, are biodegradable.
  • the agent according to the invention is easy to use. It can be marketed as a concentrate of the inhibitor and the emulsifier and can be made ready for use by the user by stirring it into water. It can be applied by dipping, spraying or spreading.
  • the goods to be treated are preferably immersed in the emulsion because the treatment times are then shortest.
  • Conventional devices such as in electroplating technology can be used to treat the goods by immersing them in the emulsion, rinsing and drying, with the difference that there is no need for electrodes and that there are no problems with the disposal of the baths and rinsing water.
  • the agent according to the invention expediently contains 0.05 to 50 g / l, preferably 5 to 20 g / l, of the inhibitor. Below a content of 0.05 g / l, the coating could be incomplete or the coating time too long, while above a content of 50 g / l it is more likely that too much of the inhibitor will be deposited on the silver surface and the deposition becomes unevenly thick.
  • the emulsifier is advantageously contained in the agent in an amount of 0.05 to 50 g / l, preferably 2 to 20 g / l. At less than 0.05 g / l, the emulsifying effect is insufficient; at more than 50 g / l, the stability of the emulsion is not further improved; a further addition of emulsifier would be uneconomical and could lead to undesired storage of the emulsifier in the protective layer lead the goods.
  • an anionic or nonionic surfactant can be added to the agent.
  • Cationic surfactants are unsuitable.
  • inhibitors are selected which have at least 12 and preferably not more than 20 C atoms in the chain. With less than 12 carbon atoms, it is sometimes not possible to achieve a well-adhering protective coating, and in some cases there is strong odor nuisance. With more than 20 carbon atoms, the inhibitors become too solid in consistency and it becomes more difficult to produce a satisfactory emulsion.
  • the inhibitors can be emulsified very finely and with long-term stability and can be applied to the surfaces to be protected in a thin but dense layer.
  • Particularly suitable emulsifiers for this purpose are branched fatty alcohols having 9 to 20 carbon atoms, in particular having 10 to 15 carbon atoms, the branched fatty alcohols preferably being alkoxylated, in particular ethoxylated, having a degree of alkoxylation of 2 to 10.
  • long-chain polyglycol ethers are also suitable and alkylphenol ethoxylates.
  • the passivating agent when adjusted to a pH of 1-10, better 1-8, preferably 2-4, the emulsifier can be washed out of the deposited inhibitor layer practically completely with water, which is important for reliable surface protection is.
  • the emulsifier At high pH, less inhibitor is washed out, which increases the protective effect and the lubricating effect; however, there may be stains on the surface that can disturb the appearance of decorative surfaces.
  • Decorative surfaces are therefore preferably passivated with an agent whose pH is lower, preferably between 2 and 4, with sufficient inhibitor substance remaining after washing out to form a dense protective layer. If the pH is above 10 there is a risk of the emulsion splitting.
  • the agent according to the invention is also suitable for passivating surfaces made of copper and copper alloys.
  • the inhibitor emulsified in water also absorbs very well on copper and copper-containing materials and protects the surface against the attack of sulfur compounds and against oxidation. The good solderability and the electrical properties are not impaired.
  • These baths are preferably used in such a way that the parts to be passivated are immersed in the approx. 40 ° C to 50 ° C warm baths. After 2 to 3 minutes, the surface of the parts is even and dense with the inhibitor wetted. The parts are then rinsed with cold water and then dried, preferably with hot air.
  • the effect of the tarnish protection layer on silver can be easily demonstrated with the help of a two percent sodium sulfide solution. Untreated silver parts tarnish immediately, treated parts remain bare over a longer period of time. The effect of the protective layer on copper was checked by passivating copper parts for several hours in a hydrogen sulfide atmosphere with 1 ppm H2S; the copper parts did not change color.

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Mechanical Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Preventing Corrosion Or Incrustation Of Metals (AREA)

Abstract

The means of temporary protection of bare silver surfaces or silver-alloy surfaces against tarnishing contains, as hydrophobic inhibitor, a long-chain aliphatic compound having at least 12 carbon atoms in the chain, namely a thiol or an esterification product thereof, water and a water-soluble emulsifier used to emulsify the inhibitor in the water, and it is adjusted to a pH of 1 to 10. The means is also suitable for passivating surfaces made of copper and copper alloys.

Description

Die Erfindung geht aus von einem Mittel zum Schutz von blanken Silberoberflächen gegen Anlaufen, welches als hydrophoben Inhibitor eine langkettige aliphatische Mercaptoverbindung mit mindestens 12 C-Atomen in der Kette und Wasser enthält.The invention is based on an agent for protecting bare silver surfaces against tarnishing, which contains, as a hydrophobic inhibitor, a long-chain aliphatic mercapto compound with at least 12 carbon atoms in the chain and water.

Silberwaren und versilberte Teile laufen in schwefelwasserstoffhaltiger Atmosphäre an und werden infolge der Bildung von Silbersulfid braun bis schwarz. Um ein Anlaufen zu verhindern, ist es bekannt, Silberoberflächen mit einer anorganischen Deckschicht, z.B. mit Rhodium oder mit Silberchromat, welche durch elektrolytische Verfahren aufgebracht werden, zu schützen. Es ist auch bekannt, Silberoberflächen durch Klarsichtlacke oder Wachse, welche durch Tauchen, Sprühen oder Bedampfen aufgebracht werden, zu schützen. Ein wesentlicher Nachteil dieser Überzüge ist, dass sie das äussere Erscheinungsbild des Silbers verändern, was insbesondere bei dekorativen Gegenständen von Nachteil ist. Bei Anwendungen in der Elektrotechnik, insbesondere bei elektrischen Kontakten, sind derartige passivierende Überzüge nicht erwünscht, weil sie den elektrischen Übergangswiderstand stark erhöhen. Ausserdem erschweren solche Passivierungsschichten das Weichlöten einer Silberoberfläche. Es sind deshalb auch Mittel bekannt, mit denen Silberoberflächen nur zeitweise vor einem Anlaufen geschützt werden, nämlich vom Zeitpunkt der Herstellung bis zum Zeitpunkt der Weiterverarbeitung bzw. der Inbenutzungnahme. So ist es aus der DE-OS 1 621 459 bekannt, langkettige aliphatische Verbindungen, die eine SH-Gruppe enthalten (Mercapto-Verbindungen), in flüchtigen organischen Lösungsmitteln, nämlich in Chlorkohlenwasserstoffen, zu lösen, mit der Lösung die zu schützenden Silberoberflächen zu behandeln und dann zu trocknen, indem man die Lösung ablaufen und die restliche, an die Oberfläche noch haftende Lösung verdampfen läßt. Bei hinreichend langkettigen aliphatischen Mercapto-Verbindungen als Inhibitoren verbleibt auf der Silberoberfläche eine transparente, farblose, im Idealfall monomolekulare Schutzschicht, welche zumindestens solange auf der Ware haftet, bis diese weiterverarbeitet wird oder zum Verbraucher gelangt. Nachteilig dabei ist, dass die Inhibitoren in halogenierten Kohlenwasserstoffen gelöst werden, welche umweltschädlich sind.Silverware and silver-plated parts tarnish in an atmosphere containing hydrogen sulfide and turn brown to black due to the formation of silver sulfide. In order to prevent tarnishing, it is known to protect silver surfaces with an inorganic cover layer, for example with rhodium or with silver chromate, which are applied by electrolytic processes. It is also known to protect silver surfaces by means of transparent lacquers or waxes, which are applied by dipping, spraying or vapor deposition. A major disadvantage of these coatings is that they do change the external appearance of the silver, which is particularly disadvantageous for decorative objects. In applications in electrical engineering, particularly in electrical contacts, such passivating coatings are not desirable because they greatly increase the electrical contact resistance. In addition, such passivation layers make soft soldering of a silver surface difficult. Therefore, means are also known with which silver surfaces are only temporarily protected from tarnishing, namely from the time of manufacture to the time of further processing or use. It is known from DE-OS 1 621 459 to dissolve long-chain aliphatic compounds which contain an SH group (mercapto compounds) in volatile organic solvents, namely in chlorinated hydrocarbons, with the solution to treat the silver surfaces to be protected and then drying by draining the solution and allowing the remaining solution still adhering to the surface to evaporate. In the case of sufficiently long-chain aliphatic mercapto compounds as inhibitors, a transparent, colorless, ideally monomolecular protective layer remains on the silver surface, which at least adheres to the goods until they are processed further or reach the consumer. The disadvantage here is that the inhibitors are dissolved in halogenated hydrocarbons, which are harmful to the environment.

Um halogenierte Kohlenwasserstoffe als Lösungsmittel zu vermeiden, ist es aus der DE-OS 39 05 850, bekannt, die Inhibitoren, bei welchen es sich wiederum um langkettige aliphatische Verbindungen mit SH-Gruppe handelt, nämlich um Mercaptoverbindungen mit 12 bis 25 C-Atomen, in organischen Lösemitteln wie Glykolen und/oder Glykoläthern mit insgesamt 4 oder 5 C-Atomen zu lösen und die zu schützenden Silberoberflächen mit dieser Lösung zu behandeln. Glykole und Glykoläther haben den Vorteil, weniger umweltschädlich zu sein als halogenierte Kohlenwasserstoffe. Sie haben jedoch den Nachteil, dass sie entflammbar sind und dass die aus der Behandlungslösung entweichenden Dämpfe ein explosives Gemisch bilden können, so dass bei dem Arbeiten mit solchen Lösungen besondere Vorsichtsmaßnahmen zu ergreifen sind. Um dem Entstehen von entflammbaren oder explosiven Gasgemischen entgegenzuwirken, ist es aus der DE-OS 39 05 850 bereits bekannt, die behandelten Oberflächen nicht dadurch zu trocknen, dass man das Lösungmittel verdampfen läßt. Vielmehr wird das Lösungsmittel von den behandelten Oberflächen durch Spülen mit wässrigen Lösungsmitteln oder mit warmem Wasser mit Detergentien entfernt. Um die Verdampfungsraten zu reduzieren, ist es aus der DE-OS 39 05 850 weiterhin bekannt, der Lösung des Inhibitors in Glykol oder Glykoläther Wasser zuzusetzen. Das Glykol und der Glykoläther lösen sich im Wasser und werden dadurch verdünnt. Es wird jedoch darauf geachtet, dass bei dieser Verdünnung die Löslichkeitsgrenze des Inhibitors im Glykol bzw. Glykoläther nicht überschritten wird, damit es nicht zu Trübungen oder Ausfällungen kommt. Durch den Wasserzusatz wird die Gefährlichkeit des Glykols bzw. des Glykoläthers zwar vermindert, aber nicht beseitigt.To avoid halogenated hydrocarbons as solvents, it is known from DE-OS 39 05 850, the inhibitors, which in turn are long-chain aliphatic compounds with SH group, namely mercapto compounds with 12 to 25 carbon atoms, in organic solvents such as glycols and / or Solve glycol ethers with a total of 4 or 5 carbon atoms and treat the silver surfaces to be protected with this solution. Glycols and glycol ethers have the advantage of being less harmful to the environment than halogenated hydrocarbons. However, they have the disadvantage that they are flammable and that the vapors escaping from the treatment solution can form an explosive mixture, so that special precautions must be taken when working with such solutions. In order to counteract the formation of flammable or explosive gas mixtures, it is already known from DE-OS 39 05 850 not to dry the treated surfaces by letting the solvent evaporate. Rather, the solvent is removed from the treated surfaces by rinsing with aqueous solvents or with warm water with detergents. To reduce the evaporation rates, it is also known from DE-OS 39 05 850 to add water to the solution of the inhibitor in glycol or glycol ether. The glycol and the glycol ether dissolve in the water and are thereby diluted. However, care is taken to ensure that with this dilution the solubility limit of the inhibitor in the glycol or glycol ether is not exceeded so that there is no clouding or precipitation. The addition of water reduces the dangerousness of the glycol or the glycol ether, but does not eliminate it.

Aus der DE-AS 1 279 428 ist es bereits bekannt, Silberwaren zum Schutz gegen Schwefelanlauf mit Hilfe von aliphatischen Thiokarbonsäuren zu schützen, welche in wässriger Emulsion angewendet werden und auf der Silberoberfläche besser haften sollen. Die wässrige Emulsion benötigt keinen Emulgator, weil die Thiokarbonsäuren eine hydrophile Carboxylgruppe haben, durch die sie teilweise sogar wasserlöslich sind. Wässrige Emulsionen von Thiokarbonsäuren haben aber nur eine geringe Standzeit und ihre Handhabung ist schwierig. Sie haben deshalb für die Tauchbehandlung oder Sprühbehandlung von Silberwaren, keinen Eingang in die Praxis gefunden, vielmehr wurden die Thiokarbonsäuren als Zusatz zu Polierpasten verwendet (DE-AS 1 279 428, Anspruch 5). Ein weiterer, besonders wesentlicher Nachteil der Thiokarbonsäuren besteht darin, dass sich an ihre hydrophile Carboxylgruppe Wasser anlagern kann, welches dem Schwefelwasserstoff, vor welchem die Silberoberfläche geschützt werden soll, letztlich den Angriff auf die Silberoberfläche doch ermöglicht, so dass man keine gegenüber Schwefelwasserstoff dichte Schutzschicht erhält. Auf dekorative Silberwaren soll das Mittel, das vor dem Anlaufen der Oberfläche schützen soll, als so gleichmässiger Film aufziehen, dass der Glanz der Oberfläche erhalten bleibt. Mit einer wässrigen Emulsion von Thiokarbonsäuren ist das kaum möglich, denn dazu genügt es nicht, den Überschuß der Emulsion von der Oberfläche ablaufen zu lassen, vielmehr müßte man die Oberfläche mit Wasser spülen; dabei würde aber ein erheblicher Teil der Thiokarbonsäure wieder abgespült, weil sie hydrophile Gruppen hat.From DE-AS 1 279 428 it is already known to protect silverware for protection against sulfur tarnishing with the aid of aliphatic thiocarboxylic acids which are used in aqueous emulsion and are said to adhere better to the silver surface. The aqueous emulsion does not require an emulsifier because the thiocarboxylic acids have a hydrophilic carboxyl group, which makes them partially water-soluble. Aqueous emulsions of thiocarboxylic acids have a short life and are difficult to handle. You have therefore found no entry into practice for the dip treatment or spray treatment of silverware, rather the thiocarboxylic acids were used as an additive to polishing pastes (DE-AS 1 279 428, claim 5). Another, particularly significant disadvantage of thiocarboxylic acids is that water can accumulate on their hydrophilic carboxyl group, which ultimately enables the hydrogen sulfide from which the silver surface is to be protected to attack the silver surface, so that there is no protective layer which is impermeable to hydrogen sulfide receives. The agent, which is intended to protect against tarnishing of the surface, should be applied to decorative silverware as a film that is so uniform that the gloss of the surface is retained. This is hardly possible with an aqueous emulsion of thiocarboxylic acids because it is not sufficient to remove the excess of the emulsion from the Letting the surface run off, rather one would have to rinse the surface with water; however, a considerable part of the thiocarboxylic acid would be rinsed off again because it has hydrophilic groups.

Der vorliegenden Erfindung liegt die Aufgabe zugrunde, ein Mittel zum zeitweiligen Schutz von blanken Silberoberflächen anzugeben, welches bequem und gefahrlos gehandhabt werden kann, auch in Tauchbädern, und umweltverträglich ist. Diese Aufgabe wird gelöst durch ein Mittel mit der im Anspruch 1 angegebenen Zusammensetzung. Ein besonders geeignetes Verfahren zum Anwenden dieses Mittels ist Gegenstand des Anspruchs 11. Vorteilhafte Weiterbildungen der Erfindung sind Gegenstand der Unteransprüche.The present invention has for its object to provide a means for the temporary protection of bare silver surfaces, which can be handled comfortably and safely, even in immersion baths, and is environmentally compatible. This object is achieved by an agent with the composition specified in claim 1. A particularly suitable method for using this agent is the subject of claim 11. Advantageous developments of the invention are the subject of the subclaims.

Das erfindungsgemässe Mittel enthält als organische Inhibitor-Substanz eine hydrophobe aliphatische Thioverbindung mit wenigstens 12 C-Atomen in der Kette aus der Gruppe der Thioalkohole und deren Veresterungsprodukten ohne hydrophile Carboxylgruppen, wobei die Thioalkohole besonders bevorzugt sind. Sie werden aber nicht in einem organischen Lösungsmittel gelöst, sondern in Form einer wässrigen Emulsion angewendet. Überraschenderweise hat es sich gezeigt, dass man mit diesen hydrophoben Verbindungen auch dann hauchdünne, aber dichte und dadurch zuverlässig passivierende Deckschichten auf Silberoberflächen oder Silberlegierungsoberflächen bilden kann, wenn die Inhibitor-Substanzen nicht in organischer Lösung angewendet werden, sondern in Form einer wässrigen Emulsion, obwohl sie in der Emulsion in Form von wesentlich größeren Teilchen vorliegen als in einer echten Lösung.As an organic inhibitor substance, the agent according to the invention contains a hydrophobic aliphatic thio compound with at least 12 C atoms in the chain from the group of thio alcohols and their esterification products without hydrophilic carboxyl groups, the thio alcohols being particularly preferred. However, they are not dissolved in an organic solvent, but used in the form of an aqueous emulsion. Surprisingly, it has been shown that extremely thin, but dense and therefore reliably passivating top layers can be formed on silver surfaces or silver alloy surfaces with these hydrophobic compounds if the inhibitor substances are not used in organic solution, but in the form of an aqueous emulsion, although they are present in the emulsion in the form of much larger particles than in a real solution.

Insbesondere hat sich gezeigt, dass der Emulgator, den man zwangsläufig benötigt, um die ausgewählten Inhibitoren in eine Emulsion zu bringen, nur in vernachlässigbarer Menge in den Inhibitor-Film eingelagert wird, der sich auf der Silberoberfläche bildet, die mit der Emulsion behandelt wurde. Nach dem Behandeln der Silberoberfläche mit der Emulsion kann der Emulgator leicht durch Spülen mit Wasser abgewaschen werden, während der passivierende Film aus der Inhibitor-Substanz auf der behandelten Silberoberfläche verbleibt.In particular, it has been shown that the emulsifier which is inevitably required to bring the selected inhibitors into an emulsion is incorporated only in a negligible amount in the inhibitor film which forms on the silver surface which has been treated with the emulsion. After treating the silver surface with the emulsion, the emulsifier can be easily washed off by rinsing with water, while the passivating film of the inhibitor substance remains on the treated silver surface.

Es ist besonders günstig, wenn die Silberoberfläche in der Emulsion bei einer Temperatur behandelt wird, die oberhalb des Schmelzpunktes der Inhibitor-Substanz liegt. In diesem Fall verteilt sich die Inhibitor-Substanz nämlich besonders bereitwillig gleichmässig dünn auf der zu passivierenden Oberfläche. Das anschließende Spülen der Oberfläche führt man dann am besten bei einer Temperatur unterhalb des Schmelzpunktes der Inhibitor-Substanz durch, was den Vorteil hat, dass diese dann besonders fest auf der passivierten Oberfläche haftet.It is particularly advantageous if the silver surface in the emulsion is treated at a temperature which is above the melting point of the inhibitor substance. In this case, the inhibitor substance is particularly readily distributed evenly and thinly on the surface to be passivated. The subsequent rinsing of the surface is then best carried out at a temperature below the melting point of the inhibitor substance, which has the advantage that it then adheres particularly firmly to the passivated surface.

Das erfindungsgemässe Mittel ist problemlos in der Handhabung. Es enthält weder ein umweltgefährdendes noch ein brennbares Lösungsmittel, sondern als Trägersubstanz der Emulsion lediglich Wasser. Die im Wasser enthaltenen Sub-Substanzen, der Inhibitor und der Emulgator, sind biologisch abbaubar.The agent according to the invention is easy to handle. It contains neither an environmentally hazardous nor a flammable solvent, but only water as the carrier substance of the emulsion. The sub-substances contained in the water, the inhibitor and the emulsifier, are biodegradable.

Das erfindungsgemässe Mittel ist leicht anzuwenden. Es kann als Konzentrat aus dem Inhibitor und dem Emulgator in den Handel gebracht und vom Anwender durch Einrühren in Wasser gebrauchsfertig gemacht werden. Es kann durch Tauchen, Sprühen oder Aufstreichen angewendet werden. Vorzugsweise taucht man die zu behandelnde Ware in die Emulsion ein, weil dann die Behandlungszeiten am kürzesten sind. Für das Behandeln der Ware durch Eintauchen in die Emulsion, Spülen und Trocknen können herkömmliche Einrichtungen wie in der galvanischen Beschichtungstechnik eingesetzt werden mit dem Unterschied, dass die Ausrüstung mit Elektroden entfällt und dass keine Probleme mit der Entsorgung der Bäder und Spülwässer bestehen.The agent according to the invention is easy to use. It can be marketed as a concentrate of the inhibitor and the emulsifier and can be made ready for use by the user by stirring it into water. It can be applied by dipping, spraying or spreading. The goods to be treated are preferably immersed in the emulsion because the treatment times are then shortest. Conventional devices such as in electroplating technology can be used to treat the goods by immersing them in the emulsion, rinsing and drying, with the difference that there is no need for electrodes and that there are no problems with the disposal of the baths and rinsing water.

Das erfindungsgemässe Mittel enthält zweckmässigerweise 0,05 bis 50 g/l, vorzugsweise 5 bis 20 g/l des Inhibitors. Unterhalb eines Gehaltes von 0,05 g/l könnte die Beschichtung unvollständig bzw. die Beschichtungsdauer zu lang sein, während oberhalb eines Gehaltes von 50 g/l eher damit zu rechnen ist, dass zu viel des Inhibitors auf der Silberoberfläche abgeschieden wird und die Abscheidung ungleichmässig dick wird.The agent according to the invention expediently contains 0.05 to 50 g / l, preferably 5 to 20 g / l, of the inhibitor. Below a content of 0.05 g / l, the coating could be incomplete or the coating time too long, while above a content of 50 g / l it is more likely that too much of the inhibitor will be deposited on the silver surface and the deposition becomes unevenly thick.

Der Emulgator ist in dem Mittel zweckmässigerweise in einer Menge von 0,05 bis 50 g/l, vorzugsweise von 2 bis 20 g/l enthalten. Bei weniger als 0,05 g/l ist die emulgierende Wirkung ungenügend, bei mehr als 50 g/l wird die Stabilität der Emulsion nicht weiter verbessert; ein weiterer Zusatz von Emulgator wäre unwirtschaftlich und könnte zu einem unerwünschten Einlagern des Emulgators in der Schutzschicht auf der Ware führen.The emulsifier is advantageously contained in the agent in an amount of 0.05 to 50 g / l, preferably 2 to 20 g / l. At less than 0.05 g / l, the emulsifying effect is insufficient; at more than 50 g / l, the stability of the emulsion is not further improved; a further addition of emulsifier would be uneconomical and could lead to undesired storage of the emulsifier in the protective layer lead the goods.

Zur Unterstützung der Benetzung können dem Mittel bis zu 2 g/l, vorzugsweise 0,05 bis 1 g/l eines anionischen oder nicht-ionischen Tensids zugesetzt werden. Kationische Tenside sind ungeeignet.To aid wetting, up to 2 g / l, preferably 0.05 to 1 g / l, of an anionic or nonionic surfactant can be added to the agent. Cationic surfactants are unsuitable.

Erfindungsgemäss werden solche Inhibitoren ausgewählt, die mindestens 12 und vorzugsweise nicht mehr als 20 C-Atome in der Kette haben. Bei weniger als 12 C-Atomen ist teils kein gut haftender Schutzüberzug erzielbar, teils treten starke Geruchsbelästigungen auf. Bei mehr als 20 C-Atomen werden die Inhibitoren in ihrer Konsistenz zu fest und es wird schwieriger, eine befriedigende Emulsion herzustellen.According to the invention, inhibitors are selected which have at least 12 and preferably not more than 20 C atoms in the chain. With less than 12 carbon atoms, it is sometimes not possible to achieve a well-adhering protective coating, and in some cases there is strong odor nuisance. With more than 20 carbon atoms, the inhibitors become too solid in consistency and it becomes more difficult to produce a satisfactory emulsion.

Es hat sich gezeigt, dass sich die Inhibitoren sehr fein und langzeitstabil emulgieren lassen und in dünner, aber dichter Schicht auf die zu schützenden Oberflächen aufziehen. Als Emulgatoren eignen sich dafür besonders verzweigte Fettalkohole mit 9 bis 20 C-Atomen, insbesondere mit 10 bis 15 C-Atomen, wobei die verzweigten Fettalkohole vorzugsweise alkoxyliert, insbesondere ethoxyliert, sind mit einem Alkoxylierungsgrad von 2 bis 10. Geeignet sind aber auch langkettige Polyglykoläther und Alkylphenolethoxylate.It has been shown that the inhibitors can be emulsified very finely and with long-term stability and can be applied to the surfaces to be protected in a thin but dense layer. Particularly suitable emulsifiers for this purpose are branched fatty alcohols having 9 to 20 carbon atoms, in particular having 10 to 15 carbon atoms, the branched fatty alcohols preferably being alkoxylated, in particular ethoxylated, having a degree of alkoxylation of 2 to 10. However, long-chain polyglycol ethers are also suitable and alkylphenol ethoxylates.

Überraschenderweise hat sich gezeigt, dass bei Einstellung des Passivierungsmittels auf einen pH-Wert von 1-10, besser 1-8, vorzugsweise 2-4, der Emulgator aus der abgeschiedenen Inhibitorschicht praktisch vollständig mit Wasser ausgewaschen werden kann, was für einen zuverlässigen Oberflächenschutz wichtig ist. Bei hohem pH-Wert wird weniger Inhibitor ausgewaschen, wodurch die Schutzwirkung und die Schmierwirkung verstärkt werden; allerdings können dabei Flecken auf der Oberfläche auftreten, die das Aussehen von dekorativen Oberflächen stören. Dekorative Oberflächen werden deshalb vorzugsweise mit einem Mittel passiviert, dessen pH-Wert niedriger liegt, vorzugsweise zwischen 2 und 4, wobei auch dann nach dem Auswaschen genügend Inhibitorsubstanz zurückbleibt, um eine dichte Schutzschicht zu bilden. Bei einem pH-Wert über 10 besteht die Gefahr einer Spaltung der Emulsion.Surprisingly, it has been found that when the passivating agent is adjusted to a pH of 1-10, better 1-8, preferably 2-4, the emulsifier can be washed out of the deposited inhibitor layer practically completely with water, which is important for reliable surface protection is. At high pH, less inhibitor is washed out, which increases the protective effect and the lubricating effect; however, there may be stains on the surface that can disturb the appearance of decorative surfaces. Decorative surfaces are therefore preferably passivated with an agent whose pH is lower, preferably between 2 and 4, with sufficient inhibitor substance remaining after washing out to form a dense protective layer. If the pH is above 10 there is a risk of the emulsion splitting.

Unerwartet hat es sich ferner gezeigt, dass das erfindungsgemässe Mittel darüberhinaus geeignet ist, Oberflächen aus Kupfer und Kupferlegierungen zu passivieren. Entsprechendes gilt damit auch für Bimetallteile aus einem Silberwerkstoff einerseits und einem Kupferwerkstoff andererseits, z.B. für Bimetall-Kontaktniete. Der in Wasser emulgierte Inhibitor zieht auch auf Kupfer und kupferhaltige Werkstoffe sehr gut auf und schützt die Oberfläche vor dem Angriff von Schwefelverbindungen und vor Oxidation. Die gute Lötbarkeit und die elektrischen Eigenschaften werden dadurch nicht verschlechtert.It has also unexpectedly been found that the agent according to the invention is also suitable for passivating surfaces made of copper and copper alloys. The same applies accordingly to bimetal parts made of a silver material on the one hand and a copper material on the other hand, for example for bimetal contact rivets. The inhibitor emulsified in water also absorbs very well on copper and copper-containing materials and protects the surface against the attack of sulfur compounds and against oxidation. The good solderability and the electrical properties are not impaired.

Beispiele von Bädern, mit denen sich deckende und gut haftende Überzüge auf Oberflächen von Silber- und Kupferwerkstoffen erzielen lassen:Examples of baths with which opaque and well-adhering coatings can be achieved on surfaces of silver and copper materials:

  • 1.
    In einem Liter deionisiertem Wasser gelöst:
    0,5 - 30 g Inhibitor:
    Octadecanthiol
    0,5 - 30 g Emulgator:
    Alkylpolyethylenglykolether
    0,00 - 1 g Tensid:
    Natriumlaurylsulfat
    pH-Wert 3 mit Mineralsäure eingestellt
    Besonders geeignet für Silber und Silberlegierungen.    1.
    Dissolved in one liter of deionized water:
    0.5 - 30 g inhibitor:
    Octadecanethiol
    0.5 - 30 g emulsifier:
    Alkyl polyethylene glycol ether
    0.00 - 1 g surfactant:
    Sodium lauryl sulfate
    pH 3 adjusted with mineral acid
    Particularly suitable for silver and silver alloys.
  • 2.
    In einem Liter deionisiertem Wasser gelöst:
    0,5 - 30 g Inhibitor:
    Octadecanthiol
    0,5 - 30 g Emulgator:
    Verzweigtes Fettalkoholethxylat mit 8 bis 16 C-Atomen (C₈ - C₁₆) und einem Ethoxylierungsgrad von 2 bis 10
    0,00 - 1 g Tensid:
    Natriumlaurylätherphosphat
    pH-Wert 2 mit einer Mineralsäure eingestellt
    Besonders geeignet für Silber und Silberlegierungen.    2nd
    Dissolved in one liter of deionized water:
    0.5 - 30 g inhibitor:
    Octadecanethiol
    0.5 - 30 g emulsifier:
    Branched fatty alcohol ethoxide with 8 to 16 carbon atoms (C₈ - C₁₆) and a degree of ethoxylation of 2 to 10
    0.00 - 1 g surfactant:
    Sodium lauryl ether phosphate
    pH 2 adjusted with a mineral acid
    Particularly suitable for silver and silver alloys.
  • 3.
    In einem Liter deionisiertem Wasser gelöst:
    0,5 - 40 g Inhibitor:
    Hexadecanthiol
    0,5 - 40 g Emulgator:
    Alkylphenolethoxylat
    0,00 - 1 g Tensid:
    Natriumlaurylsulfonat
    pH-Wert 3,5 mit einer Mineralsäure eingestellt
    Besonders geeignet für Silber und Silberlegierungen.    3rd
    Dissolved in one liter of deionized water:
    0.5 - 40 g inhibitor:
    Hexadecanethiol
    0.5 - 40 g emulsifier:
    Alkylphenol ethoxylate
    0.00 - 1 g surfactant:
    Sodium lauryl sulfonate
    pH 3.5 adjusted with a mineral acid
    Particularly suitable for silver and silver alloys.
  • 4.
    In einem Liter deionisiertem Wasser gelöst:
    0,05 - 30 g Inhibitor:
    Octadecanthiol
    0,05 - 30 g Emulgator:
    Verzweigte Fettalkoholethoxylate mit 8 bis 16 C-Atomen (C₈ - C₁₆) und einem Ethoxylierungsgrad von 2 bis 10
    0,00 - 1 g Tensid:
    Natriumlaurylsulfat
    pH-Wert 10 mit NaOH eingestellt.
    Besonders für Teile aus Kupfer oder Kupferlegierungen geeignet.    4th
    Dissolved in one liter of deionized water:
    0.05 - 30 g inhibitor:
    Octadecanethiol
    0.05 - 30 g emulsifier:
    Branched fatty alcohol ethoxylates with 8 to 16 carbon atoms (C₈ - C₁₆) and a degree of ethoxylation of 2 to 10
    0.00 - 1 g surfactant:
    Sodium lauryl sulfate
    pH 10 adjusted with NaOH.
    Particularly suitable for parts made of copper or copper alloys.

Die Anwendung dieser Bäder geschieht vorzugsweise so, dass die zu passivierenden Teile in die ca. 40°C bis 50°C warmen Bäder getaucht werden. Nach 2 bis 3 Minuten ist die Oberfläche der Teile gleichmässig und dicht mit dem Inhibitor benetzt. Die Teile werden anschließend mit kaltem Wasser gespült und dann getrocknet, vorzugsweise mit Heißluft.These baths are preferably used in such a way that the parts to be passivated are immersed in the approx. 40 ° C to 50 ° C warm baths. After 2 to 3 minutes, the surface of the parts is even and dense with the inhibitor wetted. The parts are then rinsed with cold water and then dried, preferably with hot air.

Die Wirkung der Anlaufschutzschicht auf Silber läßt sich mit Hilfe einer zweiprozentigen Natriumsulfidlösung gut nachweisen. Unbehandelte Silberteile laufen sofort an, behandelte Teile bleiben über einen längeren Zeitraum blank. Die Wirkung der Schutzschicht auf Kupfer wurde überprüft, indem passivierte Kupferteile für mehrere Stunden in einer Schwefelwasserstoffatmosphäre mit 1 ppm H₂S ausgelagert wurden; die Kupferteile verfärbten sich dabei nicht.The effect of the tarnish protection layer on silver can be easily demonstrated with the help of a two percent sodium sulfide solution. Untreated silver parts tarnish immediately, treated parts remain bare over a longer period of time. The effect of the protective layer on copper was checked by passivating copper parts for several hours in a hydrogen sulfide atmosphere with 1 ppm H₂S; the copper parts did not change color.

Claims (13)

Mittel zum zeitweiligen Schutz von blanken Silberoberflächen und Silberlegierungsoberflächen gegen Anlaufen, welches als hydrophoben Inhibitor eine langkettige aliphatische Thio-Verbindung mit mindestens einer SH-Gruppe und mindestens 12 C-Atomen in der Kette aus der Gruppe der Thioalkohole und deren Veresterungsprodukten, Wasser und einen wasserlöslichen Emulgator enthält, mit dessen Hilfe der Inhibitor in dem Wasser emulgiert ist, und auf einen pH-Wert von 1 bis 10 eingestellt ist.Agent for the temporary protection of bare silver surfaces and silver alloy surfaces against tarnishing, which as a hydrophobic inhibitor is a long-chain aliphatic thio compound with at least one SH group and at least 12 carbon atoms in the chain from the group of the thioalcohols and their esterification products, water and a water-soluble Contains emulsifier, with the help of which the inhibitor is emulsified in the water, and is adjusted to a pH of 1 to 10. Mittel nach Anspruch 1, dadurch gekennzeichnet, dass es auf einen pH-Wert kleiner 7, vorzugsweise von 2 bis 4 eingestellt ist.Agent according to claim 1, characterized in that it is adjusted to a pH of less than 7, preferably from 2 to 4. Mittel nach Anspruch 1 oder 2, dadurch gekennzeichnet, dass es 0,05 bis 50 g/l   Inhibitor, 0,05 bis 50 g/l   Emulgator, 0 bis 2 g/l   eines anionischen oder nichtionischen Tensids und als Rest Wasser enthält.Agent according to claim 1 or 2, characterized in that it 0.05 to 50 g / l inhibitor, 0.05 to 50 g / l emulsifier, 0 to 2 g / l of an anionic or nonionic surfactant and the rest contains water. Mittel nach Anspruch 3, dadurch gekennzeichnet, dass es 2 bis 20 g/l Inhibitor enthält.Agent according to claim 3, characterized in that it contains 2 to 20 g / l inhibitor. Mittel nach Anspruch 3 oder 4, dadurch gekennzeichnet, dass es 2 bis 20 g/l Emulgator enthält.Agent according to claim 3 or 4, characterized in that it contains 2 to 20 g / l emulsifier. Mittel nach Anspruch 3, 4 oder 5, dadurch gekennzeichnet, dass es 0,05 bis 1 g/l des Tensids enthält.Agent according to claim 3, 4 or 5, characterized in that it contains 0.05 to 1 g / l of the surfactant. Mittel nach einem der vorstehenden Ansprüche, dadurch gekennzeichnet, dass es keine Inhibitoren mit mehr als 20 C-Atomen in der Kette enthält.Agent according to one of the preceding claims, characterized in that it contains no inhibitors with more than 20 C atoms in the chain. Mittel nach einem der vorstehenden Ansprüche, dadurch gekennzeichnet, dass der Emulgator ausgewählt ist aus der Gruppe der verzweigten, alkoxylierten - vorzugsweise ethoxylierten - Fettalkohole mit 4 bis 20 C-Atomen und einem Alkoxylierungsgrad von 2 bis 10.Agent according to one of the preceding claims, characterized in that the emulsifier is selected from the group of branched, alkoxylated - preferably ethoxylated - fatty alcohols having 4 to 20 carbon atoms and a degree of alkoxylation of 2 to 10. Mittel nach einem der Ansprüche 1 bis 7, dadurch gekennzeichnet, dass der Emulgator ausgewählt ist aus der Gruppe der Alkylphenolethoxylate und der langkettigen Polyglykoläther.Agent according to one of claims 1 to 7, characterized in that the emulsifier is selected from the group of alkylphenol ethoxylates and long-chain polyglycol ethers. Anwendung des Mittels gemäss einem der vorstehenden Ansprüche auf den Schutz von blanken Kupfer- und Kupferlegierungsoberflächen.Application of the agent according to one of the preceding claims to the protection of bare copper and copper alloy surfaces. Verfahren zum Passivieren von blanken Silber- und Silberlegierungsoberflächen bzw. Kupfer- und Kupferlegierungsoberflächen mit einer Emulsion der in den Ansprüchen 1 bis 9 angegebenen Zusammensetzung, dadurch gekennzeichnet, dass die Oberflächen mit der Emulsion bei einer Temperatur behandelt werden, die oberhalb des Schmelzpunktes des Inhibitors liegt, und dass die Oberflächen danach bei einer Temperatur gespült werden, die unterhalb des Schmelzpunktes des Inhibitors liegt.Process for passivating bare silver and silver alloy surfaces or copper and copper alloy surfaces with an emulsion of the composition specified in claims 1 to 9, characterized in that the surfaces are treated with the emulsion at a temperature which is above the melting point of the inhibitor , and that the surfaces are then rinsed at a temperature below the melting point of the inhibitor. Verfahren nach Anspruch 11, dadurch gekennzeichnet, dass die Oberflächen mit Wasser gespült werden.A method according to claim 11, characterized in that the surfaces are rinsed with water. Verfahren nach Anspruch 11 oder 12, dadurch gekennzeichnet, dass die gespülten Oberflächen mit Heißluft getrocknet werden.A method according to claim 11 or 12, characterized in that the rinsed surfaces are dried with hot air.
EP91121903A 1990-12-22 1991-12-20 Means of temporary protection of bare silver and copper surfaces against tarnishing and method of using it Expired - Lifetime EP0492487B1 (en)

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DE19904041596 DE4041596A1 (en) 1990-12-22 1990-12-22 Compsn. for protecting silver@ surfaces against tarnishing
DE4041596 1990-12-22
DE4124955 1991-07-27
DE4124955 1991-07-27

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WO1995009255A1 (en) * 1993-09-29 1995-04-06 Basf Aktiengesellschaft Method of protecting solderable copper and copper-alloy surfaces from corrosion
EP1568800A1 (en) * 2004-02-25 2005-08-31 Posco Method of protecting metals from corrosion using thiol compounds
GB2412666A (en) * 2004-03-30 2005-10-05 Cole Paul Gilbert Water-based metal treatment composition
WO2007038915A1 (en) * 2005-10-05 2007-04-12 Otb Oberflächentechnik In Berlin Gmbh & Co Passivator and lubricant for gold, silver, and copper surfaces, and method for using the same
US7883738B2 (en) 2007-04-18 2011-02-08 Enthone Inc. Metallic surface enhancement
ITVE20100008A1 (en) * 2010-02-24 2011-08-25 Mesa S A S Di Malimpensa Simona E Davide E C METHOD FOR THE PROTECTION OF SILVER SURFACES AND ITS UNDERSTANDING ALLOYS.
US8216645B2 (en) 2007-11-08 2012-07-10 Enthone Inc. Self assembled molecules on immersion silver coatings
US10017863B2 (en) 2007-06-21 2018-07-10 Joseph A. Abys Corrosion protection of bronzes
CN108315739A (en) * 2018-02-10 2018-07-24 深圳市祥盛兴科技有限公司 A kind of chemical polishing solution and surface with chemical polishing technology
WO2021028440A1 (en) * 2019-08-13 2021-02-18 Saint-Gobain Glass France Reducing the corrosion of silver wires on a glass substrate

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CN104032289B (en) * 2013-08-23 2015-02-25 珠海罗西尼表业有限公司 Method for corrosion resistance and tarnishing resistance treatment of gold and its alloy surface

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FR1347705A (en) * 1961-09-28 1964-01-04 Minnesota Mining & Mfg Composition preventing tarnishing of copper-based surfaces
DE1282414B (en) * 1963-12-18 1968-11-07 Wmf Wuerttemberg Metallwaren Agent for protecting silver goods by passivating their surface using organic thio compounds
US3398003A (en) * 1965-04-26 1968-08-20 Verle C. Smith Silver polish-tarnish retarder containing a dialkyl disulfide having from 8 to 20 carbon atoms in each alkyl radical
CH478925A (en) * 1965-11-04 1969-09-30 Becker Hans Delu Fab Precious metal cleaning and polishing bath
DE3905850A1 (en) * 1989-02-24 1990-08-30 Blasberg Oberflaechentech Method of protecting untreated silver surfaces

Cited By (18)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1995009255A1 (en) * 1993-09-29 1995-04-06 Basf Aktiengesellschaft Method of protecting solderable copper and copper-alloy surfaces from corrosion
EP1568800A1 (en) * 2004-02-25 2005-08-31 Posco Method of protecting metals from corrosion using thiol compounds
GB2412666A (en) * 2004-03-30 2005-10-05 Cole Paul Gilbert Water-based metal treatment composition
WO2005095675A1 (en) * 2004-03-30 2005-10-13 Middlesex Silver Co. Limited Water-based metal treatment composition
GB2412666B (en) * 2004-03-30 2008-10-08 Paul Gilbert Cole Water-based metal treatment composition
WO2007038915A1 (en) * 2005-10-05 2007-04-12 Otb Oberflächentechnik In Berlin Gmbh & Co Passivator and lubricant for gold, silver, and copper surfaces, and method for using the same
US8741390B2 (en) 2007-04-18 2014-06-03 Enthone Inc. Metallic surface enhancement
US7883738B2 (en) 2007-04-18 2011-02-08 Enthone Inc. Metallic surface enhancement
US10017863B2 (en) 2007-06-21 2018-07-10 Joseph A. Abys Corrosion protection of bronzes
US8216645B2 (en) 2007-11-08 2012-07-10 Enthone Inc. Self assembled molecules on immersion silver coatings
US8323741B2 (en) 2007-11-08 2012-12-04 Abys Joseph A Self assembled molecules on immersion silver coatings
WO2011104614A1 (en) * 2010-02-24 2011-09-01 Mesa S.A.S. Di Malimpensa Simona E Davide E C. Method for protecting silver and silver alloy surfaces against tarnishing
US9057135B2 (en) 2010-02-24 2015-06-16 Agere S.R.L. Method for protecting silver and silver alloy surfaces against tarnishing
RU2556162C2 (en) * 2010-02-24 2015-07-10 Аджере С.Р.Л. Method of protecting silver and silver alloy surfaces from tarnishing
ITVE20100008A1 (en) * 2010-02-24 2011-08-25 Mesa S A S Di Malimpensa Simona E Davide E C METHOD FOR THE PROTECTION OF SILVER SURFACES AND ITS UNDERSTANDING ALLOYS.
CN108315739A (en) * 2018-02-10 2018-07-24 深圳市祥盛兴科技有限公司 A kind of chemical polishing solution and surface with chemical polishing technology
CN108315739B (en) * 2018-02-10 2019-03-22 深圳市祥盛兴科技有限公司 A kind of chemical polishing solution and surface with chemical polishing technology
WO2021028440A1 (en) * 2019-08-13 2021-02-18 Saint-Gobain Glass France Reducing the corrosion of silver wires on a glass substrate

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