Classifications

• • C—CHEMISTRY; METALLURGY
  • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
  • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
  • C25D3/00—Electroplating: Baths therefor
  • C25D3/02—Electroplating: Baths therefor from solutions
  • C25D3/56—Electroplating: Baths therefor from solutions of alloys
  • C25D3/62—Electroplating: Baths therefor from solutions of alloys containing more than 50% by weight of gold
• • C—CHEMISTRY; METALLURGY
  • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
  • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
  • C25D3/00—Electroplating: Baths therefor
  • C25D3/02—Electroplating: Baths therefor from solutions
  • C25D3/48—Electroplating: Baths therefor from solutions of gold

Definitions

• the invention relates primarily to a bath for galvanic Deposition of gold and gold alloys as well its use.
• the gold is in shape in this bathroom of a gold sulfite complex.
• the separated Layers with special aesthetic requirements, especially in the dental field are sufficient, for example with regard to the color of the Gloss or surface texture.
• certain additional requirements are made, for example in terms of biocompatibility.
• biocompatibility The materials can be particularly useful in the dental field be important, for example for allergy sufferers Gold or gold alloy layers with the highest possible purity be required.
• additives to match the galvanic Precipitation requirements at least partially fulfilled.
• Such additives are also called fine grain additives or gloss additives.
• organic additives such as polyamines, polyimines and their Mixtures or semimetal compounds, for example from Trade arsenic, antimony or thallium. All the additives mentioned can more or less strongly in the separated Gold layer can be installed. With organic additives this is problematic in the dental field because the Layer properties (e.g. ductility and firing stability) can be negatively influenced by this installation.
• antimony Sb (III) used, for example as a potassium antimony tartrate.
• the latter reacts in the bath to form gelatinous hydrate of antimony oxide, that's probably how this works Additional matters.
• the antimony oxide hydrate gel is itself not stable and unresponsive under normal bath conditions to crystalline antimony oxide that does not have the desired effect more unfolded. This is the reason that the addition to the Bath can only be added before use and that the Addition loses its effect after some time. So that is a production of a long-term functional Gold or gold alloy bath with all necessary Components not possible.
• the objects to be electroplated in shape and size and the desired layer thickness of the precipitate strongly vary and accordingly the amount to be separated Metal is such a dosage per object with a comparative one big mistake.
• This can be too strong different qualities of galvanic precipitation lead, so that even objects that are simultaneously in one Operation to be coated in the composition of the Can distinguish precipitation. This can be the deposition make it difficult for the user to handle.
• EP-B1-0 126 921 describes an aqueous bath for electroplating Deposition of gold-copper-bismuth alloys described that the gold is in the form of a gold cyanide complex contains.
• ternary alloys with high bismuth contents are kept deposited.
• the bathroom described there is suitable especially for separating rose to violet-colored Coatings on decorative objects, such as Jewelry, watches and glasses.
• the technical meaning should thereby lie in the fact that the bismuth in the alloys extraordinarily high contents up to 30% by weight and higher can be installed. This is supposed to open up new areas of application, such as z. B. the refinement of electronic components, such as plug connections, open up because of the corresponding rainfall are particularly hard and have good electrical conductivity and have abrasion resistance.
• the dental sector are the baths mentioned in EP-B1-0 126 921 because of their high toxicity as well as the fact that the bismuth with high contents in the Alloy is to be installed, not suitable.
• DE-C2-2 723 910 (corresponds to FR-A-2353656) claims a variety of additional mixtures for bathrooms electrolytic deposition of gold or gold alloys. These additional mixtures are said to improve Cause properties of the deposited precipitation.
• Mandatory components of these additional mixtures are at least an organic water-soluble nitro compound with certain general formula and at least one water soluble Metal compound of an element from the group arsenic, antimony, Bismuth, thallium and selenium.
• Additional mixtures in addition to the Nitro compound is a water soluble bismuth compound included, are also here for use in cyanidic Baths limited.
• the use of the in DE-C2-2 723 910 additional mixtures mentioned and the mixture thereof Manufactured gold baths is limited to the technical Use for plating electronic components for the semiconductor technology.
• the invention has for its object a bathroom for galvanic Deposition of gold and gold alloys available to face the disadvantages outlined above at least partially avoided.
• the galvanic Manufacture of prosthetic dental molded parts even more reliably and made safer as well as handling the baths used for this purpose are further simplified.
• the possibility is to be created for the user one with all the necessary ingredients and additives provided and thus functional bathroom at hand give.
• the corresponding bathrooms should largely with biocompatible, i.e. physiologically harmless compounds can be operated without the quality of the deposited layers is deteriorated.
• the bath according to the invention for the galvanic deposition of Gold and gold alloys based on a gold sulfite complex is characterized in that it is next to any existing Alloy metals and other common additives for such gold sulfite baths at least one bismuth compound contains.
• This bismuth compound is preferably a water-soluble bismuth compound, which the result is that the bathroom itself is preferably a is aqueous bath.
• the bismuth compound is preferably a Complex compound, preferably a so-called chelate compound.
• Such compounds are known to be cyclic Compounds in which one ligand (complexing agent) has several Coordination points of a central atom (metal) occupied, see above that it is usually particularly stable Complex compounds.
• the bismuth compound is an organic Complexing agent, preferably an organic chelating agent contains.
• complexing agents or chelating agents are here in particular NTA (nitrilotriacetic acid), HEDTA (N- (2-hydroxyethyl) ethylenediamine triacetic acid), DTPA (diethylenetriaminepentaacetic acid) and as a preferred complexing agent / chelating agent To name EDTA (ethylenediaminetetraacetic acid).
• NTA nitrilotriacetic acid
• HEDTA N- (2-hydroxyethyl) ethylenediamine triacetic acid
• DTPA diethylenetriaminepentaacetic acid
• EDTA ethylenediaminetetraacetic acid
• Bismuth compounds which can be used according to the invention are, for example water-soluble bismuth salts (e.g. sulfates, nitrates, Sulfamates, phosphates, pyrophosphates, acetates, citrates, Phosphonates, carbonates, oxides, hydroxides, etc.).
• water-soluble bismuth salts e.g. sulfates, nitrates, Sulfamates, phosphates, pyrophosphates, acetates, citrates, Phosphonates, carbonates, oxides, hydroxides, etc.
• organic complexing agents are still examples of organic complexing agents to be mentioned: organic phosphonic acids, carboxylic acids, dicarboxylic acids, Polyoxycarboxylic acids, hydroxycarboxylic acids, diketones, Diphenols, salicylaldehydes, polyamines, polyaminocarboxylates, Diols, polyols, di-polyamines, amino alcohols, Aminocarboxylic acids, aminophenols.
• the bismuth compound in the bath in a concentration between 0.05 mg / l and the saturation concentration of this bismuth compound in Bathroom is included.
• concentrations in the bath between 0.05 mg / l and 1 g / l is preferred, with within concentrations between 0.1 mg / l and 10 mg / l are to be emphasized.
• this is bath according to the invention essentially free of physiological questionable (harmful) additives / additives, the bath preferably free of arsenic, antimony and Is thallium compounds.
• physiological questionable additives / additives the bath preferably free of arsenic, antimony and Is thallium compounds.
• the antimony is in the prosthetic molding in a concentration of normally 0.2 per mille installed.
• one Antimony compound such as potassium antimony tartrate and a bismuth compound
• both antimony and bismuth in deposited molding in quantities of less than 30 ppm or 40 ppm are present (these are the detection limits at the analysis method used for these elements). This shows on the one hand that the bismuth itself is not in the molding is installed and on the other hand that the bismuth is capable is to significantly reduce the incorporation of the antimony.
• the concentration of gold in the bath according to the invention is basically not critical.
• the gold is preferably in Contain bath in a concentration between 5 and 150 g / l.
• gold concentrations in the bath are between 10 and 100 g / l, preferably between 10 and 50 g / l.
• On particular advantage of the invention shows that Gold concentrations in the bath between 30 and 48 g / l selected can be.
• precious metals are those from the so-called platinum group preferred to name, which is particularly palladium or Platinum is trading. Precious metals, especially those of Platinum group, are due to their high biocompatibility especially in the field of prosthetic dental molded parts suitable.
• the concentration of the alloy metal in the bath inside further limits can be varied. Basically, the alloy metals in the form of their preferably water-soluble salts or in the form of preferably water-soluble complex compounds be added. Preferably, the concentrations between 0.1 mg / l and 200 g / l can be selected. Within this range can be the concentration between 0.1 and 500 mg / l and in particular between 5 and 20 mg / l.
• the gold sulfite complex in the bath according to the invention can are basically all known complexes, such as they are known from the prior art.
• it is a so-called ammonium gold sulfite complex, where the gold ion complexes with the sulfite ions and as a "counter ion" at least one ammonium ion is available.
• the baths according to the invention preferably have a pH of at least 7, i.e. they are either neutral or alkaline.
• the baths are (weakly) alkaline, pH values of 7 to 9 are preferred.
• the bathroom according to the invention can be further Contain customary additives / additives, which are usually in contain such baths based on a gold sulfite complex are.
• additives are known to the person skilled in the art and within his expertise in the usual areas variable.
• conductive electrolytes are included their conductive salts, buffer systems / buffer mixtures, so-called Stabilizers and wetting agents available. Possibly. can also from prior art brighteners and / or fine grain additives be contained in the bath according to the invention.
• the invention further includes the use of the described Baths according to the invention for the production of prosthetic molded parts for the dental sector by means of galvanic deposition.
• Such use is particularly for the production of so-called dental frameworks such as crowns, bridges, superstructures etc.. intended.
• the prosthetic molded parts are galvanically deposited on a substrate. you also speaks of so-called electroforming.
• the self-supporting stable molded part is separated from the substrate and further edited.
• the substrate can be, for example around a model molded from a tooth stump or around an implant component (prefabricated or individual preprocessed).
• the invention encompasses the use at least one bismuth compound, preferably at least one a water-soluble bismuth compound for manufacturing prosthetic molded parts for the dental sector by means of galvanic Deposition.
• the bismuth compound thereby as part of a bath according to the invention, such as it was used above.
• Preferred to use Bismuth compounds have already been explained in detail above, so that to the appropriate places in the description can be referenced and referenced.
• a particularly important feature of the invention is to emphasize that the bismuth compound used in the invention can be added to the bath directly during its manufacture. This means that the user is responsible for all components and additives provided functional bath becomes. In contrast to the known baths of the prior art The user must have technology before performing the electroplating process no additive / additive, what with the above disadvantages already explained would be connected.
• Bismuth compound used according to the invention also before the bath or can take place during the galvanic deposition, if so desired.
• Such a variant can, for example also be provided if an aqueous bath is used in the manufacture of a complete or partially water-insoluble bismuth compound, e.g. Bismuth oxide was added.
• This water-insoluble compound can then by adding an appropriate complexing agent immediately before or during the galvanic deposition converted into a water-soluble bismuth compound which will then have the desired effect in the bathroom.
• the case is a further preferred variant of the invention name that the bismuth connection after a galvanic Separation for addition to the bath is added. This affects the cases where the gold and / or alloy metal concentration in the bathroom for several, especially one Large number of separations is sufficient. Then the bismuth connection correspondingly for later deposition cycles be supplemented.
• the invention is Intended for use in the manufacture of prosthetic molded parts, which is sufficient in the electroforming process Have stability. Accordingly, layer thicknesses of Molding of more than 10 microns is usually provided.
• the layer thicknesses of the molded part are preferably between 100 and 300 ⁇ m, in particular layer thicknesses of approx. 200 ⁇ m are deposited.
• Such layer thicknesses are not only for the production of the invention of crowns, but also of bridges and others Suitable for superstructures.
• the invention includes a method of manufacture of prosthetic molded parts for the dental sector made of gold and gold alloys by electrodeposition.
• this method is used to manufacture dental frameworks such as crowns, bridges, superstructures and the like. intended.
• Gold or gold alloy layer from an inventive Bath deposited on an appropriate substrate and the obtained layer separated from the substrate (demolded).
• the substrate may e.g. to one of a model molded from a tooth stump or around an industrial one prefabricated or individually machined implant component act.
• the substrate is preferably made of an electrically non-conductive Material, especially plaster or plastic built. This usually affects the cases where a model was molded from the tooth stump.
• the surface of the non-conductive The substrate is then before the galvanic deposition made conductive, especially with the help of conductive silver.
• the substrate is constructed from at least one metal that is itself already conductive.
• the substrates here include, for example, internal telescopes (usually made from a cast and milled dental alloy) or implant components, such as implant posts and the like. to call. Such parts are often made of titanium or titanium alloys.
• the method according to the invention and also the uses according to the invention are preferably characterized in that the deposition takes place at high current densities, which usually results in short electroplating times. Current densities up to 10 A / dm 2 are preferred, in particular current densities up to 8 A / dm 2 . Even with such high current densities, the bath according to the invention can still be used very well.
• the use according to the invention or the use according to the invention Methods can preferably be carried out so that the Deposition takes place in the so-called pulse-plating process.
• This type of galvanic metal deposition also worked with direct current.
• This direct current will however as a pulse current, i.e. in the form of current pulses from Breaks are interrupted, applied.
• the state of the art can here, for example, on the tape "Pulse-Plating" Publication series electroplating and surface treatment, Leuze-Verlag, Saulgau, 1990.
• the application of the pulse plating process in dental technology shows the DE-A1-198 45 506 by the applicant, the content of which by Reference is made to the content of this description.
• the Application of the pulse plating method in the present Invention has the advantage that within comparative short periods of precipitation in the desired thickness, for example of about 200 microns can be deposited.
• the use according to the invention and the use according to the invention Methods are furthermore preferably characterized in that that the separated prosthetic molded part at his Further processing with ceramic and / or plastic veneered becomes.
• a molded part veneered with ceramic is after the Application of the ceramic fired in the usual way, for example at temperatures up to about 950 ° C.
• One with plastic The molded part is veneered after the plastic has been applied to harden it with light, especially with visible Light is irradiated after the surface of the molding beforehand using suitable processes known to the person skilled in the art was conditioned.
• the bath according to the invention is excellent Manufacture of prosthetic molded parts (dental prosthetic parts) suitable.
• the characteristics of the rainfall are at least as good as those in rainfall from gold sulfite baths, for example with a metering working from antimony compounds, deposited were.
• the quality of the precipitation corresponds to bathroom according to the invention rather better the specific Requirements in dental technology.
• the gold layers obtained with the bath according to the invention are golden yellow and high-gloss, making them particularly high meet aesthetic requirements. Of course you can optionally also matt and / or rough surfaces become.
• the burning stability of these layers, which is responsible for their ceramic veneer is unavoidable, despite the possible absence of an antimony compound in the gold bath, given with reproducible security. This is after Knowledge of the applicant so far in no bathroom without one Antimony compound can work, the case.
• a further advantage of the bath according to the invention is that it is obviously insensitive to plastics introduced into the bath, which are provided, for example, as tooth stump materials or for covering metallic parts which are not to be galvanically coated.
• plastics molded plastic models
• lacquers covering lacquers
• release components during the deposition in the gold bath which have a negative effect on the effect of the fine-grain or gloss additives of the gold bath.
• This negative effect usually becomes clearer the higher the current density chosen during the deposition.
• a further advantage of the bath according to the invention is surprisingly shown in the fact that such a bath with added bismuth functions without problems and with above-average results in various devices (also from different manufacturers) used commercially in the dental field for galvanic deposition.
• the composition of the gold or gold alloy bath had to be precisely matched to the device used, or such a device, in particular in terms of its process parameters, had to be precisely matched to a specific bath.
• each manufacturer normally offered a specific gold bath for a very specific device, which was matched to this gold bath in its process parameters.
• an AGC Micro device from the applicant which usually reaches a layer thickness of 200 ⁇ m in 12 hours, can be operated with the bath according to the invention as well as an AGC MicroPlus device which already reaches the same layer thickness in 5 hours.
• the bath according to the invention is also suitable for use in devices which work with the pulse-plating method, for example the AGC speed device from the applicant.
• layer thicknesses of 200 ⁇ m are dependent on Size of the part to be electroplated in 1 to 2 hours reached.
• the bath according to the invention can thus be advantageous existing galvano devices of the user can be adapted.
• an electrolysis cell that can be used according to the examples from a vessel to hold the bath.
• This vessel is usually provided with a cover.
• Anode which can possibly consist of several parts, and at least one cathode is provided.
• the cathode On this cathode, the for example from the substrate such as a plaster stump or Post is formed, the gold or the gold alloy galvanically deposited.
• the anode is, for example made of platinum-plated titanium.
• a suitable current / voltage source is provided for separation itself a suitable current / voltage source is provided.
• a magnetic stirrer with heating is usually provided, which at the same time for a constant (usually increased) Separation temperature in the bathroom and for driving an in the existing magnetic stirring bar. Accordingly, there is also a temperature sensor in the electrolysis cell introduced.
• the baths used contain in addition to the specified components usual additives for gold sulfite baths.
• additives are known to the person skilled in the art. So act it is, for example, conductive salts (sulfites, sulfates and Phosphates), wetting agents or stabilizers such as, for example Nitro acids.
• the bathroom according to the invention differs from the well-known baths by adding the bismuth compound, where due to this addition, additives that are in usual baths are present, such as antimony compounds or nitro compounds can (but does not have to).
• the deposition result in the following table speaks of a "faultless” functionality, this should mean that the layer obtained during the deposition has no cracks, pores or holes.

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• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Electrochemistry (AREA)
• Materials Engineering (AREA)
• Metallurgy (AREA)
• Organic Chemistry (AREA)
• Electroplating And Plating Baths Therefor (AREA)

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Citations (4)

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• 2001
  • 2001-02-28 DE DE2001110743 patent/DE10110743A1/de not_active Withdrawn
  • 2001-04-04 EP EP01108448A patent/EP1236814A1/fr not_active Withdrawn

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