WO2021229481A1

WO2021229481A1 - Stainless bronze alloy and its use in galvanized products

Info

Publication number: WO2021229481A1
Application number: PCT/IB2021/054079
Authority: WO
Inventors: Lorenzo Cavaciocchi; Leandro Luconi; Matteo SIMONELLI; Mario LAVANGA
Original assignee: Bluclad S.R.L.
Priority date: 2020-05-15
Filing date: 2021-05-13
Publication date: 2021-11-18
Also published as: EP4150129A1; IT202000011203A1

Abstract

The present invention describes a copper/Tin-based alloy containing Pt and optionally Zn and/or Pd having colorimetric coordinates that can be modulated from white to yellow to pink and exhibiting striking hardness and thus wear resistance characteristics. The invention also relates to a particular sequence of galvanic deposits, wherein a first coating consisting of a Nickel-Cobalt-Phosphorus based alloy is underlying a second coating consisting of a copper/Tin based alloy containing Pt and/or Pd and optionally Zn ad, to obtain hypoallergenic, zero Ni-releasing galvanized objects.

Description

STAINLESS BRONZE ALLOY AND ITS USE IN GALVANIZED PRODUCTS

FIELD OF THE INVENTION

The present invention relates to the field of alloys, in particular to platinum - containing bronzes, to galvanized objects containing such alloys and to the method for their production and use.

BACKGROUND

Alloys based on Copper and Tin and other metals (such as Zn and/or Pd) have been extensively studied as possible low-cost substitutes for pure Palladium deposits and as Nickel substitutes for objects that have to meet hypoallergenic characteristics. WO 2017/021916 A2 (by the same Applicant) deals with alloys of Tin, Palladium, Copper and possibly Zinc for the electrodeposition of an alloy consisting of 25-45% Tin, 0-15% Zinc, 0.25-10% Palladium and Copper in a sufficient quantity to reach 100%. This electrochemical deposit has a white coloring and strong stainless qualities but is not suitable for use as a finish coat and the color thereof cannot be modulated.

WO 2018/146623 A1 (also by the same applicant) deals with an electroplating bath for the deposition of alloys Copper, Tin, Palladium and possibly Zinc with alloy metal concentrations of 10-25% Tin, 10-45% Palladium, 0-10% Zinc and enough Copper to reach 100%. This alloy varies in color from yellow to pink as the concentrations of metals in the alloy change and has a high resistance to oxidation. It is therefore possible to modulate the coloring so that it resembles as closely as possible the coloring of the overlying finishing layer with precious metals, and such an alloy makes it possible to deposit finishings of minimum thickness and to mitigate imperfections due to wear.

The aforesaid alloys seek to replicate both the white final appearance of pure Palladium or the yellow final appearance of Gold as well as their oxidation resistance characteristics but with a lower expenditure of precious metal.

However, the cost of Palladium has almost tripled in recent years, making the electroplating industry using Palladium uncompetitive compared to other technologies such as PVD (physical vapour deposition). Copper and Tin alloys containing Platinum have never been investigated as possible low-cost substitutes for pure Palladium deposits and as Nickel substitutes for objects that have to meet hypoallergenic characteristics.

Patent US2273806, for example, deals with a Platinum alloy containing by weight 0.35-5% Tin and at most 4% Copper.

It is therefore of strategic interest to find new deposits capable of replacing Palladium and Gold or alloys thereof that are less expensive but which guarantee the same level of resistance to oxidative and mechanical tests, as well as similar coloring and hypoallergenicity.

It is also the object of the present invention to offer deposit sequences such that the requirements of hypoallergenicity are met.

SUMMARY OF THE INVENTION

The present invention makes it possible to overcome the above-mentioned problems thanks to glossy and bright galvanic alloys of Bronze, comprising Copper, Tin, Platinum and possibly Zinc and/or Palladium, which surprisingly have high oxidation resistance and high hardness (hence high wear resistance) and whose coloring can be varied in hues from white to pink up to yellow.

The subject-matter of the invention is therefore an electrodeposited Copper/Tin alloy according to claim 1 , having colorimetric coordinates: L=76-86, a=0-6, b=2.5-19 and containing Platinum 5-60%,

Tin 5-60%,

Copper q.s at 100%,

Pd 0-25%

Zinc 0-10%, wherein the overall concentration Pt+Sn+Pd+Zn is 20-85% and the overall concentration Pt+Pd is 5-60%, where the % are by weight calculated on the total weight of the alloy.

A further subject of the invention is a galvanized object comprising at least one deposit consisting of the alloy subject-matter of the invention. Surprisingly, these objects have an improved corrosion and abrasion resistance than objects galvanized with known state-of-the-art alloys. The right combination of the elements in the alloy according to the invention allows to obtain deposits of varying hues of white, pink and yellow to be used as a substitute for deposits of Palladium for the white hue and of Gold for the yellow/pink hue or as a substrate for Palladium and Gold deposits, guaranteeing after intense wear a high color uniformity even for very low thicknesses of the precious metals (0-0.2 microns) with consequent reduction of the production costs compared to the use of high thickness precious metals (0.5-1 .0 microns). In addition, the convenience of using this Platinum-containing Bronze alloy, according to the invention, is particularly pronounced when used in Nickel-free galvanic cycles for passing wear and oxidation tests which would otherwise require high thicknesses of Palladium deposits.

A further subject of the present invention is also a hypoallergenic galvanized object comprising: a first coating layer comprising or consisting of a deposit of hypoallergenic Nickel-Cobalt-Phosphorus alloy overlying the preparatory layer so that it protects the base material and the underlying layers which are easily oxidized; a second coating layer, overlying the first coating layer, consisting of a Sn- Cu-Pd/Pt alloy having composition:

Sn 5-60%,

Cu q.s at 100%,

Pd 0-60%

Pt 0-60%

Zn 0-10%, where if Pd is not present Pt is present and vice versa; where the % are by weight calculated on the total weight of the alloy; wherein optionally a Flash deposit can be interposed between said layers.

The sequence of deposits of the hypoallergenic object mentioned above surprisingly ensures a Ni release below the instrumental detection limit used by the standards. DETAILED DESCRIPTION OF THE INVENTION

For the purposes of the present invention, the %s are intended by weight with respect to the total weight of the alloy.

The alloy according to the invention may possibly contain one or more other metals in a total amount lower than 10%, which, however, do not substantially change the characteristics of the alloy if their % added to the Pt+Sn+Pd+Zn % remains between 20-85%. Said one or more other metals can be, by way of non-limiting example, Indium, Gallium, Germanium, Silver, Iridium, Ruthenium, Rhodium. Gold, Molybdenum, Tungsten and Rhenium.

The alloy according to invention may possibly contain traces of brightening or grain finishing metals, where traces are meant quantities lower than 0.25% by weight on the alloy and for brightening or grain finishing metals are meant those normally used for this purpose in this field of activity, that is by way of non-limiting example, such as Bismuth, Tellurium, Molybdenum, Thallium, Antimony, Selenium and Lead.

The variation in hue bound to maintaining the high resistance to oxidative testing of the deposit is a function of the relative concentrations of the metals making up the alloy.

A first preferred embodiment of the invention is an alloy with yellow hues having colorimetric coordinates: L=-80-86, a=4-6, b=12.5-19 comprising:

Sn 5-25%; preferably 6-15%; more preferably 8-12%;

Pt 15-30%; preferably 17-25%; more preferably 18-22%;

Pd 0-15%; preferably 0-10%; more preferably 0.5-8%;

Zn 0-10% preferably 0-7%; more preferably 0.5-5%;

Cu q.s at 100 and greater than 65%; where Sn+Pt+Pd+Zn is at most 35% and Pt+Pd is at most 30%.

The yellow hue is possible by virtue of a higher presence of Cu than other metals.

A second preferred embodiment of the invention is an alloy with pink hues having colorimetric coordinates: L=76-82, a=2-5, b=8-12 when comprising:

Sn 5-35%; preferably 8-20%; more preferably 10-12%;

Pt 20-50%; preferably 25-45%; more preferably 27-35%;

Pd 0-25%; preferably 0-20%; more preferably 0.5-20%;

Zn 0-10%; preferably 0-7%; more preferably 2-5%;

Cu 45-65%; preferably 48-62%; %; more preferably 52-58%; where Sn+Pt+Pd+Zn is at most 55% and Pt+Pd is at most 50%.

According to a third preferred embodiment of the alloy of the invention, an alloy with a white hue having colorimetric coordinates may be obtained: L=82-86, a=0.2-1.5, b=2.5-5.5 when comprising: Sn 5-60%; preferably 25-60%; more preferably 35-55%;

Pt 5-60%; preferably 6-45%; more preferably 10-35%;

Pd 0-35%; preferably 0-25%; more preferably 0.5-15%;

Zn 0-10%; preferably 0-7%; more preferably 0.5-4%;

Cu q.s.at 100 and less than 45%; preferably less than 40% more preferably less than 30%; wherein Sn+Pt+Pd+Zn is at least 55% and Pt+Pd is at most 60%.

In addition, the solutions and the deposit can include the brighteners and grain finishers commonly used for this purpose including trace metals such as Bismuth, Tellurium, Molybdenum, Thallium, Antimony.

In one aspect, the present invention also relates to solutions for electrodeposition of an alloy according to the invention and the electrodeposition process thereof. Preferably the content of free Cyanide in the solutions is equal to 1 - 100 g/l, more preferably 5-60 g/l.

The above metals are preferably present in solution as soluble Oxides, Sulphates, Cyanides, Ammonium salts and other suitable soluble compounds and Cyanide is in the form of Sodium Cyanide, Potassium Cyanide or is derived from the salts of the alloying metals in the form of Cyanide complexes such as Copper Cyanide, Zinc Cyanide, Platinum Cyanide and Palladium Cyanide.

The copper content in solution is preferably 0.2-20 g/l more preferably 0.5-14 g/l. For the electrodeposition of an alloy with a yellow or pink hue, the Cu content in solution is preferably 5-14 g/l. For the electrodeposition of an alloy with white hue, the Cu content in solution is preferably 0.5-10 g/l.

The concentration of Tin in the electrolyte may vary between 2 and 30 g/l with the amount of free hydroxide that may vary between 0 and 20 g/l calculated on the basis of potassium or sodium hydroxide. For the electrodeposition of an alloy with yellow hue, the Sn content in solution is preferably 2-8 g/l. For the electrodeposition of an alloy with pink hue, the Sn content in solution is preferably 4-10 g/l. For the electrodeposition of an alloy with white hue, the Sn content in solution is preferably 8-20 g/l.

The Zn content in solution, if any, may vary between 0.05 and 10 g/l based on the relative concentration of the other metals for obtaining the alloy of the invention. The Pd content in solution, if any, may vary between 0.05 and 10 g/l based on the relative concentration of the other metals for obtaining the alloy of the invention. The Platinum content can vary from 0.05 g/l to 8 g/l, preferably for obtaining the desired alloys it can vary between 0.15 and 5 g/l.

The solution may also contain one or more other metals in an overall concentration lower than 4 g/l; wherein said one or more other metals are selected, by way of non limiting example, from the group consisting of Indium, Gallium, Germanium, Silver, Iridium, Ruthenium and Rhodium.

The solution may also contain one or more complexing agents capable of regulating the deposition of the metal components and guaranteeing stability in solution, as is known from compositions of this type.

Complexing agents suitable for this purpose can be Nitrilotriacetic Acid (NTA), Ethylenediaminetetraacetic acid (EDTA), Ethylenetriaminopentacetic acid (DTPA), salts Phosphonates of alkali metals such as Ethylenediaminetetramethyl Phosphonic Acid (EDTMPA), 1 -Hydroxyethylenediphosphonic Acid (HEDP), and salts thereof as well as derivatives or salts of polyhydroxylated organic substances such as Gluconates and more or less complex sugars.

Surfactants and surfactant mixtures well known to the person skilled in art may also be present in the solutions, such as, for example, bathers from the family of Alkyl ethers Phosphonates, Alkyl ethers Sulfonates, Alkylaryl polyol ethoxylates and the related sulphonated derivatives, quaternary ammonium salts of alkanes or aromatic compounds such as also Alkyl Betaine.

In addition, brighteners and grain finishers commonly used for this purpose may be included in the solutions, including trace metals, by way of non-limiting example, such as Bismuth, Tellurium, Molybdenum, Thallium, Antimony, Selenium and organic compounds such as Heterocycliaromatics, Non-aromatic Heterocycles, condensed cycles and heterocycles for example Nicotinamide, Sodium Saccharinate as well as reaction products between Epichlorohydrin and organic substances having Amino and Hydroxyl groups.

Asubject of the present invention is also a process for the electrodeposition of an alloy as described above said process comprising immersing an object on which to electrodeposit the alloy in a galvanic solution as described above and applying a current of 0.5-3.0 A/dmq for a time 1-20 min at a temperature of 30-70°C, preferably for 2-20 min at a temperature of 45-65°C.

In one aspect, the present invention also relates to a galvanized object comprising at least one layer consisting of an alloy as described above. A galvanized object according to the present invention shows surprisingly high resistance characteristics to oxidative and mechanical tests recognized by the major fashion houses worldwide.

Galvanized objects, including hypoallergenic objects as described below, are objects in which at least one step of the production process includes the electrodeposition of a metal or metal alloys. Preferably said objects are included in the following product classes: jewelery, costume jewelery, leather goods, clothing, small parts, watchmaking, eyewear, decorative plating, trinkets, closures, caps/perfume packages.

Preferably, the galvanized object comprising at least one layer consisting of an alloy according to the invention is comprising or consisting of: a) a base material; b) one preparatory layer that depends on the base material used and the type of glossy or matte finish to be obtained, said preparatory layer deposited above the base material; c) a first coating layer consisting of white bronze and/or a deposit of hypoallergenic Nickel-Cobalt-Phosphorus alloy deposited over the preparatory layer so that it protects the base material and the underlying layers which are easily oxidized; this in the case of Nickel-free and hypoallergenic cycles respectively; d) a second coating layer consisting of an alloy according to the present invention whose color is preferably as close as possible to the color that determines the final aesthetics of the object; e) possibly, if the second layer does not have the desired color for the final finishing, one or more final layers can be deposited that are normally composed of precious metals, non-precious metals or paints which determine the aesthetic appearance of the object. Other low thickness (less than 0.1 micron) deposits, commonly known as Flash, may be interposed between the various layers in order to apply barriers to intermetallic migration and to optimise adhesion between the various galvanic layers avoiding delamination of the upper layers from the lower ones. For each galvanic cycle, the embodiments normally provide for the interposition of flash layers, but if it is subsequently found that the cycle still passes the various tests even without flash layers, they can be omitted.

For processes containing Nickel, the first layer of white Bronze is not recommended as it increases production costs without any appreciable improvement in oxidation resistance tests, while the use of the Nickel-Cobalt-Phosphorus alloy deposit is useful.

The base material can consist or comprise Bronze, Brass, Zamak, Aluminum, Nickel silver, Steel and other Copper and Tin alloys, but also galvanizable plastics such as ABS.

The preparatory layer is chosen by the expert skilled in the art according to the base material used and the type of structural finish (not colorimetric) to be obtained. For example, for finishes with a glossy appearance, both Copper from glossy levelling Copper baths and Nickel from glossy levelling galvanic baths of Nickel can be deposited while for finishes with a matte and aged appearance, the base material can be pre-treated with a tumbling process and subsequently non-levelling Nickel or Bronze deposited to preserve the roughness obtained on the base material. Preferably in Nickel-free or hypoallergenic cycles in which the base material is Brass or Zamak the preparatory layer is Copper; when the base material is Steel preferably the preparatory layer is a flash of Gold to optimise adhesion; for cycles comprising Nickel if the base material is Brass then the preparatory layer is directly Nickel while if the base material is Zamak then it must be pre-treated with Copper before depositing the preparatory layer of Nickel. In cycles where the outer layer (Gold or Palladium) is 0.5-1 microns, introducing the alloying deposit of the present invention on top of the Nickel (white in color) and thus reducing the thicknesses of Gold to 0.1 -0.2 microns (in the yellow alloy version) and of Palladium to 0-0.05 microns (in the white alloy version) is economically advantageous.

The preparatory layer has preferably a thickness of 7-15 microns. The precious metal constituting the final layer comprises Gold, Silver, Platinum, Ruthenium, Rhodium, Palladium, Osmium, Iridium, and alloys thereof also with non precious metals such as for example Tin, Copper, Zinc, Iron, Nickel, Cobalt, more preferably Gold, Silver, Ruthenium, Rhodium and Palladium and even more preferably Gold and Palladium.

The final layer may also consist of non-precious material for low-cost products, in particular Chrome for white or black finishes, Tin and Nickel alloys and Tin and Cobalt alloys, colored or colorless, transparent or matte paints. In these cases, passing the tests is fundamentally determined by the final deposit, but if the underlay is resistant, there is still an improvement.

The first layer, if of white Bronze, can be any white Bronze. Preferably, and advantageously, the first layer of Bronze consists of a white Bronze alloy with composition that is variable between Sn 25-45%, Zn 0-15%, Pd 0.25-10%, Cu q.s. at 100% but in any case less than 60%, in accordance with what is described in patent application WO/2017/021916. The thickness of the first layer of Bronze is preferably variable from 0.5 microns to 10 microns, more preferably between 1 micron and 5 microns, even more preferably between 1.1 microns and 4 microns. The first layer if of Nickel-Cobalt-Phosphorus alloy, is a deposit preferably consisting of Co 1-70%, P 6-20%, Ni 10-90%, preferably Co 5-60%, P 8-18%, Ni 25-85, or alternatively preferably in accordance with that described in patent application WO 2017/182957 A1 "Phosphorous-Cobalt-Nickel alloy and use thereof in plating processes of non-precious metal objects with precious metals".

The thickness of the first layer of Nickel-Cobalt-Phosphorus alloy is preferably variable from 0.5 microns to 10 microns, more preferably between 0.75 microns and 6 microns, even more preferably between 1 micron and 3 microns.

The second layer made of an alloy according to the present invention, as described above, and preferably has a thickness that is variable between 0.1 microns and 4 microns, more preferably between 0.20 microns and 3 microns, even more preferably between 0.3 microns and 2.0 microns.

The second layer of Bronze with Platinum should be as close in color as possible to the final deposit of the object that determines the aesthetics thereof. Thanks to the colorimetric coordinates of the alloys as described above and the possibility of modulating them by varying the percentages of Pt, Pd, Sn and Zn, it is possible to adapt the coloring of the second layer of Bronze by virtue of the color of the outer layer.

The thickness of the final layer of precious metal depends on the thickness of the underlying Bronze with Platinum deposit subject of the invention and on the type of finish we wish to obtain. For high thicknesses of Bronze with Platinum and/or for glossy finishes, low thicknesses of precious metal are sufficient, while for low thicknesses of Bronze with Platinum and/or finishes that envisage tumbling on the finished object, greater thicknesses of precious metal are required. Tumbling can also be carried out on intermediate layers and in these cases the final thicknesses are treated as if the finish were glossy, so it is obvious that passing the tests is simplified compared to a final tumbling that could instead scratch the object in depth. The thickness may also depend on the hardness of the final deposit, in general, soft deposits such as those of Gold (about 100HV) require greater thicknesses, while harder deposits such as Palladium (about 600HV) require lower thicknesses.

In general, the thicknesses of precious metals can vary from Flash (lower than 0.05 microns) at 2 microns, more preferably from 0.1 microns to 1 .5 microns, even more preferably from 0.15 microns to 1 .0 microns.

A further subject of the present invention is a hypoallergenic galvanized object according to the invention wherein preferably said Nickel-Cobalt-Phosphorus alloy has the following composition:

Co 1-70%, preferably 5-60%; more preferably 7-40%;

P 6-20%, preferably 8-18%; more preferably 13-15%;

Ni 10-90%, preferably 25-85%; more preferably 45-80%.

Referring to Figure 1 , the hypoallergenic galvanized subject of the present invention preferably comprises: i. a base material; ii. one or more preparatory layers above the base material that depend on the base material used and the type of glossy or matte finish from which you want to start, said preparatory layers above the base material; iii. a first coating layer comprising or consisting of a deposit of hypoallergenic Nickel-Cobalt-Phosphorus alloy overlying the preparatory layer; said Nickel- Cobalt-Phosphorus alloy preferably having the following composition:

Co 1-70%, preferably 5-60%; more preferably 7-40%;

P 6-20%, preferably 8-18%; more preferably 13-15%;

Ni 10-90%, preferably 25-85%; more preferably 45-80%; iv. a second coating layer, overlying the first coating layer, consisting of a Sn-Cu- Pd/Pt bronze alloy; said bronze alloy having composition:

Sn 5-60%,

Cu q.s at 100%,

Pd 0-60%

Pt 0-60%

Zn 0-10%, where if Pd is not present Pt is present and vice versa; v. possibly, if the second layer does not have the desired color for the final finish, one or more final layers, composed of precious metals, non-precious metals or paints that determine the aesthetic appearance of the object, wherein optionally other Flash deposits can be interposed between the various layers.

Preferably the second coating layer has a composition:

Cu 15-30%, Sn 35-43% and Pd 35-42% having colorimetric coordinates L=80, a=2.8, b=8; or

Cu 20-30%, Sn 40-60%, Pd 4-16% and Pt 4-16% having colorimetric coordinates L=84, a=0.5, b=4.2; or

Cu 20-30%, Sn 45-65% Pt 10-30% having colorimetric coordinates L=84, a=0.5, b=3.8.

Preferably the first coating layer has a thickness of 1 -5 microns.

Preferably the second coating layer has a thickness of 0.5-1.5 microns.

The base material (i) and the respective preparatory layers (ii) are like the base material (a) and the preparatory layers (b) described above. In a preferred embodiment the base material (i) is brass and the overlying preparatory layer (ii) is acid copper.

In another preferred embodiment, the base material (i) is zamak and the preparatory layers (ii) are alkaline copper overlying the base material and acid copper overlying the alkaline copper.

Between the acid copper preparatory layer (ii) and the first Ni-Co-P coating layer (iii) there may be no other deposit, or a flash deposit may be interposed preferably consisting of Au, Pd, Pt, any Cu-Sn-Pd/Pt-(Zn) yellow/pink stainless alloy (including the one subject of the present invention) or other deposits recognized as suitable to provide greater adhesion and/or to create a barrier layer.

Between the first Ni-Co-P coating layer (iii) and the second Cu-Sn-Pd/Pt coating layer there may be no other deposit or a flash deposit may be interposed preferably consisting of Au, Pd, Pt or other deposits recognized as suitable to provide greater adhesion and/or to create a barrier layer.

Flash are low thickness deposits (<0.1 microns) used to improve the adhesion of the layers thanks to their stainlessness, which does not passivate them, and because they have particular affinities with the deposits they connect; they can also be useful for creating barrier layers against the intermetallic migration of metallic or other species.

The above cycles guarantee excellent resistance to tests (including the synthetic sweat test), important reduction of the finishing layers so that if the color between the finishing layer and CuSnPt and/or Pd alloy is the same, the finishing layer can be eliminated, vice versa in cases where the color does not match, the thickness of the finishing layer depends on the specifications of resistance to wear-off tests. They also guarantee a Ni release below the instrumental detection limit used by the regulations.

In cases where it is not necessary to pass the Synthetic Sweat test then it may be convenient to use the sequence of deposits shown in Fig. 2. In this embodiment, the hypoallergenic galvanized subject of the present invention has the first coating (iii) comprising a Ni-Co-P deposit on which an intermediate coating deposit consisting of a Cu-Sn-Zn or Cu-Sn-Zn-Pd white bronze stainless alloy (preferably as described in W02017/021916) having colorimetric coordinates L= 80-87, a= 0-2.5, b= 0-6 is superimposed. Flash deposits may be interposed between these coating layers.

In general, in galvanized objects, the use of a Ni-Co-P alloy (very resistant) allows the protection of the underlying oxidisable layers, guaranteeing high resistance for all those tests involving wear with Turbula before the oxidative test (this represents the most aggressive test specification currently implemented by fashion houses). However, using it as the only layer between the Copper layer that coats the base material, and the Finish, does not guarantee passing the Nickel release test, which is often passed but not always and not with certainty.

The applicant has found that if a Bronze deposit is inserted on top of the Ni-Co-P deposit, the galvanized object passes practically all the tests except for the Synthetic Sweat test (the acidity affects the bronze at the interphase with Ni-Co-P causing the deposit to delaminate). The Applicant has also found that if bronze is deposited under the Ni-Co-P deposit, an object that passes all tests but with no guarantee for Nickel release is instead obtained.

All galvanic cycles of the present invention shown above and in the figures guarantee good resistance to all tests, moreover, the thicknesses of the precious metals are considerably reduced and hence the costs, the production time is reduced and hence the costs, the total cyanide content in the products is reduced and hence the environmental impact of the process is reduced.

The present invention may be better understood in the light of the following example embodiments.

BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 shows the sequence of deposits of a hypoallergenic galvanized object according to the present invention;

Figure 2 shows a hypoallergenic galvanized object according to the present invention in a convenient embodiment when it is not necessary to pass the synthetic sweat test.

EXPERIMENTAL PART

EXAMPLE 1 - Preparation of a white alloy according to the invention The following electrolyte solution was prepared:

6 g/l Copper as Copper Cyanide 12 g/l Tin as Potassium or Sodium Stannate 0.2 g/l Zinc as Zinc Cyanide or Zinc Oxide 4.0 g/l Platinum as Cyanide complex 20 g/l Sodium or Potassium Carbonate 20 g/l Tetrasodium EDTA 40 g/l Potassium Cyanide 5 g/l Potassium hydroxide 50 ppm Sodium Laurylphosphate

A brass plate measuring 5 x 3.5 cm, on which a layer of copper had previously been deposited, was plated with the above described solution at 60°C for 10 minutes at a current of 1 .5 A/dmq.

The thickness of the deposit is equal to 0.6 microns.

By placing a drop of concentrated Nitric Acid on the deposit, no defect is formed. Under the SEM scanning electron microscope, the deposit shows a weight concentration of Platinum in the alloy of 25.2%.

The alloy deposited has the following composition:

Cu 25.3%

Sn 52.4%

Pt 22.3%

The Lab colorimetric coordinates measured with a CM-700d spectrophotometer brand KONICA MINOLTA SENSING, are: L= 84.1 , a=0.5, b=4.3

EXAMPLE 2 - Preparation of a yellow alloy according to the invention The following electrolyte solution was prepared:

8 g/l Copper as Copper Cyanide

4 g/l Tin as Potassium or Sodium Stannate

3 g/l Platinum as Ammonium tetrachloroplatinate complex

20 g/l Trisodium NTA

20 g/l Sodium or Potassium Carbonate

40 g/l Potassium Cyanide

10 g/l Potassium hydroxide

50 ppm Cocamidopropylbetaine A Brass plate measuring 5 x 3.5 cm, on which a layer of Copper had previously been deposited, was plated with the above described solution at 50°C for 15 minutes at a current of 1 .5 A/dmq.

The deposition thickness is equal to 1.2 microns.

Placing a drop of concentrated Nitric Acid on the plate immediately causes a brown zone to form where the acid is in contact with the deposit. However, the acid takes about 15 minutes to reach the attackable Copper layer. Under the SEM scanning electron microscope, the deposit shows a weight concentration of Platinum in the alloy of 18.1 %.

The alloy deposited has the following composition:

Cu 69.2%

Sn 11.3%

Zn 1.4 Pt 18.1 %

The Lab colorimetric coordinates measured with a CM-700d spectrophotometer brand KONICA MINOLTA SENSING, are: L= 82.5, a=4.7, b=16.6

EXAMPLE 3 - Preparation of a pink alloy according to the invention The following electrolyte solution was prepared:

8 g/l Copper as Copper Cyanide

6.5 g/l Tin as Potassium or Sodium Stannate

4 g/l Platinum as Ammonium tetrachloroplatinate complex

20 g/l Tetrasodium HEDP

20 g/l Sodium or Potassium Carbonate

45 g/l Potassium Cyanide

15 g/l Potassium hydroxide

50 ppm Cocamidopropylbetaine

A Brass plate measuring 5 x 3.5 cm, on which a layer of Copper had previously been deposited, was plated with the above described solution at 55°C for 10 minutes at a current of 1 .0 A/dmq.

The deposition thickness is equal to 0.98 microns. Placing a drop of concentrated Nitric Acid on the plate causes a brown zone to form where the acid is in contact with the deposit after 1min and 30 seconds. However, the acid takes about 30 minutes to reach the attackable Copper layer. Under the SEM scanning electron microscope, the deposit shows a weight concentration of Platinum in the alloy of 35.5%.

The alloy deposited has the following composition:

Cu 50.1%

Sn 14.4%

Pt 35.5% The Lab colorimetric coordinates measured with a CM-700d spectrophotometer brand KONICA MINOLTA SENSING, are: L= 78.7, a=3.1, b=11.2

EXAMPLE 4 (Comparative)

Sixteen Brass Belt Buckles have been electroplated according to a standard galvanic cycle containing Nickel with the following galvanic layers:

The objects were then subjected to the following tests after performing the TURBULA ISO 23160:2011 wear test at both 3 and 30 minutes as a pre-treatment: Table 1

The objects pass all the tests they have been subjected to.

In addition, the TURBULA wear test used as a pre-treatment showed no significant variation in color due to wear of the objects at either 3 minutes or 30 minutes. On the thirteenth Buckle, the wear test was pushed up to 120 minutes and resulted in a marked uncovering of the deposit, especially on the edges of the piece, with a clear difference in color between the yellow of the Gold and the white of the Nickel underneath.

The three remaining Buckles have been tested for Nickel Release after wear (UNI EN 12472 - UNI EN 1811). The results (4.51 pg/cm²week, 1.73 pg/cm²week, 3.88 pg/cm²week) are all negative, exceeding the limit of 0.88 pg/cm²week.

EXAMPLE 5 (Comparative)

Sixteen Brass Belt Buckles, like those used in example 4, have been electroplated with the following galvanic layers:

The objects were then subjected to the tests shown in Table 1 after performing the TURBULA ISO 23160:2011 wear test at both 3 and 30 minutes as a pre-treatment. The objects only pass the Thioacetamide test with Turbula pre-treatment 3 minutes, the Synthetic sweat test at 3 and 30 minutes and none of the other tests to which they were subjected.

The TURBULA wear test used as a pre-treatment showed no significant variation in color due to wear of the objects at either 3 minutes or 30 minutes. On the thirteenth Buckle, the wear test was pushed up to 120 minutes and resulted in a marked uncovering of the deposit, especially on the edges of the piece, with a clear difference in color between the yellow of the Gold and the white of the White Bronze underneath. The three remaining Buckles have been tested for Nickel Release after wear (UNI EN 12472 - UNI EN 1811). The results are all positive with a value below the LoD (Limit of Detection).

EXAMPLE 6 (Comparative)

The objects were then subjected to the tests in Table 1 after performing the TURBULA ISO 23160:2011 wear test at both 3 and 30 minutes as a pre-treatment. The objects do not pass any of the tests they have been subjected to.

The TURBULA wear test used as a pre-treatment showed no significant variation in color due to wear of the objects at either 3 minutes or 30 minutes. On the thirteenth Buckle, the wear test was pushed up to 120 minutes while maintaining the color unchanged thanks to the presence of the yellow Bronze under the Gold deposit. The three remaining Buckles have been tested for Nickel Release after wear (UNI EN 12472 - UNI EN 1811). The results are all positive with a value below the LoD (Limit of Detection).

EXAMPLE 7 (Comparative) Sixteen Brass Belt Buckles, like those used in example 4, have been electroplated with the following galvanic layers:

The objects were then subjected to the tests in Table 1 after performing the TURBULA ISO 23160:2011 wear test at both 3 and 30 minutes as a pre-treatment. The objects pass the Sulfur Dioxide Oxidation, Thioacetamide, Humic Heat with wear pre-treatment with Turbula 3 and Synthetic Sweat with wear pre-treatment with Turbula both at 3 and 30 minutes while they do not pass SO2/NO_X OXIDATION and Humic Heat with Skin under UNI ISO 4611:2011 with wear pre-treatment with Turbula 3 minutes nor all the other tests after wear pre-treatment at 30 minutes. The TURBULA wear test used as a pre-treatment showed no significant variation in color due to wear of the objects at either 3 minutes or 30 minutes. On the thirteenth Buckle, the wear test was pushed up to 120 minutes and resulted in a marked uncovering of the deposit, especially on the edges of the piece, with a clear difference in color between the yellow of the Gold and the white of the White Bronze underneath. The three remaining Buckles have been tested for Nickel Release after wear (UNI EN 12472 - UNI EN 1811). The results are all positive with a value below the LoD (Limit of Detection). EXAMPLE 8 (Comparative)

The objects were then subjected to the tests in Table 1 after performing the TURBULA ISO 23160:2011 wear test at both 3 and 30 minutes as a pre-treatment. The objects pass all tests following the 3-minute wear pre-treatment, while those with a 30-minute wear pre-treatment with Turbula pass only Sulfur Dioxide Oxidation, Thioacetamide, Damp Heat and Synthetic Sweat.

The TURBULA wear test used as a pre-treatment showed no significant variation in color due to wear of the objects at either 3 minutes or 30 minutes. On the thirteenth Buckle, the weariest was pushed up to 120 minutes and resulted again in a marked uncovering of the deposit, especially on the edges of the piece, with a clear difference in color between the yellow of the Gold and the white of the Palladium. The three remaining Buckles have been tested for Nickel Release after wear (UNI EN 12472 - UNI EN 1811). The results are all positive with a value below the LoD (Limit of Detection). EXAMPLE 9 - second coating with a yellow alloy of the invention

The TURBULA wear test used as a pre-treatment showed no significant variation in color due to wear of the objects at either 3 minutes or 30 minutes. On the thirteenth Buckle, the wear test was pushed up to 120 minutes while maintaining the color unchanged thanks to the presence of the yellow Bronze subject of this invention under the Gold deposit. The three remaining Buckles have been tested for Nickel Release after wear (UNI EN 12472 - UNI EN 1811). The results are all positive with a value below the LoD (Limit of Detection).

EXAMPLE 10 - second coating with a yellow alloy of the invention Sixteen Brass Belt Buckles, like those used in example 4, have been electroplated with the following galvanic layers:

The objects were then subjected to the tests in Table 1 after performing the TURBULA ISO 23160:2011 wear test at both 3 and 30 minutes as a pre-treatment. The objects pass all tests both following the 3-minute and 30-minute wear pre treatment. The tests of S02/NOx OXIDATION Internal Method and Humic Heat with Skin under UNI ISO 4611:2011 after pre-treatment with 30 minutes of TURBULA show some small oxidation points which, however, do not affect the positive result of the test. The TURBULA wear test used as a pre-treatment showed no significant variation in color due to wear of the objects at either 3 minutes or 30 minutes. On the thirteenth Buckle, the wear test was pushed up to 120 minutes while maintaining the color unchanged thanks to the presence of the yellow Bronze subject of this invention under the Gold deposit. The three remaining Buckles have been tested for Nickel Release after wear (UNI EN 12472 - UNI EN 1811). The results are all positive with a value below the LoD (Limit of Detection).

EXAMPLE 11 - second coating with a pink alloy of the invention Sixteen Brass Belt Buckles, like those used in example 4, have been electroplated with the following galvanic layers:

The objects were then subjected to the tests in Table 1 after performing the TURBULA ISO 23160:2011 wear test at both 3 and 30 minutes as a pre-treatment. The objects pass all tests both following the 3-minute and 30-minute wear pre treatment. The tests of S02/NOx OXIDATION Internal Method and Humic Heat with Skin under UNI ISO 4611:2011 after pre-treatment with 30 minutes of TURBULA show some small oxidation points which, however, do not affect the positive result of the test. The TURBULA wear test used as a pre-treatment showed no significant variation in color due to wear of the objects at either 3 minutes or 30 minutes. On the thirteenth Buckle, the wear test was pushed up to 120 minutes while maintaining the color unchanged thanks to the presence of the pale pink deposit of the Pink Bronze alloy subject of this invention under the light Gold deposit. The three remaining Buckles have been tested for Nickel Release after wear (UNI EN 12472 - UNI EN 1811). The results are all positive with a value below the LoD (Limit of Detection). EXAMPLE 12 - second coating with a white alloy of the invention

The objects were then subjected to the tests in Table 1 after performing the TURBULA ISO 23160:2011 wear test at both 3 and 30 minutes as a pre-treatment. The objects pass all tests both following the 3-minute and 30-minute wear pre treatment. The tests of S02/NOx OXIDATION Internal Method and Humic Heat with Skin under UNI ISO 4611:2011 after pre-treatment with 30 minutes of TURBULA show some small oxidation points which, however, do not affect the positive result of the test.

The TURBULA wear test used as a pre-treatment showed no significant variation in color due to wear of the objects at either 3 minutes or 30 minutes. On the thirteenth Buckle, the wear test was pushed up to 120 minutes while maintaining the color unchanged thanks to the presence of the white alloy subject of this invention under the Palladium-Nickel deposit. The three remaining Buckles have been tested for Nickel Release after wear (UNI EN 12472 - UNI EN 1811). The results are all positive with a value below the LoD (Limit of Detection).

EXAMPLE 13 - second coating with a white alloy of the invention Sixteen Brass Belt Buckles, like those used in example 4, have been electroplated with the following galvanic layers:

The objects were then subjected to the tests in Table 1 after performing the TURBULA ISO 23160:2011 wear test at both 3 and 30 minutes as a pre-treatment. The objects pass all tests both following the 3-minute and 30-minute wear pre treatment. The tests of S02/NOx OXIDATION Internal Method and Humic Heat with Skin under UNI ISO 4611:2011 after pre-treatment with 30 minutes of TURBULA show some small oxidation points which, however, do not affect the positive result of the test. The TURBULA wear test used as a pre-treatment showed no significant variation in color due to wear of the objects at either 3 minutes or 30 minutes. On the thirteenth Buckle, the wear test was pushed up to 120 minutes while maintaining the color unchanged thanks to the presence of the white alloy subject of this invention under the Palladium-Nickel deposit. The three remaining Buckles have been tested for Nickel Release after wear (UNI EN 12472 - UNI EN 1811). The results are all positive with a value below the LoD (Limit of Detection).

EXAMPLE 14 - second coating with a white alloy of the invention Sixteen Brass Belt Buckles, like those used in example 4, have been electroplated with the following galvanic layers:

The objects were then subjected to the tests shown in Table 1 after performing the TURBULA ISO 23160:2011 wear test at both 3 and 30 minutes as a pre-treatment. The objects pass all tests both following the 3-minute and 30-minute wear pre treatment.

The TURBULA wear test used as a pre-treatment showed no significant variation in color due to wear of the objects at either 3 minutes or 30 minutes. On the thirteenth Buckle, the wear test was pushed up to 120 minutes while maintaining the color unchanged thanks to the presence of the white alloy subject of this invention under the Palladium-Nickel deposit.

The three remaining Buckles have been tested for Nickel Release after wear (UNI EN 12472 - UNI EN 1811). The results are all positive with a value below the LoD (Limit of Detection). EXAMPLE 15 - second coating with a white alloy of the invention Sixteen Brass Belt Buckles, like those used in example 4, have been electroplated with the following galvanic layers:

The three remaining Buckles have been tested for Nickel Release after wear (UNI EN 12472 - UNI EN 1811). The results are all positive with a value below the LoD (Limit of Detection).

EXAMPLE 16 - second coating with a yellow alloy of the invention

The objects were then subjected to the tests shown in Table 1 after performing the TURBULA ISO 23160:2011 wear test at both 3 and 30 minutes as a pre-treatment. The objects pass all tests both following the 3-minute and 30-minute wear pre- treatment.

The TURBULA wear test used as a pre-treatment showed no significant variation in color due to wear of the objects at either 3 minutes or 30 minutes. On the thirteenth Buckle, the wear test was pushed up to 120 minutes while maintaining the color unchanged thanks to the presence of the yellow alloy deposit subject of this invention under the Gold deposit.

EXAMPLE 17 - second coating with a yellow alloy of the invention Sixteen Brass Belt Buckles, like those used in example 4, have been electroplated with the following galvanic layers:

The objects were then subjected to the tests shown in Table 1 both before and after performing the TURBULA ISO 23160:2011 wear test at both 3 and 30 minutes as a pre-treatment. The objects pass all tests both before and after the 3-minute and 30-minute wear pre-treatment despite the very aggressive final step of tumbling in urea cones.

The three remaining Buckles have been tested for Nickel Release after wear (UNI EN 12472 - UNI EN 1811). The results are all positive with a value below the LoD (Limit of Detection). EXAMPLE 18 - second coating with a white alloy of the invention

The following electrolyte solution was prepared:

4 g/l Copper as Copper Cyanide 6 g/l Tin as Potassium Stannate 0.5 g/l Zinc as Zinc Cyanide or Zinc Oxide 2.0 g/l Platinum as Cyanide complex 0.2 g/l Palladium as Palladium Tetramine Sulphate 20 g/l Potassium Carbonate 20 g/l Tetrasodium HEDP 20 g/l Potassium Cyanide

1 g/l Potassium hydroxide 50 ppm Sodium Laurylphosphate 100 ppm Sodium Saccharinate

The thus formulated bath was used at 60°C and 1 A/dm2 to deposit the second coating shown in the table below, taking 7 minutes to reach an average thickness of 1 micron.

The TURBULA wear test used as a pre-treatment, showed no significant variation in color due to wear of the objects at 3 minutes while at 30 minutes and even more markedly on the eleventh buckle on which the wear test was prolonged up to 120 minutes while maintaining the color unaltered thanks to the presence of the white alloy deposit of the subject of the present invention under the Palladium-Nickel deposit.

EXAMPLE 19 - second coating with a white alloy of the invention The following electrolyte solution was prepared:

2 g/l Copper as Copper Cyanide

15 g/l Tin as Potassium Stannate

2.0 g/l Platinum as Cyanide complex

0.1 g/l Palladium as Palladium Tetramine Sulphate

20 g/l Potassium Carbonate

40 g/l Tetrasodium HEDP

12 g/l Potassium Cyanide

6 g/l Potassium hydroxide

The thus formulated bath was used at 60°C and 1.5 A/dm2 to deposit the second coating shown in the table below, taking 3 minutes to reach an average thickness of 0.5 micron.

The three remaining Buckles have been tested for Nickel Release after wear (UNI EN 12472 - UNI EN 1811). The results are all positive with a value below the LoD (Limit of Detection). EXAMPLE 20 - second coating with a white alloy of the invention

The three remaining Buckles have been tested for Nickel Release after wear (UNI EN 12472 - UNI EN 1811). The results are all positive with a value below the LoD (Limit of Detection). EXAMPLE 21 - second coating with a Cu-Sn-Pd white alloy and first Ni-Co-P coating Sixteen Brass Belt Buckles, like those used in example 4, have been electroplated with the following galvanic layers:

The TURBULA wear test used as a pre-treatment showed no significant variation in color due to wear of the objects at 3 minutes while it showed difference in color between the pink deposit and the white Palladium-Nickel deposit at both 30 and 120 minutes. The three remaining Buckles have been tested for Nickel Release after wear (UNI EN 12472 - UNI EN 1811 ). The results are all positive with a value below the LoD (Limit of Detection).

EXAMPLE 22 - second coating with a white alloy of the invention and electroplating cycles as in fig. 2

The objects were then subjected to the tests shown in Table 1 after performing the TURBULA ISO 23160:2011 wear test at both 3 and 30 minutes as a pre-treatment. The objects pass all tests following the wear pre-treatment at both 3 minutes and 30 minutes except for the Synthetic Sweat test.

The three remaining Buckles have been tested for Nickel Release after wear (UNI EN 12472 - UNI EN 1811). The results are all positive with a value below the LoD (Limit of Detection). EXAMPLE 23 - second coating with a white alloy of the invention used as a final layer.

The objects were then subjected to the tests shown in Table 1 after performing the TURBULA ISO 23160:2011 wear test at both 3 and 30 minutes as a pre-treatment. The objects pass all tests following the wear pre-treatment at both 3 minutes and those at 30 minutes. The TURBULA wear test used as a pre-treatment showed no significant variation in color due to wear of the objects at either 3 minutes, 30 minutes or 120 minutes.

The three remaining Buckles have been tested for Nickel Release after wear (UNI EN 12472 - UNI EN 1811). The results are all positive with a value below the LoD (Limit of Detection). EXAMPLE 24 (comparative) - second coating with a Nickel-Cobalt-Phosphorus alloy Sixteen Brass Belt Buckles, like those used in example 4, have been electroplated with the following galvanic layers:

The objects were then subjected to the tests shown in Table 1 after performing the TURBULA ISO 23160:2011 wear test at both 3 and 30 minutes as a pre-treatment. The objects pass all tests following the wear pre-treatment at both 3 minutes and those at 30 minutes.

The TURBULA wear test used as a pre-treatment showed no significant variation in color due to wear of the objects at either 3 minutes, 30 minutes or 120 minutes.

The three remaining Buckles have been tested for Nickel Release after wear (UNI EN 12472 - UNI EN 1811). Two of the results are all negative, exceeding the limit of 0.88 pg/cm²week, while the third is just below the legal limit (1.21 pg/cm²week, 3.42 pg/cm²week and 0.44 pg/cm²week).

Table 2 below summarises the results of the examples 4-24 described above:

Table 2.1

Table 2.2

Table 2.3

Table 2.5

Table 2.6

Table 2.7

EXAMPLE 25(Scale-uo)

A galvanic bath, formulated like in example 1 , with a volume of 200 litres was used to perform a scale-up from laboratory volumes (0.5-1 litre) to the classic production volumes for the type of application for which the bath was designed. 24 belt buckles, with a unit surface equal to 0.7dm², were mounted on two rod frames with clamp disks and blocked onto the bridge by means of the clamp contacts of the frame. The two frames were simultaneously galvanized according to the following galvanic cycle:

The galvanic bath subject of the invention was heated to 60°C and the two frames were simultaneously galvanized by applying a current of 18A corresponding to about 1A/dm² (2.3V average) for a time equal to 16 minutes.

At the end of the galvanic cycle, the buckles were dried and sorted according to their position on the frame. As the two frames are the same and are loaded with the same number of buckles, it follows that each disc of the four that make up each frame contains 4 positions of clamps, so starting from the top there are 4 buckles per frame, thus 8 buckles that have been subjected to very similar conditions. In particular, taking into account the potential drop on the frame and the peak effect of the electric charge, the 24 buckles can be divided into 3 groups of 8 as follows: * 8 buckles in areas of low current density

• 8 buckles in areas of medium current density

• 8 buckles in areas of high current density One buckle per group was subjected to metallographic cutting for thickness analysis and quantitative and qualitative elemental analysis using a SEM Carl Zeiss' EVO MA10 scanning electron microscope with Lanthanum Hexaboride filament.

The results are shown in the tables below: Low current density

Medium current density

High current density

For each group of buckles, 6 buckles were chosen and subjected to the tests in Table 1 after having carried out the TURBULA ISO 23160: 2011 wear test at 30 minutes as a pre-treatment. The remaining two from each group were tested for Nickel Release after Wear.

The objects pass all the tests they have been subjected to. In addition, the TURBULA wear test used as a pre-treatment showed no significant variation in color due to wear of the objects.

Claims

1. An electroplated alloy having colorimetric coordinates: L=76-86, a=0-6, b=2.5-19 and containing:

Pt 5-60%;

Sn 5-60%;

Cu q.s at 100%;

Pd 0-25%

Zn 0-10%; wherein the overall concentration Pt+Sn+Pd+Zn is 20-85% and the overall concentration Pt+Pd is 5-60%; where the % are by weight calculated on the total weight of the alloy.

2. The alloy according to claim 1 further containing one or more other metals in a total amount lower than 10% and whose % added to the % Pt+Sn+Zn remains between 20-85%; wherein said one or more other metals are selected from the group consisting of Indium, Gallium, Germanium, Silver, Iridium, Ruthenium, Rhodium. Gold, Molybdenum, Tungsten and Rhenium.

3. The alloy according to any one of the preceding claims further comprising traces of brightening or grain finishing metals, where traces are meant quantities lower than 0.25% by weight on the alloy and for brightening or grain finishing metals are meant those normally used for this purpose in this field of activity, preferably chosen from the group consisting of Bismuth, Tellurium, Molybdenum, Thallium, Antimony, Selenium and Lead.

4. The alloy according to any one of the preceding claims having a yellow hue of colorimetric coordinates L=80-86, a=4-6, b=12.5-19 and comprising:

Sn 5-25%; preferably 6-15%;

Pt 15-30%; preferably 17-25%;

Pd 0-15%; preferably 0-10%;

Zn 0-10% preferably 0-7%;

Cu q.s at 100 and greater than 65%; where Sn+Pt+Zn is at most 35% and Pt+Pd is at most 30%.

5. The alloy according to any one of claims 1 -3 having a pink hue of colorimetric coordinates L=76-82, a=2-5, b=8-12 and comprising:

Sn 5-35%; preferably 8-20%;

Pt 20-50%; preferably 25-45%;

Pd 0-25%; preferably 0-20%;

Zn 0-10%; preferably 0-7%;

Cu 45-65%; preferably 48-62%; where Sn+Pd+Zn is at most 55% and Pt+Pd is 50%.

6. The alloy according to any one of claims 1-3 having a white hue of colorimetric coordinates L=82-86, a=0.2-1.5, b=2.5-5.5 and comprising:

Sn 5-60%; preferably 25-60%;

Pt 5-60%; preferably 6-45%;

Pd 0-35%; preferably 0-25%;

Zn 0-10%; preferably 0-7%;

Cu q.s.at 100 and less than 45%; preferably less than 40%; where Sn+Pd+Zn is at least 55% and Pt+Pd is at most 60%.

7. A solution for the electroplating of an alloy according to any of the preceding claims, said solution comprising

Cu in solution in a concentration 0.2-20 g/l;

Sn in solution in concentration 2-30 g/l;

Pt in solution in a concentration 0.05-8 g/l;

Pd, if present, in solution in a concentration of 0.05-8 g/l;

Zn, if present, equal to 0.05-10 g/l;

Free cyanide in concentration 1-100 g/l.

8. The solution according to claim 7 further comprising one or more other metals are selected from the group consisting of Indium, Gallium, Germanium, Silver, Iridium, Ruthenium, Rhodium. Gold, Molybdenum, Tungsten and Rhenium; and/or brighteners and grain finishers, preferably Bismuth, Tellurium, Molybdenum, Thallium, Antimony, Selenium and Lead, organic compounds such as Heterocycliaromatics, Non-aromatic Heterocycles, condensed cycles and heterocycles for example Nicotinamide, Sodium Saccharinate as well as reaction products between Epichlorohydrin and organic substances having amino and hydroxyl groups and/or one or more complexing agents, preferably selected from the group consisting of Nitrilotriacetic acid (NTA), ethylenediaminetetraacetic acid (EDTA), ethylenetriaminopentacetic acid (DTPA), salts Phosphonates of alkali metal derivatives or salts of polyhydroxylated organic substances; and/or surfactants and surfactant mixtures, preferably selected from the group consisting of bathers from the family of Alkyl ethers Phosphonates, Alkyl ethers Sulfonates, Alkylaryl polyol ethoxylates and the related sulphonated derivatives, quaternary ammonium salts of alkanes or aromatic compounds.

9. A process for the electroplating of an alloy according to any one of claims 1 - 6, said process comprising: immersing an object on which to electroplate the alloy in a galvanic solution according to any one of claims 7-8; and apply a current of 0.5-3.0 A/dmq for a time of 1 -20 min at a temperature of 30-70 °C.

10. A galvanized object comprising at least one deposit consisting of an alloy according to any one of claims 1 -6.

11 . The galvanized object according to claim 10 comprising or consisting of a) a base material; b) a preparatory layer which depends on the base material used, said preparatory layer deposited on top of the base material; c) a first coating layer consisting of white bronze and/or a deposit of hypoallergenic Nickel-Cobalt-Phosphorus alloy deposited over the preparatory layer so that it protects the base material and the underlying layers which are easily oxidized; this in the case of Nickel-free and hypoallergenic cycles respectively; d) a second coating layer consisting of an alloy according to any of claims 1-6 whose color is preferably as close as possible to the color that determines the final aesthetics of the object; e) possibly, if the second layer does not have the appropriate color for the final finish, a final layer, composed of precious metals, non-precious metals or paints which determines the aesthetic appearance of the object.

12. The galvanized object according to claim 11 wherein the final layer e) has a thickness of 0-0.2 microns.

13. A hypoallergenic galvanized object comprising: a first coating layer comprising or consisting of a deposit of hypoallergenic Nickel- Cobalt-Phosphorus alloy overlying the preparatory layer so that it protects the base material and the underlying layers which are easily oxidized; a second coating layer, overlying the first coating layer, consisting of a Sn-Cu-Pd/Pt alloy having composition:

Sn 5-60%,

Cu q.s at 100%,

Pd 0-60%

Pt 0-60%

14. The hypoallergenic galvanized object according to claim 13 wherein said Nickel-Cobalt-Phosphorus alloy has the following composition:

Co 1-70%, preferably 5-60%;

P 6-20%, preferably 8-18%;

Ni 10-90%, preferably 25-85%.

15. The hypoallergenic galvanized object according to any of claims 13-14 wherein the second coating layer has a composition:

Cu 15-30%, Sn 35-43% and Pd 35-42%; or

Cu 20-30%, Sn 40-60%, Pd 4-16% and Pt 4-16%; or

Cu 20-30%, Sn 45-65% and Pt 10-30%.

16. The hypoallergenic galvanized object according to any one of claims 13-15 comprising: i. a basic material; ii. one or more preparatory layers above the base material that depend on the base material used and the type of glossy or matte finish from which you want to start, said preparatory layers above the base material; iii. a first coating layer comprising or consisting of a deposit of hypoallergenic Nickel-Cobalt-Phosphorus alloy overlying the preparatory layer; said Nickel- Cobalt-Phosphorus alloy having the composition as indicated in claim 14: iv. a second coating layer, overlying the first coating layer, consisting of a Sn-Cu- Pd/Pt bronze alloy; said bronze alloy having composition as indicated in claim 13 or 15: v. possibly, if the second layer does not have the desired color for the final finish, one or more final layers, composed of precious metals, non-precious metals or paints that determine the aesthetic appearance of the object.

17. The hypoallergenic galvanized object according to any one of claims 13-16 wherein an intermediate coating layer consisting of a bronze alloy is interposed between the first Ni-Co-P coating and the second Cu-Sn-Pd/Pt coating layer white Cu-Sn-Zn or Cu-Sn-Zn-Pd inox.

18. The object according to any of claims 10-17 which is included in a product class belonging to the group consisting of jewelery, costume jewelery, leather goods, clothing, small parts, watchmaking, eyewear, decorative plating, trinkets, closures, caps/perfume packages.