CN1678768A - Method of treatment for reducing elution of lead from lead containing copper alloy and waterwork utensils made from lead containing copper alloy - Google Patents

Abstract

A method of treatment for reducing the elution of lead from a lead-containing copper alloy, characterized in that it comprises immersing the lead-containing copper alloy in an acidic solution which is free of chromic acid and contains a phosphoric acid or its derivative, to remove the lead in a surface portion thereof; and waterwork utensils made of a lead-containing copper alloy and treated by the method. The utensils having been treated by the method exhibit satisfactorily effective reduction in the elution of lead, and also are free from significant discoloration and from the reduction of its commercial value due to discoloration since only a little etching takes place owing to an acidic phosphoric acid or its derivative and only a fine phosphate film is formed. Further, sodium chloride may be added, the lead-containing copper alloy may be, in advance, immersed in an alkaline etching fluid, to remove the lead in a surface portion thereof, and the outer surface of the alloy may have been plated with a metal such as nickel-chromium.

Description

Lead-containing copper alloy treatment method for reducing lead leaching and plumbing appliance made of lead-containing copper alloy

technical field

The present invention relates to a treatment method for reducing lead leaching in order to reduce lead leaching from lead-containing copper alloys, and a plumbing appliance made of lead-containing copper alloy with reduced lead leaching.

Appliances for water pipelines are faucet accessories, water pipeline instruments, water heater components, warm water washing toilet components, water boilers, water heaters, water coolers, ice machines, water purifiers, warm water boilers, vending machines, ball faucets, Small containers, valves, overflow valves, heat exchangers, joints, water supply and hot water tanks, pipes, drain tables, washstands, toilets, baths, parts of domestic equipment, etc., including all appliances connected to water supply pipes.

Background technique

In the past, water pipe fittings, such as faucets, were generally cast or forged from copper alloy materials such as copper, bronze, and brass, and then processed by cutting, grinding, etc., and performing various processes such as nickel-chrome plating, painting, and ion plating. This kind of surface treatment is manufactured through the final product assembly process. For the above-mentioned copper alloys, in order to improve machinability such as machinability, lead is added to the billet in many cases. Therefore, this lead dissolves in a small amount into drinking water. When drinking this water for a long time, it may have adverse effects on the human body. In recent years, there is concern about this. question.

In Patent No. 3182765, the present inventor focused on the form of existence of lead and its physical properties and published the invention: by immersing lead-containing copper alloy in alkaline corrosion solution, chromic acid solution, and chromate solution, large Significantly reduce the dissolution of lead.

Among the methods for reducing lead elution described in Patent No. 3182765, it was announced that in the chromate treatment method, when a lead-containing copper alloy is immersed in a solution containing both chromic acid and phosphoric acid, the lead-containing copper alloy is reduced. In terms of lead dissolution, it is the most effective. However, when a lead-containing copper alloy is dipped in the chromate solution, the appearance of the dipped copper alloy part becomes whitish and dull discolored appearance, which tends to lower the commercial value. This is because a colored film is formed on the surface of the copper alloy by the phosphorochromate treatment containing chromic acid and phosphoric acid.

The present invention was made in order to solve the above-mentioned problems, and an object of the present invention is to provide a treatment method for reducing lead leaching of lead-containing copper alloys and a plumbing appliance made of lead-containing copper alloys without lowering commercial value due to discoloration of the appearance.

Contents of the invention

In order to achieve the above object, item 1 of the present invention is a treatment method for reducing lead leaching of lead-containing copper alloys, which is characterized in that the lead-containing copper alloy is immersed in an acidic solution that does not contain chromic acid but contains phosphoric acid compounds in the solution. , to remove the lead on the surface.

Therefore, due to the slight corrosion effect of the acidic phosphoric acid compound and the formation of only a slight phosphoric acid film, there is no large discoloration and no reduction in commercial value. In addition, it is also sufficiently effective in reducing lead elution.

In order to achieve the above object, item 2 of the present invention is a treatment method for reducing the dissolution of lead-containing copper alloy, which is characterized in that the lead-containing copper alloy is immersed in a solution that does not contain chromic acid but contains a phosphoric acid compound and sodium chloride in acidic solution.

Therefore, adding an appropriate amount of sodium chloride to the acidic phosphoric acid compound can improve the progress of the reaction, ensure the corrosion effect, and increase the phosphoric acid coating to ensure a stable appearance. Nor does it reduce the value of the product. In addition, it is also sufficiently effective in reducing lead elution.

In order to achieve the above object, item 3 of the present invention is a treatment method for reducing lead leaching of lead-containing copper alloys, which is characterized in that the lead-containing copper alloy is immersed in an alkaline corrosive solution to remove the lead on the surface, and then dipped In an acidic solution that does not contain chromic acid but contains phosphoric acid compounds.

Therefore, firstly, by immersing in an alkaline etching solution, the lead on the surface of the copper alloy can be roughly selectively removed, so it is compatible with the subsequent process of immersion in an acidic solution containing no chromic acid but a phosphoric acid compound in the solution to reduce the dissolution of lead. The effects complement each other, and a more sufficient effect can also be seen regarding the reduction of lead elution. In addition, after these steps, due to the slight corrosion effect of the acidic phosphoric acid compound and only a slight phosphoric acid film is formed, the lead-containing copper alloy is not accompanied by large discoloration and does not reduce the commercial value.

In order to achieve the above object, item 4 of the present invention is a treatment method for reducing the leaching of lead-containing copper alloy, which is characterized in that the lead-containing copper alloy is immersed in an alkaline corrosive solution to remove the lead on the surface, and then dipped In an acidic solution that does not contain chromic acid but contains phosphoric acid compounds and sodium chloride in the solution.

Therefore, firstly, by immersing in an alkaline etching solution, the lead on the surface of the copper alloy can be roughly selectively removed. Therefore, it is different from the subsequent step of immersing in an acidic solution that does not contain chromic acid but contains a phosphoric acid compound and sodium chloride. The effects of reducing the elution of lead complement each other, and a more sufficient effect is also seen for the reduction of elution of lead. In addition, after these steps, by adding an appropriate amount of sodium chloride to the acidic phosphoric acid compound, the progress of the reaction can be improved, the corrosion effect can be ensured, and the phosphoric acid coating can be increased to ensure a stable appearance. Nor does it reduce the value of the product. In addition, it is also sufficiently effective in reducing lead elution.

In order to achieve the above object, item 5 of the present invention is a treatment method for reducing lead leaching of lead-containing copper alloys according to items 1 and 3 of the invention, which is characterized in that the outer surface is mainly treated by plating, and the unplated surface is removed. Lead applied mainly on internal surfaces.

Therefore, the plated portion of the outer surface does not cause a dissolution reaction and a corrosion reaction in the above-mentioned immersion step of the alkaline etching solution and the immersion step of an acidic solution containing a phosphoric acid compound but not containing chromic acid in the solution, Therefore, discoloration does not occur, and the effect of reducing the elution of lead can be achieved only on the main inner surface where the lead-containing copper alloy is exposed without plating. Of course, the internal surface will not be accompanied by large discoloration due to the slight corrosion effect of the acidic phosphoric acid compound and only a slight phosphoric acid film is formed.

In order to achieve the above object, item 6 of the present invention is a treatment method for reducing lead leaching of lead-containing copper alloys according to item 3 of the invention, which is characterized in that the plating on the outer surface is mainly carried out after nickel plating. of plating.

Lead-containing copper alloy plumbing appliances such as faucet fittings are often plated with chrome after nickel plating in order to impart decorative properties, corrosion resistance, and abrasion resistance to the exterior surface, and this plating has been widely used in the past. In the case of this plating, since no dissolution reaction and corrosion reaction are caused in the above-mentioned immersion step of the alkaline etching solution and the immersion step of the acidic solution containing a phosphoric acid compound, discoloration does not occur, and it can be realized that only the untreated Plating treatment so that the lead-containing copper alloy exposes the major internal surfaces reduces the effect of lead leaching. Of course, since there is only a little corrosion effect of the acidic phosphoric acid compound and only a slight phosphoric acid film is formed on the inner surface, it will not be accompanied by a large discoloration.

In order to achieve the above object, the seventh aspect of the present invention is the lead-containing copper alloy plumbing appliance according to the first to sixth inventions, which is immersed in an acidic solution containing a phosphoric acid compound.

Therefore, due to the slight corrosion effect of the acidic phosphoric acid compound and the formation of only a slight phosphoric acid film, it is not accompanied by large discoloration of the copper alloy surface containing lead, and it has a sufficient effect on reducing the dissolution of lead, so it is possible to provide unreduced products. Valuable plumbing appliances.

A brief description of the drawings

Fig. 1 is a diagram showing a faucet fitting made of bronze casting used in an example of the present invention.

Fig. 2(a) is an enlarged photo of the surface of a water pipe appliance made of a lead-containing copper alloy before the lead-containing copper alloy of the present invention is treated to reduce lead elution, and Fig. 2(b) is a cross-sectional photo thereof.

Fig. 3(a) is an enlarged photo of the surface of a water pipe appliance made of a lead-containing copper alloy after the lead-containing copper alloy of the present invention has been treated to reduce lead elution, and Fig. 3(b) is a cross-sectional photo thereof.

BEST MODE FOR CARRYING OUT THE INVENTION

By immersing in the acidic solution containing phosphoric acid compound but not containing chromic acid in the solution of the present invention, due to a little corrosion effect on the surface of the lead-containing copper alloy and the formation of a slight phosphoric acid film, it not only has a great effect on reducing the dissolution of lead The reduction effect, and there is no major discoloration in appearance. This is because the coating of phosphoric acid alone is colorless while the mixed coating of chromium and phosphorus is slightly colored.

By adding an appropriate amount of active agent sodium chloride to the acidic solution containing phosphoric acid compound but not containing chromic acid in the solution of the present invention, the progress of the reaction is improved, the corrosion effect and the formation of a small phosphoric acid film are increased, and a stable appearance can be ensured. .

The active agent includes sodium chloride, sodium sulfate, sodium fluoride, sodium nitrate, etc., and the addition amount is about 0.1-10g/L, often added alone or several kinds.

Phosphoric acid compounds include potassium phosphate, sodium phosphate, calcium phosphate, ammonium phosphate, zinc phosphate, etc., and the addition amount is about 0.1-50g/L, often added alone or several kinds. In order to make the solution added with these compounds acidic, inorganic acids such as phosphoric acid, nitric acid, sulfuric acid, and hydrofluoric acid are added. Adding amount is about 0.1-50g/L, often added alone or several kinds. In addition, organic acids such as acetic acid, oxalic acid, citric acid, formic acid, butyric acid, and propionic acid may be added. The pH of the solution is 2 or less, preferably 1 or less. As additives, metal compounds such as zinc, iron, copper, manganese, and nickel may be added as appropriate. Phosphate chemical surface treatment liquids are widely commercially available, and these can also be used.

The treatment temperature is about normal temperature -70°C, and the treatment time is between a few seconds and a few minutes, which is appropriately determined according to the shape and size of the object to be treated. In the case of parts with complex shapes, care should be taken not to generate air bubbles during immersion in the solution, and the object to be processed can also be shaken in order to improve the efficiency of the treatment. After treatment, in order to eliminate appearance defects caused by residual water droplets and residual water film, etc., it is desirable to quickly wash with water, and then dry after washing with hot water or hot air.

It is also possible to selectively dissolve and remove lead from the surface of lead-containing copper alloys by immersing in an alkaline etching solution before immersing in an acidic solution containing no chromic acid but a phosphoric acid compound in the solution. Lead is an amphoteric metal. It does not form an alloy in copper alloy but exists in the form of lead element. Therefore, through the action of alkaline corrosion solution, the copper alloy matrix does not react basically, and only the lead compound can be selectively dissolved and removed. Therefore, it is possible to reduce the load in the step of immersing an acidic solution containing a phosphoric acid compound but not containing chromic acid in the solution. In addition, it also functions as a degreasing process for removing dirt such as oil components adhering to the lead-containing copper alloy in the previous process, so it is a very efficient process.

The main component of the alkaline corrosion solution is one or several kinds of alkali dissolved in sodium hydroxide, potassium hydroxide, sodium carbonate, sodium phosphate, sodium tripolyphosphate, sodium metasilicate, sodium orthosilicate, etc. solution. The concentration is generally several g/L-tens of g/L, and it is normal by the combination of the components used. The treatment temperature is about 60-90°C, and the treatment time is between a few minutes and dozens of minutes, which is appropriately determined according to the shape and size of the object to be treated. In the case of parts with complex shapes, care should be taken not to generate air bubbles when dipping in the solution, and the object to be processed can also be shaken in order to improve processing efficiency. After the treatment, it is preferable to quickly wash with water and proceed to the next process.

In order to improve the penetration and wettability of the alkaline corrosive liquid, a surfactant can also be added for the purpose of reducing the surface tension of the liquid. As surfactants, anionic surfactants or nonionic surfactants are often used, and these are used alone or in combination. Examples of anionic surfactants include sodium higher fatty acid, sulfated oil, sodium higher alcohol sulfate, sodium alkylbenzene sulfate, sodium higher alkyl ether sulfate, and sodium α-olefin sulfate. In addition, as nonionic surfactants, there are alkyl polyoxyethylene ethers, alkylphenyl polyoxyethylene ethers, fatty acid ethylene oxide adducts, polypropylene glycol ethylene oxide adducts (Prolonic) . The amount added is generally several g/L-tens of g/L.

In addition, in order to prevent lead from becoming hydroxide and re-adhesion, and to promote the dissolution of lead, a chelating agent can be added to the alkaline corrosion solution. As the chelating agent, for example, compounds that easily form a complex with lead, such as EDTA, ethylenediamine, triethanolamine, thiourea, Rochelle's salt, and tartaric acid, are preferable. The amount added is generally several g/L-tens of g/L.

When an oxidizing agent is added to an alkaline etching solution, lead is oxidized, and a two-step reaction occurs through redissolving lead oxide (PbO ₂ ) in alkali. Since this reaction is faster than the one-step reaction in which lead is dissolved in alkali, lead removal is promoted as a result, removal efficiency can be improved, and treatment time can be shortened. As an oxidizing agent, organic oxidizing compounds such as sodium m-nitrobenzenesulfonate and sodium p-nitrobenzoate, inorganic compounds such as hypochlorite, bleaching powder, hydrogen peroxide, potassium permanganate, persulfate, and perchlorate are used. . The amount added is generally several g/L-tens of g/L.

Appliances for water pipes, including faucet fittings, are sometimes plated for the purpose of aesthetic appearance, corrosion resistance, and abrasion resistance. The manufacturing method is generally to perform electroplating as a known technology after performing a known plating pretreatment. , electroless plating, displacement plating or dry plating, so it is not particularly limited. Among these plating methods, nickel plating followed by chromium plating is the most common in terms of quality and cost. In addition to that, there are gold plating, silver plating, rhodium plating, platinum plating, copper plating, tin plating, tin-cobalt alloy plating, tin-nickel alloy plating, etc. As a dry plating method, there are vacuum evaporation, ion plating, sputtering, CVD method, etc., and there are titanium nitride, titanium carbide, zirconium nitride, chromium nitride, silicon carbide, diamond, aluminum oxide, titanium carbonitride wait.

In many cases, such plating does not have a plating layer on the inner surface of leaded copper alloy plumbing appliances including faucet fittings, so the copper alloy matrix is exposed in this part. In the present invention, by immersing the lead-containing copper alloy in the above-mentioned alkaline corrosion solution, or in an acidic solution containing no chromic acid but a phosphoric acid compound in the solution, the part with the plating layer does not cause any change and effectively removes Copper alloy exposed part of the lead.

(Example)

Hereinafter, the present invention will be described more specifically through examples, but the present invention is not limited thereto, and of course many changes can be made within the scope of the technical idea of the present invention.

Using the bronze casting faucet fittings shown in FIG. 1 under the conditions shown below, lead removal treatment was performed under various treatment conditions, and the appearance state and the effect of reducing lead elution were evaluated (Experiment 1).

The treatment process is carried out in the order of treatment in acidic solution after alkali corrosion treatment. Fig. 2(a), (b) and Fig. 3(a), (b) are the enlarged photos of the surface before and after the treatment, and the enlarged photos of the cross section. Comparing these photographs, it is known that after the treatment, lead was eluted from a portion of 5-6 μm on the surface.

Appearance was visually evaluated, and the effect of reducing lead elution was analyzed in accordance with JIS-S-3200-7 (2000) "Apparatus for plumbing - Test method for leaching performance". The concentration of eluted lead was analyzed. Table 1 summarizes the processing conditions, the state of appearance, and the amount of lead leached. The condition of alkali corrosion is to use the liquid of sodium hydroxide 50g/L + sodium p-nitrobenzoate 1g/L, and uniformly use the conditions of 80°C and 10 minutes.

For the state of appearance, the level of severe discoloration is judged as x, the level of discoloration is a problem, and the level of discoloration is not problematic.

Table 1 Treatment conditions and experimental results of Experiment 1 Conditions of treatment in acidic solutions after alkaline etching state of appearance Dissolution of lead (ppb) Chromic anhydride concentration (g/L) 85% phosphoric acid concentration (ml/L) Processing temperature (℃) Processing time (seconds) 10 10 50 30 △ 3 50 not added 50 30 ○ 15 not added 10 50 30 ○ 10 10 10 50 300 x 1 50 not added 50 300 ○ 5 not added 10 50 300 ○ 3 Alkaline corrosion only, no treatment in acidic solution. ○ 39 unprocessed product. ○ 880

From these results, it is clear that the treatment in an acidic solution containing both chromic anhydride and phosphoric acid causes discoloration in appearance, but treatment in a single acidic solution has no problem in appearance, and the amount of lead eluted is small when treated with phosphoric acid alone.

Next, lead removal treatment was performed in a state where sodium chloride was added, and the state of appearance and the effect of reducing lead elution were evaluated (Experiment 2). The treatment process is carried out in the order of treatment in acidic solution after alkali corrosion treatment. Appearance evaluation method and effect of reducing lead elution The concentration of eluted lead was analyzed in accordance with JIS-S-3200-7 (2000) "Apparatus for plumbing - Test method for leaching performance". Table 2 summarizes the treatment conditions, the state of appearance, and the amount of lead leached. The condition of alkali corrosion is to use the liquid of sodium hydroxide 50g/L + sodium p-nitrobenzoate 1g/L, uniformly under the conditions of 60°C and 5 minutes.

For the state of appearance, the level of discoloration is serious and there is a big problem with the product, and the level of discoloration is a problem, and the level of discoloration is a problem. The level where there is no problem in the product without discoloration is judged as ◎.

Table 2 Treatment conditions and experimental results of Experiment 2 Treatment in acidic solution following alkaline corrosion state of appearance Dissolution of lead (ppb) 85% phosphoric acid concentration (ml/L) Sodium chloride (g/L) Processing temperature (℃) Processing time (seconds) 10 - 55 300 ○ 2 10 0.5 55 300 ◎ 2

From these results, it is clear that the treatment in an acidic solution containing both sodium chloride and phosphoric acid further suppressed the discoloration of the appearance, and there was no problem with the amount of eluted lead.

Next, with regard to the faucet fittings made of bronze castings of FIG. 1 that were subjected to nickel plating and chrome plating, lead removal treatment was performed under various treatment conditions, and the state of appearance and the effect of reducing lead elution were judged (Experiment 3). The treatment process is carried out in the order of treatment in acidic solution after alkali corrosion treatment. Appearance evaluation method and lead leaching evaluation method were also carried out in the same way as in Experiment 1. The appearance was visually evaluated, and the effect of reducing lead leaching was in accordance with JIS-S-3200-7 (2000) "Utensils for water pipes - leaching Performance Test Method" analyzes the concentration of leached lead. Table 3 summarizes the processing conditions, the state of appearance, and the amount of lead leached. The condition of alkali corrosion is to use the liquid of sodium hydroxide 50g/L + sodium p-nitrobenzoate 1g/L, uniformly under the conditions of 60°C and 5 minutes.

As for the state of appearance, the level of discoloration is serious and there is a big problem with the product as ×, the level of discoloration is a problem with the product as △, the level of discoloration is almost no problem with the product is ○,

Table 3 Treatment conditions and experimental results of Experiment 3 Treatment in acidic solution following alkaline corrosion State of the appearance (internal bronze part) ※1 Dissolution of lead (ppb) Chromic anhydride concentration (g/L) 85% phosphoric acid concentration (ml/L) Processing temperature (℃) Processing time (seconds) 10 10 50 30 △ 2 50 not added 50 30 ○ 10 not added 10 50 30 ○ 9 10 10 50 300 x 1 50 not added 50 300 ○ 4 not added 10 50 300 ○ 2 Alkali corrosion only is not treated in acidic solution. ○ 12 unprocessed product. (nickel-chrome plated product) ○ 18

*1: There is no abnormality such as discoloration of the nickel-chrome plated part on the surface.

From these results, it is clear that even if the nickel-chrome plated product is treated in an acidic solution containing both chromic anhydride and phosphoric acid, the bronze part on the inner surface will change color, but the appearance will not be the same when treated in a single acidic solution. There is no problem, and the amount of lead leaching is small when phosphoric acid is treated alone. In addition, abnormalities such as discoloration were not observed at all on the nickel-chrome-plated part of the surface, and it was confirmed that the method of reducing lead elution according to the present invention can be utilized for the plated product as well.

The present invention exerts the following effects by the above configuration. That is, due to the slight corrosion effect of the acidic phosphoric acid compound and the formation of only a slight phosphoric acid film, there is no significant discoloration and no reduction in commercial value. In addition, by supplementing the active agent sodium chloride in an appropriate amount in the acidic solution containing phosphoric acid compound but not containing chromic acid in the solution of the present invention, the progress of the reaction is improved, the corrosion effect and the formation of a small phosphoric acid film are increased, and the stability can be ensured. It also has a sufficient effect on reducing the elution of lead. In addition, by first immersing in an alkaline etching solution, the lead on the surface of the copper alloy can be roughly selectively removed. Therefore, it is compatible with the subsequent process of immersion in an acidic solution that does not contain chromic acid but contains a phosphoric acid compound. The effects complement each other, and a more sufficient effect can also be seen regarding the reduction of lead elution. In addition, after these steps, lead-containing copper alloys do not undergo significant discoloration, and the commercial value does not decrease.

The plated part of the outer surface does not cause a dissolution reaction or a corrosion reaction in the above-mentioned immersion step of the alkaline etching solution and the immersion step of an acidic solution containing a phosphoric acid compound but does not contain chromic acid in the solution, and therefore does not cause corrosion. Discoloration occurs, and it is possible to achieve the effect of reducing lead elution only on the main inner surface exposed by the lead-containing copper alloy without plating treatment. Of course, its inner surface will not be accompanied by major discoloration.

Lead-containing copper alloy plumbing appliances such as faucet fittings are often plated with chrome after nickel-chrome plating in order to impart decorative properties, corrosion resistance, and abrasion resistance to the exterior surface, and this plating has been widely used in the past. In the case of this plating, discoloration does not occur because neither dissolution reaction nor corrosion reaction occurs in the immersion step of the above-mentioned alkaline etching solution and the immersion step of an acidic solution containing a phosphoric acid compound but does not contain chromic acid in the solution. , and can achieve: the effect of reducing the dissolution of lead only on the main internal surface exposed by the lead-containing copper alloy without plating treatment. Of course, its inner surface will not be accompanied by major discoloration.

In this example, the plating treatment was performed before the immersion step in the acidic solution containing a phosphoric acid compound, but the plating treatment may be performed after the immersion step.

Industrial applicability

The lead-containing copper alloy treatment method for reducing lead leaching and the lead-containing copper alloy water plumbing fixture of the present invention can be used for various fixtures connected to water supply pipes.

Claims (7)

1. the processing method of the plumbous stripping of the reduction of a leaded copper alloy is characterized in that, leaded copper alloy is immersed in do not contain chromic acid in the solution but in the acid solution of phosphoric acid compound.

2. the processing method of the plumbous stripping of the reduction of a leaded copper alloy is characterized in that, leaded copper alloy is immersed in do not contain chromic acid in the solution but in the acid solution of phosphoric acid compound and sodium chloride.

3. the processing method of the plumbous stripping of the reduction of a leaded copper alloy is characterized in that, leaded copper alloy is immersed in the lead of removing the surface in the corrosive liquid of alkalescence, then is immersed in not contain chromic acid in the solution but in the acid solution of phosphoric acid compound.

4. the processing method of the plumbous stripping of the reduction of a leaded copper alloy, it is characterized in that, leaded copper alloy is immersed in the lead of removing the surface in the corrosive liquid of alkalescence, then is immersed in and does not contain chromic acid in the solution but in the acid solution of phosphoric acid compound and sodium chloride.

5. according to the processing method of the plumbous stripping of reduction of the described leaded copper alloy of 1 of claim the and the 3rd, it is characterized in that, mainly is that outer surface carries out plating and processes.

6. according to the processing method of the plumbous stripping of reduction of the described leaded copper alloy of 5 of claims the, it is characterized in that, mainly to the plating of outer surface, is the plating of implementing chromium plating after the nickel plating.

7. the waterpipe utensil of the described leaded copper alloy system of 1 the-the 6th of claim the is characterized in that, is immersed in not contain chromic acid in the solution but contain in the acid solution of phosphate cpd.

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