JP4190260B2 - Surface treatment method for lead-containing copper alloy and water contact member made of copper alloy - Google Patents

Description

【００６３】
表１からも明らかなように、比較例に比べて本発明の方法を用いることにより鉛溶出量をきわめて微量に抑えることができる。溶剤脱脂の比較例１やアルカリ脱脂の比較例２は鉛溶出量がきわめて大きい。アルカリエッチングの比較例３や酸エッチング比較例４ではエッチングにより表面の鉛が除去されるので鉛溶出量は減少している。しかし、実施例１〜８の本発明を行うと、エッチングと同時に形成されるりん酸塩皮膜の遮蔽効果により比較例３，４の１／２〜１／４まで鉛溶出量が減少していることが判る。
【００６４】
【発明の効果】
水栓金具、水道配管、配管バルブ、水道メーター、給湯機用熱交換器、ポンプ用品、配管継ぎ手などで適用されている鉛含有銅合金に本発明の方法を適用することにより、表面の鉛の除去と、深部の鉛溶出を防止するりん酸塩皮膜の形成を同時に行うことができる。このように本発明により有害物質の溶出を極めて経済的に防止することができる。
【図面の簡単な説明】
【図１】は本発明の表面処理を鉛含有銅合金に適用した場合の表面の深さ方向分析をＧＤＳにより行った図。この表面処理は実施例２に相当する。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a surface treatment method for preventing lead from eluting from the surface of a lead-containing copper alloy and a water contact member made of copper alloy treated according to the present invention.
[0002]
[Prior art]
Lead elution prevention treatment from lead-containing copper alloys is performed on copper alloy members related to water contact members, such as faucet fittings, water pipes, pipe valves, water meters, heat exchangers for water heaters, pump supplies, pipe joints, etc. Has been applied. This is because copper alloys such as bronze, which are excellent in castability, machinability and economy, are used for the above-mentioned members, and these copper alloys have good characteristics such as machinability and machinability. For this reason, a predetermined amount of lead is added.
[0003]
That is, since a very small amount of lead is eluted from the water contact member into tap water and the like, and this affects the human body and the use environment, this elution prevention technique has been studied.
[0004]
At present, it is difficult to obtain good machinability and machinability without adding lead to a copper alloy, and no alternative metal for lead has been found.
[0005]
[Problems to be solved by the invention]
An object of the present invention is to provide a surface treatment method and a surface-treated water contact member for preventing lead from eluting from a copper alloy material excellent in machinability and machinability containing lead. .
[0006]
[Means for Solving the Problems]
As a result of intensive studies to achieve the technical problem, the present inventor has selected one of the lead-containing copper alloys selected from Zn, Fe, Mn, Ca, Ni, Cu, Co, Zr, Sn, Mg, and Al. Alternatively, surface treatment with a chemical conversion treatment solution containing two or more kinds of metal ions, nitrite ions, phosphate ions and nitrate ions removes lead existing on the surface by selective etching, and It has been found that the formation of a phosphate film containing the above-mentioned metal on the surface and covering it further has the effect of preventing the elution of lead remaining in the deep part.
[0007]
In addition, according to the knowledge of the present inventors, it is possible to remove a certain amount of lead by selective etching of lead with nitric acid or the like, but this method completely exposes the surface of lead remaining inside the hole. The elution of lead cannot be prevented, and when exposed to a corrosive environment, the surface is rusted and discolored. However, according to the present invention, it has been found that since the phosphate coating covers the substrate surface densely, there is almost no elution of lead, and discoloration due to rusting can be prevented.
[0008]
That is, in the present invention, the lead-containing copper alloy is made of one or more metal ions selected from Zn, Fe, Mn, Ca, Ni, Cu, Co, Zr, Sn, Mg, and Al, nitrite ions, by contact with a chemical conversion solution containing phosphate ions and nitrate ions, to remove lead on the surface, and by forming a phosphate film containing the aforementioned metal on the surface thereof, a lead-containing copper alloy In addition to preventing elution of lead from water, it is characterized by imparting a discoloration preventing effect.
[0009]
Furthermore wherein the chemical conversion treatment liquid, hydrogen peroxide, and more preferably contains one or more selected from peroxo compounds.
[0010]
Prior to the chemical conversion treatment, one step or two or more steps of degreasing, pickling and surface adjustment can be performed as a pretreatment.
[0011]
The pickling performed as a pretreatment prior to the chemical conversion treatment is more preferably an acidic aqueous solution containing fluorine ions and nitrate ions.
[0012]
More preferably, the acidic aqueous solution further contains a surfactant and / or a chelating agent.
[0013]
The present invention also has a phosphate film of one or more metals selected from Zn, Fe, Mn, Ca, Ni, Cu, Co, Zr, Sn, Mg, and Al on the surface of the copper alloy. This is a lead-containing copper alloy-made wetted member.
[0014]
Moreover, it is a lead-containing copper alloy wetted member in which the metal phosphate film is one or more poorly soluble phosphates selected from Zn, Ca, Sn, and Mg.
[0015]
[Embodiments of the Invention]
Details of the present invention will be described below. The material targeted by the present invention is a copper alloy material containing lead in order to improve workability, and is a copper alloy wetted member.
[0016]
The chemical conversion treatment (phosphate treatment) used in the present invention is a treatment in which a metal material is etched and an insoluble phosphate film is formed on the surface of the material due to the increase in pH of the surface that occurs at that time.
[0017]
In the present invention, taking advantage of this chemical conversion treatment, one or more metal ions selected from Zn, Fe, Mn, Ca, Ni, Cu, Co, Zr, Sn, Mg, and Al, and nitrite ions, In addition, by treating with a chemical conversion treatment solution containing phosphate ions and nitrate ions, lead existing on the surface of the lead-containing copper alloy is selectively etched and removed, and at the same time, the surface from which the lead has been removed is removed. A phosphate film containing metal ions is formed on the surface. By covering the surface with the phosphate film, it is possible to prevent the elution of lead remaining in the deep part of the lead-containing copper alloy material.
[0018]
That is, according to the present invention, the lead-containing copper alloy material surface is coated with a phosphate film by selectively removing lead existing on the surface of the lead-containing copper alloy and forming a phosphate film on the surface. Due to the two effects of preventing elution from the raw material, lead elution is prevented and can be applied to a water contact member made of copper alloy.
[0019]
FIG. 1 shows a test piece obtained by treating a lead-containing copper alloy material (JIS H5111 (BC6) bronze cast round bar cut product) with a chemical conversion solution containing Zn, Ca metal ions, phosphate ions and nitrate ions. Is a result of elemental analysis in the depth direction using GDS (Glow Discharge Emission Spectrometer: System 3860, manufactured by Rigaku Corporation).
[0020]
As is apparent from FIG. 1, lead is not detected on the surface of the lead-containing copper alloy material, and the presence of a Ca, Zn, P, O phosphate film is confirmed.
[0021]
Hereinafter, the chemical conversion treatment solution used in the present invention will be described. The metal ions in the chemical conversion solution are one or more selected from Zn, Fe, Mn, Ca, Ni, Cu, Co, Zr, Sn, Mg, and Al, and the amount of these ions is not particularly limited. In view of economy and the like, the total metal ion amount is preferably 0.5 to 100 g, more preferably 2 to 40 g in 1 L of the chemical conversion treatment liquid.
[0022]
Although the amount of phosphate ions is not particularly limited, 1 to 100 g is preferable in 1 L of the chemical conversion treatment liquid, and more preferably 10 to 50 g in view of economy.
[0023]
The amount of nitrate ions is not particularly limited, but is preferably 0.1 to 100 g, more preferably 5 to 50 g, in 1 L of the chemical conversion solution. If it is less than 0.1 g, surface etching at the time of film formation may be insufficient, and if it exceeds 100 g, surface etching at the time of film formation will be excessive and a film may not be formed.
[0024]
It is to contain nitrite ion of conversion treatment solution. Further , the chemical reaction can be performed more efficiently by adding one or more selected from hydrogen peroxide and peroxo compounds. The addition amount of one or more selected from nitrite ions, hydrogen peroxide, and a peroxo compound is not particularly limited, but is preferably 0.1 to 10 g as the addition amount in 1 L of the chemical conversion treatment liquid.
[0025]
The treatment conditions in the chemical conversion treatment solution of the present invention are not particularly limited, but considering the reactivity, economy, safety, etc., the treatment temperature of the treatment bath is preferably 30 to 100 ° C., and the treatment time is 1 A range of ˜60 minutes is preferred.
[0026]
In general, when chemical conversion treatment is performed, one step or two or more steps of degreasing, pickling and surface adjustment are performed as pretreatment. After the degreasing and pickling steps other than the surface adjustment step, it is customary to perform water washing and remove the degreasing and pickling solutions.
[0027]
The degreasing step is preferably performed when the object to be treated is markedly contaminated with organic substances such as cutting oil and rust preventive oil. This is because, when such surface contamination due to organic substances is significant, the contact between the chemical conversion treatment liquid and the material metal is hindered, and there is a possibility that a sufficient film forming reaction does not occur.
[0028]
There is no limitation in particular about the degreasing agent used at a degreasing process, A commercially available alkali degreasing agent etc. can be used.
[0029]
The pickling step is preferably applied when a strong oxide film is formed on the surface of the object to be processed. This is because if a strong oxide film is present on the surface of the object to be processed, there is a possibility that a film cannot be formed without causing a sufficient etching reaction even if the surface treatment is performed with the chemical conversion treatment liquid. The surface lead partially dissolves by pickling, but it cannot be reduced to the target lead elution prevention amount of the present invention.
[0030]
The acid that can be used in the pickling step is not particularly limited, but inorganic acids such as hydrochloric acid, nitric acid and sulfuric acid, and organic acids typified by acetic acid are suitable. However, the acid can be used in an acidic aqueous solution containing fluorine ions and nitrate ions. It is more preferable to wash.
[0031]
In consideration of the removability of the oxide film and the dissolution loss of the material, the range of 0.1 to 20 g as fluorine ions and 20 to 90 g as nitrate ions is more preferable in 1 L of acidic aqueous solution.
[0032]
Furthermore, in order to effectively remove the oxide film, it is more preferable to add a surfactant and / or a chelating agent to the acidic aqueous solution. The type of surfactant and / or chelating agent is not particularly limited as long as it can be used in an acidic aqueous solution.
[0033]
Although it does not specifically limit as a processing condition of pickling, It is preferable to process for 3 to 30 minutes at 5-80 degreeC when an environmental problem, safety | security, and economical efficiency are considered.
[0034]
In the surface conditioning step, immediately before performing the surface treatment in the chemical conversion treatment bath, the object to be treated is brought into contact with a titanium compound colloidal surface conditioning liquid or a phosphate compound colloidal surface conditioning liquid, and the chemical conversion of the next process is performed without washing with water. This is a method of processing. By employing the surface adjustment step, the phosphate film can be formed more quickly and a dense film can be formed.
[0035]
After performing the surface treatment of the present invention, the object to be treated is sufficiently washed with water and dried. Although there is no particular limitation on the conditions in the water washing step, in consideration of the use in the water contact member, clean water is preferable, and ion exchange water, distilled water, or the like can be appropriately used. Further, the washing time is preferably in the range of 1 to 60 minutes, and more preferably when the washing step is performed in multiple stages.
[0036]
The drying temperature is not particularly limited, but is preferably in the range of 40 to 130 ° C. in consideration of economy.
[0037]
The above-described treatment liquid and treatment step can be applied to a copper alloy wetted member, whereby 1 selected from Zn, Fe, Mn, Ca, Ni, Cu, Co, Zr, Sn, Mg, and Al. A lead-containing copper alloy wetted member having a phosphate film of seeds or two or more metals can be provided.
[0038]
Furthermore, it is preferable that the metal phosphate coating is a lead-containing copper alloy wetted member which is one or more hardly soluble phosphates selected from Zn, Ca, Sn, and Mg.
[0039]
Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to these examples. In all of the following examples and comparative examples, clean water was used.
[0040]
(Example 1)
In the examples, a JISH5111 (BC6) bronze cast round bar machined product (Cu: 83.0-87.0%, Pb: 1.5-2.0%, Zn: 4. 0 to 6.0%, Sn: 4.0 to 6.0%, Ni: 1.0% or less, Fe: 0.3% or less, P: 0.05% or less, Sb: 0.2% or less, A surface of a disk sample having a diameter of 42.4 × 10 mm made by cutting Al: 0.01% or less) was used as a raw material, and various amounts of surface treatment were performed to test the elution amount of lead.
[0041]
As a chemical conversion treatment solution, first, zinc oxide is dissolved in an aqueous solution of phosphoric acid and nitric acid to prepare an aqueous solution having concentrations of Zn: 12 g / L, phosphoric acid: 12 g / L, nitric acid: 20 g / L, and then What added sodium nitrite 2g / L as nitrite ion was prepared.
[0042]
In the surface treatment step, first, the test material was immersed in a degreasing solution adjusted to 20 g / L of Fine Cleaner 4360 manufactured by Nippon Parkerizing Co., Ltd. at 60 ° C. for 5 minutes. Thereafter, it was sufficiently washed with running water, and immersed in the above chemical conversion solution at 50 ° C. for 5 minutes. Thereafter, it was washed with running water and dried in a drying furnace at 90 ° C. for 10 minutes.
[0043]
(Example 2)
As a chemical conversion treatment solution, zinc oxide and calcium nitrate are first dissolved in an aqueous solution of phosphoric acid and nitric acid, Zn: 3.3 g / L, Ca: 6.8 g / L, phosphoric acid: 12 g / L, nitric acid: 25 g / L Then, an aqueous solution with a concentration of 1 liter / L of sodium nitrite was added as nitrite ions.
[0044]
In the surface treatment step, first, the test material was immersed in a degreasing solution adjusted to 20 g / L of Fine Cleaner 4360 manufactured by Nippon Parkerizing Co., Ltd. at 60 ° C. for 5 minutes. Thereafter, it was sufficiently washed with running water, and immersed in the above chemical conversion solution at 70 ° C. for 10 minutes. Thereafter, it was washed with running water and dried in a drying furnace at 90 ° C. for 10 minutes.
[0045]
(Example 3)
As a chemical conversion treatment solution, zinc oxide and magnesium nitrate are first dissolved in an aqueous solution of phosphoric acid and nitric acid, and Zn: 3.3 g / L, Mg: 2 g / L, phosphoric acid: 12 g / L, nitric acid: 20 g / L. Then, an aqueous solution with 2 g / L of sodium nitrite added as nitrite ions was used.
[0046]
In the surface treatment step, first, the test material was immersed in a degreasing solution prepared by adjusting Fine Tester 4360 manufactured by Nippon Parkerizing Co., Ltd. to 20 g / L at 50 ° C. for 5 minutes. Thereafter, it was sufficiently washed with running water, and immersed in the above chemical conversion solution at 70 ° C. for 10 minutes. Thereafter, it was washed with running water and dried in a drying furnace at 90 ° C. for 10 minutes.
[0047]
Example 4
As a chemical conversion treatment solution, first, magnesium nitrate is dissolved in an aqueous solution of phosphoric acid and nitric acid to prepare an aqueous solution having concentrations of Mg: 5 g / L, phosphoric acid: 12 g / L, nitric acid: 20 g / L, and then What added sodium nitrite 2g / L as nitrite ion was used.
[0048]
In the surface treatment step, the test material was first subjected to immersion treatment at 60 ° C. for 10 minutes with a degreasing solution in which Fine Cleaner 4360 manufactured by Nippon Parkerizing Co., Ltd. was adjusted to 20 g / L. Thereafter, it was sufficiently washed with running water, and immersed in the above chemical conversion solution at 70 ° C. for 10 minutes. Thereafter, it was washed with running water and dried in a drying furnace at 90 ° C. for 10 minutes.
[0049]
(Example 5)
First, manganese phosphate is dissolved in an aqueous solution of phosphoric acid and nitric acid as a chemical conversion treatment solution to prepare an aqueous solution having a concentration of Mn: 5 g / L, phosphoric acid: 20 g / L, nitric acid: 25 g / L, Further, after that, 1 g / L of sodium nitrite was added as nitrite ion.
[0050]
In the surface treatment step, first, the test material was immersed in a degreasing solution adjusted to 20 g / L of Fine Cleaner 4360 manufactured by Nippon Parkerizing Co., Ltd. at 60 ° C. for 5 minutes. Thereafter, it was sufficiently washed with running water, and immersed in the above chemical conversion solution at 90 ° C. for 10 minutes. Thereafter, it was washed with running water and dried in a drying furnace at 90 ° C. for 10 minutes.
[0051]
(Example 6)
As a chemical conversion treatment solution, zinc oxide and manganese biphosphate are first dissolved in an aqueous solution of phosphoric acid and nitric acid, and Zn: 5 g / L, Mn: 2 g / L, phosphoric acid: 15 g / L, nitric acid: 25 g / L. Then, an aqueous solution with 2 g / L of sodium nitrite added as nitrite ions was used.
[0052]
In the surface treatment step, first, the test material was immersed in a degreasing solution adjusted to 20 g / L of Fine Cleaner 4360 manufactured by Nippon Parkerizing Co., Ltd. at 60 ° C. for 5 minutes. Thereafter, it was sufficiently washed with running water, and immersed in the above chemical conversion solution at 60 ° C. for 10 minutes. Thereafter, it was washed with running water and dried in a drying furnace at 90 ° C. for 10 minutes.
[0053]
(Example 7)
As a chemical conversion treatment solution, first, zinc oxide is dissolved in an aqueous solution of phosphoric acid and nitric acid to prepare an aqueous solution having concentrations of Zn: 12 g / L, phosphoric acid: 12 g / L, nitric acid: 20 g / L, and then What added sodium nitrite 2g / L as nitrite ion was prepared.
[0054]
In the surface treatment step, first, the test material was immersed in a degreasing solution adjusted to 20 g / L of Fine Cleaner 4360 manufactured by Nippon Parkerizing Co., Ltd. at 60 ° C. for 5 minutes. Thereafter, the plate was sufficiently washed with running water, and then immersed in an acidic aqueous solution adjusted to 60 g / L of nitric acid for pickling at 30 ° C. for 10 minutes. Thereafter, it was sufficiently washed with running water, and immersed in the above chemical conversion solution at 50 ° C. for 5 minutes. Thereafter, it was washed with running water and dried in a drying furnace at 90 ° C. for 10 minutes.
[0055]
(Example 8)
As a chemical conversion treatment solution, zinc oxide and calcium nitrate are first dissolved in an aqueous solution of phosphoric acid and nitric acid, Zn: 3.3 g / L, Ca: 6.8 g / L, phosphoric acid: 12 g / L, nitric acid: 25 g / L Then, an aqueous solution with a concentration of 1 liter / L of sodium nitrite was added as nitrite ions.
[0056]
In the surface treatment step, first, the test material was immersed in a degreasing solution adjusted to 20 g / L of Fine Cleaner 4360 manufactured by Nippon Parkerizing Co., Ltd. at 60 ° C. for 5 minutes. Then, after sufficiently washing with running water, immersion treatment was performed at 20 ° C. for 10 minutes in an acidic aqueous solution adjusted to 50 g / L nitric acid and 3 g / L hydrofluoric acid as pickling. Thereafter, it was sufficiently washed with running water, and immersed in the above chemical conversion solution at 70 ° C. for 10 minutes. Thereafter, it was washed with running water and dried in a drying furnace at 90 ° C. for 10 minutes.
[0057]
(Comparative Example 1)
Degreasing was performed by immersing a test material similar to the example in normal temperature acetone for 10 minutes and then allowing it to air dry.
[0058]
(Comparative Example 2)
The same test material as in the example was immersed in a degreasing solution prepared by adjusting fine cleaner 4360 manufactured by Nippon Parkerizing Co., Ltd. to 20 g / L at 60 ° C. for 5 minutes. Thereafter, it was sufficiently washed with running water and dried in a drying furnace at 90 ° C. for 10 minutes.
[0059]
(Comparative Example 3)
The same test material as in the example was immersed in a degreasing solution prepared by adjusting fine cleaner 4360 manufactured by Nippon Parkerizing Co., Ltd. to 20 g / L at 60 ° C. for 5 minutes. Thereafter, it was thoroughly washed with running water. Thereafter, it was immersed in a treatment solution of 50 g / L of sodium hydroxide and 2 g / L of a surfactant (sodium alkenyl sulfonate) at 80 ° C. for 10 minutes for alkali etching. Thereafter, it was sufficiently washed with running water and dried in a drying furnace at 90 ° C. for 10 minutes.
[0060]
(Comparative Example 4)
In the same manner as in the examples, the test material was immersed in a degreasing solution prepared by adjusting fine cleaner 4360 manufactured by Nippon Parkerizing Co., Ltd. to 20 g / L at 60 ° C. for 5 minutes. Thereafter, it was thoroughly washed with running water. Then, it was immersed in 5% nitric acid aqueous solution for 5 minutes at room temperature, and acid etching was performed. Thereafter, it was sufficiently washed with running water and dried in a drying furnace at 90 ° C. for 10 minutes.
[0061]
Lead elution tests were performed using the samples of Examples 1 to 6 and Comparative Examples 1 to 4. In the test, 100 mL of deionized water whose pH was confirmed to be approximately 7 was placed in a beaker and placed in a water bath set at a temperature of 25 ° C. It was carried out by immersing so as to immerse and holding for one day. After completion of the test, the amount of lead eluted in each deionized water was measured by ICP (Inductively Coupled High Frequency Plasma Spectrometer). The results are shown in Table 1.
[0062]
[Table 1]

[0063]
As is clear from Table 1, the amount of lead elution can be suppressed to a very small amount by using the method of the present invention as compared with the comparative example. Comparative Example 1 for solvent degreasing and Comparative Example 2 for alkaline degreasing have very large lead elution amounts. In the alkaline etching comparative example 3 and the acid etching comparative example 4, the lead elution amount is reduced because the lead on the surface is removed by the etching. However, when the present invention of Examples 1 to 8 is carried out, the lead elution amount is reduced to 1/2 to 1/4 of Comparative Examples 3 and 4 due to the shielding effect of the phosphate film formed simultaneously with the etching. I understand that.
[0064]
【The invention's effect】
By applying the method of the present invention to lead-containing copper alloys applied to faucet fittings, water pipes, pipe valves, water meters, water heater heat exchangers, pump supplies, pipe joints, etc. Removal and formation of a phosphate film that prevents deep lead elution can be performed simultaneously. As described above, the elution of harmful substances can be extremely economically prevented by the present invention.
[Brief description of the drawings]
BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is a diagram in which a surface depth direction analysis is performed by GDS when a surface treatment of the present invention is applied to a lead-containing copper alloy. This surface treatment corresponds to Example 2.

Claims (7)

Lead-containing copper alloy is made of one or more metal ions selected from Zn, Fe, Mn, Ca, Ni, Cu, Co, Zr, Sn, Mg, and Al, nitrite ions, and phosphate ions. Lead that prevents lead elution, characterized by removing lead on the surface and contacting the surface with a chemical conversion treatment solution containing nitrate ions and forming a phosphate film containing the aforementioned metal on the surface A surface treatment method for a copper alloy. The chemical conversion treatment solution of hydrogen peroxide in the further, and those containing one or more selected from peroxo compounds, the surface treatment method of the lead-containing copper alloy according to claim 1. The surface treatment method for a lead-containing copper alloy according to claim 1 or 2, wherein one or two or more steps of degreasing, pickling and surface adjustment are performed as pretreatment prior to the chemical conversion treatment. The surface treatment method for a lead-containing copper alloy according to claim 3, wherein the pickling performed as a pretreatment prior to the chemical conversion treatment is pickling using an acidic aqueous solution containing fluorine ions and nitrate ions. The lead-containing copper alloy surface treatment method according to claim 4, wherein the acidic aqueous solution is a pickling aqueous solution further containing a surfactant and / or a chelating agent. One or two selected from Zn, Fe, Mn, Ca, Ni, Cu, Co, Zr, Sn, Mg, and Al on the surface produced by the surface treatment method according to claim 1. A lead-containing copper alloy wetted member comprising a phosphate film of a metal of at least one species. The water contact member made of lead-containing copper alloy according to claim 6, wherein the metal phosphate film is one or more hardly soluble phosphates selected from Zn, Ca, Sn, and Mg.

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