JP2012057225A - Plating pretreatment method - Google Patents
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- JP2012057225A JP2012057225A JP2010202602A JP2010202602A JP2012057225A JP 2012057225 A JP2012057225 A JP 2012057225A JP 2010202602 A JP2010202602 A JP 2010202602A JP 2010202602 A JP2010202602 A JP 2010202602A JP 2012057225 A JP2012057225 A JP 2012057225A
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本発明は、シリンダブロックなどのアルミニウム合金製部材の表面のメッキ前処理方法に関する。 The present invention relates to a pretreatment method for plating a surface of an aluminum alloy member such as a cylinder block.
アルミニウム合金製シリンダブロックのピストン摺動面にはＮｉ−ＳｉＣメッキが施される。このメッキ前処理として亜鉛下地被膜が一般に形成される。この亜鉛下地被膜を形成する方法として特許文献１や特許文献２に開示されるダブル亜鉛置換法が知られている。 Ni-SiC plating is applied to the piston sliding surface of the aluminum alloy cylinder block. As this pretreatment for plating, a zinc undercoat is generally formed. As a method of forming this zinc undercoat, a double zinc substitution method disclosed in Patent Document 1 and Patent Document 2 is known.
ダブル亜鉛置換法は図４に示すように、油膜などを脱脂処理したアルミニウム合金素材を亜鉛溶液に浸漬して亜鉛皮膜を形成する。この亜鉛皮膜は凹凸が顕著で直接この上にＮｉ−ＳｉＣなどのメッキ層を形成すると剥離しやすいため、硝酸によって表面のＺｎを溶解して凹凸を小さくするとともに、酸素分子によってＺｎとＡｌを結合し強固なＺｎ−Ｏ−Ａｌ膜を形成する。その後、再度亜鉛溶液に浸漬してＺｎ−Ｏ−Ａｌ膜上に亜鉛皮膜を形成する。 In the double zinc replacement method, as shown in FIG. 4, an aluminum alloy material obtained by degreasing an oil film or the like is immersed in a zinc solution to form a zinc film. This zinc film has conspicuous irregularities and easily peels off when a plated layer such as Ni-SiC is formed directly on this zinc film. Therefore, the surface Zn is dissolved by nitric acid to reduce the irregularities, and oxygen molecules bind Zn and Al. Then, a strong Zn—O—Al film is formed. After that, it is immersed again in a zinc solution to form a zinc film on the Zn—O—Al film.
また、アルミニウム材料の表面に耐食性や上塗り塗料との密着性に優れた緻密な皮膜を形成する手段として陽極電解が知られている。特許文献３ではこの陽極電解に用いる電解液として、ジルコニウム、チタン及びバナジウムからなる群より選ばれる少なくとも一種、リン酸類およびゲル化・沈殿防止剤を含有するものが提案されている。 Further, anodic electrolysis is known as a means for forming a dense film excellent in corrosion resistance and adhesion with a top coating on the surface of an aluminum material. Patent Document 3 proposes an electrolyte containing at least one selected from the group consisting of zirconium, titanium, and vanadium, phosphoric acids, and a gelling / precipitation inhibitor as an electrolytic solution used for the anodic electrolysis.
特許文献１、２に開示されるダブル亜鉛置換法にあっては、亜鉛下地被膜を形成するには、粗い亜鉛置換被膜を形成した後、硝酸などで溶解させて亜鉛を含む不動態被膜とし、この不動態被膜を緻密な亜鉛下地膜に置換するため、最低３回の工程が必要になる。 In the double zinc substitution method disclosed in Patent Documents 1 and 2, in order to form a zinc base coating, after forming a rough zinc substitution coating, it is dissolved in nitric acid to form a passive coating containing zinc. In order to replace this passive film with a dense zinc base film, at least three steps are required.
また特許文献３に開示される方法を亜鉛下地被膜の形成に応用することはできない。 Further, the method disclosed in Patent Document 3 cannot be applied to the formation of a zinc undercoat.
上記課題を解決すべく本願のメッキ前処理方法は、脱脂と変質層の除去が終了したアルミニウム合金製品の表面に亜鉛置換処理液に浸漬して粗い亜鉛皮膜を形成し、この粗い亜鉛皮膜が形成されたアルミニウム合金製品をアルカリ溶液を電解液とした電解槽に浸漬して陽極電解を行い、母材のアルミニウム合金から活性な酸素を発生させ、この活性な酸素（Ｏ）により前記亜鉛皮膜を構成する亜鉛（Ｚｎ）とアルミニウム（Ａｌ）とを結合して強固なＡｌ−Ｏ−Ｚｎ被膜を形成する。 In order to solve the above-mentioned problems, the plating pretreatment method of the present application forms a rough zinc film by immersing it in a zinc-replacement treatment solution on the surface of an aluminum alloy product that has been degreased and removal of the altered layer, and this rough zinc film is formed. The resulting aluminum alloy product is immersed in an electrolytic bath using an alkaline solution as an electrolytic solution, and anodic electrolysis is performed to generate active oxygen from the base aluminum alloy, and the active oxygen (O) constitutes the zinc coating. Bonding zinc (Zn) and aluminum (Al) to form a strong Al—O—Zn film.
前記陽極電解における電解量は１０クーロン／ｄｍ２以上５０クーロン／ｄｍ２以下、電解時間は５秒以上６０秒以下とすることが好ましい。また、電解液としては前工程で用いた亜鉛置換溶液をそのまま用いる。 The amount of electrolysis in the anodic electrolysis is preferably 10 coulomb / dm 2 or more and 50 coulomb / dm 2 or less, and the electrolysis time is preferably 5 seconds or more and 60 seconds or less. Further, as the electrolytic solution, the zinc replacement solution used in the previous step is used as it is.
従来にあっては亜鉛下地被膜の形成は、粗い亜鉛皮膜を形成し、この亜鉛皮膜を硝酸などで溶解させて亜鉛を含む不動態被膜とし、この不動態被膜をＺｎ−Ｏ−Ａｌからなる緻密な下地膜に置換するという少なくとも３工程が必要であったが、本発明によればこれを１工程にすることができ、メッキ前処理のサイクルタイムが短縮され効率が大幅に向上する。また、工程数削減に伴って専用及び汎用設備の投資削減ができる。
また、従来では硝酸などの酸によってＺｎ−Ｏ−Ａｌ被膜を形成する酸を発生させていたが、本発明によれば酸処理が不要になる。
Conventionally, the formation of a zinc undercoating is performed by forming a rough zinc coating and dissolving the zinc coating with nitric acid or the like to form a passive coating containing zinc. The passive coating is a dense Zn-O-Al coating. However, according to the present invention, this can be made one step, and the cycle time of the plating pretreatment is shortened and the efficiency is greatly improved. In addition, investment in dedicated and general-purpose facilities can be reduced with the reduction in the number of processes.
Conventionally, an acid for forming a Zn—O—Al film is generated by an acid such as nitric acid. However, according to the present invention, acid treatment is not required.
以下に本発明の実施の形態を添付図面に基づいて説明する。図１に示すように本実施例にあっては、変質層の除去とアルミニウム合金成分の除去（スマットの溶解も含む）を電解処理により１工程で行っている。 Embodiments of the present invention will be described below with reference to the accompanying drawings. As shown in FIG. 1, in this embodiment, removal of the deteriorated layer and removal of the aluminum alloy component (including dissolution of the smut) are performed in one step by electrolytic treatment.
この電解処理の条件としては、例えば、濃度１０vol％以上５０vol％以下の硫酸を電解液とし、１０Ａ／ｄｍ２以上１００Ａ／ｄｍ２以下の電流密度で５秒以上３０秒以下の電解時間とするか、電解液として濃度１０vol％以上４０vol％以下のリン酸と濃度３vol％以上１２vol％以下の硝酸との混酸を用い、１０Ａ／ｄｍ２以上１００Ａ／ｄｍ２以下の電流密度で１０秒以上６０秒以下の電解時間とするのが好ましい。 Do As the conditions of the electrolysis, for example, the concentration of 10 vol% or more 50 vol% or less of sulfuric acid as the electrolyte, and 10A / dm 2 or more 100A / dm 2 or less at a current density of 5 seconds 30 seconds or less electrolysis time , using a mixed acid of concentration 10 vol% or more 40 vol% or less of phosphoric acid and concentration 3 vol% or more 12 vol% or less of nitric acid as an electrolytic solution, 10A / dm 2 or more 100A / dm 2 60 seconds or less at a current density of more than 10 seconds It is preferable to set the electrolysis time.
尚、前記アルミニウム合金表面を電解液に浸漬中に、超音波処理を施すことで、表面に残渣が残ることが防げる。 In addition, it can prevent that a residue remains on the surface by performing ultrasonic treatment during the immersion of the said aluminum alloy surface in electrolyte solution.
また、変質層の除去とアルミニウム合金成分の除去については、従来のアルカリエッチングと酸洗を用いてもよく、更にはリン酸と硝酸と酸性フッ化アンモニウム（酸性フッ化カリウム）の混合液、リン酸と硝酸との混酸などを用いることで変質層の除去とアルミニウム合金成分の除去を１工程で済ますことも可能である。 For removal of the deteriorated layer and removal of the aluminum alloy component, conventional alkali etching and pickling may be used. Furthermore, a mixed solution of phosphoric acid, nitric acid and acidic ammonium fluoride (acidic potassium fluoride), phosphorus By using a mixed acid of acid and nitric acid, it is possible to remove the deteriorated layer and the aluminum alloy component in one step.
また本発明にあっては、前記亜鉛下地皮膜の形成は同一溶液内での電解、即ち、粗い亜鉛皮膜を陽極電解し、電解で発生した活性な酸素によって、Ｚｎ元素とＡｌ元素を結合して緻密なＺｎ−Ｏ−Ａｌ膜を形成するようにしている。 In the present invention, the formation of the zinc undercoating is performed by electrolysis in the same solution, that is, by anodic electrolysis of a rough zinc coating, and by combining Zn element and Al element by active oxygen generated by electrolysis. A dense Zn—O—Al film is formed.
即ち図２に示すように、亜鉛置換処理液に浸漬してアルミニウム合金製品の表面に粗い亜鉛皮膜を形成する。次いでアルミニウム合金製品を陽極として電解を行う。すると、アルミニウム合金から活性な酸素が発生し、この酸素によってＺｎとＡｌとが結合し、緻密なＺｎ−Ｏ−Ａｌ被膜が形成される。その後、緻密なＺｎ−Ｏ−Ａｌ被膜の表面に亜鉛の皮膜が置換によって再度形成される。 That is, as shown in FIG. 2, a rough zinc film is formed on the surface of the aluminum alloy product by dipping in a zinc replacement treatment solution. Next, electrolysis is performed using the aluminum alloy product as an anode. Then, active oxygen is generated from the aluminum alloy, Zn and Al are combined by this oxygen, and a dense Zn—O—Al film is formed. Thereafter, a zinc film is formed again on the surface of the dense Zn—O—Al film by replacement.
以下に上記の電解条件（クーロン／ｄｍ２）について、好ましい範囲を検証した実験結果を示す。 The experimental result which verified the preferable range about said electrolysis conditions (coulomb / dm < 2 >) below is shown.
好適か否かの判断はＮｉ−ＳｉＣメッキ膜の密着性を基準として判断した。また、検証は図３に示すＪＩＳ−Ｈ８５０４−１１（押出し試験方法）によって行った。
押出し試験方法は、先ずめっき面に対し裏側から底厚１．５ｍｍを残しφ６．５ｍｍの平底の穴をあけ、次いで、φ２５ｍｍの穴があいた受台の上に試料を乗せ、φ６．３ｍｍのピンを前記平底の穴に刺し込み、打ち抜く。
打ち抜かれた破片部のめっきの状態変化を調べ密着性◎○×の判定を行った。
◎はめっきの剥がれが全く観られない、○は一部にめっきの剥がれが観られる、×は全周にめっきの剥がれが観られる、を表す。
The determination as to whether or not it was suitable was made based on the adhesion of the Ni—SiC plating film. Moreover, verification was performed by JIS-H8504-11 (extrusion test method) shown in FIG.
For the extrusion test method, a flat bottom hole with a diameter of φ6.5 mm was left from the back side with respect to the plated surface, and then a sample was placed on a cradle with a hole with a diameter of φ25 mm, and a pin with a diameter of φ6.3 mm Is inserted into the hole in the flat bottom and punched out.
A change in the state of plating on the punched piece part was examined, and adhesion ◎ ○ × was determined.
◎ indicates that no peeling of the plating is observed, ○ indicates that peeling of the plating is partially observed, and × indicates that peeling of the plating is observed on the entire circumference.
上記の(表１)〜表（５）から明らかなように、脱脂と変質層の除去が終了したアルミニウム合金製品を陽極電解して、表面に亜鉛皮膜を形成する電解条件としては、電解量を１０クーロン／ｄｍ２以上５０クーロン／ｄｍ２以下、電解時間は５秒以上６０秒以下とするのが好ましい。
尚、電解液温度については７０℃としたが、電解液温度については２０℃以上であればよい。
As is clear from the above (Table 1) to Table (5), the electrolytic condition for forming the zinc film on the surface by anodic electrolysis of the aluminum alloy product after the degreasing and removal of the altered layer is as follows. It is preferable that the time is 10 coulomb / dm 2 or more and 50 coulomb / dm 2 or less, and the electrolysis time is 5 seconds or more and 60 seconds or less.
Although the electrolytic solution temperature is 70 ° C., the electrolytic solution temperature may be 20 ° C. or higher.
本発明に係るメッキ前処理工程は、例えばエンジンのシリンダブロックなどのアルミニウム合金製部材に施すメッキの前処理として利用することができる。
The plating pretreatment process according to the present invention can be used as a pretreatment for plating applied to an aluminum alloy member such as an engine cylinder block.
Claims (3)
In plating pretreatment method according to claim 1, wherein the electrolyte amount in the anode electrolyte 10 coulombs / dm 2 to 50 coulombs / dm 2 or less, before plating, characterized by the following 60 seconds 5 seconds electrolysis time Processing method.
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106337171A (en) * | 2015-07-07 | 2017-01-18 | 株式会社神户制钢所 | Bottom-deposited substrate for Ni-coating technology, laminate body having Ni-coated layer and magnetic recording medium |
| JP2017021884A (en) * | 2015-07-07 | 2017-01-26 | 株式会社神戸製鋼所 | GROUND LAYER COATING SUBSTRATE USED FOR Ni PLATING, LAMINATE INCLUDING Ni PLATING LAYER, AND MAGNETIC RECORDING MEDIUM |
| WO2018181399A1 (en) * | 2017-03-31 | 2018-10-04 | 古河電気工業株式会社 | Plated wire rod material, method for producing same, and cable, electric wire, coil and spring member, each of which is formed using same |
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2010
- 2010-09-10 JP JP2010202602A patent/JP2012057225A/en active Pending
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106337171A (en) * | 2015-07-07 | 2017-01-18 | 株式会社神户制钢所 | Bottom-deposited substrate for Ni-coating technology, laminate body having Ni-coated layer and magnetic recording medium |
| JP2017021884A (en) * | 2015-07-07 | 2017-01-26 | 株式会社神戸製鋼所 | GROUND LAYER COATING SUBSTRATE USED FOR Ni PLATING, LAMINATE INCLUDING Ni PLATING LAYER, AND MAGNETIC RECORDING MEDIUM |
| WO2018181399A1 (en) * | 2017-03-31 | 2018-10-04 | 古河電気工業株式会社 | Plated wire rod material, method for producing same, and cable, electric wire, coil and spring member, each of which is formed using same |
| JP6452912B1 (en) * | 2017-03-31 | 2019-01-16 | 古河電気工業株式会社 | Plated wire rod and its manufacturing method, and cable, electric wire, coil and spring member formed using the same |
| CN110494597A (en) * | 2017-03-31 | 2019-11-22 | 古河电气工业株式会社 | Plating wire and rod and its manufacturing method and cable, electric wire, coil and the spring member formed using it |
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