JPH05287555A - Surface-treated steel sheet excellent in coating suitability and its production - Google Patents
Surface-treated steel sheet excellent in coating suitability and its productionInfo
- Publication number
- JPH05287555A JPH05287555A JP9522392A JP9522392A JPH05287555A JP H05287555 A JPH05287555 A JP H05287555A JP 9522392 A JP9522392 A JP 9522392A JP 9522392 A JP9522392 A JP 9522392A JP H05287555 A JPH05287555 A JP H05287555A
- Authority
- JP
- Japan
- Prior art keywords
- steel sheet
- zinc
- layer
- treated
- silica
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
Landscapes
- Chemically Coating (AREA)
- Electroplating Methods And Accessories (AREA)
- Other Surface Treatments For Metallic Materials (AREA)
Abstract
Description
【0001】[0001]
【産業上の利用分野】本発明は、塗装性にすぐれる表面
処理鋼板及びその製造方法に関し、詳しくは、厳しい加
工を受けても、また、種々多様な条件下において長期間
にわたつて保管された後であつても、塗装性が劣化しな
い電解クロメート処理亜鉛系めつき鋼板及びその製造方
法に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a surface-treated steel sheet having excellent coatability and a method for producing the same, and more particularly, to a surface-treated steel sheet which has undergone severe processing and is stored for a long period of time under various conditions. TECHNICAL FIELD The present invention relates to an electrolytic chromate-treated zinc-based plated steel sheet which does not deteriorate in paintability and a manufacturing method thereof.
【0002】[0002]
【従来の技術】鋼板の防錆を目的として、鋼板に亜鉛め
つきや亜鉛系合金めつきを施した後に、更に、その表面
にクロメート処理を施すことは、従来、広く行なわれて
おり、そのようなクロメート処理亜鉛系めつき鋼板は、
家庭電気製品、自動車、建材等の幅広い分野で多量に用
いられている。2. Description of the Related Art It has been widely practiced in the past to subject a steel sheet to zinc plating or zinc-based alloy plating and then subject the surface thereof to a chromate treatment for the purpose of preventing corrosion of the steel sheet. Such chromate-treated zinc-based plated steel sheets are
It is used in large quantities in a wide range of fields such as home appliances, automobiles, and building materials.
【0003】しかしながら、近年、このようなクロメー
ト処理亜鉛系めつき鋼板に対する要求はますますその厳
しさを増しつつあり、単なる一次防錆技術としてのみで
なく、塗装なしでも、長期の使用に耐え得る高耐食性
や、リン酸塩処理等の塗装前処理なしでも、良好な塗膜
密着性を有する塗装性、更には、これら二つの性能を併
せ有することが要求されている。However, in recent years, the demand for such chromate-treated zinc-based plated steel sheets is becoming more and more severe, and not only as a simple primary anticorrosion technique, but also capable of withstanding long-term use without painting. It is required to have high corrosion resistance, coatability with good coating adhesion even without pretreatment such as phosphate treatment, and further to have these two properties in combination.
【0004】従来、一般に行なわれているクロメート処
理は、塗布型、反応型及び電解型の3種類に分類され、
これらのなかで、下地の鋼板の反応性の相違にそれほど
影響されないこと、ラインの高速化に対応して、短時間
で処理が可能であること、更に、被膜量の制御が容易で
あり、均一処理が可能であること等から、従来、電解ク
ロメート処理が広く採用されている。しかし、この電解
クロメート処理によつて得られる被膜は、Cr3+が主体で
あつて、Cr6+が少ないために、塗布型及び反応型クロメ
ート処理によつて得られる被膜に比べて、塗装性はすぐ
れるものの、耐食性に劣るといわれている。Conventionally, the chromate treatment generally performed is classified into three types: coating type, reaction type and electrolytic type.
Among these, it is not so much affected by the difference in reactivity of the base steel sheet, it can be processed in a short time corresponding to the speeding up of the line, and the amount of coating is easy to control and uniform. Conventionally, electrolytic chromate treatment has been widely adopted because it can be treated. However, the coating obtained by this electrolytic chromate treatment is mainly composed of Cr 3+ and has a small amount of Cr 6+ , so that the coating properties are better than those obtained by the coating type and reactive type chromate treatments. Although excellent, it is said to have poor corrosion resistance.
【0005】そこで、耐食性と塗装性とを兼ね備えたク
ロメート処理亜鉛系めつき鋼板を製造するために、従
来、例えば、カチオン型コロイダルシリカを含有する浴
で亜鉛系めつき鋼板を陰極電解処理する方法(特公昭6
1−54800号公報)や、コロイダルシリカ、アルミ
ナゾル及びフツ化物を含む浴で亜鉛系めつき鋼板を陰極
電解処理する方法(特開昭62−278298号公報)
等が提案されている。Therefore, in order to produce a chromate-treated zinc-plated steel sheet having both corrosion resistance and paintability, a conventional method is, for example, a method of subjecting a zinc-plated steel sheet to cathodic electrolytic treatment in a bath containing cationic colloidal silica. (Japanese Patent Publication 6
1-54800) or a method of subjecting a zinc-plated steel sheet to cathodic electrolytic treatment in a bath containing colloidal silica, alumina sol and fluoride (JP-A-62-278298).
Etc. have been proposed.
【0006】しかしながら、これらの方法によつて得ら
れる表面処理鋼板も、厳しい加工を行なつたときに、塗
膜が剥離したり、或いは保管条件によつては、長期間に
わたつて保管された後に塗装性が劣化する等、本来、す
ぐれているとされている塗装性にも未だ問題が残つてい
る。更に、電解浴中にシリカを配合した場合に、浴のpH
によつては、粒子が凝集する等、浴の管理が困難になる
という製造上の問題も残つている。However, the surface-treated steel sheet obtained by these methods also has a coating film that peels off when subjected to severe processing, or is stored for a long period of time depending on storage conditions. There is still a problem with the paintability that is originally said to be excellent, such as deterioration in paintability later. Furthermore, when silica is mixed in the electrolytic bath, the pH of the bath
However, there still remains a manufacturing problem that it is difficult to control the bath, such as agglomeration of particles.
【0007】[0007]
【発明が解決しようとする課題】本発明は、従来のクロ
メート処理亜鉛系めつき鋼板及びその製造における上記
した問題を解決するためになされたものであつて、厳し
い加工を受けても、また、種々多様な保管条件下に長期
間にわたつて保管された後であつても、塗装性が劣化し
ないクロメート処理亜鉛系めつき鋼板及びそのような表
面処理鋼板の製造方法を提供することを目的とする。DISCLOSURE OF THE INVENTION The present invention has been made to solve the above-mentioned problems in the conventional chromate-treated zinc-based plated steel sheet and its production. An object of the present invention is to provide a chromate-treated zinc-based plated steel sheet and a method for producing such a surface-treated steel sheet, in which paintability does not deteriorate even after being stored for a long period of time under various storage conditions. To do.
【0008】[0008]
【課題を解決するための手段】本発明による塗装性にす
ぐれる表面処理鋼板は、亜鉛系めつき層の上に金属クロ
ム層を有し、その上にCr3+主体であつて、Cr6+を含むク
ロム酸化物と水和酸化物からなる層を有し、更にその上
にシリカ層を有することを特徴とする。本発明による塗
装性にすぐれる表面処理鋼板は、図1に示すように、原
板である亜鉛系めつき鋼板1の上に金属クロム層2を有
し、その上にCr3+主体であつて、Cr6+を含むクロム酸化
物と水和酸化物からなる層3を有し、更にその上にシリ
カ層4を有する。A surface-treated steel sheet having excellent coatability according to the present invention has a metallic chromium layer on a zinc-based plating layer, and is composed mainly of Cr 3+ and has Cr 6 +. It is characterized in that it has a layer made of chromium oxide containing + and a hydrated oxide, and further has a silica layer thereon. As shown in FIG. 1, a surface-treated steel sheet having excellent coatability according to the present invention has a metallic chromium layer 2 on a zinc-based plated steel sheet 1 which is an original plate, on which a Cr 3+ main component is mainly formed. , Cr 6+ containing chromium oxide and a hydrated oxide layer 3, and a silica layer 4 thereon.
【0009】亜鉛系めつき鋼板1は、素地の鋼板に対し
て、犠牲防食能を有する亜鉛めつきを施して、鋼板の耐
食性を向上させる目的のために、従来より広く用いられ
るものであつて、特に限定されるものではない。従つ
て、本発明において、亜鉛系めつき鋼板は、特に限定さ
れるものではなく、純亜鉛めつきのほかに、亜鉛−ニッ
ケル、亜鉛−鉄、亜鉛−アルミニウム等の各種の亜鉛合
金めつき鋼板を含む。また、これら亜鉛系めつき鋼板を
製造する手法としては、電気めつき法、溶融めつき法、
蒸着めつき法等を挙げることができるが、特に、これら
に限定されるものではない。The zinc-based plated steel sheet 1 has been widely used in the past for the purpose of improving the corrosion resistance of the steel sheet by subjecting the base steel sheet to zinc plating having a sacrificial anticorrosion ability. It is not particularly limited. Therefore, in the present invention, the zinc-plated steel sheet is not particularly limited, and in addition to pure zinc plating, various zinc alloy plated steel sheets such as zinc-nickel, zinc-iron, zinc-aluminum, etc. Including. Further, as a method for producing these zinc-based plated steel sheets, an electric plating method, a fusion plating method,
The vapor deposition method and the like can be mentioned, but the method is not particularly limited thereto.
【0010】金属クロム層2は、下地の亜鉛系めつき層
及び上層のCr3+主体であつて、Cr6+を含むクロム酸化物
及び水和酸化物層と密着することによつて、下地の亜鉛
めつき層とクロメート被膜との密着性を維持するために
重要である。その付着量は、特に限定されるものではな
いが、多すぎるときは、上層のクロム酸化物と水和酸化
物層が薄くなつて、好ましくないので、全Cr付着量の2
/5以下とすることが望ましい。The metal chromium layer 2 is mainly composed of a zinc-based plating layer as an underlying layer and an upper Cr 3+ layer, and is adhered to a chromium oxide and hydrated oxide layer containing Cr 6+ to form an underlying layer. It is important for maintaining the adhesion between the zinc plating layer and the chromate film. The amount of adhesion is not particularly limited, but if it is too large, the chromium oxide and hydrated oxide layers in the upper layer become thin, which is not preferable.
It is desirable to be / 5 or less.
【0011】クロム酸化物及び水和酸化物層3は、上層
に対してすぐれた密着性を有すると同時に、Cr6+による
被膜の自己修復作用によつて耐食性を向上させる。Cr付
着量は、特に限定されるものではないが、耐食性及び塗
装性の改善効果を有効に発揮させるためには、少なくと
も5mg/m2必要であり、好ましくは10mg/m2以上であ
る。Cr付着量の上限量も何ら限定されるものではない
が、製造費用の問題もあり、更には、Cr付着量を多くし
すぎても、それに見合つて、耐食性が改善されるもので
もなく、また、クロメート被膜自体の凝集破壊によつ
て、塗装性が劣化することもあるので、通常は、200
mg/m2以下がよい。The chromium oxide and hydrated oxide layer 3 has excellent adhesion to the upper layer and, at the same time, improves the corrosion resistance by the self-repairing action of the coating film by Cr 6+ . The Cr deposition amount is not particularly limited, but it is necessary to be at least 5 mg / m 2 and preferably 10 mg / m 2 or more in order to effectively exert the effect of improving the corrosion resistance and the coating property. The upper limit of the Cr adhesion amount is not limited at all, but there is also a problem of manufacturing cost, and even if the Cr adhesion amount is too large, the corrosion resistance is not improved in proportion to it, and also, Since the chromate film itself may undergo cohesive failure, the coatability may deteriorate.
Less than mg / m 2 is good.
【0012】また、クロム酸化物及び水和酸化物被膜中
のCr6+量も特に限定されるものではないが、通常、全Cr
量に対して、0.002〜0.2の範囲であることが好まし
い。クロム酸化物及び水和酸化物被膜中のCr6+量の下限
量が全Cr量に対して0.002よりも少ないときは、自己
修復作用が弱く、耐食性の向上が望めず、他方、0.2を
越えるときは、被膜の着色が著しいうえに、塗膜密着性
を損なうおそれもあるからである。The amount of Cr 6+ in the chromium oxide and hydrated oxide coatings is not particularly limited either, but normally, the total Cr content is
It is preferably in the range of 0.002-0.2 based on the amount. When the lower limit of the Cr 6+ content in the chromium oxide and hydrated oxide coating is less than 0.002 with respect to the total Cr content, the self-repairing action is weak and improvement in corrosion resistance cannot be expected. When it exceeds 0.2, not only the coloring of the coating becomes remarkable but also the coating adhesion may be impaired.
【0013】本発明による表面処理鋼板においては、ク
ロメート被膜の表面上にシリカ層4を有することが一つ
の重要な特徴をなす。シリカを被膜中に共析させたクロ
メート処理亜鉛系めつき鋼板は、シリカを含有しないク
ロメート処理亜鉛系めつき鋼板に比べて、塗装性及び耐
食性にすぐれていることが、従来より知られている。し
かしながら、本発明者らは、シリカを被膜中に共析させ
たクロメート処理亜鉛系めつき鋼板であつても、厳しい
加工を受けた場合や、種々の環境下で長期間にわたつて
保管された場合には、塗装性が著しく劣化することがあ
ることを見出した。In the surface-treated steel sheet according to the present invention, one important feature is to have the silica layer 4 on the surface of the chromate film. It has been conventionally known that chromate-treated zinc-based plated steel sheets in which silica is co-deposited in the coating have superior coatability and corrosion resistance compared to chromate-treated zinc-based plated steel sheets that do not contain silica. .. However, the present inventors have found that even a chromate-treated zinc-based plated steel sheet in which silica is codeposited in a coating film is stored for a long period of time under severe processing or under various environments. In some cases, it has been found that the paintability may be significantly deteriorated.
【0014】そこで、本発明者らは、かかる問題を解決
するために鋭意研究した結果、被膜の表面にシリカ層を
有するクロメート処理亜鉛系めつき鋼板は、被膜中にシ
リカを共析させたクロメート処理亜鉛系めつき鋼板と同
等の耐食性を有すると共に、厳しい加工を受けた場合
や、種々の環境下で長期間にわたつて保管された場合に
おいても、すぐれた塗装性を維持し得ることを見出し
た。The inventors of the present invention have conducted extensive studies to solve such problems, and as a result, in a chromate-treated zinc-based plated steel sheet having a silica layer on the surface of the coating, chromate obtained by co-depositing silica in the coating. It has been found that it has the same corrosion resistance as the treated zinc-based plated steel sheet, and it can maintain excellent paintability even when subjected to severe processing or when it is stored for a long time in various environments. It was
【0015】被膜の表面にシリカ層を有するクロメート
処理亜鉛系めつき鋼板が、厳しい加工を受けた場合や、
種々の環境下で長期間にわたつて保管された場合におい
ても、すぐれた塗装性を維持する理由は、未だ必ずしも
明らかてはないが、以下のように考えられる。即ち、図
2に模式的に示すように、電解クロメート被膜中にシリ
カを共析させたクロメート処理亜鉛系めつき鋼板におい
ては、被膜中に多くのシリカが取り込まれるために、被
膜の最表面でのシリカの分散状態が必ずしも均一ではな
く、被膜表面のシリカの有する極性基と塗膜の接触率が
低くなる。このような被膜の状態でも、未加工或いは保
管なしに使用する場合は、被膜と塗膜との密着性は維持
されるが、加工を行なつた場合や、種々の条件下で長期
間にわたつて保管した場合には、被膜の変形や変性によ
つて、クロメート被膜の表面のシリカの有する極性基密
度が良好な塗膜密着性を維持するのに不十分となる。When a chromate-treated zinc-based plated steel sheet having a silica layer on the surface of the coating is subjected to severe processing,
The reason why the excellent paintability is maintained even when stored for a long period of time under various environments is not always clear, but it is considered as follows. That is, as schematically shown in FIG. 2, in a chromate-treated zinc-based plated steel sheet in which silica is co-deposited in an electrolytic chromate coating, a large amount of silica is incorporated into the coating, and therefore, the outermost surface of the coating The state of silica dispersion is not always uniform, and the contact ratio between the polar group of silica on the surface of the coating and the coating becomes low. Even in such a state of the coating, the adhesion between the coating and the coating is maintained when it is used without being processed or stored, but when it is processed or it is used for a long time under various conditions. When stored for a while, the polar group density of silica on the surface of the chromate coating becomes insufficient to maintain good coating adhesion due to the deformation and modification of the coating.
【0016】これに対して、被膜の表面にシリカ層を有
するクロメート処理亜鉛系めつき鋼板は、図3に示すよ
うに、クロメート被膜の表面に均一なシリカ層を有して
いるために、表面における極性基密度が極めて高く、加
工を行なつたり、種々の条件下で長期間にわたつて保管
して、クロメート被膜の変形や変性が起こつたりした場
合においても、被膜表面のシリカ層は均一であり、その
極性基密度が良好な塗膜密着性を維持するのに十分とな
る。On the other hand, the chromate-treated zinc-based plated steel sheet having a silica layer on the surface of the coating has a uniform silica layer on the surface of the chromate coating, as shown in FIG. The polar group density is extremely high and the silica layer on the coating surface is uniform even if it is processed or stored under various conditions for a long time and the chromate coating is deformed or modified. And its polar group density is sufficient to maintain good coating adhesion.
【0017】本発明において、シリカの付着量は、特に
限定されるものではないが、クロメート被膜上に均一に
付着させ、塗装性の改善効果を有効に発揮させるために
は、少なくとも5mg/m2以上であることが好ましい。他
方、その上限量は、特に限定されるものではないが、し
かし、余りに多くしても、それに見合う効果を得ること
ができるものでもなく、また、製造費用や製造の安定性
を考慮して、通常、100mg/m2以下であることが望ま
しい。In the present invention, the amount of silica deposited is not particularly limited, but at least 5 mg / m 2 is required in order to deposit the silica uniformly on the chromate film and effectively exert the effect of improving the coatability. The above is preferable. On the other hand, the upper limit amount is not particularly limited, but even if it is too large, it is not possible to obtain an effect commensurate with it, and in consideration of manufacturing cost and manufacturing stability, Usually, it is desirable that the amount is 100 mg / m 2 or less.
【0018】本発明によるかかる表面処理鋼板は、無水
クロム酸及び重クロム酸から選ばれる少なくとも1種
と、硫酸イオン、塩素イオン、硝酸イオン及びフッ素イ
オンから選ばれる少なくとも1種のアニオンとを含む溶
液中で亜鉛系めつき鋼板を陰極として電解処理を行な
い、その後、乾燥することなく、電解クロメート処理亜
鉛系めつき鋼板をコロイダルシリカを含有する溶液にて
処理することによつて得ることができる。The surface-treated steel sheet according to the present invention is a solution containing at least one selected from chromic anhydride and dichromic acid and at least one anion selected from sulfate ion, chloride ion, nitrate ion and fluorine ion. It can be obtained by electrolytically treating the zinc-plated steel sheet with a zinc-based plated steel sheet as a cathode, and then treating the electrolytic chromate-treated zinc-plated steel sheet with a solution containing colloidal silica without drying.
【0019】即ち、本発明によれば、先ず、無水クロム
酸及び重クロム酸から選ばれる少なくとも1種と、硫酸
イオン、塩素イオン、硝酸イオン及びフッ素イオンから
選ばれる少なくとも1種のアニオンとを含む溶液を電解
浴とし、この浴中にて亜鉛系めつき鋼板を陰極として電
解処理を行なつて、亜鉛めつき層の上に金属クロム層を
形成させ、その上にCr3+が主体であつて、Cr6+を含むク
ロム酸化物及び水和酸化物層を有するクロメート被膜を
形成させる。That is, according to the present invention, first, at least one selected from chromic anhydride and dichromic acid and at least one anion selected from sulfate ion, chloride ion, nitrate ion and fluorine ion are contained. The solution is used as an electrolytic bath, and in this bath, a zinc-based plated steel sheet is used as the cathode for electrolytic treatment to form a metallic chromium layer on the zinc plated layer, and Cr 3+ is the main component on the layer. Form a chromate film having a chromium oxide layer containing Cr 6+ and a hydrated oxide layer.
【0020】本発明において、電解クロメート処理温度
は、特に、限定されるものではないが、浴温の管理の容
易さや経済性を考慮すれば、実用的には、通常、常温か
ら70℃の範囲が好適である。電流密度も、何ら制限さ
れるものではないが、20A/dm2を越えるときは、電
流効率が低下し、経済上、不利であるので、通常、20
A/dm2以下であることが好ましい。電解時間もまた、
何ら制約を受けるものではないが、通常、10秒以下の
範囲が工業上、好適である。In the present invention, the electrolytic chromate treatment temperature is not particularly limited, but in consideration of easiness of bath temperature control and economical efficiency, practically, it is usually in the range of normal temperature to 70 ° C. Is preferred. The current density is not limited either, but when it exceeds 20 A / dm 2 , the current efficiency is lowered and it is economically disadvantageous.
It is preferably A / dm 2 or less. The electrolysis time is also
Although not subject to any restriction, a range of 10 seconds or less is usually industrially suitable.
【0021】次に、本発明によれば、上記した電解処理
を行なつた後、乾燥することなく、電解クロメート処理
亜鉛系めつき鋼板をコロイダルシリカを含有する溶液に
て処理することによつて、塗装性にすぐれる表面処理鋼
板を得ることができる。電解クロメート処理亜鉛系めつ
き鋼板をコロイダルシリカを含有する溶液にて処理する
には、例えば、電解クロメート処理亜鉛系めつき鋼板を
コロイダルシリカを含有する溶液に浸漬するか、又は電
解クロメート処理亜鉛系めつき鋼板にコロイダルシリカ
を含有する溶液を噴霧する等すればよい。Next, according to the present invention, after the above electrolytic treatment is performed, the electrolytic chromate-treated zinc-based plated steel sheet is treated with a solution containing colloidal silica without being dried. It is possible to obtain a surface-treated steel sheet having excellent coatability. To treat an electrolytic chromate-treated zinc-based plated steel sheet with a solution containing colloidal silica, for example, dip the electrolytic chromate-treated zinc-based plated steel sheet in a solution containing colloidal silica, or electrolytic chromate-treated zinc-based A solution containing colloidal silica may be sprayed onto the plated steel sheet.
【0022】この方法によれば、電解クロメート処理亜
鉛系めつき鋼板の表面の活性なクロメート層と液中のコ
ロイダルシリカとの反応によつて、被膜の表面に均一な
シリカ層を有する電解クロメート処理亜鉛系めつき鋼板
を製造することができ、コロイダルシリカを含む電解浴
中で亜鉛系めつき鋼板を陰極電解する方法によつては得
ることができなかつた、被膜表面に均一なシリカ層を有
する電解クロメート処理亜鉛系めつき鋼板を得ることが
できる。According to this method, the reaction between the active chromate layer on the surface of the electrolytically chromate-treated zinc-plated steel sheet and colloidal silica in the liquid results in electrolytic chromate treatment having a uniform silica layer on the surface of the coating film. A zinc-based plated steel sheet can be produced, which cannot be obtained by the method of cathodic electrolysis of a zinc-based plated steel sheet in an electrolytic bath containing colloidal silica, and has a uniform silica layer on the coating surface. An electrolytic chromate-treated zinc-based plated steel sheet can be obtained.
【0023】本発明において、コロイダルシリカ溶液の
濃度は、特に限定されるものではないが、通常、1〜3
00g/lの範囲である。濃度が1g/lよりも小さい
ときは、得られるシリカ層が不均一となり、塗装性の改
善効果に乏しく、他方、300g/lを越えるとき、浴
中のシリカがゲル化しやすく、溶液の管理が困難となつ
て、経済的に不利となる。In the present invention, the concentration of the colloidal silica solution is not particularly limited, but usually 1 to 3
It is in the range of 00 g / l. When the concentration is less than 1 g / l, the obtained silica layer becomes non-uniform and the effect of improving the coatability is poor, while when it exceeds 300 g / l, the silica in the bath tends to gel and the solution management is difficult. Difficult and economically disadvantageous.
【0024】前記コロイダルシリカの溶液は、鋼板に接
触させることによつて、クロメート被膜を造膜する作用
を有する溶液でなければ、特に制約を受けるものではな
く、液のpHも特に限定されず、液中のコロイダルシリカ
が最も安定して存在するpHで用いることができる。ま
た、コロイダルシリカの溶液の温度も、何ら限定される
ものではないが、通常、実用的には、常温から70℃の
範囲がよい。更に、本発明において、電解クロメート処
理亜鉛系めつき鋼板をコロイダルシリカを含有する溶液
にて処理する時間は、工業上は、通常、10秒以下が好
適である。The colloidal silica solution is not particularly limited unless it has a function of forming a chromate film by bringing it into contact with a steel sheet, and the pH of the solution is not particularly limited, either. It can be used at the pH at which the colloidal silica in the liquid is most stable. Further, the temperature of the colloidal silica solution is not limited at all, but usually it is preferably in the range of room temperature to 70 ° C. for practical use. Further, in the present invention, industrially, the time for treating the electrolytic chromate-treated zinc-based plated steel sheet with the solution containing colloidal silica is usually 10 seconds or less.
【0025】[0025]
【実施例】以下に実施例を挙げて本発明を説明するが、
本発明はこれら実施例により何ら限定されるものではな
い。尚、以下の実施例及び比較例においては、亜鉛系め
つき鋼板を処理した後、温度60℃で10分間乾燥し
て、後述する塗装性試験及び耐食性試験に供した。The present invention will be described below with reference to examples.
The present invention is not limited to these examples. In addition, in the following Examples and Comparative Examples, a zinc-based plated steel sheet was treated, dried at a temperature of 60 ° C. for 10 minutes, and subjected to a paintability test and a corrosion resistance test described below.
【0026】実施例1 公知の方法で清浄にした電気亜鉛めつき鋼板(亜鉛付着
量:20g/m2)を以下の条件で陰極電解処理した。 電気浴組成 CrO3 :50g/l SO4 2-/CrO3:0.004 浴温度 45℃ 電解条件 電流密度:5A/dm2 電解時間:2秒 この後、このように処理した鋼板をシリカ濃度30g/
l、温度45℃の液に2秒間浸漬した。Example 1 A galvanized steel sheet (zinc coverage: 20 g / m 2 ) cleaned by a known method was subjected to cathodic electrolysis treatment under the following conditions. Electric bath composition CrO 3 : 50 g / l SO 4 2− / CrO 3 : 0.004 Bath temperature 45 ° C. Electrolysis conditions Current density: 5 A / dm 2 Electrolysis time: 2 seconds After that, the steel sheet treated in this way had a silica concentration. 30 g /
It was dipped in a liquid having a temperature of 45 ° C. for 2 seconds.
【0027】実施例2 公知の方法で清浄にした電気亜鉛めつき鋼板(亜鉛付着
量:20g/m2)を以下の条件で陰極電解処理した。 電気浴組成 CrO3 :50g/l SO4 2-/CrO3:0.004 浴温度 45℃ 電解条件 電流密度:5A/dm2 電解時間:2秒 この後、このように処理した鋼板をシリカ濃度100g
/l、温度45℃の液に2秒間浸漬した。Example 2 A galvanized steel sheet (zinc coverage: 20 g / m 2 ) cleaned by a known method was subjected to cathodic electrolytic treatment under the following conditions. Electric bath composition CrO 3 : 50 g / l SO 4 2− / CrO 3 : 0.004 Bath temperature 45 ° C. Electrolysis conditions Current density: 5 A / dm 2 Electrolysis time: 2 seconds After that, the steel sheet treated in this way had a silica concentration. 100g
/ L and the temperature of 45 ° C. for 2 seconds.
【0028】実施例3 公知の方法で清浄にした電気亜鉛めつき鋼板(亜鉛付着
量:20g/m2)を以下の条件で陰極電解処理した。 電気浴組成 CrO3 :50g/l SO4 2-/CrO3:0.004 浴温度 45℃ 電解条件 電流密度:5A/dm2 電解時間:2秒 この後、このように処理した鋼板をシリカ濃度200g
/l、温度45℃の液に2秒間浸漬した。Example 3 A galvanized steel sheet (zinc coverage: 20 g / m 2 ) cleaned by a known method was subjected to cathodic electrolysis treatment under the following conditions. Electric bath composition CrO 3 : 50 g / l SO 4 2− / CrO 3 : 0.004 Bath temperature 45 ° C. Electrolysis conditions Current density: 5 A / dm 2 Electrolysis time: 2 seconds After that, the steel sheet treated in this way had a silica concentration. 200 g
/ L and the temperature of 45 ° C. for 2 seconds.
【0029】実施例4 公知の方法で清浄にした電気亜鉛めつき鋼板(亜鉛付着
量:20g/m2)を以下の条件で陰極電解処理した。 電気浴組成 CrO3 :30g/l SO4 2-/CrO3:0.006 浴温度 45℃ 電解条件 電流密度:5A/dm2 電解時間:2秒 この後、このように処理した鋼板をシリカ濃度30g/
l、温度45℃の液に2秒間浸漬した。Example 4 A galvanized steel sheet (zinc coverage: 20 g / m 2 ) cleaned by a known method was subjected to cathodic electrolysis treatment under the following conditions. Electrolytic bath composition CrO 3 : 30 g / l SO 4 2- / CrO 3 : 0.006 Bath temperature: 45 ° C Electrolysis conditions Current density: 5 A / dm 2 Electrolysis time: 2 seconds After that, the steel plate treated in this way had a silica concentration. 30 g /
It was dipped in a liquid having a temperature of 45 ° C. for 2 seconds.
【0030】実施例5 公知の方法で清浄にした電気亜鉛めつき鋼板(亜鉛付着
量:90g/m2)を以下の条件で陰極電解処理した。 電気浴組成 CrO3 :50g/l SO4 2-/CrO3:0.004 浴温度 45℃ 電解条件 電流密度:5A/dm2 電解時間:6秒 この後、このように処理した鋼板をシリカ濃度30g/
l、温度45℃の液に2秒間浸漬した。Example 5 A galvanized steel sheet (zinc coverage: 90 g / m 2 ) cleaned by a known method was subjected to cathodic electrolysis treatment under the following conditions. Electrolytic bath composition CrO 3 : 50 g / l SO 4 2- / CrO 3 : 0.004 Bath temperature 45 ° C Electrolysis conditions Current density: 5 A / dm 2 Electrolysis time: 6 seconds After this, the steel plate treated in this way was treated with silica. 30 g /
It was dipped in a liquid having a temperature of 45 ° C. for 2 seconds.
【0031】実施例6 公知の方法で清浄にした電気亜鉛めつき鋼板(亜鉛付着
量:20g/m2)を以下の条件で陰極電解処理した。 電気浴組成 CrO3 :50g/l SO4 2-/CrO3:0.004 浴温度 45℃ 電解条件 電流密度:10A/dm2 電解時間:2秒 この後、このように処理した鋼板をシリカ濃度30g/
l、温度45℃の液に2秒間浸漬した。Example 6 A galvanized steel sheet (zinc coverage: 20 g / m 2 ) cleaned by a known method was subjected to cathodic electrolytic treatment under the following conditions. Electrolytic bath composition CrO 3 : 50 g / l SO 4 2− / CrO 3 : 0.004 Bath temperature 45 ° C. Electrolysis conditions Current density: 10 A / dm 2 Electrolysis time: 2 seconds After that, the steel plate treated in this way had a silica concentration. 30 g /
It was dipped in a liquid having a temperature of 45 ° C. for 2 seconds.
【0032】実施例7 公知の方法で清浄にした電気亜鉛めつき鋼板(亜鉛付着
量:20g/m2)を以下の条件で陰極電解処理した。 電気浴組成 CrO3 :50g/l SO4 2-/CrO3:0.004 浴温度 45℃ 電解条件 電流密度:5A/dm2 電解時間:2秒 この後、このように処理した鋼板をシリカ濃度30g/
l、温度45℃の液に2秒間浸漬した。Example 7 A galvanized steel sheet (zinc coverage: 20 g / m 2 ) cleaned by a known method was subjected to cathodic electrolytic treatment under the following conditions. Electric bath composition CrO 3 : 50 g / l SO 4 2− / CrO 3 : 0.004 Bath temperature 45 ° C. Electrolysis conditions Current density: 5 A / dm 2 Electrolysis time: 2 seconds After that, the steel sheet treated in this way had a silica concentration. 30 g /
It was dipped in a liquid having a temperature of 45 ° C. for 2 seconds.
【0033】実施例8 公知の方法で清浄にした溶融亜鉛めつき鋼板(亜鉛付着
量:90g/m2)を以下の条件で陰極電解処理した。 電気浴組成 CrO3 :50g/l SO4 2-/CrO3:0.004 浴温度 45℃ 電解条件 電流密度:5A/dm2 電解時間:2秒 この後、このように処理した鋼板をシリカ濃度30g/
l、温度45℃の液に2秒間浸漬した。Example 8 A galvanized steel sheet (zinc coverage: 90 g / m 2 ) cleaned by a known method was subjected to cathodic electrolytic treatment under the following conditions. Electric bath composition CrO 3 : 50 g / l SO 4 2− / CrO 3 : 0.004 Bath temperature 45 ° C. Electrolysis conditions Current density: 5 A / dm 2 Electrolysis time: 2 seconds After that, the steel sheet treated in this way had a silica concentration. 30 g /
It was dipped in a liquid having a temperature of 45 ° C. for 2 seconds.
【0034】実施例9 公知の方法で清浄にした亜鉛−ニッケルめつき鋼板(亜
鉛付着量:20g/m2、ニッケル付着量:2.2g/m2)
を以下の条件で陰極電解処理した。 電気浴組成 CrO3 :50g/l SO4 2-/CrO3:0.004 浴温度 45℃ 電解条件 電流密度:5A/dm2 電解時間:2秒 この後、このように処理した鋼板をシリカ濃度30g/
l、温度45℃の液に2秒間浸漬した。Example 9 Zinc-nickel plated steel sheet cleaned by a known method (zinc coverage: 20 g / m 2 , nickel coverage: 2.2 g / m 2 ).
Was subjected to cathodic electrolysis treatment under the following conditions. Electric bath composition CrO 3 : 50 g / l SO 4 2− / CrO 3 : 0.004 Bath temperature 45 ° C. Electrolysis conditions Current density: 5 A / dm 2 Electrolysis time: 2 seconds After that, the steel sheet treated in this way had a silica concentration. 30 g /
It was dipped in a liquid having a temperature of 45 ° C. for 2 seconds.
【0035】比較例1 公知の方法で清浄にした電気亜鉛めつき鋼板(亜鉛付着
量:20g/m2)を以下の条件で陰極電解処理した。 電気浴組成 CrO3 :50g/l SO4 2-/CrO3:0.004 浴温度 45℃ 電解条件 電流密度:5A/dm2 電解時間:2秒Comparative Example 1 A galvanized steel sheet (zinc coverage: 20 g / m 2 ) cleaned by a known method was subjected to cathodic electrolysis treatment under the following conditions. Electric bath composition CrO 3 : 50 g / l SO 4 2- / CrO 3 : 0.004 Bath temperature 45 ° C Electrolysis conditions Current density: 5 A / dm 2 Electrolysis time: 2 seconds
【0036】比較例2 公知の方法で清浄にした電気亜鉛めつき鋼板(亜鉛付着
量:20g/m2)を以下の条件で陰極電解処理した。 電気浴組成 CrO3 :50g/l SO4 2-/CrO3:0.004 SiO2ゾル :30g/l 浴温度 45℃ 電解条件 電流密度:5A/dm2 電解時間:2秒Comparative Example 2 A galvanized steel sheet (zinc coverage: 20 g / m 2 ) cleaned by a known method was subjected to cathodic electrolytic treatment under the following conditions. Electric bath composition CrO 3 : 50 g / l SO 4 2- / CrO 3 : 0.004 SiO 2 sol: 30 g / l Bath temperature 45 ° C. Electrolysis conditions Current density: 5 A / dm 2 Electrolysis time: 2 seconds
【0037】比較例3 公知の方法で清浄にした電気亜鉛めつき鋼板(亜鉛付着
量:20g/m2)を以下の条件で陰極電解処理した。 電気浴組成 CrO3 :50g/l SO4 2-/CrO3:0.004 SiO2ゾル :100g/l 浴温度 45℃ 電解条件 電流密度:5A/dm2 電解時間:2秒Comparative Example 3 A galvanized steel sheet (zinc coverage: 20 g / m 2 ) cleaned by a known method was subjected to cathodic electrolysis treatment under the following conditions. Electric bath composition CrO 3 : 50 g / l SO 4 2- / CrO 3 : 0.004 SiO 2 sol: 100 g / l Bath temperature 45 ° C. Electrolysis conditions Current density: 5 A / dm 2 Electrolysis time: 2 seconds
【0038】比較例4 公知の方法で清浄にした溶融亜鉛めつき鋼板(亜鉛付着
量:90g/m2)を以下の条件で陰極電解処理した。 電解浴組成 CrO3 :50g/l SO4 2-/CrO3:0.004 SiO2ゾル :30g/l 浴温度 45℃ 電解条件 電流密度:5A/dm2 電解時間:2秒Comparative Example 4 A molten zinc plated steel sheet (zinc coverage: 90 g / m 2 ) cleaned by a known method was subjected to cathodic electrolysis treatment under the following conditions. Electrolyte bath composition CrO 3 : 50 g / l SO 4 2- / CrO 3 : 0.004 SiO 2 sol: 30 g / l Bath temperature 45 ° C. Electrolysis conditions Current density: 5 A / dm 2 Electrolysis time: 2 seconds
【0039】比較例5 公知の方法で清浄にした電気亜鉛めつき鋼板(亜鉛付着
量:20g/m2)を以下の条件で陰極電解処理した。 電解浴組成 CrO3 :30g/l SO4 2-/CrO3:0.006 SiO2ゾル :30g/l 浴温度 45℃ 電解条件 電流密度:5A/dm2 電解時間:2秒Comparative Example 5 A galvanized steel sheet (zinc coverage: 20 g / m 2 ) cleaned by a known method was subjected to cathodic electrolysis treatment under the following conditions. Electrolyte bath composition CrO 3 : 30 g / l SO 4 2- / CrO 3 : 0.006 SiO 2 sol: 30 g / l Bath temperature 45 ° C. Electrolysis conditions Current density: 5 A / dm 2 Electrolysis time: 2 seconds
【0040】比較例6 公知の方法で清浄にした電気亜鉛めつき鋼板(亜鉛付着
量:20g/m2)を以下の条件で陰極電解処理した。 電解浴組成 CrO3 :50g/l SO4 2-/CrO3:0.004 SiO2ゾル :30g/l 浴温度 45℃ 電解条件 電流密度:5A/dm2 電解時間:6秒Comparative Example 6 A galvanized steel sheet (zinc coverage: 20 g / m 2 ) cleaned by a known method was subjected to cathodic electrolysis treatment under the following conditions. Electrolytic bath composition CrO 3 : 50 g / l SO 4 2- / CrO 3 : 0.004 SiO 2 sol: 30 g / l Bath temperature 45 ° C. Electrolysis conditions Current density: 5 A / dm 2 Electrolysis time: 6 seconds
【0041】比較例7 公知の方法で清浄にした電気亜鉛めつき鋼板(亜鉛付着
量:20g/m2)を以下の条件で陰極電解処理した。 電解浴組成 CrO3 :50g/l SO4 2-/CrO3:0.004 SiO2ゾル :30g/l 浴温度 45℃ 電解条件 電流密度:10A/dm2 電解時間:2秒Comparative Example 7 A galvanized steel sheet (zinc coverage: 20 g / m 2 ) cleaned by a known method was subjected to cathodic electrolysis treatment under the following conditions. Electrolyte bath composition CrO 3 : 50 g / l SO 4 2- / CrO 3 : 0.004 SiO 2 sol: 30 g / l Bath temperature 45 ° C. Electrolysis conditions Current density: 10 A / dm 2 Electrolysis time: 2 seconds
【0042】比較例8 公知の方法で清浄にした電気亜鉛めつき鋼板(亜鉛付着
量:20g/m2)を市販のリン酸塩溶液で処理した。Comparative Example 8 A galvanized steel sheet (zinc coverage: 20 g / m 2 ) cleaned by a known method was treated with a commercially available phosphate solution.
【0043】以上のようにして得られたそれぞれの電解
クロメート処理亜鉛系めつき鋼板について、以下の方法
によつて耐食性及び塗装性試験を行なつた。塗装性試験 試料作製の直後と、温度60℃、相対湿度30%の雰囲
気下で80日間保管した後とに、それぞれアミノアルキ
ド系塗料をバーコーターにて塗布し、焼付けて、厚さ2
0μmの塗膜を形成し、塗膜の密着性試験を行なつた。
塗膜の密着性は、塗膜の表面に1mm×1mmの碁盤目をカ
ツターナイフにて罫書きし、エリクセン試験機で6mm押
出した後、粘着テープを貼着し、次いで、そのテープを
剥離して、その際の塗膜の残存率にて評価した。○は塗
膜剥離なし、△は塗膜が一部剥離した、×は塗膜の大部
分が剥離した、を示す。耐食性試験 JIS Z−2371に規定されている方法に準じて、
塩水噴霧試験を行なつて、白錆発生面積率が1%になる
までの時間を測定し、この時間によつて評価した。即
ち、1%白錆発生時間が○は120時間以上、△は70
〜120時間、×は70時間以下を示す。The electrolytic chromate-treated zinc-based plated steel sheets obtained as described above were tested for corrosion resistance and paintability by the following methods. Paintability test Immediately after preparation of the sample and after storage in an atmosphere at a temperature of 60 ° C. and a relative humidity of 30% for 80 days, an aminoalkyd-based paint was applied by a bar coater and baked to a thickness of 2
A coating film having a thickness of 0 μm was formed and an adhesion test of the coating film was performed.
The adhesion of the coating film is determined by marking the surface of the coating film with a 1 mm x 1 mm grid with a cutter knife, extruding 6 mm with an Erichsen tester, applying an adhesive tape, and then peeling off the tape. The residual rate of the coating film at that time was evaluated. O indicates that the coating film was not peeled off, Δ indicates that the coating film was partially peeled off, and X indicates that most of the coating film was peeled off. Corrosion resistance test According to the method specified in JIS Z-2371,
A salt spray test was conducted to measure the time until the white rust occurrence area ratio reached 1%, and the time was evaluated. That is, 1% white rust occurrence time is 120 hours or more, and Δ is 70
~ 120 hours, x indicates 70 hours or less.
【0044】前記実施例及び比較例について、上記の塗
装性試験及び耐食性試験の結果を表1に示す。本発明の
実施例によれば、いずれも、耐食性、試料作成直後及び
保管後の塗装性のすべてにすぐれている。一方、被膜に
シリカを含まない比較例1、シリカを被膜中に共析させ
た比較例2〜7及びリン酸塩処理を行なつた比較例8
は、いずれも、耐食性、試料作成直後及び保管後の塗装
性のうちの少なくとも一つ、特に、保管後野塗装性に劣
つている。Table 1 shows the results of the paintability test and the corrosion resistance test of the above Examples and Comparative Examples. According to the examples of the present invention, all are excellent in corrosion resistance, coatability immediately after sample preparation and after storage. On the other hand, Comparative Example 1 in which the coating does not contain silica, Comparative Examples 2 to 7 in which silica is co-deposited in the coating, and Comparative Example 8 in which the phosphate treatment is performed.
All of them are inferior in at least one of corrosion resistance, coatability immediately after preparation of the sample and after storage, particularly, coatability after storage.
【0045】[0045]
【表1】 [Table 1]
【0046】[0046]
【発明の効果】以上のように、本発明の方法によれば、
亜鉛系めつき層の上に金属クロム層を有し、その上にCr
3+主体であつて、Cr6+を含むクロム酸化物と水和酸化物
からなる層を有し、更にその上にシリカ層を有するの
で、厳しい加工を受けても、また、種々多様な条件下に
おいて長期間にわたつて保管された後であつても、安定
して、すぐれた塗装性を有する。As described above, according to the method of the present invention,
It has a metallic chromium layer on the zinc-based plating layer, and Cr on it.
It is mainly composed of 3+ and has a layer consisting of chromium oxide containing Cr 6+ and hydrated oxide, and further has a silica layer on top of it, so even if it is subjected to severe processing, it can be used under various conditions. It has stable and excellent coatability even after being stored for a long period of time underneath.
【図1】は、本発明による表面処理鋼板の深さ方向の組
成変化をESCAによつて分析した図である。FIG. 1 is a diagram in which a composition change in a depth direction of a surface-treated steel sheet according to the present invention is analyzed by ESCA.
【図2】は、被膜中にシリカを共析させたクロメート処
理亜鉛系めつき鋼板を示す模式図である。FIG. 2 is a schematic view showing a chromate-treated zinc-based plated steel sheet in which silica is co-deposited in the coating.
【図3】は、本発明に従つて、クロメート被膜上に均一
なシリカ層を有するクロメート処理亜鉛系めつき鋼板を
示す模式図である。FIG. 3 is a schematic diagram showing a chromate-treated zinc-based plated steel sheet having a uniform silica layer on a chromate film according to the present invention.
【符号の説明】 1…塗膜、2…シリカの有する極性基(水酸基)、3…
コロイダルシリカ、4…Cr3+を主体とし、Cr6+を含むク
ロム酸化物及び水和酸化物からなる層、5…金属クロム
層、6…亜鉛系めつき層。[Explanation of Codes] 1 ... Coating film, 2 ... Polar group (hydroxyl group) of silica, 3 ...
Colloidal silica, 4 ... A layer mainly composed of Cr 3+ and made of chromium oxide and hydrated oxide containing Cr 6+ , 5 ... Metal chromium layer, 6 ... Zinc-based plating layer.
フロントページの続き (72)発明者 梶田 富男 神戸市中央区脇浜町1丁目3番18号 株式 会社神戸製鋼所神戸本社内Front Page Continuation (72) Inventor Tomio Kajita 1-3-18 Wakihamacho, Chuo-ku, Kobe City Kobe Steel, Ltd. Kobe Head Office
Claims (3)
その上にCr3+が主体であつて、Cr6+を含むクロム酸化物
と水和酸化物からなる層を有し、更にその上にシリカ層
を有することを特徴とする塗装性にすぐれる表面処理鋼
板。1. A metallic chromium layer on a zinc-based plating layer,
Cr 3+ is the main constituent on top of it, and it has a layer consisting of chromium oxide containing Cr 6+ and hydrated oxide, and has a silica layer on top of it, which is excellent in coatability. Surface treated steel sheet.
少なくとも1種とアニオンとを含む溶液中で亜鉛系めつ
き鋼板を陰極として電解処理を行ない、その後、乾燥す
ることなく、電解クロメート処理亜鉛系めつき鋼板をコ
ロイダルシリカを含有する溶液にて処理することを特徴
とする塗装性にすぐれる表面処理鋼板の製造方法。2. An electrolytic chromate-treated zinc is electrolyzed in a solution containing at least one selected from chromic anhydride and dichromic acid and an anion using a zinc-plated steel sheet as a cathode, and then without drying. A method for producing a surface-treated steel sheet having excellent coatability, which comprises treating a steel plate with a base material with a solution containing colloidal silica.
イオン又はフツ素イオンであることを特徴とする請求項
2記載の塗装性にすぐれる表面処理鋼板の製造方法。3. The method for producing a surface-treated steel sheet having excellent coatability according to claim 2, wherein the anion is a sulfate ion, a chlorine ion, a nitrate ion or a fluorine ion.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP9522392A JPH05287555A (en) | 1992-04-15 | 1992-04-15 | Surface-treated steel sheet excellent in coating suitability and its production |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP9522392A JPH05287555A (en) | 1992-04-15 | 1992-04-15 | Surface-treated steel sheet excellent in coating suitability and its production |
Publications (1)
Publication Number | Publication Date |
---|---|
JPH05287555A true JPH05287555A (en) | 1993-11-02 |
Family
ID=14131753
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP9522392A Pending JPH05287555A (en) | 1992-04-15 | 1992-04-15 | Surface-treated steel sheet excellent in coating suitability and its production |
Country Status (1)
Country | Link |
---|---|
JP (1) | JPH05287555A (en) |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
KR19990038332A (en) * | 1997-11-04 | 1999-06-05 | 이구택 | Chromate treatment method excellent in corrosion resistance and resin adhesion |
US6858321B2 (en) * | 2002-04-05 | 2005-02-22 | Yuken Industry Co., Ltd. | Corrosion resistant member |
-
1992
- 1992-04-15 JP JP9522392A patent/JPH05287555A/en active Pending
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
KR19990038332A (en) * | 1997-11-04 | 1999-06-05 | 이구택 | Chromate treatment method excellent in corrosion resistance and resin adhesion |
US6858321B2 (en) * | 2002-04-05 | 2005-02-22 | Yuken Industry Co., Ltd. | Corrosion resistant member |
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