JP2007162040A - Method for evaluating corrosion resistance in highly corrosion resistant member, highly corrosion resistant member and its production method - Google Patents

Method for evaluating corrosion resistance in highly corrosion resistant member, highly corrosion resistant member and its production method Download PDF

Info

Publication number
JP2007162040A
JP2007162040A JP2005356134A JP2005356134A JP2007162040A JP 2007162040 A JP2007162040 A JP 2007162040A JP 2005356134 A JP2005356134 A JP 2005356134A JP 2005356134 A JP2005356134 A JP 2005356134A JP 2007162040 A JP2007162040 A JP 2007162040A
Authority
JP
Japan
Prior art keywords
trivalent chromate
resistant member
plating layer
corrosion resistance
chromate film
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
Application number
JP2005356134A
Other languages
Japanese (ja)
Inventor
Takaaki Hayashida
高章 林田
Takayuki Sakakibara
隆之 榊原
Yukinori Kato
幸則 加藤
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Chuo Hatsujo KK
Chuo Spring Co Ltd
Original Assignee
Chuo Hatsujo KK
Chuo Spring Co Ltd
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Chuo Hatsujo KK, Chuo Spring Co Ltd filed Critical Chuo Hatsujo KK
Priority to JP2005356134A priority Critical patent/JP2007162040A/en
Publication of JP2007162040A publication Critical patent/JP2007162040A/en
Pending legal-status Critical Current

Links

Images

Classifications

    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C2222/00—Aspects relating to chemical surface treatment of metallic material by reaction of the surface with a reactive medium
    • C23C2222/10—Use of solutions containing trivalent chromium but free of hexavalent chromium

Landscapes

  • Chemical Treatment Of Metals (AREA)
  • Other Surface Treatments For Metallic Materials (AREA)

Abstract

<P>PROBLEM TO BE SOLVED: To provide an evaluating method capable of determining whether the corrosion resistance of a tervalent chromate film is good or not even without performing a corrosion resistance test, to provide a highly corrosion resistant member with a tervalent chromate film having high corrosion resistance, and to provide its production method. <P>SOLUTION: In the highly corrosion resistant member having: a substrate made of steel; a plating layer formed on the surface of the substrate; and a tervalent chromate film formed on the surface of the plating layer, whether the corrosion resistance of the tervalent chromate film is good or not is determined based on the value of the concentration ratio (Si/Cr) between silica and chromium in the tervalent chromate film. Further, the highly corrosion resistant member having the tervalent chromate film is composed in such a manner that the value of the concentration ratio (Si/Cr) between silica and chromium in the tervalent chromate film reaches ≥0.75. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

本発明は、６価クロムフリーの３価クロメート皮膜を持つ高耐食性部材の耐食性評価方法、高耐食性部材、およびその製造方法に関する。   The present invention relates to a method for evaluating corrosion resistance of a highly corrosion-resistant member having a hexavalent chromium-free trivalent chromate film, a highly corrosion-resistant member, and a method for producing the same.

自動車部品等の鋼製部材の防錆方法として、亜鉛や亜鉛合金めっき（以下、亜鉛系めっきと称す。）が広く用いられている。しかし、亜鉛系めっきのみでは白錆が発生し易いため、多くの場合は亜鉛系めっきの上に目的に応じたクロメート処理が施される。これまでのクロメート処理には、６価クロムが使用されてきた。しかし、処理品から溶出する６価クロムの人体や環境への影響が問題となり、近年では、６価クロムの使用を規制する動きが活発になってきている。６価クロムを使用しないクロメート処理として、例えば、３価クロムを用いたクロメート処理（以下、３価クロメート処理と称す。）がある（例えば、特許文献１、２参照。）
特開２００５−１２６７９７号公報 特開２００５−２４００６８号公報 Zinc and zinc alloy plating (hereinafter referred to as zinc-based plating) are widely used as a rust prevention method for steel members such as automobile parts. However, since white rust is likely to occur only with zinc-based plating, in many cases, chromate treatment according to the purpose is performed on the zinc-based plating. Until now, hexavalent chromium has been used for chromate treatment. However, the influence of hexavalent chromium eluted from treated products on the human body and the environment has become a problem, and in recent years, there has been an active movement to regulate the use of hexavalent chromium. As a chromate treatment that does not use hexavalent chromium, for example, there is a chromate treatment using trivalent chromium (hereinafter referred to as trivalent chromate treatment) (see, for example, Patent Documents 1 and 2).
Japanese Patent Laid-Open No. 2005-126797 Japanese Patent Laid-Open No. 2005-240068

一般に、３価クロメート処理により形成された３価クロメート皮膜は、皮膜の損傷に対する自己修復性がないといわれている。このため、６価クロムを用いたクロメート処理により形成された従来の皮膜と比較して、３価クロメート皮膜は傷に対して弱く、耐食性が低いことが問題となる。   In general, a trivalent chromate film formed by trivalent chromate treatment is said to have no self-repairing property against damage to the film. For this reason, compared with the conventional film | membrane formed by the chromate process using hexavalent chromium, a trivalent chromate film | membrane is weak with respect to a crack, and it has a problem that corrosion resistance is low.

３価クロメート皮膜の耐食性を向上させるため、例えば、３価クロメート処理の処理液（以下、３価クロメート処理液と称す。）にシリカ（Ｓｉ）を添加する試みがなされている。しかし、繰り返し使用された３価クロメート処理液を用いると、Ｓｉを添加しても充分な耐食性が得られない場合があることがわかった。   In order to improve the corrosion resistance of the trivalent chromate film, for example, attempts have been made to add silica (Si) to a trivalent chromate treatment liquid (hereinafter referred to as a trivalent chromate treatment liquid). However, it has been found that when a trivalent chromate treatment solution that has been used repeatedly is used, sufficient corrosion resistance may not be obtained even if Si is added.

本発明は、このような実状を鑑みてなされたものであり、３価クロメート皮膜が形成された高耐食性部材において、耐食性試験を行わなくても３価クロメート皮膜の耐食性の良否を判断することのできる評価方法を提供することを課題とする。また、耐食性に優れた３価クロメート皮膜を持つ高耐食性部材、およびその製造方法を提供することを課題とする。   The present invention has been made in view of such a situation, and in a highly corrosion-resistant member formed with a trivalent chromate film, it is possible to judge whether the trivalent chromate film has good corrosion resistance without performing a corrosion resistance test. It is an object to provide an evaluation method that can be used. It is another object of the present invention to provide a highly corrosion-resistant member having a trivalent chromate film excellent in corrosion resistance and a method for producing the same.

本発明者は、３価クロメート皮膜の耐食性について鋭意研究を重ねた結果、処理を繰り返して劣化した３価クロメート処理液を使用した場合に、３価クロメート皮膜中のＳｉとＣｒとの濃度比（Ｓｉ／Ｃｒ）の値と、同皮膜の耐食性との間に相関関係があることを見いだした。このような知見に基づいてなされた本発明の高耐食性部材の耐食性評価方法（以下、適宜「本発明の評価方法」と称す。）は、鋼製の基体と、該基体の表面に形成されためっき層と、該めっき層の表面に形成された３価クロメート皮膜と、を持つ高耐食性部材の耐食性評価方法であって、該３価クロメート皮膜中のシリカとクロムとの濃度比（Ｓｉ／Ｃｒ）の値に基づいて該３価クロメート皮膜の耐食性の良否を判断することを特徴とする（請求項１に対応）。   As a result of intensive research on the corrosion resistance of the trivalent chromate film, the present inventor, when using a trivalent chromate treatment solution that has deteriorated by repeated treatment, the concentration ratio of Si and Cr in the trivalent chromate film ( It has been found that there is a correlation between the value of (Si / Cr) and the corrosion resistance of the film. A corrosion resistance evaluation method for a highly corrosion-resistant member of the present invention based on such knowledge (hereinafter referred to as “the evaluation method of the present invention” as appropriate) was formed on a steel base and the surface of the base. A corrosion resistance evaluation method for a highly corrosion-resistant member having a plating layer and a trivalent chromate film formed on the surface of the plating layer, wherein the concentration ratio of silica and chromium in the trivalent chromate film (Si / Cr ), The quality of the corrosion resistance of the trivalent chromate film is judged (corresponding to claim 1).

後の実施例等で詳しく説明するが、本発明の評価方法では、３価クロメート皮膜中のＳｉ／Ｃｒの値に基づいて、その皮膜が所望の耐久性を有するか否かを判断する。すなわち、本発明の評価方法によれば、３価クロメート処理液の劣化の程度に関わらず、３価クロメート皮膜中のＳｉ／Ｃｒの値を算出するだけで、その皮膜の耐食性を簡便に予測することができる。また、従来は、３価クロメート処理液を、処理回数や処理時間で管理していた。このため、所定の処理回数等を超えれば、機械的に、つまり劣化の程度を測定することなく、３価クロメート処理液を交換したり、新しい同処理液を補充していた。しかし、本発明の評価方法によれば、形成された３価クロメート皮膜中のＳｉ／Ｃｒの値で、３価クロメート処理液の劣化の程度を把握することができる。つまり、３価クロメート皮膜中のＳｉ／Ｃｒの値で、３価クロメート処理液を管理することができる。このため、より合理的な３価クロメート処理が可能となる。   As will be described in detail in Examples and the like later, in the evaluation method of the present invention, it is determined whether or not the film has a desired durability based on the value of Si / Cr in the trivalent chromate film. That is, according to the evaluation method of the present invention, the corrosion resistance of the film can be easily predicted by simply calculating the value of Si / Cr in the trivalent chromate film regardless of the degree of deterioration of the trivalent chromate treatment solution. be able to. Conventionally, the trivalent chromate treatment liquid is managed by the number of treatments and the treatment time. For this reason, if the predetermined number of treatments is exceeded, the trivalent chromate treatment solution is replaced or a new treatment solution is replenished mechanically, that is, without measuring the degree of deterioration. However, according to the evaluation method of the present invention, the degree of deterioration of the trivalent chromate treatment liquid can be grasped from the value of Si / Cr in the formed trivalent chromate film. That is, the trivalent chromate treatment liquid can be managed by the value of Si / Cr in the trivalent chromate film. For this reason, a more rational trivalent chromate treatment becomes possible.

また、本発明の高耐食性部材は、鋼製の基体と、該基体の表面に形成されためっき層と、該めっき層の表面に形成された３価クロメート皮膜と、を持ち、該３価クロメート皮膜中のシリカとクロムとの濃度比（Ｓｉ／Ｃｒ）の値が０．７５以上であることを特徴とする（請求項４に対応）。   The highly corrosion-resistant member of the present invention has a steel base, a plating layer formed on the surface of the base, and a trivalent chromate film formed on the surface of the plating layer. The concentration ratio (Si / Cr) of silica and chromium in the film is 0.75 or more (corresponding to claim 4).

本発明の高耐食性部材は、Ｓｉ／Ｃｒの値が０．７５以上である３価クロメート皮膜が形成されている。本発明者が見いだした上記相関関係により、Ｓｉ／Ｃｒの値が０．７５以上であれば、３価クロメート皮膜の耐食性は高いことがわかった。この理由は明らかではないが、３価クロメート皮膜にＳｉが多量に含まれることで、その遮蔽効果等により耐食性が向上すると考えられる。このように、本発明の高耐食性部材は、人体、環境への負担が少ないことに加え、耐食性も良好である。   In the highly corrosion-resistant member of the present invention, a trivalent chromate film having a Si / Cr value of 0.75 or more is formed. From the above correlation found by the present inventor, it was found that when the value of Si / Cr is 0.75 or more, the corrosion resistance of the trivalent chromate film is high. The reason for this is not clear, but it is thought that the corrosion resistance is improved due to the shielding effect and the like by containing a large amount of Si in the trivalent chromate film. As described above, the highly corrosion-resistant member of the present invention has good corrosion resistance in addition to less burden on the human body and the environment.

また、本発明の高耐食性部材の製造方法は、亜鉛めっき層または亜鉛合金めっき層を持つ上記本発明の高耐食性部材の製造方法であって、鋼製の基体の表面に亜鉛めっき層または亜鉛合金めっき層を形成するめっき工程と、形成されためっき層の表面を３価クロメート処理液に接触させて、シリカとクロムとの濃度比（Ｓｉ／Ｃｒ）の値が０．７５以上である３価クロメート皮膜を形成する３価クロメート処理工程と、を含み、該３価クロメート処理工程における該３価クロメート処理液の温度は２０℃以上５０℃以下、ｐＨは１．６以上２．６以下、不純物である鉄、亜鉛の濃度は鉄：３０ｐｐｍ以下、亜鉛：１．５％以下、接触時間は１５秒以上５０秒以下であることを特徴とする（請求項６に対応）。本発明の製造方法によれば、劣化した３価クロメート処理液を使用しても、上記本発明の高耐食性部材を安定して簡便に製造することができる。   The method for producing a highly corrosion-resistant member of the present invention is a method for producing the highly corrosion-resistant member of the present invention having a galvanized layer or a zinc alloy plated layer, wherein the galvanized layer or zinc alloy is formed on the surface of the steel substrate. A plating process for forming a plating layer, and a surface of the formed plating layer is brought into contact with a trivalent chromate treatment solution, so that the value of the concentration ratio of silica and chromium (Si / Cr) is 0.75 or more. A trivalent chromate treatment step for forming a chromate film, wherein the temperature of the trivalent chromate treatment solution in the trivalent chromate treatment step is from 20 ° C to 50 ° C, the pH is from 1.6 to 2.6, impurities The iron and zinc concentrations are: iron: 30 ppm or less, zinc: 1.5% or less, and the contact time is 15 seconds or more and 50 seconds or less (corresponding to claim 6). According to the production method of the present invention, the highly corrosion-resistant member of the present invention can be stably and easily produced even when a deteriorated trivalent chromate treatment solution is used.

以下、本発明の高耐食性部材の耐食性評価方法、高耐食性部材、およびその製造方法の実施形態について詳しく説明する。なお、本明細書で説明する内容は、本発明に係る高耐食性部材の耐食性評価方法、高耐食性部材およびその製造方法に、適宜適用することができる。   Hereinafter, embodiments of the corrosion resistance evaluation method, the high corrosion resistance member, and the manufacturing method thereof of the high corrosion resistance member of the present invention will be described in detail. In addition, the content demonstrated by this specification is applicable suitably to the corrosion resistance evaluation method of the highly corrosion-resistant member which concerns on this invention, a highly corrosion-resistant member, and its manufacturing method.

〈高耐食性部材の耐食性評価方法〉
本発明の評価方法の適用対象となる高耐食性部材は、鋼製の基体と、該基体の表面に形成されためっき層と、該めっき層の表面に形成された３価クロメート皮膜と、を持つ。 <Method for evaluating corrosion resistance of highly corrosion-resistant materials>
A highly corrosion-resistant member to which the evaluation method of the present invention is applied has a steel base, a plating layer formed on the surface of the base, and a trivalent chromate film formed on the surface of the plating layer. .

基体は、硬鋼線材、オイルテンパー線材、ばね用鋼帯等の鋼製の部材であればよく、その形状等は特に限定されない。例えば、ばね座金、薄板ばね、コイルばね、ねじりコイルばね等の種々の部品が含まれる。   The substrate may be a steel member such as a hard steel wire, an oil tempered wire, or a spring steel strip, and the shape thereof is not particularly limited. For example, various components such as a spring washer, a thin plate spring, a coil spring, and a torsion coil spring are included.

基体の表面にはめっき層が形成される。めっき層の種類は特に限定されるものではないが、鉄の防錆めっきとして有用な亜鉛めっき層または亜鉛合金めっき層が望ましい。これら亜鉛系のめっき層は、常法により形成すればよい。例えば、所定のめっき浴に基体を一回ないしは複数回浸漬させればよい。亜鉛めっきには、シアン浴、酸性浴、ジンケート浴があり、亜鉛合金めっきには酸性浴、ジンケート浴がある。めっき層の厚さは特に限定されるものではなく、例えば、５μｍ以上３０μｍ以下であるとよい。   A plating layer is formed on the surface of the substrate. The type of the plating layer is not particularly limited, but a zinc plating layer or a zinc alloy plating layer useful as an anticorrosive plating of iron is desirable. These zinc-based plating layers may be formed by a conventional method. For example, the substrate may be immersed once or a plurality of times in a predetermined plating bath. Zinc plating includes a cyan bath, an acid bath, and a zincate bath, and zinc alloy plating includes an acid bath and a zincate bath. The thickness of a plating layer is not specifically limited, For example, it is good in it being 5 micrometers or more and 30 micrometers or less.

めっき層の表面には３価クロメート皮膜が形成される。３価クロメート皮膜は、３価クロム化合物、Ｓｉ等を含む３価クロメート処理液を用いた３価クロメート処理により形成すればよい。例えば、上記めっき処理を施した基体を、所定の３価クロメート処理液に浸浸させればよい。ここで、３価クロメート処理液の種類は特に限定されるものではない。例えば、Ｓｉを含有した３価クロメート液を単独で用いてもよく（一液型）、Ｓｉを含有しない３価クロメート液とＳｉ含有液とを混合して用いてもよい（二液型）。３価クロメート皮膜の厚さは特に限定されるものではなく、例えば、０．５μｍ以上１．０μｍ以下であるとよい。   A trivalent chromate film is formed on the surface of the plating layer. The trivalent chromate film may be formed by trivalent chromate treatment using a trivalent chromate treatment solution containing a trivalent chromium compound, Si, and the like. For example, the substrate subjected to the plating treatment may be immersed in a predetermined trivalent chromate treatment solution. Here, the kind of trivalent chromate treatment liquid is not particularly limited. For example, a trivalent chromate solution containing Si may be used alone (one-component type), or a trivalent chromate solution not containing Si and a Si-containing solution may be mixed and used (two-component type). The thickness of the trivalent chromate film is not particularly limited, and may be, for example, 0.5 μm or more and 1.0 μm or less.

本発明の評価方法では、３価クロメート皮膜中のシリカとクロムとの濃度比（Ｓｉ／Ｃｒ）の値に基づいて、３価クロメート皮膜の耐食性の良否を判断する。３価クロメート皮膜中のＳｉおよびＣｒの定量分析は、例えば、ＥＤＸ（エネルギー分散型蛍光Ｘ線分析装置）により行えばよい。そして、予め得られているＳｉ／Ｃｒ値と耐食性との相関関係から、所望の耐食性を満足するＳｉ／Ｃｒ値を決定し、そのＳｉ／Ｃｒ値を基準として、３価クロメート皮膜の耐食性を評価する。なお、Ｓｉ／Ｃｒ値と耐食性との相関関係を作成する際の耐食性は、例えば、塩水噴霧試験（ＪＩＳ Ｚ ２３７１）により、白錆が皮膜面積の５％以上発生する時間（白錆発生時間）で表すことができる。例えば、後の実施例で示す図１の相関関係において、目標とする耐食性を白錆発生時間で２４０時間以上と設定した場合には、Ｓｉ／Ｃｒ値が０．７５以上の３価クロメート皮膜を耐食性良好と判断する。   In the evaluation method of the present invention, the quality of the corrosion resistance of the trivalent chromate film is judged based on the value of the concentration ratio (Si / Cr) between silica and chromium in the trivalent chromate film. The quantitative analysis of Si and Cr in the trivalent chromate film may be performed by, for example, EDX (energy dispersive X-ray fluorescence analyzer). Then, from the correlation between the Si / Cr value obtained in advance and the corrosion resistance, the Si / Cr value satisfying the desired corrosion resistance is determined, and the corrosion resistance of the trivalent chromate film is evaluated based on the Si / Cr value. To do. In addition, the corrosion resistance when creating the correlation between the Si / Cr value and the corrosion resistance is, for example, a time during which white rust is generated by 5% or more of the film area (white rust generation time) by a salt spray test (JIS Z 2371). It can be expressed as For example, in the correlation of FIG. 1 shown in the later examples, when the target corrosion resistance is set to 240 hours or more in white rust occurrence time, a trivalent chromate film having a Si / Cr value of 0.75 or more is formed Judged to have good corrosion resistance.

〈高耐食性部材〉
本発明の高耐食性部材は、鋼製の基体と、該基体の表面に形成されためっき層と、該めっき層の表面に形成された３価クロメート皮膜と、を持ち、該３価クロメート皮膜中のシリカとクロムとの濃度比（Ｓｉ／Ｃｒ）の値が０．７５以上である。 <High corrosion resistance material>
The highly corrosion-resistant member of the present invention has a steel base, a plating layer formed on the surface of the base, and a trivalent chromate film formed on the surface of the plating layer. The concentration ratio of silica to chromium (Si / Cr) is 0.75 or more.

基体、めっき層、３価クロメート皮膜、およびＳｉ／Ｃｒ値については、上記本発明の評価方法において述べた通りである。本発明の高耐食性部材には、Ｓｉ／Ｃｒ値が０．７５以上の３価クロメート皮膜が形成されている。このため、前出図１の相関関係によれば、塩水噴霧試験（ＪＩＳ Ｚ ２３７１）で白錆発生時間が２４０時間以上という高い耐食性を有する。   The substrate, the plating layer, the trivalent chromate film, and the Si / Cr value are as described in the evaluation method of the present invention. A trivalent chromate film having a Si / Cr value of 0.75 or more is formed on the highly corrosion-resistant member of the present invention. For this reason, according to the correlation of the above-mentioned FIG. 1, it has high corrosion resistance with white rust generation | occurrence | production time being 240 hours or more by a salt spray test (JIS Z 2371).

〈高耐食性部材の製造方法〉
本発明の高耐食性部材の製造方法は、めっき工程と、３価クロメート処理工程と、を含む。以下、各工程について説明する。 <Manufacturing method of high corrosion resistance member>
The manufacturing method of the highly corrosion-resistant member of the present invention includes a plating step and a trivalent chromate treatment step. Hereinafter, each step will be described.

（１）めっき工程
本工程は、鋼製の基体の表面に亜鉛めっき層または亜鉛合金めっき層を形成する工程である。基体、亜鉛系のめっき層については、上記本発明の評価方法において述べた通りである。亜鉛系のめっき層を形成するには、所定のめっき浴に基体を浸漬させればよい。この場合、本工程の後に、ベーキング処理を行い、水洗することが望ましい。さらに、必要に応じてめっき層の表面を酸で処理して、活性化させることが望ましい。酸による活性化処理の後、水洗して次の工程に供すればよい。 (1) Plating step This step is a step of forming a zinc plating layer or a zinc alloy plating layer on the surface of a steel substrate. The substrate and the zinc-based plating layer are as described in the evaluation method of the present invention. In order to form a zinc-based plating layer, the substrate may be immersed in a predetermined plating bath. In this case, it is desirable to perform a baking process and wash with water after this step. Furthermore, it is desirable that the surface of the plating layer be activated with an acid as necessary. After the activation treatment with an acid, it may be washed with water and used for the next step.

（２）３価クロメート処理工程
本工程は、めっき工程で形成されためっき層の表面を３価クロメート処理液に接触させてシリカとクロムとの濃度比（Ｓｉ／Ｃｒ）の値が０．７５以上である３価クロメート皮膜を形成する工程である。本工程は、従来の反応型クロメート処理と同様に実施することができる。例えば、めっき層と３価クロメート処理液との接触を、めっき層が形成された基体を３価クロメート処理液に浸浸させて行えばよい。 (2) Trivalent chromate treatment step In this step, the surface of the plating layer formed in the plating step is brought into contact with a trivalent chromate treatment solution so that the concentration ratio of silica and chromium (Si / Cr) is 0.75. This is a step of forming the above trivalent chromate film. This step can be carried out in the same manner as the conventional reactive chromate treatment. For example, the contact between the plating layer and the trivalent chromate treatment liquid may be performed by immersing the substrate on which the plating layer is formed in the trivalent chromate treatment liquid.

また、処理条件により形成される３価クロメート皮膜中のＳｉ／Ｃｒ値が変化する。よって、Ｓｉ／Ｃｒ値が０．７５以上である３価クロメート皮膜を形成するためには、以下の処理条件を満たす必要がある。すなわち、３価クロメート処理液の温度は２０℃以上５０℃以下とする。２５℃以上３５℃以下とすると好適である。ｐＨは１．６以上２．６以下とする。ｐＨを２．４以下、さらには２．０以下とするとより好適である。めっき層と３価クロメート処理液との接触時間は１５秒以上５０秒以下とする。２０秒以上とすると好適である。また、３価クロメート処理液は、繰り返し使用されることで劣化する。つまり、３価クロメート処理液中の不純物濃度が高くなる。不純物としては、めっき層が亜鉛系の場合、鉄、亜鉛等が挙げられる。不純物の濃度は低い方が望ましいことから、例えば、鉄の濃度を３０ｐｐｍｍ以下、亜鉛の濃度を１．５％以下とするとよい。鉄の濃度を１０ｐｐｍ以下、亜鉛の濃度を１．０％以下とするとより好適である。   Further, the Si / Cr value in the trivalent chromate film formed varies depending on the processing conditions. Therefore, in order to form a trivalent chromate film having a Si / Cr value of 0.75 or more, the following processing conditions must be satisfied. That is, the temperature of the trivalent chromate treatment solution is set to 20 ° C. or more and 50 ° C. or less. It is preferable that the temperature is 25 ° C. or more and 35 ° C. or less. The pH is 1.6 or more and 2.6 or less. It is more preferable that the pH is 2.4 or less, and further 2.0 or less. The contact time between the plating layer and the trivalent chromate treatment solution is 15 seconds to 50 seconds. It is preferable to set it to 20 seconds or more. In addition, the trivalent chromate treatment solution deteriorates due to repeated use. That is, the impurity concentration in the trivalent chromate treatment solution is increased. Examples of the impurities include iron and zinc when the plating layer is zinc-based. Since it is desirable that the impurity concentration is low, for example, the iron concentration may be 30 ppmm or less and the zinc concentration may be 1.5% or less. It is more preferable that the iron concentration is 10 ppm or less and the zinc concentration is 1.0% or less.

次に、実施例を挙げて本発明をより具体的に説明する。   Next, an example is given and the present invention is explained more concretely.

（１）サンプルの製造
硬鋼線材製の試験片に亜鉛めっきを施し、さらに種々の処理条件で３価クロメート処理を行った。まず、脱脂、酸洗等の前処理を行った試験片に、市販の亜鉛めっき液を用いて電気亜鉛めっきを施した。亜鉛めっきは、ジンケート浴と酸性浴との２種類で行った。ジンケート浴には、金属亜鉛と水酸化ナトリウムとを主成分とする浴を、酸性浴には、金属源として塩化亜鉛を、電導度塩として塩化アンモニウムを用いた浴を、それぞれ使用した。形成された亜鉛めっき層の厚さは、約８〜１３μｍであった。亜鉛めっき後に２００℃でベーキング処理を行い、水洗後、硝酸水溶液に室温で５秒間浸漬して活性化処理を行った。その後、水洗し、種々の条件で３価クロメート処理を行った。３価クロメート処理液には、商品名「ジャスコＴＲ−１７５Ａ」（日本表面化学株式会社製；３価クロメート液）と、商品名「ジャスコＴＲ−１７５Ｂ」（日本表面化学株式会社製；Ｓｉ含有液）との２液を用いた。処理条件は、液温度３０±５℃、ｐＨ２±０．２、不純物濃度として鉄１０ｐｐｍ、亜鉛０．７％、浸漬時間２０〜４０秒とした。３価クロメート処理後に、水洗し、約６０℃で５分間乾燥を行った。形成された３価クロメート皮膜の厚さは、０．５〜１．０μｍであった。 (1) Manufacture of a sample The test piece made from a hard steel wire was galvanized, and further, trivalent chromate treatment was performed under various treatment conditions. First, electrogalvanization was performed on a test piece subjected to pretreatment such as degreasing and pickling using a commercially available zinc plating solution. Zinc plating was performed in two types, a zincate bath and an acid bath. For the zincate bath, a bath containing zinc metal and sodium hydroxide as main components was used. For the acidic bath, a bath using zinc chloride as the metal source and ammonium chloride as the conductivity salt was used. The thickness of the formed galvanized layer was about 8 to 13 μm. After galvanization, a baking treatment was performed at 200 ° C., and after washing with water, an activation treatment was performed by dipping in an aqueous nitric acid solution at room temperature for 5 seconds. Thereafter, it was washed with water and subjected to trivalent chromate treatment under various conditions. The trivalent chromate treatment liquid includes a trade name “Jusco TR-175A” (manufactured by Nihon Surface Chemical Co., Ltd .; trivalent chromate liquid) and a trade name “Jusco TR-175B” (manufactured by Nihon Surface Chemical Co., Ltd .; Si-containing liquid). ) And 2 liquids were used. The treatment conditions were a liquid temperature of 30 ± 5 ° C., a pH of 2 ± 0.2, an impurity concentration of 10 ppm of iron, zinc of 0.7%, and an immersion time of 20 to 40 seconds. After the trivalent chromate treatment, it was washed with water and dried at about 60 ° C. for 5 minutes. The thickness of the formed trivalent chromate film was 0.5 to 1.0 μm.

（２）塩水噴霧試験
製造したサンプルについて塩水噴霧試験（ＪＩＳ Ｚ ２３７１）を行い、耐食性を調査した。各サンプルの耐食性は、３価クロメート皮膜面積に対して白錆が５％以上発生するのに要する時間で表した。 (2) Salt spray test The manufactured sample was subjected to a salt spray test (JIS Z 2371) to investigate the corrosion resistance. The corrosion resistance of each sample was expressed as the time required for white rust to occur at 5% or more with respect to the trivalent chromate film area.

（３）Ｓｉ、Ｃｒの定量分析
製造したサンプルの３価クロメート皮膜中の元素分析をＥＤＸ（エネルギー分散型蛍光Ｘ線分析装置）で行った。そして、各サンプルについて３価クロメート皮膜中のＳｉとＣｒとの濃度比（Ｓｉ／Ｃｒ）を求めた。 (3) Quantitative analysis of Si and Cr Elemental analysis in the trivalent chromate film of the manufactured sample was performed with EDX (energy dispersive X-ray fluorescence analyzer). And the density | concentration ratio (Si / Cr) of Si and Cr in a trivalent chromate film | membrane was calculated | required about each sample.

（４）Ｓｉ／Ｃｒ値と耐食性との相関関係
製造したサンプルについて、３価クロメート皮膜中のＳｉ／Ｃｒ値と耐食性との関係を調べた。結果を図１に示す。図１に示すように、Ｓｉ／Ｃｒ値と耐食性との間には相関関係があり、Ｓｉ／Ｃｒ値が大きくなると耐食性（白錆発生時間）が向上する。これより、例えば、白錆発生時間が２４０時間以上の耐食性を目標とする場合には、Ｓｉ／Ｃｒ値が０．７５以上であればよいことがわかった。すなわち、Ｓｉ／Ｃｒ値が０．７５以上の３価クロメート皮膜を持つ部材は、耐食性に優れると判断してよい。このように、図１を用いれば、３価クロメート皮膜中のＳｉ／Ｃｒ値を算出するだけで、その皮膜の耐食性を簡便に予測することができる。 (4) Correlation between Si / Cr value and corrosion resistance The relationship between the Si / Cr value in the trivalent chromate film and the corrosion resistance was examined for the manufactured samples. The results are shown in FIG. As shown in FIG. 1, there is a correlation between the Si / Cr value and the corrosion resistance, and the corrosion resistance (white rust occurrence time) improves as the Si / Cr value increases. From this, it was found that, for example, when corrosion resistance with white rust occurrence time of 240 hours or more is targeted, the Si / Cr value should be 0.75 or more. That is, it may be determined that a member having a trivalent chromate film having a Si / Cr value of 0.75 or more is excellent in corrosion resistance. Thus, if FIG. 1 is used, the corrosion resistance of the film can be easily predicted by simply calculating the Si / Cr value in the trivalent chromate film.

（５）ＥＰＭＡ
さらに、３価クロメート皮膜中のＳｉ／Ｃｒ値が０．５、３の２つのサンプルについて、ＥＰＭＡ（電子線マイクロアナライザ）による面分析を行った。結果を図２に示す。図２は、各サンプルの３価クロメート皮膜の反射電子像、およびＣｒ、Ｓｉの元素分布を示す。図２に示すように、Ｓｉ／Ｃｒ値の違いで、Ｃｒ、Ｓｉの分布が異なることがわかる。Ｓｉ／Ｃｒ値＝３のサンプルは、Ｓｉ／Ｃｒ値＝０．５のサンプルに比べて、Ｃｒ、Ｓｉともに多く分布していた。 (5) EPMA
Further, surface analysis by EPMA (electron beam microanalyzer) was performed on two samples having Si / Cr values of 0.5 and 3 in the trivalent chromate film. The results are shown in FIG. FIG. 2 shows the reflected electron image of the trivalent chromate film of each sample and the element distribution of Cr and Si. As shown in FIG. 2, it can be seen that the distribution of Cr and Si differs depending on the Si / Cr value. In the sample with Si / Cr value = 3, both Cr and Si were more distributed than the sample with Si / Cr value = 0.5.

３価クロメート皮膜中のＳｉ／Ｃｒ値と耐食性との関係を示すグラフである。It is a graph which shows the relationship between the Si / Cr value in a trivalent chromate film | membrane, and corrosion resistance. ＥＰＭＡによる３価クロメート皮膜の面分析の結果を示す図である。It is a figure which shows the result of the surface analysis of the trivalent chromate film | membrane by EPMA.

Claims (6)

鋼製の基体と、
該基体の表面に形成されためっき層と、
該めっき層の表面に形成された３価クロメート皮膜と、
を持つ高耐食性部材の耐食性評価方法であって、
該３価クロメート皮膜中のシリカとクロムとの濃度比（Ｓｉ／Ｃｒ）の値に基づいて該３価クロメート皮膜の耐食性の良否を判断することを特徴とする高耐食性部材の耐食性評価方法。 A steel substrate;
A plating layer formed on the surface of the substrate;
A trivalent chromate film formed on the surface of the plating layer;
A corrosion resistance evaluation method for a highly corrosion resistant member having
A method for evaluating the corrosion resistance of a highly corrosion-resistant member, wherein the quality of the corrosion resistance of the trivalent chromate film is judged based on the value of the concentration ratio (Si / Cr) of silica and chromium in the trivalent chromate film. 前記めっき層は亜鉛めっき層または亜鉛合金めっき層である請求項１に記載の高耐食性部材の耐食性評価方法。   The method for evaluating corrosion resistance of a highly corrosion-resistant member according to claim 1, wherein the plating layer is a zinc plating layer or a zinc alloy plating layer. 前記シリカとクロムとの濃度比（Ｓｉ／Ｃｒ）の値が０．７５以上かどうかで耐食性を判断する請求項１に記載の高耐食性部材の耐食性評価方法。   The method for evaluating corrosion resistance of a highly corrosion-resistant member according to claim 1, wherein the corrosion resistance is determined based on whether the concentration ratio (Si / Cr) between silica and chromium is 0.75 or more. 鋼製の基体と、
該基体の表面に形成されためっき層と、
該めっき層の表面に形成された３価クロメート皮膜と、を持ち、
該３価クロメート皮膜中のシリカとクロムとの濃度比（Ｓｉ／Ｃｒ）の値が０．７５以上であることを特徴とする高耐食性部材。 A steel substrate;
A plating layer formed on the surface of the substrate;
A trivalent chromate film formed on the surface of the plating layer,
A highly corrosion-resistant member having a concentration ratio (Si / Cr) of silica and chromium in the trivalent chromate film of 0.75 or more. 前記めっき層は、亜鉛めっき層または亜鉛合金めっき層である請求項４に記載の高耐食性部材。   The highly corrosion-resistant member according to claim 4, wherein the plating layer is a zinc plating layer or a zinc alloy plating layer. 請求項５に記載の高耐食性部材の製造方法であって、
鋼製の基体の表面に亜鉛めっき層または亜鉛合金めっき層を形成するめっき工程と、
形成されためっき層の表面を３価クロメート処理液に接触させて、シリカとクロムとの濃度比（Ｓｉ／Ｃｒ）の値が０．７５以上である３価クロメート皮膜を形成する３価クロメート処理工程と、を含み、
該３価クロメート処理工程における該３価クロメート処理液の温度は２０℃以上５０℃以下、ｐＨは１．６以上２．６以下、不純物である鉄、亜鉛の濃度は鉄：３０ｐｐｍ以下、亜鉛：１．５％以下、接触時間は１５秒以上５０秒以下であることを特徴とする高耐食性部材の製造方法。 It is a manufacturing method of the highly corrosion-resistant member according to claim 5,
A plating step of forming a galvanized layer or a zinc alloy plated layer on the surface of the steel substrate;
A trivalent chromate treatment in which the surface of the formed plating layer is brought into contact with a trivalent chromate treatment solution to form a trivalent chromate film having a silica / chromium concentration ratio (Si / Cr) value of 0.75 or more. Including a process,
In the trivalent chromate treatment step, the temperature of the trivalent chromate treatment solution is 20 ° C. or more and 50 ° C. or less, the pH is 1.6 or more and 2.6 or less, and the concentrations of iron and zinc as impurities are iron: 30 ppm or less, zinc: A method for producing a highly corrosion-resistant member, characterized in that the contact time is not shorter than 1.5% and not longer than 15 seconds and not longer than 50 seconds.
JP2005356134A 2005-12-09 2005-12-09 Method for evaluating corrosion resistance in highly corrosion resistant member, highly corrosion resistant member and its production method Pending JP2007162040A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP2005356134A JP2007162040A (en) 2005-12-09 2005-12-09 Method for evaluating corrosion resistance in highly corrosion resistant member, highly corrosion resistant member and its production method

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP2005356134A JP2007162040A (en) 2005-12-09 2005-12-09 Method for evaluating corrosion resistance in highly corrosion resistant member, highly corrosion resistant member and its production method

Publications (1)

Publication Number Publication Date
JP2007162040A true JP2007162040A (en) 2007-06-28

Family

ID=38245295

Family Applications (1)

Application Number Title Priority Date Filing Date
JP2005356134A Pending JP2007162040A (en) 2005-12-09 2005-12-09 Method for evaluating corrosion resistance in highly corrosion resistant member, highly corrosion resistant member and its production method

Country Status (1)

Country Link
JP (1) JP2007162040A (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2019004163A1 (en) * 2017-06-29 2019-01-03 ユケン工業株式会社 Rust prevention member and method for producing same

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS6360287A (en) * 1986-08-29 1988-03-16 Dowa Teppun Kogyo Kk Method and device for producing spring steel for cold forming having excellent corrosion resistance
JPH09228069A (en) * 1996-02-21 1997-09-02 Nippon Denko Kk Method for purifying chromium plating solution or chromate solution and device therefor
JP2000239854A (en) * 1999-02-15 2000-09-05 Kawasaki Steel Corp High corrosion resistant steel sheet for fuel tank
JP2000282176A (en) * 1999-04-02 2000-10-10 Sumitomo Electric Ind Ltd Steel wire for heat resistant spring, and its production
JP2003166075A (en) * 2001-11-30 2003-06-13 Dipsol Chem Co Ltd Treatment solution for forming hexavalent chromium- free rust preventive coating on plated film with zinc and zinc alloy, hexavalent chromium-free rust preventive coating and method for forming the same

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS6360287A (en) * 1986-08-29 1988-03-16 Dowa Teppun Kogyo Kk Method and device for producing spring steel for cold forming having excellent corrosion resistance
JPH09228069A (en) * 1996-02-21 1997-09-02 Nippon Denko Kk Method for purifying chromium plating solution or chromate solution and device therefor
JP2000239854A (en) * 1999-02-15 2000-09-05 Kawasaki Steel Corp High corrosion resistant steel sheet for fuel tank
JP2000282176A (en) * 1999-04-02 2000-10-10 Sumitomo Electric Ind Ltd Steel wire for heat resistant spring, and its production
JP2003166075A (en) * 2001-11-30 2003-06-13 Dipsol Chem Co Ltd Treatment solution for forming hexavalent chromium- free rust preventive coating on plated film with zinc and zinc alloy, hexavalent chromium-free rust preventive coating and method for forming the same

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2019004163A1 (en) * 2017-06-29 2019-01-03 ユケン工業株式会社 Rust prevention member and method for producing same
CN110799670A (en) * 2017-06-29 2020-02-14 油研工业股份有限公司 Rust-proof member and method for producing same
EP3647463A4 (en) * 2017-06-29 2021-05-05 Yuken Industry Co., Ltd. Rust prevention member and method for producing same
US11851767B2 (en) 2017-06-29 2023-12-26 Yuken Industry Co., Ltd. Rust prevention member and method for producing same

Similar Documents

Publication Publication Date Title
JP5914949B2 (en) Trivalent chromium corrosion-resistant chemical conversion coating and trivalent chromium chemical conversion treatment solution
Verbruggen et al. Molybdate-phosphate conversion coatings to protect steel in a simulated concrete pore solution
Walker et al. Molybdate based conversion coatings for zinc and zinc alloy surfaces: a review
JP2016132784A (en) Trivalent chromium black chemical conversion coating treatment solution, trivalent chromium containing water-soluble finish treatment solution and method for treating metal base material
JP2016132785A (en) Trivalent chromium chemical conversion coating treatment solution and method for treating metal base material
Gan et al. A highly anticorrosive chromium-free conversion coating prepared on electroless Ni–P coating
JPWO2010032702A1 (en) Aqueous solution for blackening chemical conversion treatment on zinc or zinc alloy surface and method for forming blackened rust preventive film using the aqueous solution for treatment
Park et al. Ultra-high corrosion resistance of Al-Mg-Si film on steel sheet formed by PVD Mg coating and heat treatment
KR20150015448A (en) Trivalent chromium-conversion processing solution containing aluminum-modified colloidal silica
JP4472965B2 (en) Method for forming hexavalent chromium-free corrosion-resistant film on trivalent chromate solution and zinc-nickel alloy plating using the same
JP4846988B2 (en) Finishing agent for chemical conversion film containing no hexavalent chromium
JP2007162040A (en) Method for evaluating corrosion resistance in highly corrosion resistant member, highly corrosion resistant member and its production method
CA2361137A1 (en) Zinc-comprising-plated high tension steel sheet
JP4393349B2 (en) Cold-rolled steel sheet with excellent phosphatability and post-coating salt hot water resistance
JP2004263240A (en) Black plating system free from hexavalent chromium
JP5153063B2 (en) Steel surface treatment method
US20060257682A1 (en) Corrosion protection of galvanized steel using a cerium salt-based solution and detection of the amount of corrosion resistance enhancement
JP5300113B2 (en) Metal surface treatment agent, metal surface treatment method using metal surface treatment agent, and iron component subjected to surface treatment
JP2002285346A (en) Zinc phosphate treated galvanized steel sheet having excellent corrosion resistance and color tone
JP5332543B2 (en) Surface-treated steel sheet and manufacturing method thereof
Chantorn et al. Phosphating of Mn modified Zn for low alloy steels SA335P22
JP4147141B2 (en) Trivalent chromate treatment method and steel material with chromate film
WO2019131766A1 (en) Metal surface treatment agent, metal material having surface treatment film, and method for manufacturing same
JP2000252042A (en) Spark plug and manufacture thereof
JP7228973B2 (en) METAL MATERIAL WITH FILM AND MANUFACTURING METHOD THEREOF

Legal Events

Date Code Title Description
A621 Written request for application examination

Effective date: 20081118

Free format text: JAPANESE INTERMEDIATE CODE: A621

A977 Report on retrieval

Effective date: 20100126

Free format text: JAPANESE INTERMEDIATE CODE: A971007

A131 Notification of reasons for refusal

Effective date: 20110607

Free format text: JAPANESE INTERMEDIATE CODE: A131

A521 Written amendment

Free format text: JAPANESE INTERMEDIATE CODE: A523

Effective date: 20110725

A131 Notification of reasons for refusal

Effective date: 20120403

Free format text: JAPANESE INTERMEDIATE CODE: A131

A02 Decision of refusal

Free format text: JAPANESE INTERMEDIATE CODE: A02

Effective date: 20120821