JP3031404B2 - Surface treatment method for stainless steel for high purity alcohol - Google Patents
Surface treatment method for stainless steel for high purity alcoholInfo
- Publication number
- JP3031404B2 JP3031404B2 JP6061268A JP6126894A JP3031404B2 JP 3031404 B2 JP3031404 B2 JP 3031404B2 JP 6061268 A JP6061268 A JP 6061268A JP 6126894 A JP6126894 A JP 6126894A JP 3031404 B2 JP3031404 B2 JP 3031404B2
- Authority
- JP
- Japan
- Prior art keywords
- stainless steel
- treatment method
- surface treatment
- alcohol
- metal ions
- 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.)
- Expired - Lifetime
Links
Landscapes
- ing And Chemical Polishing (AREA)
- Cleaning And De-Greasing Of Metallic Materials By Chemical Methods (AREA)
- Chemical Treatment Of Metals (AREA)
Description
【０００１】[0001]
【産業上の利用分野】本発明は、金属イオンの溶出を極
端に嫌う電子工業、医薬品製造等の分野において使用さ
れる配管・機器を構成するステンレス鋼の表面処理方法
に関し、詳しくは、高純度アルコールに対する金属イオ
ンの溶出量の極めて少ないステンレス鋼の表面処理方法
に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for surface treatment of stainless steel constituting piping and equipment used in the fields of the electronics industry, pharmaceutical manufacturing, and the like, which extremely dislikes elution of metal ions. The present invention relates to a surface treatment method for stainless steel in which the amount of metal ions eluted in alcohol is extremely small.
【０００２】[0002]
【従来の技術および発明が解決しようとする課題】従来
より、金属イオンの溶出を抑えるために、機器・配管等
の構成材料であるステンレス鋼の表面を研磨して平滑化
する方法が知られている。例えば、バフ研磨を施したス
テンレス鋼は、表面にスクラッチのある粒状の組織とな
るため、Ｆｅ、Ｃｒ、Ｎｉの酸化物の不動態被膜は不均
一に形成され、Ｆｅイオン他のすべての金属イオンの溶
出量はｐｐｍからｐｐｂのレベルであり、このレベルの
溶出量では、金属イオンの溶出を極端に嫌う電子工業、
医薬品製造等の分野に適用することはできない。2. Description of the Related Art Conventionally, there has been known a method of polishing and smoothing the surface of stainless steel, which is a constituent material of equipment and piping, in order to suppress elution of metal ions. I have. For example, buff polished stainless steel has a granular structure with scratches on the surface, so that the passive film of oxides of Fe, Cr, and Ni is formed unevenly, and Fe ions and all other metal ions The elution amount is from ppm to ppb. At this level of elution amount, the electronics industry, which extremely dislikes elution of metal ions,
It cannot be applied to fields such as pharmaceutical manufacturing.
【０００３】また、電解研磨を施したステンレス鋼で
は、上記した粒状の組織は電気化学的溶解で除去され、
加工変質層を持たない平滑な健全組織が得られるが、そ
の表面に形成される自然酸化による不動態酸化被膜（図
３参照）は数Åから十数Åと薄く、この場合も金属イオ
ンの溶出量がｐｐｂのレベルであり、本発明の目標とす
るレベルを満たすものではない。[0003] In stainless steel subjected to electrolytic polishing, the above-mentioned granular structure is removed by electrochemical dissolution.
Although a smooth and healthy structure without a work-affected layer can be obtained, the passive oxide film (see FIG. 3) formed on its surface by natural oxidation is as thin as several to several tens of millimeters. The amount is at the level of ppb and does not meet the target level of the present invention.
【０００４】さらに、本発明に関連する技術として、超
純水製造供給装置を構成する機器、配管の構成材料から
超純水中への金属イオンの溶出を抑制するものとして、
特開平２−１４１５６６号公報には、「ステンレス鋼の
表面にバフ仕上げおよび電解研磨を施して光沢仕上面と
し、油分等の付着物を完全に除去した後、３５０〜４５
０℃の温度で１５〜３０分間の加熱処理により仕上面に
着色酸化被膜を形成し、この着色酸化被膜を弱酸で洗浄
することを特徴とする超純水製造供給装置用機器配管材
料」に関する発明が開示されている。この材料によれ
ば、弱酸洗浄により鉄分の多い着色酸化被膜が除去され
るため、高温の超純水に長時間接触しても金属イオンの
溶出が殆ど起こらない。しかし、この材料も、高純度ア
ルコールに長時間接触すれば、１００ｐｐｔ程度の金属
イオンの溶出が見られ、本発明の目標とするレベルを満
たすものではない。[0004] Further, as a technique related to the present invention, as a technique for suppressing elution of metal ions from the constituent materials of the equipment and piping constituting the ultrapure water production and supply apparatus into the ultrapure water,
Japanese Patent Application Laid-Open No. 2-141566 discloses that "a surface of stainless steel is buffed and electrolytically polished to give a glossy finished surface, and after a deposit such as oil is completely removed, 350 to 45
Invention relating to "Piping material for equipment for ultrapure water production and supply equipment, characterized in that a colored oxide film is formed on the finished surface by heat treatment at a temperature of 0 ° C. for 15 to 30 minutes and the colored oxide film is washed with a weak acid. Is disclosed. According to this material, since the colored oxide film containing a large amount of iron is removed by weak acid cleaning, elution of metal ions hardly occurs even when the material is brought into contact with high-temperature ultrapure water for a long time. However, even when this material is in contact with high-purity alcohol for a long time, metal ions of about 100 ppt are eluted, which does not satisfy the target level of the present invention.
【０００５】本発明は従来の技術の有するこのような問
題点に鑑みてなされたものであって、その目的は、高純
度アルコールへの金属イオンの溶出量が極く少ない高純
度アルコール用ステンレス鋼の表面処理方法を提供する
ことにある。The present invention has been made in view of the above-mentioned problems of the prior art, and an object of the present invention is to provide a stainless steel for high-purity alcohol which has a very small amount of metal ions eluted into high-purity alcohol. To provide a surface treatment method.
【０００６】[0006]
【課題を解決するための手段】上記目的を達成するため
に本発明の要旨は、ステンレス鋼表面に電解研磨処理を
施した後、酸化雰囲気中で４００〜５００℃で１〜３時
間加熱することにより、１００〜２００Åの厚みの鉄系
酸化物層を表面に形成することを特徴とする高純度アル
コール用ステンレス鋼の表面処理方法にある。In order to achieve the above object, the gist of the present invention is to provide a stainless steel surface which has been subjected to an electrolytic polishing treatment and then heated in an oxidizing atmosphere at 400 to 500 ° C. for 1 to 3 hours. And forming an iron-based oxide layer having a thickness of 100 to 200 ° on the surface of the stainless steel for high-purity alcohol.
【０００７】本発明において、鉄系酸化物の厚みとは、
図１において、Ｏ2 濃度が最表面の値の半分の値になる
までの厚さをアルゴンによるスパッタリングの鉄換算で
求めた値をいう。In the present invention, the thickness of the iron-based oxide is
In FIG. 1, a value obtained by converting the thickness until the O 2 concentration becomes half the value of the outermost surface in iron conversion by sputtering with argon is referred to.
【０００８】[0008]
【作用】アルコールへのＯ2 の溶解度は数十ｐｐｍ程度
（於２５℃）もあり、この程度のＯ2 濃度になると、Ｃ
ｒは過不動態化して不安定な６価となり、溶出しやすく
なる。しかし、ＦｅはＯ2 濃度が高くなると、安定な酸
化物（Ｆｅ2 Ｏ3 ）となり、溶出しにくくなる。従っ
て、ステンレス鋼の表面に鉄系酸化物を形成することに
より、アルコールへの金属イオンの溶出を抑制すること
ができる。この鉄系酸化物の厚みは、１００Å未満では
不十分であるが、２００Å超では厚すぎて脆くなる。加
熱温度が４００℃未満では、酸化被膜の形成が不十分で
あり、５００℃より高温に加熱すると、酸化被膜が過度
に厚くなると同時に脆くなる。同様に加熱時間が１時間
より短いと、酸化被膜の形成が不十分であり、一方、３
時間より長くなると、酸化被膜が過厚となる。[Action] The solubility of O 2 to alcohol is about several tens of ppm (at 25 ° C.) also has, at a O 2 concentration of the extent, C
r is overpassivated to become unstable hexavalent, and is easily eluted. However, when the O 2 concentration increases, Fe becomes a stable oxide (Fe 2 O 3 ) and is less likely to elute. Therefore, by forming an iron-based oxide on the surface of stainless steel, elution of metal ions into alcohol can be suppressed. If the thickness of the iron-based oxide is less than 100 °, it is insufficient, but if it exceeds 200 °, it is too thick and brittle. When the heating temperature is lower than 400 ° C., formation of the oxide film is insufficient, and when the temperature is higher than 500 ° C., the oxide film becomes excessively thick and becomes brittle. Similarly, if the heating time is shorter than 1 hour, formation of an oxide film is insufficient, while
If the time is longer than the time, the oxide film becomes too thick.
【０００９】[0009]
【実施例】以下、実施例として、ＳＵＳ３１６Ｌステン
レス鋼製の管径２５Ａ、長さ５００ｍｍのパイプを製作
し、りん酸・硫酸系電解液により電解電流密度１０Ａ／
ｄｍ2 の条件で電解研磨し、表面の加工変質層を１０〜
５０μｍ除去することで健全な母材表面を得、次いで抵
抗率１８ＭΩ・ｃｍ以上の超純水により精密洗浄を行っ
てから、酸化雰囲気で（４００〜５００℃）×２時間の
加熱処理を行うことにより、厚みが１００〜２００Åで
強固で緻密なＦｅ系酸化物（ＦｅＯ、Ｆｅ2Ｏ3 、Ｆｅ
3 Ｏ4)の層（図１および図２参照）が表面に形成された
ステンレス鋼製パイプを得た。図１は、本発明の表面処
理方法によるステンレス鋼表面の厚さ方向の原子濃度分
布を示す図であり、図２は同ステンレス鋼表面のＦｅの
結合状態を示す図である。図２に明らかなように、最表
層〜表面近傍にはＦｅ0 のピークがなく、表面付近の組
成はＦｅ3 Ｏ4 、Ｆｅ2 Ｏ3 およびＦｅＯからなるＦｅ
酸化物を主体とするものであることが分かり、図１より
この表面は略１００％鉄系酸化物からなることが理解で
きる。なお、鉄系酸化物の中で最も酸化が進んだ３価の
鉄（Ｆｅ2 Ｏ3 ）がアルコール溶液に対して安定してい
る。EXAMPLES Hereinafter, as an example, a pipe made of SUS316L stainless steel and having a pipe diameter of 25 A and a length of 500 mm was manufactured, and an electrolytic current density of 10 A / P was produced using a phosphoric acid / sulfuric acid-based electrolyte.
Electro-polishing under the condition of dm 2 , and the damaged layer on the surface
Obtain a sound base material surface by removing 50 μm, then perform precision cleaning with ultrapure water having a resistivity of 18 MΩ · cm or more, and then perform heat treatment (400 to 500 ° C.) × 2 hours in an oxidizing atmosphere. And a strong and dense Fe-based oxide (FeO, Fe 2 O 3 , Fe
A stainless steel pipe having a 3 O 4 ) layer (see FIGS. 1 and 2) formed on the surface was obtained. FIG. 1 is a diagram showing the atomic concentration distribution in the thickness direction of the stainless steel surface by the surface treatment method of the present invention, and FIG. 2 is a diagram showing the bonding state of Fe on the stainless steel surface. As is apparent from FIG. 2, there is no peak of Fe 0 from the outermost layer to the vicinity of the surface, and the composition near the surface is Fe 3 O 4 , Fe 2 O 3 and FeO composed of FeO.
It is understood that the oxide is mainly composed of an oxide, and it can be understood from FIG. 1 that this surface is made of approximately 100% iron-based oxide. The most oxidized trivalent iron (Fe 2 O 3 ) among the iron-based oxides is stable with respect to the alcohol solution.
【００１０】また、比較例として、バフ研磨のみを行っ
た同上ステンレス鋼製パイプと、同上条件で電解研磨の
みを行った同上ステンレス鋼製パイプを作製した。[0010] As comparative examples, a stainless steel pipe subjected to buffing only and a stainless steel pipe subjected to electrolytic polishing only under the same conditions were produced.
【００１１】次いで、これらの各パイプに高純度イソプ
ロピルアルコールを満たし、２０℃で５６日間保持した
後、パイプ内の高純度イソプロピルアルコール中に溶出
した金属イオンをＩＣＰ−ＭＳ（誘導結合プラズマ質量
分析計）で求めた。その結果を以下の表１に示す。Next, each of these pipes is filled with high-purity isopropyl alcohol and kept at 20 ° C. for 56 days, and then the metal ions eluted into the high-purity isopropyl alcohol in the pipe are subjected to ICP-MS (inductively coupled plasma mass spectrometry). ). The results are shown in Table 1 below.
【００１２】[0012]
【表１】 [Table 1]
【００１３】表１に明らかなように、本発明の表面処理
方法によるパイプからの全金属イオン溶出量は１０ｐｐ
ｔ未満であり、極めて優れた耐溶出性を有していること
がわかる。しかし、バフ研磨や電解研磨によるものの金
属イオン溶出量は極めて多く、本発明の目標とするレベ
ルを満たすものではない。As apparent from Table 1, the elution amount of all metal ions from the pipe by the surface treatment method of the present invention is 10 pp.
It is understood that the compound has extremely excellent elution resistance. However, the amount of metal ions eluted by buffing or electrolytic polishing is extremely large and does not satisfy the target level of the present invention.
【００１４】なお、上記溶出試験において、高純度アル
コールとしてイソプロピルアルコールを使用したが、エ
チルアルコール・メチルアルコール・ブチルアルコール
等の高純度アルコールを使用してもよい。Although isopropyl alcohol is used as the high-purity alcohol in the above-mentioned dissolution test, a high-purity alcohol such as ethyl alcohol, methyl alcohol, or butyl alcohol may be used.
【００１５】[0015]
【発明の効果】以上説明したように、本発明によれば高
純度アルコールに対する金属イオンの溶出量の極めてす
くないステンレス鋼の表面処理方法を提供することがで
き、電子工業、医薬品製造等の産業の発達に対する貢献
度は極めて大なるものがある。As described above, according to the present invention, it is possible to provide a surface treatment method for stainless steel in which the amount of metal ions eluted with respect to high-purity alcohol is extremely small. The contribution to development can be quite large.
【図１】本発明の表面処理方法によるステンレス鋼表面
の厚さ方向の原子濃度分布を示す図である。FIG. 1 is a view showing an atomic concentration distribution in a thickness direction of a stainless steel surface by a surface treatment method of the present invention.
【図２】本発明の表面処理方法によるステンレス鋼表面
のＦｅの結合状態を示す図である。FIG. 2 is a view showing the bonding state of Fe on the surface of stainless steel by the surface treatment method of the present invention.
【図３】ステンレス鋼を電解研磨した直後の表面の厚さ
方向の原子濃度分布を示す図である。FIG. 3 is a view showing an atomic concentration distribution in a thickness direction of a surface immediately after electrolytic polishing of stainless steel.
───────────────────────────────────────────────────── フロントページの続き (72)発明者 去来川 辰彦 兵庫県神戸市須磨区南落合１−13−９ (56)参考文献 特開 昭64−31956（ＪＰ，Ａ) (58)調査した分野(Int.Cl.7，ＤＢ名) C23C 8/10 - 8/18 ──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Tatsuhiko Shirakawa 1-13-9 Minami-Ochiai, Suma-ku, Kobe-shi, Hyogo (56) References JP-A-64-31956 (JP, A) (58) Investigated Field (Int.Cl. 7 , DB name) C23C 8/10-8/18
Claims (1)
た後、酸化雰囲気中で４００〜５００℃で１〜３時間加
熱することにより、１００〜２００Åの厚みの鉄系酸化
物層を表面に形成することを特徴とする高純度アルコー
ル用ステンレス鋼の表面処理方法。1. A after being subjected to electrolytic polishing stainless steel surfaces, by heating for 1-3 hours at 400 to 500 ° C. in an oxidizing atmosphere, forming an iron-based oxide layer having a thickness of 100~200Å the surface High-purity alcohol
Surface treatment method for stainless steel .
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP6061268A JP3031404B2 (en) | 1994-03-30 | 1994-03-30 | Surface treatment method for stainless steel for high purity alcohol |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP6061268A JP3031404B2 (en) | 1994-03-30 | 1994-03-30 | Surface treatment method for stainless steel for high purity alcohol |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH07268599A JPH07268599A (en) | 1995-10-17 |
| JP3031404B2 true JP3031404B2 (en) | 2000-04-10 |
Family
ID=13166315
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP6061268A Expired - Lifetime JP3031404B2 (en) | 1994-03-30 | 1994-03-30 | Surface treatment method for stainless steel for high purity alcohol |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3031404B2 (en) |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE102004053474B4 (en) * | 2003-11-21 | 2014-02-06 | Merck Patent Gmbh | Method and system for filling, transporting, storing and removing liquid crystals |
| JP2008047381A (en) | 2006-08-14 | 2008-02-28 | Toyo Seikan Kaisha Ltd | Stainless steel member for fuel cell |
| JP5286551B2 (en) * | 2006-08-14 | 2013-09-11 | 東洋製罐株式会社 | Coil spring for fuel cell |
| SG11202008033RA (en) | 2018-03-02 | 2020-09-29 | Tokuyama Corp | Stainless steel member and production method thereof |
-
1994
- 1994-03-30 JP JP6061268A patent/JP3031404B2/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| JPH07268599A (en) | 1995-10-17 |
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