JPH0437160B2 - - Google Patents
Info
- Publication number
- JPH0437160B2 JPH0437160B2 JP8312488A JP8312488A JPH0437160B2 JP H0437160 B2 JPH0437160 B2 JP H0437160B2 JP 8312488 A JP8312488 A JP 8312488A JP 8312488 A JP8312488 A JP 8312488A JP H0437160 B2 JPH0437160 B2 JP H0437160B2
- Authority
- JP
- Japan
- Prior art keywords
- stainless steel
- treatment
- concentration
- electrolytic treatment
- minutes
- 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
Links
- 238000011282 treatment Methods 0.000 claims description 32
- 239000010935 stainless steel Substances 0.000 claims description 26
- 229910001220 stainless steel Inorganic materials 0.000 claims description 26
- 238000000034 method Methods 0.000 claims description 14
- 238000005868 electrolysis reaction Methods 0.000 claims description 13
- 150000003839 salts Chemical class 0.000 claims description 13
- 239000007864 aqueous solution Substances 0.000 claims description 9
- 239000012266 salt solution Substances 0.000 claims description 8
- UMGDCJDMYOKAJW-UHFFFAOYSA-N thiourea Chemical compound NC(N)=S UMGDCJDMYOKAJW-UHFFFAOYSA-N 0.000 claims description 6
- 150000002500 ions Chemical class 0.000 claims description 5
- PEDCQBHIVMGVHV-UHFFFAOYSA-N Glycerine Chemical compound OCC(O)CO PEDCQBHIVMGVHV-UHFFFAOYSA-N 0.000 claims description 4
- 229920002472 Starch Polymers 0.000 claims description 3
- XSQUKJJJFZCRTK-UHFFFAOYSA-N Urea Natural products NC(N)=O XSQUKJJJFZCRTK-UHFFFAOYSA-N 0.000 claims description 3
- BFNBIHQBYMNNAN-UHFFFAOYSA-N ammonium sulfate Chemical compound N.N.OS(O)(=O)=O BFNBIHQBYMNNAN-UHFFFAOYSA-N 0.000 claims description 3
- 229910052921 ammonium sulfate Inorganic materials 0.000 claims description 3
- 235000011130 ammonium sulphate Nutrition 0.000 claims description 3
- KGBXLFKZBHKPEV-UHFFFAOYSA-N boric acid Chemical compound OB(O)O KGBXLFKZBHKPEV-UHFFFAOYSA-N 0.000 claims description 3
- 239000004327 boric acid Substances 0.000 claims description 3
- 239000008107 starch Substances 0.000 claims description 3
- 235000019698 starch Nutrition 0.000 claims description 3
- DJHGAFSJWGLOIV-UHFFFAOYSA-N Arsenic acid Chemical compound O[As](O)(O)=O DJHGAFSJWGLOIV-UHFFFAOYSA-N 0.000 claims description 2
- CWYNVVGOOAEACU-UHFFFAOYSA-N Fe2+ Chemical compound [Fe+2] CWYNVVGOOAEACU-UHFFFAOYSA-N 0.000 claims description 2
- WQZGKKKJIJFFOK-GASJEMHNSA-N Glucose Natural products OC[C@H]1OC(O)[C@H](O)[C@@H](O)[C@@H]1O WQZGKKKJIJFFOK-GASJEMHNSA-N 0.000 claims description 2
- 230000003213 activating effect Effects 0.000 claims description 2
- 239000000654 additive Substances 0.000 claims description 2
- 235000011124 aluminium ammonium sulphate Nutrition 0.000 claims description 2
- 150000003863 ammonium salts Chemical class 0.000 claims description 2
- 229940000488 arsenic acid Drugs 0.000 claims description 2
- WQZGKKKJIJFFOK-VFUOTHLCSA-N beta-D-glucose Chemical compound OC[C@H]1O[C@@H](O)[C@H](O)[C@@H](O)[C@@H]1O WQZGKKKJIJFFOK-VFUOTHLCSA-N 0.000 claims description 2
- 235000010338 boric acid Nutrition 0.000 claims description 2
- 238000004140 cleaning Methods 0.000 claims description 2
- 239000008103 glucose Substances 0.000 claims description 2
- 235000011187 glycerol Nutrition 0.000 claims description 2
- YWYZEGXAUVWDED-UHFFFAOYSA-N triammonium citrate Chemical compound [NH4+].[NH4+].[NH4+].[O-]C(=O)CC(O)(CC([O-])=O)C([O-])=O YWYZEGXAUVWDED-UHFFFAOYSA-N 0.000 claims description 2
- 230000000996 additive effect Effects 0.000 claims 1
- LCQXXBOSCBRNNT-UHFFFAOYSA-K ammonium aluminium sulfate Chemical compound [NH4+].[Al+3].[O-]S([O-])(=O)=O.[O-]S([O-])(=O)=O LCQXXBOSCBRNNT-UHFFFAOYSA-K 0.000 claims 1
- 238000005260 corrosion Methods 0.000 description 28
- 230000007797 corrosion Effects 0.000 description 26
- 238000012360 testing method Methods 0.000 description 12
- 239000013535 sea water Substances 0.000 description 10
- 239000011651 chromium Substances 0.000 description 6
- 230000000694 effects Effects 0.000 description 5
- 238000007654 immersion Methods 0.000 description 4
- 239000000203 mixture Substances 0.000 description 4
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 description 3
- 239000000463 material Substances 0.000 description 3
- 239000000243 solution Substances 0.000 description 3
- VEXZGXHMUGYJMC-UHFFFAOYSA-M Chloride anion Chemical compound [Cl-] VEXZGXHMUGYJMC-UHFFFAOYSA-M 0.000 description 2
- 239000007795 chemical reaction product Substances 0.000 description 2
- 229910001430 chromium ion Inorganic materials 0.000 description 2
- 239000011248 coating agent Substances 0.000 description 2
- 238000000576 coating method Methods 0.000 description 2
- 150000001875 compounds Chemical class 0.000 description 2
- 239000010949 copper Substances 0.000 description 2
- 239000003792 electrolyte Substances 0.000 description 2
- 150000004677 hydrates Chemical class 0.000 description 2
- 239000007788 liquid Substances 0.000 description 2
- 229910052751 metal Inorganic materials 0.000 description 2
- 239000002184 metal Substances 0.000 description 2
- 229910021645 metal ion Inorganic materials 0.000 description 2
- 238000004381 surface treatment Methods 0.000 description 2
- JIAARYAFYJHUJI-UHFFFAOYSA-L zinc dichloride Chemical compound [Cl-].[Cl-].[Zn+2] JIAARYAFYJHUJI-UHFFFAOYSA-L 0.000 description 2
- WZUKKIPWIPZMAS-UHFFFAOYSA-K Ammonium alum Chemical compound [NH4+].O.O.O.O.O.O.O.O.O.O.O.O.[Al+3].[O-]S([O-])(=O)=O.[O-]S([O-])(=O)=O WZUKKIPWIPZMAS-UHFFFAOYSA-K 0.000 description 1
- VYZAMTAEIAYCRO-UHFFFAOYSA-N Chromium Chemical compound [Cr] VYZAMTAEIAYCRO-UHFFFAOYSA-N 0.000 description 1
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 1
- ZOKXTWBITQBERF-UHFFFAOYSA-N Molybdenum Chemical compound [Mo] ZOKXTWBITQBERF-UHFFFAOYSA-N 0.000 description 1
- 241000219094 Vitaceae Species 0.000 description 1
- 229910045601 alloy Inorganic materials 0.000 description 1
- 239000000956 alloy Substances 0.000 description 1
- GCPXMJHSNVMWNM-UHFFFAOYSA-N arsenous acid Chemical compound O[As](O)O GCPXMJHSNVMWNM-UHFFFAOYSA-N 0.000 description 1
- PLKYGPRDCKGEJH-UHFFFAOYSA-N azane;2-hydroxypropane-1,2,3-tricarboxylic acid;iron Chemical compound N.[Fe].OC(=O)CC(O)(C(O)=O)CC(O)=O PLKYGPRDCKGEJH-UHFFFAOYSA-N 0.000 description 1
- 238000004210 cathodic protection Methods 0.000 description 1
- 229910052804 chromium Inorganic materials 0.000 description 1
- GRWVQDDAKZFPFI-UHFFFAOYSA-H chromium(III) sulfate Chemical compound [Cr+3].[Cr+3].[O-]S([O-])(=O)=O.[O-]S([O-])(=O)=O.[O-]S([O-])(=O)=O GRWVQDDAKZFPFI-UHFFFAOYSA-H 0.000 description 1
- 230000000052 comparative effect Effects 0.000 description 1
- 229910052802 copper Inorganic materials 0.000 description 1
- 229910000365 copper sulfate Inorganic materials 0.000 description 1
- ARUVKPQLZAKDPS-UHFFFAOYSA-L copper(II) sulfate Chemical compound [Cu+2].[O-][S+2]([O-])([O-])[O-] ARUVKPQLZAKDPS-UHFFFAOYSA-L 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 235000021021 grapes Nutrition 0.000 description 1
- 239000003673 groundwater Substances 0.000 description 1
- 239000010842 industrial wastewater Substances 0.000 description 1
- 239000008235 industrial water Substances 0.000 description 1
- 239000004615 ingredient Substances 0.000 description 1
- 238000009434 installation Methods 0.000 description 1
- 238000012423 maintenance Methods 0.000 description 1
- 229910052750 molybdenum Inorganic materials 0.000 description 1
- 239000011733 molybdenum Substances 0.000 description 1
- 230000007935 neutral effect Effects 0.000 description 1
- 229910052759 nickel Inorganic materials 0.000 description 1
- 238000007747 plating Methods 0.000 description 1
- 238000002203 pretreatment Methods 0.000 description 1
- 239000000047 product Substances 0.000 description 1
- 229920006395 saturated elastomer Polymers 0.000 description 1
- 230000000087 stabilizing effect Effects 0.000 description 1
- HPGGPRDJHPYFRM-UHFFFAOYSA-J tin(iv) chloride Chemical compound Cl[Sn](Cl)(Cl)Cl HPGGPRDJHPYFRM-UHFFFAOYSA-J 0.000 description 1
- 229910052725 zinc Inorganic materials 0.000 description 1
- 239000011701 zinc Substances 0.000 description 1
- 235000005074 zinc chloride Nutrition 0.000 description 1
- 239000011592 zinc chloride Substances 0.000 description 1
Landscapes
- Preventing Corrosion Or Incrustation Of Metals (AREA)
Description
（産業上の利用分野）
本発明はステンレス鋼の欠点である中性塩化物
環境などで発生する孔食、隙間腐食等の局部腐食
を防止し、比較的安価な汎用ステンレス鋼でも海
水などの使用に耐えるよう、表面処理により耐食
性を付与する方法に関する。
（従来の技術）
ステンレス鋼の局部腐食防止法としては、従来
からMg，Zn，Al等を犠牲陽極すなわち消耗電極
として用い、陰極防食する方法が行なわれている
が、電極の消耗によりその寿命は短かく、電極の
交換などメンテナンスに手間がかかり、かつ、電
極取付けの困難な場所例えば管の内部等に対して
は適用し難い欠点がある。またこの方法では大気
中の塩分や海水飛沫等の付着により発生する乾湿
型の局部発錆を防止することは困難である。
一方、ステンレス鋼の局部腐食を材質的に抑制
するためには、高クロム、高ニツケル、高モリブ
デン等の高次の合金組成が必要であり、極めて高
価になる。その上、局部腐食の発生環境は、海水
はじめ地下水、工業用水、排水等極めて広範囲に
わたつており、局部腐食を成分組成から防止する
ことは経済的にも極めて困難である。本発明者ら
は、先願（特願昭53−55002、特公昭57−8195）
において比較的安価なステンレス鋼を用いても局
部腐食を発生することなく、広く使用できるよう
な表面処理方法を開発した。
上記先願発明は一応の耐食性を有するステンレ
ス鋼を提供するものであるが、その後更に研究し
たところ、クロムイオンを含有する特定の塩類水
溶液中で陽極電解処理と陰極電解処理を併用する
場合、更に著しい耐食性の向上が得られることを
見出し、本発明をなしたものである。
（発明の目的）
本発明は、先願発明を更に改良したもので、汎
用のステンレス鋼に、効率良く高い耐食性を付与
する方法を提供するものである。
（発明の構成）
本発明は、一般のステンレス鋼の濃度0.5〜20
％のCr3+を含む塩類水溶液中に浸して電流密度
5A／ｄm2以下、電解時間10分以下の予備処理
（陽極電解処理）を行なつてステンレス鋼表面を
清浄にし、かつ活性化した後、陽極電解処理に使
用したのと同一の処理浴中で、電流密度0.1〜
10A／ｄm2、電解時間１〜30分の陰極電解処理を
行ない、銅表面に対して水溶液に含有する金属の
反応生成化合物を鍍着させて耐食性を付与するス
テンレス鋼の防食処理法である。
塩類水溶液としては、下記の〜のものを使
用できる。
濃度0.5〜20％のCr3+を含む塩類水溶液。
前記に、更にクエン酸鉄アンモニウム0.05
〜2.0％、アンモニウムみようばん0.01〜0.5％、
硫安0.01〜2.0％などのアンモニウム塩類を単
独又は複数添加したもの。
前記，に、更に濃度0.1〜10％の範囲で、
Cuイオンを含む塩類、Niイオンを含む塩類及
びブドウ糖を単独又は複数添加したもの。
前記，，に、更に微量添加物として濃
度0.01〜0.5％の範囲でチオ尿素、でん粉、硼
酸、グリセリン及び亜ひ酸を単独又は複数添加
したもの。
本発明は、前記〜の塩類水溶液を使用し
て、陽極電解処理と陰極電解処理を併用する方法
であり、液組成及び濃度、電流密度、電解時間等
は各所範囲内で適宜選択実施できる。
なお、陽極電解処理を行なわず陰極電解処理の
みを実施しても、表面特性はある程度改善される
が、特に優れた耐食性を得るには陽極電解処理と
陰極電解処理を併用することが必要である。
本発明の陰極電解処理によつて、ステンレス鋼
上に析出する反応生成化合物は、未だ明確に解明
されていないが、いわゆるメツキ処理によつて析
出される金属とは異なり、電解液中に含まれる各
金属イオンの複雑な水和物からなるものと考えら
れ、数μ以下の薄い着色皮膜で、海水中において
も溶解消失することはない。
本発明による防食効果の理論的説明は明らかで
ないが、実験的にその効果は十分に認められる。
公知の陽極電解処理では、塩化錫、塩化亜鉛等
の塩化物水溶液を初め、他の塩類水溶液を自由に
使用するが、本発明では後続の陽極電解処理に使
用するクロムイオンを含む塩類水溶液と同一の塩
類水溶液を、ステンレス鋼の極性のみを変えて、
予備処理としての陽極電解処理にも使用するの
で、作業性、経済性の点から最も好ましい方法で
ある。
本発明で使用する液組成及び濃度、電流密度、
電解時間等を限定した理由は、これらの範囲内に
おいて、所期の耐食性が得られたからである。
実施例においては、Cr3+塩として、硫酸クロム
をあげたが、これに限定されるものではなく、他
のCr塩も使用できる。
なお、本発明においてクエン酸鉄アンモニウ
ム、硫酸銅、硼酸、でん粉はステンレス鋼表面の
水和物被覆特性を改善し、硫安はPHを安定させ、
ブドウ等はCr3+の安定化に効果がある。
また、チオ尿素、亜ひ酸は低電流電解に効果が
ある。以下、実施例により更に詳しく説明する。
（実施例）
［海水浸漬による隙間腐食試験］
隙間腐食はステンレス鋼の局部腐食の中で最も
防止困難なものなので、海水による隙間腐食試験
を行ない、本発明による陰極電解処理の効果を確
認した。
海水浸漬T.P.の形状及びその取付方法は第１
図、第２図及び第３図に示す通りで、等間隙に孔
明加工４を施した２枚の塩ビ帯状板３，３の間に
ステンレス鋼T.P.１（150×25×１mm）を孔明部
分４と４の中間にはさみ、塩ビ製ボルト・ナツト
５を孔明部分４に差し込み40Kgｆcmのトルクで締
めつけて、ステンレス鋼T.P.１を固定した。同
様にしてステンレス鋼T.P.を取り付けた塩ビ帯
状板３，３を製作した。T.P.を固定した２本の
塩ビ帯状板は、第２図のように並列的に塩ビ製枠
２に取付ける。
また、第３図のように塩ビ帯状板の下部板３の
端部を塩ビアングル２と塩ビボルト・ナツト５で
固定してもよい。第２図又は第３図のように固定
したT.P.１を海水に浸漬試験する。
試験はステンレス鋼T.P.と塩ビ帯状板との間
に設定した隙間部における腐食の有無を検討し
た。試験に供したステンレス鋼の主要成分は第１
表に示す通りであり、防食処理を施した電解槽は
１槽（200mm深さ×50mm巾×100mm長さ）及び、
１／２槽（200mm深さ×25mm巾×100mm長さ）を使
用した。
本発明の防食効果は電解処理溶液の種類及び濃
度、電流密度、電解時間で決まるが、防食効果が
飽和する電解時間は使用する溶液の種類、溶液の
濃度、電流密度等によつて微妙に相違して必ずし
も一定しない。後述の実施例では、予備処理電解
時間を５分、陰極電解処理時間を10分とした。
このように各種塩類水溶液で電解処理した試験
片の海水浸漬隙間腐食試験結果を第３表に示す。
また、比較材として未処理材の海水浸漬隙間腐
食試験結果を第２表に示す。
第２表及び第３表で明らかなように、ステンレ
ス鋼表面を陽極電解処理と陰極電解処理を併用し
て処理した本発明試験片の寿命は、未処理材の３
日以内と大きく異なり、その耐食性が著しく向上
している。その中には430で２年を超え、304で
3.5年を超える寿命を示し、なお試験を継続中の
ものもあり、更に寿命の伸びが期待される。
(Industrial Application Field) The present invention prevents local corrosion such as pitting corrosion and crevice corrosion that occurs in neutral chloride environments, which is a disadvantage of stainless steel, and even relatively inexpensive general-purpose stainless steel can be used in seawater, etc. This invention relates to a method of imparting corrosion resistance through surface treatment to withstand corrosion. (Prior art) As a method to prevent local corrosion of stainless steel, cathodic protection has been used in the past by using Mg, Zn, Al, etc. as a sacrificial anode, or a consumable electrode. It has the disadvantage that it is short, requires time and effort for maintenance such as electrode replacement, and is difficult to apply to places where it is difficult to attach the electrode, such as inside a pipe. In addition, with this method, it is difficult to prevent local rusting of the wet and dry type that occurs due to the adhesion of salt in the atmosphere, seawater droplets, etc. On the other hand, in order to suppress local corrosion of stainless steel materially, a high-order alloy composition such as high chromium, high nickel, and high molybdenum is required, which is extremely expensive. Moreover, the environment in which local corrosion occurs is extremely wide-ranging, including seawater, groundwater, industrial water, and waste water, and it is economically extremely difficult to prevent local corrosion from changing the composition of ingredients. The inventors have previously applied for
We have developed a surface treatment method that can be used widely without causing local corrosion even when using relatively inexpensive stainless steel. The above-mentioned prior invention provides stainless steel with a certain degree of corrosion resistance, but further research has revealed that when anodic electrolytic treatment and cathodic electrolytic treatment are used together in a specific aqueous salt solution containing chromium ions, It was discovered that a significant improvement in corrosion resistance could be obtained, and the present invention was made based on this discovery. (Object of the Invention) The present invention is a further improvement of the prior invention, and provides a method for efficiently imparting high corrosion resistance to general-purpose stainless steel. (Structure of the Invention) The present invention is based on a general stainless steel with a concentration of 0.5 to 20.
Current density immersed in an aqueous salt solution containing % Cr3 +
After cleaning and activating the stainless steel surface by pre-treatment (anodic electrolytic treatment) at 5 A/dm 2 or less and electrolysis time of 10 minutes or less, the stainless steel surface is cleaned and activated in the same treatment bath used for anodic electrolytic treatment. , current density 0.1~
This is an anticorrosive treatment method for stainless steel in which a cathodic electrolytic treatment is performed at 10 A/dm 2 for an electrolysis time of 1 to 30 minutes, and a reaction product compound of a metal contained in an aqueous solution is plated onto the copper surface to impart corrosion resistance. As the aqueous salt solution, the following ~ can be used. Aqueous salt solution containing Cr 3+ at a concentration of 0.5-20%. In addition to the above, ferrous ammonium citrate 0.05
~2.0%, ammonium alum 0.01~0.5%,
Ammonium salts such as ammonium sulfate 0.01 to 2.0% are added singly or in combination. In addition to the above, in a concentration range of 0.1 to 10%,
Salts containing Cu ions, salts containing Ni ions, and glucose added singly or in combination. In addition to the above, one or more of thiourea, starch, boric acid, glycerin and arsenic acid are added as trace additives in a concentration range of 0.01 to 0.5%. The present invention is a method in which anodic electrolytic treatment and cathodic electrolytic treatment are combined using the above-mentioned aqueous salt solutions, and the liquid composition and concentration, current density, electrolysis time, etc. can be appropriately selected and carried out within various ranges. Note that even if only cathodic electrolytic treatment is performed without anodic electrolytic treatment, the surface properties will be improved to some extent, but in order to obtain particularly excellent corrosion resistance, it is necessary to use both anodic electrolytic treatment and cathodic electrolytic treatment. . The reaction product compound deposited on stainless steel by the cathodic electrolytic treatment of the present invention is not clearly understood yet, but unlike the metal deposited by so-called plating treatment, it is contained in the electrolyte. It is thought to be composed of complex hydrates of various metal ions, and is a thin colored film of several micrometers or less that will not dissolve or disappear even in seawater. Although the theoretical explanation for the anticorrosion effect of the present invention is not clear, the effect has been sufficiently confirmed experimentally. In known anodic electrolysis treatments, chloride aqueous solutions such as tin chloride and zinc chloride, as well as other salt aqueous solutions, are freely used; however, in the present invention, the same aqueous salt solution containing chromium ions is used in the subsequent anodic electrolysis treatment. salt aqueous solution by changing only the polarity of the stainless steel.
Since it is also used for anodic electrolytic treatment as a preliminary treatment, it is the most preferred method from the viewpoint of workability and economic efficiency. Liquid composition and concentration used in the present invention, current density,
The reason why the electrolysis time etc. were limited is that the desired corrosion resistance was obtained within these ranges. In the examples, chromium sulfate was used as the Cr 3+ salt, but the present invention is not limited to this, and other Cr salts can also be used. In addition, in the present invention, ammonium iron citrate, copper sulfate, boric acid, and starch improve the hydrate coating properties of the stainless steel surface, and ammonium sulfate stabilizes the PH.
Grapes etc. are effective in stabilizing Cr 3+ . Additionally, thiourea and arsenous acid are effective in low current electrolysis. A more detailed explanation will be given below using examples. (Example) [Crevice corrosion test by seawater immersion] Since crevice corrosion is the most difficult type of local corrosion of stainless steel to prevent, a crevice corrosion test using seawater was conducted to confirm the effectiveness of the cathodic electrolytic treatment according to the present invention. The shape of seawater immersion TP and its installation method are the first.
As shown in Figures 2 and 3, stainless steel TP1 (150 x 25 x 1 mm) is placed between two PVC strip plates 3, 3 with perforations 4 at equal intervals. 4, insert the PVC bolt/nut 5 into the perforated part 4 and tighten with a torque of 40 kgfcm to fix the stainless steel TP1. In the same manner, PVC strip plates 3 and 3 to which stainless steel TP was attached were manufactured. The two PVC strip plates to which the TP is fixed are attached to the PVC frame 2 in parallel as shown in Figure 2. Alternatively, as shown in FIG. 3, the end portion of the lower plate 3 of the PVC strip plate may be fixed with a PVC angle 2 and a PVC bolt/nut 5. TP1 fixed as shown in Figure 2 or Figure 3 is immersed in seawater for a test. The test investigated the presence or absence of corrosion in the gap set between stainless steel TP and PVC strip. The main components of the stainless steel used in the test were
As shown in the table, there is one electrolytic cell (200mm depth x 50mm width x 100mm length) with anti-corrosion treatment.
A 1/2 tank (200 mm depth x 25 mm width x 100 mm length) was used. The anticorrosion effect of the present invention is determined by the type and concentration of the electrolytic treatment solution, current density, and electrolysis time, but the electrolytic time at which the anticorrosion effect is saturated varies slightly depending on the type of solution used, the concentration of the solution, the current density, etc. It is not necessarily constant. In the examples described below, the pretreatment electrolysis time was 5 minutes, and the cathode electrolysis treatment time was 10 minutes. Table 3 shows the results of the seawater immersion crevice corrosion test of test pieces electrolytically treated with various salt aqueous solutions as described above. Additionally, Table 2 shows the results of the seawater immersion crevice corrosion test for untreated materials as comparative materials. As is clear from Tables 2 and 3, the life of the test piece of the present invention, in which the stainless steel surface was treated using a combination of anodic electrolytic treatment and cathodic electrolytic treatment, was 3 times longer than that of untreated material.
Its corrosion resistance is significantly improved. Among them, 430 were over two years old and 304 were over two years old.
Some products have shown a lifespan of over 3.5 years, and testing is still ongoing, so it is expected that the lifespan will further increase.
【表】【table】
【表】【table】
【表】
ある。
表中、寿命が＞で示されているものは、現在
試験がなお継続中のものである。
（発明の効果）
本発明によると、ステンレス鋼を陽極電解処理
と陰極電解処理を併用して処理することにより、
ステンレス鋼の表面に電解液中に含まれる各金属
イオンの複雑な水和物からなる防食化成膜が形成
されると考えられ、この防食化成膜により、ステ
ンレス鋼を中性塩化物環境等で使用する場合大巾
な耐食性改善が可能となる。更に、陽極電解処理
と陰極電解処理を同一のCrイオン含有水溶液で
行なうので、極めて効率良い方法である。[Table] Yes.
In the table, those whose lifespan is > are currently undergoing testing.
(Effects of the Invention) According to the present invention, by treating stainless steel using a combination of anodic electrolytic treatment and cathodic electrolytic treatment,
It is thought that an anti-corrosion coating consisting of complex hydrates of various metal ions contained in the electrolyte is formed on the surface of stainless steel. When used in , it is possible to significantly improve corrosion resistance. Furthermore, since the anodic electrolytic treatment and the cathodic electrolytic treatment are performed using the same Cr ion-containing aqueous solution, it is an extremely efficient method.
第１図〜第３図は、隙間腐食試験T.P.の取付
け状態を示す説明図である。
１……ステンレス鋼T.P.、４……孔、２……
塩ビ枠（アングル）、５……塩ビボルト・ナツト、
３……塩ビ帯状板。
FIGS. 1 to 3 are explanatory diagrams showing how the crevice corrosion test TP is installed. 1... Stainless steel TP, 4... Hole, 2...
PVC frame (angle), 5...PVC bolt/nut,
3...PVC strip.
Claims (1)
塩類水溶液中に浸して電流密度5A／ｄm2以下、
電解時間10分以下の陽極電解処理を行なつて、そ
の表面を清浄化し、活性化した後、該塩類水溶液
中で電流密度0.1〜10A／ｄm2、電解時間１〜30
分の陰極電解処理を行なうことを特徴とするステ
ンレス鋼の防食処理法。 ２ 塩類水溶液が、クエン酸鉄アンモニウム0.05
〜2.0％、アンモニウムみようばん0.01〜0.5％、
硫安0.01〜2.0％などのアンモニウム塩類を単独
又は複数含有する特許請求の範囲第１項記載の方
法。 ３ 塩類水溶液が、濃度0.1〜10％の範囲で、Cu
イオンを含む塩類、Niイオンを含む塩類及びブ
ドウ糖を単独又は複数含有する特許請求の範囲第
１〜第２項のいずれか１つに記載の方法。 ４ 塩類水溶液が、微量添加物として、濃度0.01
〜0.5％の範囲で、チオ尿素、でん粉、硼酸、グ
リセリン及び亜ひ酸を単独又は複数含有する特許
請求の範囲第１〜第３項のいずれか１つに記載の
方法。[Claims] 1 Stainless steel is immersed in an aqueous salt solution containing Cr 3+ at a concentration of 0.5 to 20%, and the current density is 5 A/dm 2 or less,
After cleaning and activating the surface by performing anodic electrolysis treatment for an electrolysis time of 10 minutes or less, the electrolysis time is 1 to 30 minutes at a current density of 0.1 to 10 A/dm 2 in the salt aqueous solution.
An anticorrosion treatment method for stainless steel characterized by cathodic electrolytic treatment for 30 minutes. 2 The aqueous salt solution contains ferrous ammonium citrate 0.05
~2.0%, ammonium alum 0.01~0.5%,
The method according to claim 1, which contains one or more ammonium salts such as 0.01 to 2.0% ammonium sulfate. 3 Salt aqueous solution contains Cu at a concentration range of 0.1 to 10%.
The method according to any one of claims 1 to 2, which contains salts containing ions, salts containing Ni ions, and glucose singly or in combination. 4 Salt aqueous solution is used as a trace additive at a concentration of 0.01
The method according to any one of claims 1 to 3, containing one or more of thiourea, starch, boric acid, glycerin, and arsenic acid in the range of 0.5%.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP8312488A JPS63270498A (en) | 1988-04-06 | 1988-04-06 | Anticorrosive treatment of stainless steel |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP8312488A JPS63270498A (en) | 1988-04-06 | 1988-04-06 | Anticorrosive treatment of stainless steel |
Related Parent Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP20832384A Division JPS6187897A (en) | 1984-10-05 | 1984-10-05 | Anticorrosive treatment of stainless steel |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS63270498A JPS63270498A (en) | 1988-11-08 |
| JPH0437160B2 true JPH0437160B2 (en) | 1992-06-18 |
Family
ID=13793456
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP8312488A Granted JPS63270498A (en) | 1988-04-06 | 1988-04-06 | Anticorrosive treatment of stainless steel |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS63270498A (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6004448A (en) * | 1995-06-06 | 1999-12-21 | Atotech Usa, Inc. | Deposition of chromium oxides from a trivalent chromium solution containing a complexing agent for a buffer |
| JP5299887B2 (en) * | 2008-03-26 | 2013-09-25 | 奥野製薬工業株式会社 | Electrolytic solution for trivalent chromium plating film |
| CN102672878A (en) * | 2011-03-14 | 2012-09-19 | 鸿富锦精密工业（深圳）有限公司 | Stainless steel and resin compound and manufacturing method thereof |
-
1988
- 1988-04-06 JP JP8312488A patent/JPS63270498A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS63270498A (en) | 1988-11-08 |
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