JPH037735B2 - - Google Patents
Info
- Publication number
- JPH037735B2 JPH037735B2 JP30300488A JP30300488A JPH037735B2 JP H037735 B2 JPH037735 B2 JP H037735B2 JP 30300488 A JP30300488 A JP 30300488A JP 30300488 A JP30300488 A JP 30300488A JP H037735 B2 JPH037735 B2 JP H037735B2
- Authority
- JP
- Japan
- Prior art keywords
- amount
- effect
- electricity
- corrosion
- alloy
- 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
- 239000012535 impurity Substances 0.000 claims description 2
- 230000000694 effects Effects 0.000 description 16
- 230000005611 electricity Effects 0.000 description 16
- 238000005260 corrosion Methods 0.000 description 15
- 230000007797 corrosion Effects 0.000 description 11
- 229910000838 Al alloy Inorganic materials 0.000 description 7
- 239000000463 material Substances 0.000 description 7
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 4
- 229910045601 alloy Inorganic materials 0.000 description 4
- 239000000956 alloy Substances 0.000 description 4
- 238000004210 cathodic protection Methods 0.000 description 4
- 229910052738 indium Inorganic materials 0.000 description 4
- 238000002844 melting Methods 0.000 description 4
- 230000008018 melting Effects 0.000 description 4
- 229910052725 zinc Inorganic materials 0.000 description 4
- 229910000676 Si alloy Inorganic materials 0.000 description 3
- 239000013078 crystal Substances 0.000 description 3
- 230000007423 decrease Effects 0.000 description 3
- 239000013535 sea water Substances 0.000 description 3
- 230000003213 activating effect Effects 0.000 description 2
- 229910052742 iron Inorganic materials 0.000 description 2
- 239000000203 mixture Substances 0.000 description 2
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 2
- 229910052726 zirconium Inorganic materials 0.000 description 2
- CWYNVVGOOAEACU-UHFFFAOYSA-N Fe2+ Chemical compound [Fe+2] CWYNVVGOOAEACU-UHFFFAOYSA-N 0.000 description 1
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 1
- 229910000846 In alloy Inorganic materials 0.000 description 1
- GRYLNZFGIOXLOG-UHFFFAOYSA-N Nitric acid Chemical compound O[N+]([O-])=O GRYLNZFGIOXLOG-UHFFFAOYSA-N 0.000 description 1
- 229910000831 Steel Inorganic materials 0.000 description 1
- 229910007610 Zn—Sn Inorganic materials 0.000 description 1
- 229910052782 aluminium Inorganic materials 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 238000004090 dissolution Methods 0.000 description 1
- 238000010828 elution Methods 0.000 description 1
- 239000011521 glass Substances 0.000 description 1
- 229910052739 hydrogen Inorganic materials 0.000 description 1
- 239000001257 hydrogen Substances 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 238000000034 method Methods 0.000 description 1
- 238000002156 mixing Methods 0.000 description 1
- 229910017604 nitric acid Inorganic materials 0.000 description 1
- 229920006395 saturated elastomer Polymers 0.000 description 1
- 239000010935 stainless steel Substances 0.000 description 1
- 229910001220 stainless steel Inorganic materials 0.000 description 1
- 239000010959 steel Substances 0.000 description 1
- 238000010998 test method Methods 0.000 description 1
- 229910052718 tin Inorganic materials 0.000 description 1
- 125000000391 vinyl group Chemical group [H]C([*])=C([H])[H] 0.000 description 1
- 229920002554 vinyl polymer Polymers 0.000 description 1
Description
〔産業上の利用分野〕
本発明は、鉄系材料の陰極防食に使用される流
電陽極用アルミニウム合金に関する。
〔従来の技術〕
流電陽極用材料としては、陽極電位が出来るだ
け卑であり、発生電気量が大きく、且つ耐用年数
を満足するために溶け残りを生じることなく、陽
極表面からむらなく一様に溶解することが要求さ
れる。
上記の要件を満足する材料として、Alは、単
位重量当たりの発生電気量がZn，Mg等に比して
大きく、陽極電位も本来は極めて卑であつて、大
きな防食電流を取り出すことが出来るが、Alは
そのまゝの状態では酸化被膜に覆われているた
め、海水中での陽極電位は−0.7〜−0.9Vvs.，S.
C.E.（飽和甘汞電極基準、以下陽極電位は同じ）
しか示さず、海水中でそのまゝ使用した場合、鉄
鋼を防食することは困難である。
このため、流電陽極としては、陽極電位を−
1.0V程度とする目的で、AlにZn，Sn，In，Zn−
In，Zn−Sn，In−Sn等さまざまの元素を各種の
配合比率で添加したものが提案又は実用化されて
いる。
その中で例えば、Al−Zn−In−Si系合金は陽
極電位が−1.0Vvs.，S.C.E.より卑電位を示し、
電気量も2.65A・hr／ｇを安定して維持できるも
のの、腐食、溶解が均一に進行せず、溶解表面の
平滑性も乏しいため、孔食や溝腐食（腐食が溝状
で両側が残る）等による自己腐食や実使用環境中
における合金の部分的脱落を引き起こし実用上の
寿命が短くなるという欠点があつた。
〔発明が解決しようとする課題〕
本発明の課題は、上記の問題点を解決し、鉄系
材料を陰極防食するに充分なる陽極電位と電気量
を示し、且つ溶解表面の均一性と平滑性を備えた
流電陽極用Al合金を提供することを課題とする。
〔課題を解決するための手段〕
この課題を解決するために、本発明者等は種々
研究を行なつた結果、Al−Zn−In−Si合金にTi，
Ｂ及びZrの３種類の元素を添加することにより、
鉄系材料を陰極防食するのに充分なる電位と電気
量を維持し、且つ溶解表面の均一性と平滑性が著
しく改善されることを見出し本発明に到達した。
即ち、本発明はZn0.5〜6.0重量％，Ti0.005〜
0.1重量％，In0.01〜0.05重量％，Si0.05〜0.3重量
％，B0.001〜0.02重量％，Zr0.0005〜0.01重量％
を含み、残部が実質的にAl及び不可避不純物か
らなる流量陽極用アルミニウム合金を課題解決の
手段とする。
〔作用〕
本発明における各成分の作用を以下に説明す
る。
１ Zn0.5〜6.0％（重量％以下同じ）
Alを主体とする合金において、Alを活性にす
る効果については、ZnはInに比較すると小さい
が、InをAl中に均一に分散させる作用を有し、
均一な溶解表面を形成するのに有効に働く。
更にZnの添加はAl合金の水素過電圧を増大さ
せる効果があり、均一な溶解表面を形成する効果
と共に局部アノード、局部カソードの形成による
自己腐食を抑制し、発生有効電気量を増大させる
効果がある。しかしZnの含有量が0.5％未満では
Inを合金中に均一に分散させる作用が不充分であ
り、6.0％を超えると、逆に電気量が減少するの
でZnは0.5〜6.0％とした。
２ In0.01〜0.05％
InはAl合金を活性化し、陽極電位を大きく卑
にする作用を有するが、Znが0.5〜6.0％の範囲に
おいて、Inが0.01％未満ではその作用が弱く陽極
電位が充分卑にならない。又0.05％を超えて含有
すると、陽極電位は卑になるが、In自体不均一に
分散し、そのために局部腐食を生じて電気量が低
下する。よつてInの添加量は0.01〜0.05％とした。
３ Si0.05〜0.3％
SiはNn0.5〜6.0％，In0.01〜0.05％を含有した
Al合金において、0.05〜0.3％含有させると、そ
の電気量が増大する。Siが0.05％より少ないとそ
の効果はなく、又0.3％を超えると再びその効果
がなくなると共に陽極電位が上昇し防食機能が低
下する。よつてSiの添加量は0.05〜0.3％とした。
４ Ti0.005〜0.1％，B0.001〜0.02％
上記のAl−Zn−In−Si合金にTi0.005〜0.1％及
びB0.001〜0.02％を添加すると、結晶組織が粗大
な柱状晶から微細な粒状晶へと変化し、それに伴
なつて合金の溶出が均一となり、孔食、溝腐食な
らびに腐食生成物の付着を防止する。その結果、
溶解表面の均一性と平滑性が向上する。Tiは
0.005％未満、Ｂは0.001％未満ではその効果は充
分ではなく、Tiは0.1％を超え、Ｂは0.02％を超
えると有効発生電気量の低下を招く。従つてTi
及びＢの添加量はTi0.005〜0.1％，B0.001〜0.02
％とした。
５ Zr0.0005〜0.01％
上記のAl−Zn−In−Si合金に、Zrを0.0005〜
0.01％添加すると、その電気量を更に増大させる
ことが出来る。Zrの作用はAlの酸化物被膜の半
導体的性質に関係すると考えられ、極めて微量の
添加でも顕著な効果が現われるが、この場合Siの
共存が必要であつて、Zr単独では殆ど効果がな
い。Zrは0.0005％未満では電気量の増大効果が充
分ではなく、0.01％を超えると結晶粒界に粗大に
分布するようになり電気量が低下する。
〔実施例〕
実施試験は日本学術振興会第97委員会の電気防
食第12分科会の「流電陽極試験法」に基ずいて以
下に説明する方法で行なつた。
容量１のガラス製ビーカーに、第１表に示し
た組成の人工海水1000mlを入れた電解槽に、第２
表に示すそれぞれの組成の直径20mmの棒状試料の
一部を露出面積20cm2になるようにビニールテープ
でシールしたものを陽極として槽内の中央部に吊
し、陰極は槽の内壁に沿つたステンレス鋼の円筒
を用いた。
試料を直流電源の＋極に、又陰極板（円筒）を
その一極に結線し、可変抵抗及び電量計を回路内
に直列につないで通電し、陽極電流密度1mA／
cm2、液温25℃として240時間電解試験を行ない、
毎日一回照合電極と電圧計を用いて陽極の電位を
測定し、同時に電気量を測定した。
電解試験時間を経過後、液中より試料を取り出
し、ブラシで水洗後60％濃硝酸溶液に３〜５分間
浸漬して水洗し、乾燥して試料の表面状態を調査
した。
得られた結果を第２表に示す。
[Industrial Application Field] The present invention relates to an aluminum alloy for galvanic anodes used for cathodic protection of ferrous materials. [Prior art] As a material for a galvanic anode, the anode potential is as base as possible, the amount of electricity generated is large, and in order to satisfy the service life, it is necessary to use a material that is uniformly distributed from the anode surface without leaving any undissolved residue. required to be dissolved in As a material that satisfies the above requirements, Al generates a large amount of electricity per unit weight compared to Zn, Mg, etc., and the anode potential is originally extremely base, so it is possible to extract a large anti-corrosion current. , Al is covered with an oxide film in its original state, so the anode potential in seawater is -0.7 to -0.9V vs., S.
CE (Saturated Amane electrode standard, hereinafter the anode potential is the same)
However, it is difficult to protect steel from corrosion if it is used directly in seawater. Therefore, as a galvanic anode, the anode potential is -
Zn, Sn, In, Zn− is added to Al for the purpose of approximately 1.0V.
Products in which various elements such as In, Zn-Sn, and In-Sn are added in various blending ratios have been proposed or put into practical use. Among them, for example, Al-Zn-In-Si alloy has an anode potential of -1.0V vs., which is less noble than SCE.
Although the amount of electricity can be stably maintained at 2.65A・hr/g, corrosion and dissolution do not proceed uniformly, and the melting surface is not smooth, resulting in pitting corrosion and groove corrosion (corrosion remains in the form of grooves on both sides). ), etc., and the alloy partially falls off in the actual usage environment, resulting in a shortened practical life. [Problems to be Solved by the Invention] It is an object of the present invention to solve the above-mentioned problems, to exhibit sufficient anode potential and quantity of electricity for cathodic protection of iron-based materials, and to provide uniformity and smoothness of the melted surface. An object of the present invention is to provide an Al alloy for galvanic anodes having the following properties. [Means for Solving the Problem] In order to solve this problem, the present inventors conducted various studies and found that Ti, Ti,
By adding three types of elements, B and Zr,
The inventors have discovered that a sufficient potential and quantity of electricity can be maintained for cathodic protection of iron-based materials, and that the uniformity and smoothness of the melted surface can be significantly improved, leading to the present invention. That is, in the present invention, Zn0.5~6.0% by weight, Ti0.005~
0.1% by weight, In0.01~0.05% by weight, Si0.05~0.3% by weight, B0.001~0.02% by weight, Zr0.0005~0.01% by weight
A means for solving the problem is an aluminum alloy for a flow rate anode, which contains Al and the remainder substantially consists of Al and unavoidable impurities. [Action] The action of each component in the present invention will be explained below. 1 Zn0.5 to 6.0% (same as below weight%) In alloys mainly composed of Al, Zn has a smaller effect on activating Al than In, but it has the effect of uniformly dispersing In in Al. have,
Works effectively to form a uniform melting surface. Furthermore, the addition of Zn has the effect of increasing the hydrogen overvoltage of the Al alloy, has the effect of forming a uniform melting surface, suppresses self-corrosion due to the formation of local anodes and local cathodes, and has the effect of increasing the amount of effective electricity generated. . However, if the Zn content is less than 0.5%,
The effect of uniformly dispersing In in the alloy is insufficient, and if it exceeds 6.0%, the amount of electricity will decrease, so Zn was set at 0.5 to 6.0%. 2 In 0.01 to 0.05% In has the effect of activating the Al alloy and greatly lowering the anode potential, but in the range of 0.5 to 6.0% Zn, if In is less than 0.01%, the effect is weak and the anode potential becomes lower. Don't be mean enough. If the content exceeds 0.05%, the anode potential becomes base, but In itself is dispersed non-uniformly, causing local corrosion and lowering the amount of electricity. Therefore, the amount of In added was set to 0.01 to 0.05%. 3 Si0.05-0.3% Si contained Nn0.5-6.0%, In 0.01-0.05%
In an Al alloy, when it is contained in an amount of 0.05 to 0.3%, the amount of electricity increases. If Si is less than 0.05%, there is no effect, and if it exceeds 0.3%, the effect is lost again and the anode potential increases, reducing the anticorrosion function. Therefore, the amount of Si added was set to 0.05 to 0.3%. 4 Ti0.005~0.1%, B0.001~0.02% When Ti0.005~0.1% and B0.001~0.02% are added to the above Al-Zn-In-Si alloy, the crystal structure changes from coarse columnar crystals. It changes into fine granular crystals, and as a result, the elution of the alloy becomes uniform, preventing pitting corrosion, groove corrosion, and adhesion of corrosion products. the result,
Improves the uniformity and smoothness of the melted surface. Ti is
If Ti is less than 0.005% and B is less than 0.001%, the effect will not be sufficient, and if Ti exceeds 0.1% and B exceeds 0.02%, the effective amount of electricity generated will decrease. Therefore Ti
The amount of B added is Ti0.005~0.1%, B0.001~0.02
%. 5 Zr0.0005~0.01% Zr is added to the above Al-Zn-In-Si alloy from 0.0005~
Adding 0.01% can further increase the amount of electricity. The effect of Zr is thought to be related to the semiconducting properties of the Al oxide film, and even a very small amount of addition produces a remarkable effect, but in this case the coexistence of Si is required, and Zr alone has almost no effect. When Zr is less than 0.0005%, the effect of increasing the amount of electricity is not sufficient, and when it exceeds 0.01%, it becomes coarsely distributed at grain boundaries and the amount of electricity decreases. [Example] Practical tests were conducted in accordance with the method described below based on the "Galvanic Anode Test Method" of the 12th Subcommittee on Cathodic Protection of the 97th Committee of the Japan Society for the Promotion of Science. A glass beaker with a capacity of 1 is filled with 1000 ml of artificial seawater having the composition shown in Table 1.
A portion of a rod-shaped sample with a diameter of 20 mm of each composition shown in the table was sealed with vinyl tape so that the exposed area was 20 cm 2 and was hung in the center of the tank as an anode, and a cathode was placed along the inner wall of the tank. A stainless steel cylinder was used. Connect the sample to the + pole of a DC power supply and the cathode plate (cylindrical) to one pole, connect a variable resistor and a coulometer in series in the circuit, and apply electricity until the anode current density is 1 mA/
cm 2 and a liquid temperature of 25°C for 240 hours.
Once a day, the potential of the anode was measured using a reference electrode and a voltmeter, and at the same time, the amount of electricity was measured. After the electrolytic test time had elapsed, the sample was taken out of the solution, washed with water using a brush, immersed in a 60% concentrated nitric acid solution for 3 to 5 minutes, washed with water, dried, and the surface condition of the sample was investigated. The results obtained are shown in Table 2.
【表】【table】
【表】【table】
【表】【table】
本発明流電陽極用アルミニウム合金は、高い発
生電気量を有し、陽極電位も充分卑であり、更に
従来の材料に比し溶解表面の均一性と平滑性が著
しく改善され、孔食や溝腐食等による自己腐食や
実使用環境中における合金の部分的脱落を防止し
て長期間に亘つて安定した防食機能を有する。
The aluminum alloy for galvanic anodes of the present invention has a high amount of electricity generated, the anode potential is sufficiently base, and the uniformity and smoothness of the melting surface are significantly improved compared to conventional materials, preventing pitting corrosion and grooves. It has a stable anti-corrosion function over a long period of time by preventing self-corrosion due to corrosion and partial shedding of the alloy in the actual usage environment.
Claims (1)
Si0.05〜0.3重量％，Ti0.005〜0.1重量％，B0.001
〜0.02重量％，Zr0.0005〜0.01重量％を含み、残
部が実質的にAl及び不可避不純物からなること
を特徴とする流電陽極用アルミニウム合金。1 Zn0.5-6.0% by weight, In0.01-0.05% by weight,
Si0.05~0.3wt%, Ti0.005~0.1wt%, B0.001
-0.02% by weight of Zr, 0.0005-0.01% by weight of Zr, and the remainder substantially consists of Al and inevitable impurities.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP30300488A JPH02149637A (en) | 1988-11-30 | 1988-11-30 | Aluminum alloy for galvanic anode |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP30300488A JPH02149637A (en) | 1988-11-30 | 1988-11-30 | Aluminum alloy for galvanic anode |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH02149637A JPH02149637A (en) | 1990-06-08 |
| JPH037735B2 true JPH037735B2 (en) | 1991-02-04 |
Family
ID=17915780
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP30300488A Granted JPH02149637A (en) | 1988-11-30 | 1988-11-30 | Aluminum alloy for galvanic anode |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH02149637A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2017207505A (en) * | 2015-05-29 | 2017-11-24 | シスメックス株式会社 | Method for measuring uptake ability of cholesterol of lipoprotein and reagent kit |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP3183604B2 (en) * | 1994-02-16 | 2001-07-09 | 住友金属鉱山株式会社 | Aluminum alloy for galvanic anodic protection of steel bars in reinforced concrete and corrosion protection method using the same |
| US6673309B1 (en) * | 1994-02-16 | 2004-01-06 | Corrpro Companies, Inc. | Sacrificial anode for cathodic protection and alloy therefor |
-
1988
- 1988-11-30 JP JP30300488A patent/JPH02149637A/en active Granted
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2017207505A (en) * | 2015-05-29 | 2017-11-24 | シスメックス株式会社 | Method for measuring uptake ability of cholesterol of lipoprotein and reagent kit |
Also Published As
| Publication number | Publication date |
|---|---|
| JPH02149637A (en) | 1990-06-08 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| LAPS | Cancellation because of no payment of annual fees |