JPS6339677B2 - - Google Patents
Info
- Publication number
- JPS6339677B2 JPS6339677B2 JP58122274A JP12227483A JPS6339677B2 JP S6339677 B2 JPS6339677 B2 JP S6339677B2 JP 58122274 A JP58122274 A JP 58122274A JP 12227483 A JP12227483 A JP 12227483A JP S6339677 B2 JPS6339677 B2 JP S6339677B2
- Authority
- JP
- Japan
- Prior art keywords
- aluminum material
- potential
- corrosion
- sacrificial anode
- aluminum
- 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
- 229910052782 aluminium Inorganic materials 0.000 claims description 69
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 claims description 69
- 239000000463 material Substances 0.000 claims description 68
- 238000005260 corrosion Methods 0.000 claims description 40
- 230000007797 corrosion Effects 0.000 claims description 39
- 238000000034 method Methods 0.000 claims description 24
- 238000004210 cathodic protection Methods 0.000 claims description 13
- 230000001629 suppression Effects 0.000 claims description 4
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 18
- 239000007769 metal material Substances 0.000 description 10
- 239000003513 alkali Substances 0.000 description 4
- 239000000956 alloy Substances 0.000 description 4
- 229910000831 Steel Inorganic materials 0.000 description 3
- 229910045601 alloy Inorganic materials 0.000 description 3
- 230000007423 decrease Effects 0.000 description 3
- 238000010586 diagram Methods 0.000 description 3
- 230000000694 effects Effects 0.000 description 3
- 229910052751 metal Inorganic materials 0.000 description 3
- 239000013535 sea water Substances 0.000 description 3
- 239000010959 steel Substances 0.000 description 3
- ZOMNIUBKTOKEHS-UHFFFAOYSA-L dimercury dichloride Chemical class Cl[Hg][Hg]Cl ZOMNIUBKTOKEHS-UHFFFAOYSA-L 0.000 description 2
- 238000006056 electrooxidation reaction Methods 0.000 description 2
- 238000002474 experimental method Methods 0.000 description 2
- 239000002184 metal Substances 0.000 description 2
- 238000010422 painting Methods 0.000 description 2
- 229910052725 zinc Inorganic materials 0.000 description 2
- 239000011701 zinc Substances 0.000 description 2
- 229910000838 Al alloy Inorganic materials 0.000 description 1
- FYYHWMGAXLPEAU-UHFFFAOYSA-N Magnesium Chemical compound [Mg] FYYHWMGAXLPEAU-UHFFFAOYSA-N 0.000 description 1
- HCHKCACWOHOZIP-UHFFFAOYSA-N Zinc Chemical compound [Zn] HCHKCACWOHOZIP-UHFFFAOYSA-N 0.000 description 1
- 239000002253 acid Substances 0.000 description 1
- 150000007513 acids Chemical class 0.000 description 1
- 239000010407 anodic oxide Substances 0.000 description 1
- 239000002585 base Substances 0.000 description 1
- 239000003575 carbonaceous material Substances 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 230000006866 deterioration Effects 0.000 description 1
- 238000007654 immersion Methods 0.000 description 1
- 230000006698 induction Effects 0.000 description 1
- 239000008235 industrial water Substances 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 229910052749 magnesium Inorganic materials 0.000 description 1
- 239000011777 magnesium Substances 0.000 description 1
- 230000007935 neutral effect Effects 0.000 description 1
- 239000003973 paint Substances 0.000 description 1
- 238000000926 separation method Methods 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 230000002123 temporal effect Effects 0.000 description 1
- 229910000859 α-Fe Inorganic materials 0.000 description 1
Landscapes
- Prevention Of Electric Corrosion (AREA)
Description
【発明の詳細な説明】
本発明は、アルミニウムおよびアルミニウム合
金材（以下アルミニウム材という）の陰極防食方
法に関するものである。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for cathodic protection of aluminum and aluminum alloy materials (hereinafter referred to as aluminum materials).
アルミニウム材は、軽量にして熱伝導性がよ
く、しかも中性環境においては比較的腐食を受け
難い金属材料であるので、近時、化学機器などの
構造材として広く使用されているのであるが、例
えばこれを熱交換器や貯液槽などの海水や工業用
水（以下水という）に直接触れる箇所に使用した
場合、しばしば孔食や粒界腐食などの所謂電気化
学的原因に基づく不均一腐食を生ずることが知ら
れている。 Aluminum is a metal material that is lightweight, has good thermal conductivity, and is relatively resistant to corrosion in neutral environments, so it has recently been widely used as a structural material for chemical equipment, etc. For example, when this product is used in areas that come into direct contact with seawater or industrial water (hereinafter referred to as water), such as heat exchangers or liquid storage tanks, it often causes uneven corrosion due to so-called electrochemical causes such as pitting corrosion and intergranular corrosion. known to occur.
このような水に触れる箇所に使用されたアルミ
ニウム材の電気化学的腐食を防ぐ方法として、ア
ルミニウム材表面に陽極酸化皮膜を施すか、また
は塗料などで塗装することも行われているが、こ
のような皮膜処理や塗装のみによつたのでは、皮
膜や塗装面に存在する潜在的な欠陥や、使用中に
おける皮膜の劣化や塗装面の別離などによつて、
必ずしも腐食性環境下において長期に渉つて十分
な防食効果を期待することができなかつた。 In order to prevent electrochemical corrosion of aluminum materials used in areas that come into contact with water, methods such as applying an anodic oxide film to the surface of the aluminum material or painting it with paint are also used. If only proper film treatment and painting were used, there would be potential defects in the film or painted surface, deterioration of the film during use, separation of the painted surface, etc.
It was not always possible to expect a sufficient corrosion protection effect over a long period of time in a corrosive environment.
従来、このような水中に浸漬された金属材の電
気化学的腐食を防止する方法として、金属材に水
中においてその金属材より卑な自然電位を示す他
の金属材を取付けて、水中における防食しようと
する金属材の電位を常に孔食電位より低く抑制す
る所謂犠性陽極法や、水中に設けた対極と金属材
との間に、外部電源を使用して継続的に微弱な防
食電流を流すことによつて、水中における金属材
の電位を孔食電位以下になるように抑制する所謂
陰極防食法が知られており、鋼材などの腐食防止
に広く用いられて効果を挙げている。 Conventionally, as a method to prevent electrochemical corrosion of metal materials immersed in water, attempts have been made to attach other metal materials that exhibit a lower natural potential than the metal material in water to prevent corrosion in water. The so-called sacrificial anode method, which always suppresses the potential of the metal material to be lower than the pitting corrosion potential, or the so-called sacrificial anode method, which uses an external power source to continuously flow a weak anti-corrosion current between the metal material and a counter electrode installed in water. In particular, a so-called cathodic protection method is known in which the potential of metal materials in water is suppressed to below the pitting corrosion potential, and is widely used and effective for preventing corrosion of steel materials.
本発明者らは、水中に浸漬したアルミニウム材
に上記した犠性陽極や外部電源を使用する陰極防
食法を適用すべく種々実験を重ねた。しかしなが
ら、アルミニウム材の場合、単に上記したような
従来の犠性陽極や外部電源を使用した陰極防食法
を適用したのでは、必ずしも鋼材におけるごとき
満足すべき防食効果を発揮させることができなか
つた。この理由は、アルミニウム材は鋼材とは異
なつて、酸およびアルカリに溶ける所謂両性金属
であることによるものである。 The present inventors have conducted various experiments in order to apply the above-mentioned cathodic protection method using a sacrificial anode and an external power source to an aluminum material immersed in water. However, in the case of aluminum materials, simply applying the conventional cathodic protection method using a sacrificial anode or an external power source as described above does not necessarily provide the same satisfactory corrosion protection effect as with steel materials. The reason for this is that, unlike steel, aluminum is a so-called amphoteric metal that dissolves in acids and alkalis.
すなわち、アルミニウム材が水中において実質
的に腐食を受けないで長期間安定して存在するた
めには、アルミニウム材の合金の種類や浸漬環境
などによつても幾分異なるのであるが、その水中
における電位が孔食電位を上限として、それより
0.3ないし0.4V程度低い狭い巾の電位域内に保た
れねばならないことが知られている。したがつ
て、例えば犠性陽極を使用してアルミニウム材を
防食するためには、被防食材としてのアルミニウ
ム材全体に渉つて、その陰極電位が可及的に上記
安定電位域内に保たれるように抑制する必要があ
るのであるが、犠性陽極として水中におけるアル
ミニウム材の自然電位に比較的近い電位をもつた
金属材を使用した場合、アルミニウム材の犠性陽
極に近接した箇所においては、アルミニウム材と
犠性陽極との間に流れる陰極電流によつて適正な
電位抑制が行われるのであるが、アルミニウム材
の犠性陽極と距離的に離れている箇所は、水の電
気抵抗に起因して陰極電流の流れが少なくなるた
めに、十分な電位抑制を行うことができず、この
部分において孔食や粒界腐食の発生することが避
け難く、またアルミニウム材の犠性陽極から距離
的に離れた箇所にまで電位抑制をしようとして、
アルミニウム材に対して十分に卑な自然電位をも
つた金属材を犠性陽極として使用すると、アルミ
ニウム材の犠性陽極に近い箇所においては過度の
電位抑制が行われ、この部分に所謂アルカリ腐食
を起し勝ちとなるのであつた。このことは犠性陽
極の代りに外部電源を使用する陰極防食法におい
ても全く同様であつて、アルミニウム材の対極に
近接した箇所の陰極電位を適正に保つごとくに外
部電源の電圧を調節すると、対極から距離的に離
れた電位抑制が不十分となり、また、アルミニウ
ム材の対極から離れた箇所まで十分に電位抑制を
しようとすると、対極に近い部分において過度の
電位抑制が行われ、この箇所にアルカリ腐食を起
すのであつた。 In other words, in order for an aluminum material to exist stably for a long time in water without being substantially corroded, it depends somewhat on the type of aluminum material's alloy and the immersion environment. The potential is set at the pitting potential as an upper limit, and
It is known that the voltage must be kept within a narrow potential range as low as 0.3 to 0.4V. Therefore, for example, in order to protect aluminum material using a sacrificial anode, the cathode potential must be kept within the above stable potential range as much as possible over the entire aluminum material to be protected. However, if a metal material with a potential relatively close to the natural potential of the aluminum material in water is used as the sacrificial anode, aluminum Appropriate potential suppression is carried out by the cathode current flowing between the aluminum material and the sacrificial anode, but in areas of the aluminum material that are far away from the sacrificial anode, the potential is suppressed due to the electrical resistance of water. Because the flow of cathode current decreases, sufficient potential cannot be suppressed, and it is difficult to avoid pitting corrosion and intergranular corrosion in this area. In an attempt to suppress the potential to the point where
If a metal material with a sufficiently base natural potential relative to aluminum material is used as a sacrificial anode, the potential will be excessively suppressed in the area near the sacrificial anode of the aluminum material, causing so-called alkaline corrosion in this area. It was an early victory. This is exactly the same in the cathodic protection method that uses an external power source instead of a sacrificial anode; if the voltage of the external power source is adjusted to maintain an appropriate cathode potential near the counter electrode of the aluminum material, Potential suppression at distances away from the counter electrode becomes insufficient, and if an attempt is made to sufficiently suppress the potential at a location far away from the counter electrode of the aluminum material, excessive potential suppression occurs at a portion close to the counter electrode, and this location This caused alkali corrosion.
このように従来の犠性陽極や外部電源を使用し
た陰極防食法によつたのでは、アルミニウム材全
体に渉つてその陰極電位を適正に保つことが難し
く、このために陰極防食法のアルミニウム材への
適用の範囲を著しく狭めていたのであつた。 With conventional cathodic protection methods that use sacrificial anodes and external power sources, it is difficult to maintain an appropriate cathode potential throughout the aluminum material. This significantly narrowed the scope of application.
本発明者らは、犠性陽極や外部電源を使用した
陰極防食法をアルミニウム材に適用した場合に生
ずる上記したような欠点を防止すべく、更に研究
を重ねた結果、水中に浸漬されたアルミニウム材
に負のパルス電圧を断続的に繰返して印加して、
その陰極電位を間欠的に抑制することによつて、
犠性陽極（外部電流法によるときは対極）に近い
箇所において過防食によるアルカリ腐食を起させ
ることなしに、アルミニウム材全体に渉つて広範
囲に孔食または粒界腐食を防止し得ることを見出
した。 In order to prevent the above-mentioned drawbacks that occur when cathodic protection methods using sacrificial anodes and external power sources are applied to aluminum materials, the inventors of the present invention have conducted further research and found that aluminum immersed in water By repeatedly applying a negative pulse voltage to the material,
By intermittently suppressing the cathode potential,
It has been found that pitting corrosion or intergranular corrosion can be prevented over a wide area throughout the aluminum material without causing alkaline corrosion due to excessive corrosion protection in locations near the sacrificial anode (counter electrode when using the external current method). .
本発明は、上記発見に基づいてなされたもので
ある。 The present invention has been made based on the above discovery.
すなわち、本発明は、犠牲陽極または外部電源
を使用したアルミニウム材の陰極防食法におい
て、該アルミニウム材に犠牲陽極または外部電源
から負のパルス電圧を繰り返し印加することによ
つて、少なくとも犠牲陽極または対極（外部電源
使用の場合）に近接した部分におけるアルミニウ
ム材の陰極電位を、あらかじめ設定された時間的
間隔をもつて、アルカリ腐食域にまで間欠的に繰
り返しし抑制することを特徴とするアルミニウム
材の陰極防食法である。 That is, the present invention provides a cathodic protection method for aluminum materials using a sacrificial anode or an external power source, by repeatedly applying a negative pulse voltage to the aluminum material from the sacrificial anode or the external power source. (When using an external power supply) The cathode potential of the aluminum material in the vicinity of the aluminum material is intermittently repeatedly suppressed to the alkaline corrosion region at preset time intervals. This is a cathodic protection method.
以下、本発明の方法を更に具体的に説明する。 The method of the present invention will be explained in more detail below.
第１図は、本発明の方法を実施するための装置
の態様を示す設明図である。第１図ａは、電源と
して犠性陽極を使用した場合の例であつて、図に
おいて、１は水中に浸漬された被防食材としての
アルミニウム材、２は、アルミニウム材１に近接
して水中に設けられた犠性陽極であつて、犠性陽
極２としては亜鉛やマグネシウムまたはこれらの
合金材のように水中における自然電位やアルミニ
ウム材に比べて低い金属極を使用する。アルミニ
ウム材１と犠性陽極２とは導線によつて電流断続
装置３に結ばれて、陰極電流回路４，４が形成さ
れている。電流断続装置３は、陰極電流回路４，
４を断続的に開閉して、アルミニウム材１に負の
パルス電圧が繰返して印加され、アルミニウム材
１の陰極電位Ｖが間欠的に抑制されるごとくに構
成されている。５は、水中に浸漬された標準参照
電極、６は電圧波形観察のためのオツシロスコー
プであつて、導線によつてアルミニウム材１に結
ばれて、作動中におけるアルミニウム材１の陰極
電位の変化を観測し得るごとくになつている。 FIG. 1 is a schematic diagram showing an embodiment of an apparatus for carrying out the method of the invention. Figure 1a shows an example of using a sacrificial anode as a power source. As the sacrificial anode 2, a metal electrode such as zinc, magnesium, or an alloy thereof, which has a lower natural potential in water than an aluminum material, is used. The aluminum material 1 and the sacrificial anode 2 are connected to a current interrupter 3 by a conductive wire to form a cathode current circuit 4, 4. The current interrupter 3 includes a cathode current circuit 4,
4 is intermittently opened and closed, a negative pulse voltage is repeatedly applied to the aluminum material 1, and the cathode potential V of the aluminum material 1 is intermittently suppressed. 5 is a standard reference electrode immersed in water, and 6 is an oscilloscope for observing voltage waveforms, which is connected to the aluminum material 1 by a conductive wire to monitor changes in the cathode potential of the aluminum material 1 during operation. It has become possible to observe
第１図ｂは、外部電源を使用して本発明の方法
を実施する場合を例示したものであつて、図にお
いて、２′は、第１図ａにおける犠性陽極２の代
りに設けられた対極であつて、対極２′は、その
使用環境において比較的腐食を受け難い金属また
は炭素材のごときで製られている。７は、陰極回
路４，４に挿入された直流電源装置であつて、電
流断続装置８の作動に応じて、アルミニウム材１
と対極２との間に直流電源装置７からの陰極電流
が断続的に流され、これによつてアルミニウム材
１の陰極電位Ｖが間欠的に抑制されるごとくに構
成されている。 FIG. 1b shows an example of carrying out the method of the present invention using an external power source, in which 2' is provided in place of the sacrificial anode 2 in FIG. 1a. The counter electrode 2' is made of a metal or carbon material that is relatively resistant to corrosion in the environment in which it is used. 7 is a DC power supply device inserted into the cathode circuits 4, 4, and the aluminum material 1
A cathode current from a DC power supply device 7 is intermittently passed between the aluminum material 1 and the counter electrode 2, whereby the cathode potential V of the aluminum material 1 is intermittently suppressed.
第２図は、第１図の装置によつて、犠性陽極を
用いて本発明の方法を実施した場合の被防食材と
してのアルミニウム材の比較的犠性陽極に近い部
分における陰極電位の時間的変化を例示したもの
である。図において、縦軸はアルミニウム材１の
陰極電位（飽和カロメル電極を基準とした電位）、
横軸は時間の経過を表わす。すなわち、アルミニ
ウム材１の電位は、はじめはその環境における自
然電位であるa1点を示しているが、電流断続装置
８が作動して、陰極電流回路４，４が短時間閉ざ
されると、犠性陽極２とアルミニウム材１とが電
気的に短絡して、アルミニウム材１に犠性陽極２
から負のパルス電圧が印加されて、その陰極電位
Ｖはアルカリ腐食域内のb1点にまで急速に引下げ
られる。次いで、陰極電流回路４，４が開かれる
と、アルミニウム材１の陰極電位Ｖは直ちに上昇
に転ずる。このときの陰極電位Ｖの上昇は、曲線
b1→a2に示されるように、初期においては急速に
回復するが、その後ゆるやかな上昇を続けて、そ
の自然電位付近のa2点にまで上昇する。次いで電
流断続装置３によつて再び閉ざされてアルミニウ
ム材１に負のパルス電圧が印加されると、アルミ
ニウム材１の陰極電位Ｖはa2点から再びアルカリ
腐食域のb2点にまで急速に引下げられ、その後、
曲線b2→a3に沿つての上昇が繰返される。上記
は、アルミニウム材１に印加するパルス電源とし
て犠性陽極２を使用した場合であるが、犠性陽極
２の代りに外部電源装置７を使用してアルミニウ
ム材１にパルス電圧を印加する場合においても、
アルミニウム材１の陰極電位Ｖは、犠性陽極２を
使用した場合におけると全く同様の時間的変化を
示す。 FIG. 2 shows the time of the cathode potential in a portion of the aluminum material to be protected relatively close to the sacrificial anode when the method of the present invention is carried out using the sacrificial anode with the apparatus shown in FIG. This is an example of a change. In the figure, the vertical axis is the cathode potential of aluminum material 1 (potential with respect to the saturated calomel electrode),
The horizontal axis represents the passage of time. That is, the potential of the aluminum material 1 initially shows a single point a, which is the natural potential in the environment, but when the current interrupter 8 is activated and the cathode current circuits 4, 4 are closed for a short time, The sacrificial anode 2 and the aluminum material 1 are electrically short-circuited, and the sacrificial anode 2 is connected to the aluminum material 1.
A negative pulse voltage is applied from , and the cathode potential V is rapidly lowered to point b 1 within the alkali corrosion zone. Next, when the cathode current circuits 4, 4 are opened, the cathode potential V of the aluminum material 1 immediately starts to rise. The rise in cathode potential V at this time is the curve
As shown in b 1 → a 2 , it recovers rapidly in the initial stage, but then continues to rise slowly until it reaches point a 2 , which is near its natural potential. Then, when the current interrupter 3 closes again and a negative pulse voltage is applied to the aluminum material 1, the cathode potential V of the aluminum material 1 rapidly increases from point a2 to point b2 in the alkaline corrosion region again. was withdrawn and then
The rise along the curve b 2 → a 3 is repeated. The above is a case where the sacrificial anode 2 is used as a pulsed power source applied to the aluminum material 1, but in a case where the external power supply device 7 is used instead of the sacrificial anode 2 to apply a pulsed voltage to the aluminum material 1. too,
The cathode potential V of the aluminum material 1 shows exactly the same temporal change as in the case where the sacrificial anode 2 is used.
上記から判るように、本発明は、アルミニウム
材に犠性陽極または外部電源を使用して負のパル
ス電圧を断続的に繰返して印加することによつ
て、アルミニウム材の陰極電位を間欠的に抑制す
るアルミニウム材の陰極防食法であるが、上記本
発明の方法におけるアルミニウム材に印加するパ
ルス電圧の大きさは、一般的にはそれによつてア
ルミニウム材の陰極電位がその自然電位より0.3
〜0.8V低下する程度であれば十分であるが、特
にアルカリ腐食を起し難い環境においては1V程
度の低下をも許容し得る。アルミニウム材に印加
する１回のパルス電圧の印加時間ｔは、負電圧の
大きさや腐食環境によつても幾分異なるのである
が、アルミニウム材が電位低下によるアルカリ腐
食域に長時間曝されることを避けるために少なく
とも数秒以内に留めることが望ましく、一般的に
は0.01〜２秒程度であることが適当である。ま
た、パルス電圧の印加から、次の印加までの間隔
Ｔは、然程厳格に規定する必要はないが、一般的
には0.5〜60秒程度（但しＴ＞ｔ）であるが、陽
極酸化皮膜を施したアルミニウム材に対しては10
分程度をも許容し得る。 As can be seen from the above, the present invention intermittently suppresses the cathode potential of the aluminum material by repeatedly and intermittently applying a negative pulse voltage to the aluminum material using a sacrificial anode or an external power source. In general, the magnitude of the pulse voltage applied to the aluminum material in the method of the present invention is such that the cathodic potential of the aluminum material is 0.3 below its natural potential.
A drop of ~0.8V is sufficient, but a drop of about 1V can be tolerated, especially in environments where alkali corrosion is difficult to occur. The application time t of one pulse voltage applied to the aluminum material varies somewhat depending on the magnitude of the negative voltage and the corrosive environment, but it is important to note that the aluminum material is exposed to an alkaline corrosion region due to a potential drop for a long time. In order to avoid this, it is desirable to keep the time within at least a few seconds, and generally it is appropriate that the time is about 0.01 to 2 seconds. In addition, the interval T from the application of a pulse voltage to the next application does not need to be specified very strictly, but it is generally about 0.5 to 60 seconds (however, T > t). 10 for aluminum materials treated with
Even a minute is acceptable.
上述のように、従来の陰極防食法においては、
犠性陽極または外部電源を使用して、被防食材と
してのアルミニウム材の陰極電位を常に狭い安定
域内に保つように調節するのであるのに対して、
本発明の方法においては、アルミニウム材に負の
パルス電圧を断続的に印加するのであつて、この
パルス電圧の印加によつて、アルミニウム材の陰
極電位は一時的にはアルカリ腐食域にまで低下す
るのであるが、パルス電圧の印加が解かれるとア
ルミニウム材の電位ははじめは速やかに回復し、
その後ゆるやかに上昇するのであるから、アルミ
ニウム材が実質的にアルカリ腐食域にある時間は
ごく短時間であつて、かつ、アルカリ腐食の開始
には誘導期間があるので、この間において腐食を
受けることはほとんどない。したがつて、常時連
続的に陰極電流を流す従来の陰極防食法に比べ
て、アルミニウム材に印加する負電圧を十分に大
きくしても過防食によるアルカリ腐食を起させる
恐れがないので、苛酷な条件においてもアルミニ
ウム材全体に渉つて広範囲に防食効果を発揮させ
ることができるのである。 As mentioned above, in the conventional cathodic protection method,
In contrast, sacrificial anodes or external power supplies are used to adjust the cathode potential of the aluminum material to be protected so that it is always kept within a narrow stable range.
In the method of the present invention, a negative pulse voltage is intermittently applied to the aluminum material, and by applying this pulse voltage, the cathode potential of the aluminum material temporarily decreases to the alkaline corrosion range. However, when the application of the pulse voltage is removed, the potential of the aluminum material quickly recovers, and
Since the rise is gradual after that, the time that the aluminum material is actually in the alkaline corrosion region is very short, and since there is an induction period before alkaline corrosion starts, corrosion will not occur during this period. rare. Therefore, compared to the conventional cathodic protection method in which a cathode current is passed continuously at all times, even if the negative voltage applied to the aluminum material is sufficiently large, there is no risk of alkaline corrosion caused by over-protection. Even under certain conditions, the anticorrosion effect can be exerted over a wide range of areas throughout the aluminum material.
次に、本発明の実施例を示す。 Next, examples of the present invention will be shown.
実施例 １
被防食材試片としてA1100アルミニウム板材
（800mm長×100mm巾×１mm厚）を使用し実験に供
した。Example 1 An A1100 aluminum plate (800 mm long x 100 mm wide x 1 mm thick) was used as a specimen to be subjected to corrosion protection and subjected to an experiment.
試片の両側の長手方向に沿つて流路巾約５mmの
水路をつくり、板の一方の端からほぼ10cm離れた
位置に防食用の巾40mm×長さ70mm×厚さ15mmの犠
性陽極（材質A263合金；Mg−6.0％Al−3.0％Zn
−0.2％Mn）を設け、犠性陽極と試片の間に、犠
性陽極と試片が間欠的に短絡できるような電流断
続装置を備えた陰極電流回路を設けた。使用水は
天然海水（水温約20℃）とし、ほぼ20cm／Secの
流速で流路に沿つて流した。 A channel with a channel width of approximately 5 mm was created along the longitudinal direction on both sides of the specimen, and a sacrificial anode (width 40 mm x length 70 mm x thickness 15 mm) for corrosion protection was placed approximately 10 cm away from one end of the plate. Material A263 alloy; Mg-6.0%Al-3.0%Zn
-0.2% Mn), and a cathode current circuit equipped with a current interrupter that could intermittently short-circuit the sacrificial anode and the specimen was provided between the sacrificial anode and the specimen. The water used was natural seawater (water temperature approximately 20°C), which was flowed along the channel at a flow rate of approximately 20 cm/sec.
試片に印加するパルス電圧の印加条件として、
１回のパルス電圧の印加時間ｔを0.2秒とし、印
加間隔Ｔが５秒となるように電流断続装置を調節
して、試片の電位の間欠的制御を行つた。 The conditions for applying the pulse voltage to the specimen are as follows:
The electric potential of the specimen was controlled intermittently by adjusting the current intermittent device so that the application time t of one pulse voltage was 0.2 seconds and the application interval T was 5 seconds.
このようにして10カ月の継続して試験を行つた
が、この間における孔食の発生は全くなく、アル
カリ腐食も認められなかつた。 The test was continued in this manner for 10 months, but no pitting corrosion occurred during this period, and no alkali corrosion was observed.
実施例 ２
被防食材試片としてA1100アルミニウム板材
（寸法実施例１と同じ）を使用した。Example 2 An A1100 aluminum plate (same dimensions as Example 1) was used as a specimen to be protected against corrosion.
試片の両側に実施例１におけると同様の水路を
つくり、水路の一方の端からほぼ10cm離れた位置
に防食用の径10mm×長さ10mmの対極（材質フエラ
イト）を設置し、この対極と試片の間に間欠的に
試片が陰極となるように通電できるように直流電
源装置と電流断続装置とを備えた陰極電流回路を
設けた。使用水は実施例１と同様に天然海水と
し、ほぼ20cm／Secの流速で流した。 A water channel similar to that in Example 1 was made on both sides of the specimen, and a counter electrode (ferrite material) with a diameter of 10 mm and a length of 10 mm for corrosion protection was installed approximately 10 cm away from one end of the water channel. A cathode current circuit including a DC power supply device and a current interrupter was provided between the test pieces so that current could be applied intermittently so that the test pieces served as cathodes. The water used was natural seawater as in Example 1, and was flowed at a flow rate of approximately 20 cm/Sec.
試片に印加するパルス電圧は、パルス電圧の印
加時における試片の電位が水中に浸漬された標準
参照電極（飽和カロメル電極）を基準として
0.8V程度低下するように、また、１回のパルス
電圧の印加時間ｔが0.06秒、印加間隔Ｔが10秒と
なるように、オツシロスコープを観察しながら、
直流電源装置および電流断続装置を調節し、この
設定条件で試片電位の間欠制御を行つた。 The pulse voltage applied to the specimen is based on the standard reference electrode (saturated calomel electrode) that is immersed in water and the potential of the specimen when the pulse voltage is applied.
While observing with an oscilloscope, so that the voltage decreases by about 0.8V, and the application time t of one pulse voltage is 0.06 seconds, and the application interval T is 10 seconds.
The DC power supply and current intermittent device were adjusted, and the specimen potential was controlled intermittently under these setting conditions.
このようにして５カ月の連続試験を行つた結
果、この間における孔食腐食の発生は皆無であ
り、また、アルカリ腐食も認められなかつた。 As a result of conducting a continuous test in this manner for 5 months, there was no occurrence of pitting corrosion during this period, and no alkaline corrosion was observed.
第１図ａおよびｂは、本発明の実施態様を例示
する説明図、第２図は、本発明方法によつた場合
のアルミニウム材の陰極電位の時間変化を例示し
たものである。
図において、１……アルミニウム材、２……犠
性陽極、２′……対極、３……電流断続装置、４，
４……陰極電流回路、５……標準参照電極、６…
…オツシロスコープ、７……直流電源装置。
FIGS. 1a and 1b are explanatory diagrams illustrating embodiments of the present invention, and FIG. 2 is a diagram illustrating changes over time in the cathode potential of an aluminum material according to the method of the present invention. In the figure, 1...aluminum material, 2...sacrificial anode, 2'...counter electrode, 3...current interrupter, 4,
4... Cathode current circuit, 5... Standard reference electrode, 6...
...oscilloscope, 7...DC power supply device.
Claims (1)
ウム材の陰極防食法において、該アルミニウム材
に犠牲陽極または外部電源から短時間負のパルス
電圧を繰り返し印加することによつて、少なくと
も犠牲陽極または対極（外部電源使用の場合）に
近接した部分におけるアルミニウム材の陰極電位
を、あらかじめ設定された時間的間隔をもつて、
アルカリ腐食域にまで間欠的に繰り返し抑制する
ことを特徴とするアルミニウム材の陰極防食法。1. In cathodic protection of aluminum materials using a sacrificial anode or external power source, at least the sacrificial anode or counter electrode (external power source) is (in case of use), the cathode potential of the aluminum material in the vicinity of
A cathodic protection method for aluminum materials that is characterized by repeated intermittent suppression of corrosion even in the alkaline corrosion range.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP58122274A JPS6029478A (en) | 1983-07-05 | 1983-07-05 | Cathodic corrosion protection method of aluminum material |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP58122274A JPS6029478A (en) | 1983-07-05 | 1983-07-05 | Cathodic corrosion protection method of aluminum material |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS6029478A JPS6029478A (en) | 1985-02-14 |
| JPS6339677B2 true JPS6339677B2 (en) | 1988-08-05 |
Family
ID=14831900
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP58122274A Granted JPS6029478A (en) | 1983-07-05 | 1983-07-05 | Cathodic corrosion protection method of aluminum material |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS6029478A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0270945A (en) * | 1988-09-05 | 1990-03-09 | Mitsubishi Motors Corp | Acceleration slip preventing device for vehicle |
| JPH0270937A (en) * | 1988-09-05 | 1990-03-09 | Mitsubishi Motors Corp | Acceleration slip preventing device for vehicle |
Families Citing this family (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0270082A (en) * | 1987-06-15 | 1990-03-08 | Pacific Fuarukon:Kk | Device for electrically regulating electrode in electrolytic cell and method for electrically regulating inside of the cell |
| KR890002745A (en) * | 1987-07-10 | 1989-04-11 | 리즈리 개리 | Electronic control circuit for cathode protection system |
| US8999137B2 (en) | 2004-10-20 | 2015-04-07 | Gareth Kevin Glass | Sacrificial anode and treatment of concrete |
| US8211289B2 (en) | 2005-03-16 | 2012-07-03 | Gareth Kevin Glass | Sacrificial anode and treatment of concrete |
| GB0505353D0 (en) | 2005-03-16 | 2005-04-20 | Chem Technologies Ltd E | Treatment process for concrete |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS58167783A (en) * | 1982-03-30 | 1983-10-04 | Nippon Light Metal Co Ltd | Cathodic corrosion-proofness of aluminum material |
-
1983
- 1983-07-05 JP JP58122274A patent/JPS6029478A/en active Granted
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS58167783A (en) * | 1982-03-30 | 1983-10-04 | Nippon Light Metal Co Ltd | Cathodic corrosion-proofness of aluminum material |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0270945A (en) * | 1988-09-05 | 1990-03-09 | Mitsubishi Motors Corp | Acceleration slip preventing device for vehicle |
| JPH0270937A (en) * | 1988-09-05 | 1990-03-09 | Mitsubishi Motors Corp | Acceleration slip preventing device for vehicle |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS6029478A (en) | 1985-02-14 |
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