EP0651075B1 - Aluminium alloy based cathodic protection consumable anode - Google Patents
Aluminium alloy based cathodic protection consumable anode Download PDFInfo
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- EP0651075B1 EP0651075B1 EP94402419A EP94402419A EP0651075B1 EP 0651075 B1 EP0651075 B1 EP 0651075B1 EP 94402419 A EP94402419 A EP 94402419A EP 94402419 A EP94402419 A EP 94402419A EP 0651075 B1 EP0651075 B1 EP 0651075B1
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- aluminium
- sea water
- based alloy
- cathodic protection
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C21/00—Alloys based on aluminium
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- 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
- C23F—NON-MECHANICAL REMOVAL OF METALLIC MATERIAL FROM SURFACE; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL; MULTI-STEP PROCESSES FOR SURFACE TREATMENT OF METALLIC MATERIAL INVOLVING AT LEAST ONE PROCESS PROVIDED FOR IN CLASS C23 AND AT LEAST ONE PROCESS COVERED BY SUBCLASS C21D OR C22F OR CLASS C25
- C23F13/00—Inhibiting corrosion of metals by anodic or cathodic protection
- C23F13/02—Inhibiting corrosion of metals by anodic or cathodic protection cathodic; Selection of conditions, parameters or procedures for cathodic protection, e.g. of electrical conditions
- C23F13/06—Constructional parts, or assemblies of cathodic-protection apparatus
- C23F13/08—Electrodes specially adapted for inhibiting corrosion by cathodic protection; Manufacture thereof; Conducting electric current thereto
- C23F13/12—Electrodes characterised by the material
- C23F13/14—Material for sacrificial anodes
Definitions
- the present invention relates to the application of a reactive anode or consumable made of an aluminum-based alloy with cathodic protection in sea water of iron, steels and alloys sensitive to corrosion and embrittlement by hydrogen.
- Performance and characteristics electrochemicals of such an anode which are mainly the electrochemical potential at zero flow, the current supplied by unit of area at a given potential, the yield electrochemical, mass energy or amount of current delivered per unit mass of anode dissolved in Ampere-hours per kilogram, are determined by the alloy whose anode reactive is constituted.
- Patent FR 2 377 455 describes alloy compositions comprising percentages by weight of aluminum or zinc of 8 to 40%, the rest being zinc or aluminum.
- aluminum-based alloys with a addition of zinc they have iron impurities, silicon, copper and must have a purity at least equal to 99, 80%.
- Electrode potential stabilizers, such as mercury, indium, manganese, titanium can be added.
- Patent FR 2 449 730 discloses a composition protective aluminum-based alloy containing gallium in the proportions of 0.005 to 3.5% by weight and magnesium in the proportions of 0.1 to 1% by weight, and having good electrochemical properties.
- Patent FR 2 616 806 describes an alloy composition based on aluminum containing percentages by weight in indium from 0.005 to 0.05, zinc from 0.05 to 8, gallium from 0.003 to 0.05, manganese 0.01 to 0.3, iron 0.03 to 0.3 and in magnesium from 0.02 to 2 and in silicon from 0.03 to 0.4.
- Patent BE-A-667,337 describes compositions high purity aluminum-based alloy comprising 0.1% by weight of gallium, usable as consumable anodes, but operating at relatively oxidation potentials high in the range of +0.9 V.
- Patent DE-A-2150102 mentions a composition of aluminum-based alloy comprising 0.2% by weight of gallium for a galvanic anode operating at a potential of -0.81 V, but other elements are necessary in relatively high proportions, especially zinc in the proportion of 5% by weight.
- the object of the invention is therefore to use an anode reactive or consumable for cathodic protection, made from an aluminum-based alloy composition comprising a minor proportion of zinc and capable of operate in a limited potential range of - 870 mV to - 700 mV by reference to the potential of a calomel electrode saturated, which corresponds to the area in which embrittlement by hydrogen from steels and high limit alloys elasticity is low.
- the subject of the invention is therefore the application of a reactive anode made of an aluminum-based alloy, for cathodic protection in seawater of steels and alloys with high elastic limit against corrosion in seawater. and hydrogen embrittlement, operating in a range of electrochemical potential in seawater from - 870 mV to - 700 mV by reference to the potential of a saturated calomel electrode, the aluminum-based alloy comprising the composition following indicated in percentage by weight: Gallium or Cadmium 0.03 to 0.20% Manganese 0.15% max Iron 0.15% max Silicon 0.15% max Zinc 0.15% max Indium 0.007% max Mercury 0.007% max Magnesium 0.10% max Titanium 0.02% max Various 0.01% max Aluminum the rest.
- the mode of use according to the invention makes it possible to properly protect from widespread corrosion and corrosion by galvanic coupling of steels moderately allies, notably with the nickel element, in the field of cathodic potential included in the range of - 870 mV at - 700 mV / DHW, different from the usual range of - 850 mV at - 1100 mV / DHW. In this area of protection, the kinetics of Hydrogen evolution is significantly reduced.
- the percentage by weight of gallium is preferably equal to 0.1%.
- the composition of aluminum-based alloy includes cadmium in a range of values from 0.03 to 0.20% by weight in replacement of gallium.
- the percentage by weight of cadmium is preferably equal to 0.1%.
- the composition of aluminum-based alloy includes cadmium in a range values from 0.03 to 0.20% by weight in addition to the alloy composition already comprising gallium in the range from 0.03 to 0.20% by weight.
- the protection anode cathodic may include at least one wedge lamella in steel for regulating the anode potential at low flow.
- the anode of cathodic protection is characterized in that the ratio of area between the aluminum alloy part and the or the lamellae is less than 5, preferably equal to 1.5.
- the aluminum-based alloy is cast on a mounting bracket and electrical conduction in steel.
- Figure 1 is a sectional view of a reactive anode according to the invention.
- the reactive cathodic protection anode comprises a cylindrical part 2 of aluminum-based alloy having the electrochemical properties targeted for protection, casting on a core 3 or fixing and conduction support electric and one or more steel wedging strips 1.
- the lamellae serve as anode potential regulators at low flow, because aluminum alloys have a unstable potential at low flow.
- the aluminum alloy according to the invention has a content of gallium which can vary from 0.03 to 0.20% by weight and so preferred equal to 0.1%.
- the contents of manganese, iron, zinc, silicon are at most 0.15% by weight, those of indium and mercury at most 0.007% by weight, that of magnesium at maximum of 0.10% by weight, that of titanium maximum of 0.02% in weight.
- the basic aluminum has a purity at least equal to 99.80% by weight.
- This alloy is due to gallium, according to an anodic dissolution mechanism for gallium in solution solid then precipitation of finely divided metal at the aluminum surface.Gallium, while promoting uniform activation of the anode surface, helps maintain constant anode potential.
- titanium in the form of Ti ⁇ makes it possible to control the particle size in the desired range.
- Another alloy composition according to the invention includes a content of 0.03% to 0.20% by weight of cadmium and preferably equal to 0.10%, replacing gallium or addition to the composition already comprising gallium.
- the area ratio between alloy part 2 aluminum and the lamella (s) 1 is less than 5, preferably equal to 1.5 for optimal protection.
- An alloy cast in an anode according to the invention was tested, comprising the following weight percentages: Gallium 0.102% Iron 0.046% Silicon 0.035% Zinc 0.065% Titanium 0.02% max Manganese ⁇ 0.15% Other ⁇ 0.01% Aluminum the rest.
- the resting potential in seawater is - 850 mV +/- 50 mV / DHW.
- the anode potential measured with a current density of 30 mA / dm 2 is - 800 mV / DHW.
- the mass energy is 1937 Ah / kg.
- Tests were carried out in accordance with a NACE (National Association Corrosion Engineer) specification involving 15 days of exposure to seawater of samples of diameter 38 mm, height 16.8 mm, active surface 0.4095 dm 2 with a flow rate of 25.4 mA.
- the average potential is - 804 mV / DHW and the electrochemical efficiency of 80%.
- the corrosion rate is of the order of 1 to 10 micrometers / year at - 700 mV / DHW for high limit steel elasticity type Ni 5%; it is of the same order of magnitude at a potential of - 760 mV / DHW for typical structural steel E28.
- corrosion becomes significant at a potential greater than - 600 mV / DHW.
- the kinetics of hydrogen release is further reduced by a factor of 10 between - 800 mV and - 1020 mV and by a factor of 20 to - 1060 mV.
- the resting potential in seawater is - 850 mV +/- 50 mV / DHW.
- the anode potential measured at 2 mA / cm 2 is - 730 mV / DHW.
- the mass energy is 2384 Ah / kg and the yield 80% electrochemical.
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Description
La présente invention concerne l'application d' une anode réactive ou consommable constituée dans un alliage à base d'aluminium à la protection cathodique en eau de mer du fer, des aciers et alliages sensibles à la corrosion et à la fragilisation par l'hydrogène.The present invention relates to the application of a reactive anode or consumable made of an aluminum-based alloy with cathodic protection in sea water of iron, steels and alloys sensitive to corrosion and embrittlement by hydrogen.
Il est d'usage de considérer que la corrosion est négligeable pour une concentration en fer inférieure ou égale à 10 -6 mole/litre , soit un potentiel d'électrode inférieur ou égal à - 850 mV par référence au potentiel d'une électrode au calomel saturé(ECS). Le domaine de potentiel rencontré pour la protection cathodique des navires en eau de mer et des structures off shore est compris entre - 850 mV et - 1100 mV.It is customary to consider that corrosion is negligible for an iron concentration less than or equal to 10 -6 mole / liter, or an electrode potential less than or equal to - 850 mV by reference to the potential of an electrode at saturated calomel (ECS). The potential range encountered for the cathodic protection of ships in seawater and offshore structures is between - 850 mV and - 1100 mV.
A ces potentiels, l'utilisation d'anodes réactives de protection connues protège totalement l'acier contre la corrosion généralisée et la corrosion par couplage galvanique qui peuvent se produire en eau de mer. Mais la réduction de l'eau désaérée entraíne à la surface de l'acier ainsi protégé un dégagement d'hydrogène, qui peut entraíner une corrosion supplémentaire. Il est en effet connu que l'hydrogène fragilise certains aciers à haute limite d'élasticité et leurs soudures ainsi que les alliages de titane et que la sensibilité à la corrosion sous contrainte due à l'hydrogène décroít fortement à des potentiels supérieurs à - 800 mV.At these potentials, the use of reactive anodes known protection fully protects steel against generalized corrosion and corrosion by galvanic coupling which can occur in seawater. But the reduction in deaerated water entrained on the surface of the steel thus protected release of hydrogen, which can lead to corrosion additional. It is indeed known that hydrogen weakens certain high yield strength steels and their welds as well as titanium alloys and that the sensitivity to corrosion under stress due to hydrogen strongly decreases to potentials greater than - 800 mV.
Les performances et les caractéristiques électrochimiques d'une telle anode qui sont principalement le potentiel électrochimique à débit nul, le courant débité par unité de surface à un potentiel donné, le rendement électrochimique, l'énergie massique ou quantité de courant débité par unité de masse d'anode dissoute en Ampère-heure par kilogramme, sont déterminées par l'alliage dont l'anode réactive est constituée.Performance and characteristics electrochemicals of such an anode which are mainly the electrochemical potential at zero flow, the current supplied by unit of area at a given potential, the yield electrochemical, mass energy or amount of current delivered per unit mass of anode dissolved in Ampere-hours per kilogram, are determined by the alloy whose anode reactive is constituted.
On connaít déjà des alliages d'aluminium et de zinc
pour la confection d'anodes de protection d'une structure
métallique en contact avec un milieu électrolytique agressif.
Le brevet FR 2 377 455 décrit des compositions d'alliages
comprenant des pourcentages en poids d'aluminium ou de zinc de
8 à 40 %, le reste étant constitué de zinc ou d'aluminium.
Concernant les alliages à base d'aluminium comportant une
addition de zinc , ils présentent des impuretés de fer,
silicium, cuivre et doivent avoir une pureté au moins égale à
99, 80%. Des stabilisateurs de potentiel d'électrode , tels que
mercure, indium, manganèse, titane peuvent être ajoutés.We already know aluminum and zinc alloys
for making structure protection anodes
metal in contact with an aggressive electrolytic medium.
Le brevet FR 2 449 730 divulgue une composition
d'alliage protecteur à base d'aluminium contenant du gallium
dans les proportions de 0,005 à 3,5% en poids et du magnésium
dans les proportions de 0,1 à 1% en poids , et présentant de
bonnes propriétés électrochimiques.
On connaít aussi un alliage d'aluminium de protection marine contenant 0,04% en poids de mercure et de 2 à 4,5% en poids de zinc, avec des impuretés de fer, silicium, titane, ayant une énergie massique élevée de 2790 Ampère-heure par kilogramme. Cet alliage est efficace à un potentiel inférieur à - 1045 mV/ECS, avec une densité de courant de 1,5 mA/cm2.There is also known a marine protection aluminum alloy containing 0.04% by weight of mercury and 2 to 4.5% by weight of zinc, with impurities of iron, silicon, titanium, having a high specific energy of 2790 Ampere-hours per kilogram. This alloy is effective at a potential below - 1045 mV / DHW, with a current density of 1.5 mA / cm 2 .
On connaít aussi un alliage d'aluminium de protection marine comprenant 0,02% en poids d'indium et 5% en poids de zinc, d'énergie massique moindre que le précédent.We also know a protective aluminum alloy marine comprising 0.02% by weight of indium and 5% by weight of zinc, of less mass energy than the previous one.
Le brevet FR 2 616 806 décrit une composition d'alliage
à base d'aluminium contenant des pourcentages en poids en
indium de 0,005 à 0,05, en zinc de 0,05 à 8, en gallium de
0,003 à 0,05, en manganèse de 0,01 à 0,3, en fer de 0,03 à 0,3
et en magnésium de 0,02 à 2 et en silicium de 0,03 à 0,4.
Ces différentes compositions d'alliages connues sont efficaces contre la corrosion généralisée et la corrosion par couplage galvanique dans le domaine de potentiel électronégatif relativement bas de - 1000 à - 1100 mV mais ne protègent pas de la corrosion sous contraintes par fragilisation par l'hydrogène , qui ne peut être évitée qu'à des potentiels supérieurs à - 800 mV. Les aciers ne sont donc pas totalement protégés de la corrosion à des potentiels d'électrode inférieurs à - 860 mV/ECS par des anodes réactives ayant des compositions d'alliages à base d'aluminium connues.These various known alloy compositions are effective against generalized corrosion and corrosion by galvanic coupling in the electronegative potential domain relatively low from - 1000 to - 1100 mV but do not protect from corrosion under stress by hydrogen embrittlement , which can only be avoided at potentials greater than - 800 mV. Steels are therefore not fully protected from corrosion at electrode potentials less than - 860 mV / DHW by reactive anodes having compositions of known aluminum-based alloys.
Le brevet BE-A-667 337 décrit des compositions d'alliage à base d'aluminium de haute pureté comprenant 0,1 % en poids de gallium, utilisables comme anodes consommables, mais fonctionnant à des potentiels d'oxydation relativement élevés de l'ordre de +0,9 V.Patent BE-A-667,337 describes compositions high purity aluminum-based alloy comprising 0.1% by weight of gallium, usable as consumable anodes, but operating at relatively oxidation potentials high in the range of +0.9 V.
Le brevet DE-A-2150102 mentionne une composition d'alliage à base d'aluminium comprenant 0,2 % en poids de gallium pour une anode galvanique fonctionnant à un potentiel de -0,81 V, mais d'autres éléments sont nécessaires dans des proportions relativement fortes, en particulier zinc dans la proportion de 5% en poids.Patent DE-A-2150102 mentions a composition of aluminum-based alloy comprising 0.2% by weight of gallium for a galvanic anode operating at a potential of -0.81 V, but other elements are necessary in relatively high proportions, especially zinc in the proportion of 5% by weight.
Le but de l'invention est donc d'utiliser une anode réactive ou consommable pour la protection cathodique, confectionnée dans une composition d'alliage à base d'aluminium comprenant une proportion mineure de zinc et capable de fonctionner dans une gamme de potentiel limitée de - 870 mV à - 700 mV par référence au potentiel d'une électrode au calomel saturé, qui correspond au domaine dans lequel la fragilisation par l'hydrogène des aciers et des alliages à haute limite d'élasticité est faible.The object of the invention is therefore to use an anode reactive or consumable for cathodic protection, made from an aluminum-based alloy composition comprising a minor proportion of zinc and capable of operate in a limited potential range of - 870 mV to - 700 mV by reference to the potential of a calomel electrode saturated, which corresponds to the area in which embrittlement by hydrogen from steels and high limit alloys elasticity is low.
L'invention a donc pour objet l'application d'une anode
réactive constituée en un alliage à base d'aluminium, à la
protection cathodique en eau de mer des aciers et alliages à
haute limite d'élasticité contre la corrosion en eau de mer et
la fragilisation à l'hydrogène, fonctionnant dans un domaine de
potentiel électrochimique en eau de mer de - 870 mV à - 700 mV
par référence au potentiel d'une électrode au calomel saturé,
l'alliage à base d'aluminium comprenant la composition suivante
indiquée en pourcentage en poids :
Le mode d'utilisation selon l'invention permet de protéger correctement de la corrosion généralisée et de la corrosion par couplage galvanique des aciers moyennement alliés, notamment avec l'élément nickel, dans le domaine de potentiel cathodique compris dans la plage de - 870 mV à - 700 mV/ECS, différent du domaine habituel de - 850 mV à - 1100 mV/ECS. Dans ce domaine de protection, la cinétique de dégagement d'hydrogène est réduite notablement.The mode of use according to the invention makes it possible to properly protect from widespread corrosion and corrosion by galvanic coupling of steels moderately allies, notably with the nickel element, in the field of cathodic potential included in the range of - 870 mV at - 700 mV / DHW, different from the usual range of - 850 mV at - 1100 mV / DHW. In this area of protection, the kinetics of Hydrogen evolution is significantly reduced.
Le pourcentage en poids de gallium est de préférence égal à 0,1%.The percentage by weight of gallium is preferably equal to 0.1%.
Dans un autre mode d'utilisation, la composition d'alliage à base d'aluminium comprend du cadmium dans une plage de valeurs de 0,03 à 0,20% en poids en remplacement du gallium.In another mode of use, the composition of aluminum-based alloy includes cadmium in a range of values from 0.03 to 0.20% by weight in replacement of gallium.
Le pourcentage en poids de cadmium est de préférence égal à 0,1%.The percentage by weight of cadmium is preferably equal to 0.1%.
Dans une autre variante d'utilisation, la composition d'alliage à base d'aluminium comprend du cadmium dans une plage de valeurs de 0,03 à 0,20% en poids en addition à la composition d'alliage comprenant déjà du gallium dans la plage de 0,03 à 0,20% en poids.In another variant of use, the composition of aluminum-based alloy includes cadmium in a range values from 0.03 to 0.20% by weight in addition to the alloy composition already comprising gallium in the range from 0.03 to 0.20% by weight.
Dans une variante d'utilisation, l'anode de protection cathodique peut comporter au moins une lamelle de calage en acier pour la régulation du potentiel d'anode à faible débit.In a variant of use, the protection anode cathodic may include at least one wedge lamella in steel for regulating the anode potential at low flow.
Dans une autre variante d'utilisation, l'anode de protection cathodique est caractérisée en ce que le rapport de superficie entre la partie en alliage à base d'aluminium et la ou les lamelles est inférieur à 5, de préférence égal à 1,5.In another variant of use, the anode of cathodic protection is characterized in that the ratio of area between the aluminum alloy part and the or the lamellae is less than 5, preferably equal to 1.5.
Préférentiellement, l'alliage à base d'aluminium est coulé sur un support de fixation et conduction électrique en acier.Preferably, the aluminum-based alloy is cast on a mounting bracket and electrical conduction in steel.
D'autres caractéristiques et avantages de l'invention ressortiront plus clairement de la description suivante, en référence au dessin unique annexé et aux exemples suivants.Other characteristics and advantages of the invention will emerge more clearly from the following description, in reference to the single appended drawing and to the following examples.
La figure 1 est une vue en coupe d'une anode réactive selon l'invention. Figure 1 is a sectional view of a reactive anode according to the invention.
L'anode réactive de protection cathodique comprend une
partie cylindrique 2 en alliage à base d'aluminium ayant les
propriétés électrochimiques visées pour la protection, coulée
sur une âme 3 ou support de fixation et de conduction
électrique et une ou plusieurs lamelles 1 de calage en acier.
Les lamelles servent de régulateurs de potentiel d'anode à
faible débit , car les alliages d'aluminium présentent un
potentiel instable à faible débit.The reactive cathodic protection anode comprises a
L'alliage d'aluminium selon l'invention a une teneur en gallium pouvant varier de 0,03 à 0,20% en poids et de façon préférée égale à 0,1%. Les teneurs en manganèse , fer, zinc, silicium sont au maximum de 0,15% en poids, celles d'indium et mercure au maximum de 0,007% en poids, celle de magnésium au maximum de 0,10% en poids, celle de titane au maximum de 0,02% en poids. L'aluminium de base a une pureté au moins égale à 99,80% en poids.The aluminum alloy according to the invention has a content of gallium which can vary from 0.03 to 0.20% by weight and so preferred equal to 0.1%. The contents of manganese, iron, zinc, silicon are at most 0.15% by weight, those of indium and mercury at most 0.007% by weight, that of magnesium at maximum of 0.10% by weight, that of titanium maximum of 0.02% in weight. The basic aluminum has a purity at least equal to 99.80% by weight.
L'activation de cet alliage est due au gallium, selon un mécanisme de dissolution anodique du gallium en solution solide , puis de précipitation du métal finement divisé à la surface de l'aluminium.Le gallium, tout en favorisant l'activation uniforme de la surface d'anode, aide au maintien d'un potentiel d'anode constant.The activation of this alloy is due to gallium, according to an anodic dissolution mechanism for gallium in solution solid then precipitation of finely divided metal at the aluminum surface.Gallium, while promoting uniform activation of the anode surface, helps maintain constant anode potential.
L'addition de titane sous forme de Tiβ permet de maítriser la granulométrie dans la plage souhaitée.The addition of titanium in the form of Tiβ makes it possible to control the particle size in the desired range.
Une autre composition d'alliage selon l'invention comprend une teneur de 0,03% à 0,20% en poids de cadmium et de façon préférée égale à 0,10%, en remplacement du gallium ou en addition à la composition comprenant déjà du gallium.Another alloy composition according to the invention includes a content of 0.03% to 0.20% by weight of cadmium and preferably equal to 0.10%, replacing gallium or addition to the composition already comprising gallium.
Le rapport de superficie entre la partie 2 en alliage
d'aluminium et la ou les lamelles 1 est inférieur à 5, de
préférence égal à 1,5 pour une protection optimale.The area ratio between
On a testé un alliage coulé en une anode selon
l'invention comprenant les pourcentages en poids suivants :
Le potentiel au repos dans l'eau de mer est de - 850 mV +/-50 mV/ECS.The resting potential in seawater is - 850 mV +/- 50 mV / DHW.
Le potentiel anodique mesuré avec une densité de courant de 30 mA/dm2 est de - 800 mV/ECS.The anode potential measured with a current density of 30 mA / dm 2 is - 800 mV / DHW.
L'énergie massique est de 1937 Ah/kg.The mass energy is 1937 Ah / kg.
Des essais ont été réalisés conformément à une spécification NACE (National Association Corrosion Engineer) impliquant 15 jours d'exposition à l'eau de mer d'échantillons de diamètre 38 mm, de hauteur 16,8 mm, de surface active 0,4095 dm2 avec un débit de 25,4 mA. Le potentiel moyen est de - 804 mV/ECS et le rendement électrochimique de 80%.Tests were carried out in accordance with a NACE (National Association Corrosion Engineer) specification involving 15 days of exposure to seawater of samples of diameter 38 mm, height 16.8 mm, active surface 0.4095 dm 2 with a flow rate of 25.4 mA. The average potential is - 804 mV / DHW and the electrochemical efficiency of 80%.
Des essais réalisés conformément à une spécification DNV (Det Norske Veritas) impliquant 4 jours d'exposition à l'eau de mer d'échantillons de diamètre 38 mm, de hauteur 16,8 mm, de surface active 0,4095 dm2 avec un débit variable de 16,4 mA à 163,8 mA ont permis d'observer un potentiel moyen de - 770 mV et un rendement électrochimique de 70%.Tests carried out in accordance with a DNV (Det Norske Veritas) specification involving 4 days of exposure to seawater of samples of diameter 38 mm, height 16.8 mm, active surface 0.4095 dm 2 with a variable flow from 16.4 mA to 163.8 mA allowed an average potential of - 770 mV and an electrochemical efficiency of 70% to be observed.
On a mesuré les vitesses de corrosion généralisée et sous couplage galvanique dans de l'eau de mer naturelle à température ambiante de deux types d'acier protégés par des anodes réactives selon l'invention : un acier à haute limite d'élasticité moyennement allié au nickel type Ni 5% et un acier de construction type E28. Aucune corrosion n'a été constatée à un potentiel de - 800 mV/ECS pour ces deux types d'acierWe measured the generalized corrosion rates and under galvanic coupling in natural sea water at ambient temperature of two types of steel protected by reactive anodes according to the invention: a high limit steel of elasticity moderately alloyed with nickel type Ni 5% and a steel of construction type E28. No corrosion was found at a potential of - 800 mV / DHW for these two types of steel
La vitesse de corrosion est de l'ordre de 1 à 10 micromètres/an à - 700 mV/ECS pour l'acier à haute limite d'élasticité type Ni 5% ; elle est du même ordre de grandeur à un potentiel de - 760 mV/ECS pour l'acier de construction type E28. Par contre, la corrosion devient significative à un potentiel supérieur à - 600 mV/ECS. Concernant la corrosion sous contrainte par l'hydrogène, celle-ci n'est pas significative dans la gamme de potentiel visée. La cinétique de dégagement de l'hydrogène est de plus réduite d'un facteur 10 entre - 800 mV et - 1020 mV et d'un facteur 20 à - 1060 mV.The corrosion rate is of the order of 1 to 10 micrometers / year at - 700 mV / DHW for high limit steel elasticity type Ni 5%; it is of the same order of magnitude at a potential of - 760 mV / DHW for typical structural steel E28. On the other hand, corrosion becomes significant at a potential greater than - 600 mV / DHW. Regarding corrosion under hydrogen stress, this is not significant in the targeted potential range. The kinetics of hydrogen release is further reduced by a factor of 10 between - 800 mV and - 1020 mV and by a factor of 20 to - 1060 mV.
On a testé un alliage coulé en une anode selon
l'invention et comprenant les pourcentages en poids suivants :
Le potentiel au repos dans l'eau de mer est de - 850 mV +/- 50 mV/ECS.The resting potential in seawater is - 850 mV +/- 50 mV / DHW.
Le potentiel anodique mesuré à 2 mA/cm2 est de - 730 mV/ECS.The anode potential measured at 2 mA / cm 2 is - 730 mV / DHW.
L'énergie massique est de 2384 Ah/kg et le rendement électrochimique de 80%.The mass energy is 2384 Ah / kg and the yield 80% electrochemical.
Des mesures de vitesses de corrosion effectuées avec ce type d'anode réactive dans les mêmes conditions que précédemment ont donné des résultats similaires à ceux obtenus avec des anodes réactives comprenant du gallium.Corrosion rate measurements made with this type of reactive anode under the same conditions as previously gave similar results to those obtained with reactive anodes comprising gallium.
Claims (8)
- The application of a reactive anode consisting in an aluminium-based alloy ( 2 ), for the cathodic protection in sea water of steels and alloys having a high tensile yield strength with a tendency to corrode in sea water and become brittle in the presence of hydrogen, operating in a field of electrochemical potential in sea water from - 870 mV to - 700mV by reference to the potential of a saturated calomel electrode, the aluminium-based alloy comprising the following composition indicated in percentage in weight :
Gallium or Cadmium 0.03 to 0.20 % Manganese 0.15 % max. Iron 0.15 % max Silicon 0.15 % max. Zinc 0.15 % max. Indium 0.007 % max. Mercury 0.007 % max. Magnesium 0.10 % max. Titanium 0.02 % max. Miscellaneous 0.01 % max. Aluminium the rest - The application of a reactive anode consisting in an aluminium-based alloy ( 2 ), for the cathodic protection in sea water of steels and alloys having a high tensile yield strength with a tendency to corrode in sea water and become brittle in the presence of hydrogen, operating in a field of electrochemical potential in sea water from - 870 mV to - 700mV by reference to the potential of a saturated calomel electrode, the aluminium-based alloy comprising the following composition indicated in percentage in weight :
Gallium 0.03 to 0.20 % Cadmium 0.03 to 0.20 % Manganese 0.15 % max. Iron 0.15 % max Silicon 0.15 % max. Zinc 0.15 % max. Indium 0.007 % max. Mercury 0.007 % max. Magnesium 0.10 % max. Titanium 0.02 % max. Miscellaneous 0.01 % max. Aluminium the rest - The application of a reactive anode consisting in an aluminium-based alloy ( 2 ), for the cathodic protection in sea water of steels and alloys having a high tensile yield strength with a tendency to corrode in sea water and become brittle in the presence of hydrogen, according to claim 1, the aluminium-based alloy comprising the following composition indicated in percentage in weight :
Gallium or Cadmium 0.10 % Manganese 0.15 % max. Iron 0.15 % max Silicon 0.15 % max. Zinc 0.15 % max. Indium 0.007 % max. Mercury 0.007 % max. Magnesium 0.10 % max. Titanium 0.02 % max. Miscellaneous 0.01 % max. Aluminium the rest - The application of a reactive anode consisting in an aluminium-based alloy ( 2 ), for the cathodic protection in sea water of steels and alloys having a high tensile yield strength with a tendency to corrode in sea water and become brittle in the presence of hydrogen, according to claim 1, the aluminium-based alloy comprising the following composition indicated in percentage in weight :
Cadmium 0.10 % Manganese 0.15 % max. Iron 0.15 % max Silicon 0.15 % max. Zinc 0.15 % max. Indium 0.007 % max. Mercury 0.007 % max. Magnesium 0.10 % max. Titanium 0.02 % max. Miscellaneous 0.01 % max. Aluminium the rest - The application of a reactive anode consisting in an aluminium-based alloy ( 2 ), for the cathodic protection in sea water of steels and alloys having a high tensile yield strength with a tendency to corrode in sea water and become brittle in the presence of hydrogen, according to any of claims 1 to 4, the anode comprising at least one steel setting strip (1) for regulating the anode potential at a low output.
- The application of a reactive anode consisting in an aluminium-based alloy ( 2 ), for the cathodic protection in sea water of steels and alloys having a high tensile yield strength with a tendency to corrode in sea water and become brittle in the presence of hydrogen, according to claim 5, characterised in that the surface ratio between part ( 2 ) consisting in aluminium-based alloy and the strip(s) (1) is lower than 5.
- The application of a reactive anode consisting in an aluminium-based alloy ( 2 ), for the cathodic protection in sea water of steels and alloys having a high tensile yield strength with a tendency to corrode in sea water and become brittle in the presence of hydrogen, according to claim 6, characterised in that the surface ratio between part ( 2 ) consisting in aluminium-based alloy and the strip(s) (1) is equal to 1.5.
- The application of a reactive anode consisting in an aluminium-based alloy ( 2 ), for the cathodic protection in sea water of steels and alloys having a high tensile yield strength with a tendency to corrode in sea water and become brittle in the presence of hydrogen, according to any of claims 1 to 7, characterised in that the aluminium-based is cast on a steel support ( 3 ) for attachment and electric conduction.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| FR9312916 | 1993-10-29 | ||
| FR9312916A FR2713244B1 (en) | 1993-10-29 | 1993-10-29 | Consumable cathode protection anode made of aluminum alloy. |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| EP0651075A1 EP0651075A1 (en) | 1995-05-03 |
| EP0651075B1 true EP0651075B1 (en) | 1999-06-02 |
Family
ID=9452341
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| EP94402419A Expired - Lifetime EP0651075B1 (en) | 1993-10-29 | 1994-10-27 | Aluminium alloy based cathodic protection consumable anode |
Country Status (6)
| Country | Link |
|---|---|
| US (1) | US5547560A (en) |
| EP (1) | EP0651075B1 (en) |
| DE (1) | DE69418817T2 (en) |
| ES (1) | ES2131652T3 (en) |
| FR (1) | FR2713244B1 (en) |
| NO (1) | NO307661B1 (en) |
Families Citing this family (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE10213289A1 (en) * | 2001-03-30 | 2002-11-14 | Yokohama Rubber Co Ltd | Elastomer and steel cord composite and process for making the same |
| US9243150B2 (en) * | 2005-04-21 | 2016-01-26 | The United States Of America As Represented By The Secretary Of The Navy | Oxide coated metal pigments and film-forming compositions |
| US9243333B2 (en) * | 2012-09-27 | 2016-01-26 | The United States Of America, As Represented By The Secretary Of The Navy | Coated aluminum alloy pigments and corrosion-resistant coatings |
| CN104018164A (en) * | 2014-04-18 | 2014-09-03 | 天津恒仁石油设备有限公司 | Zinc-aluminium-cadmium alloy sacrificial anode |
| CN106124282B (en) | 2016-07-26 | 2019-07-16 | 广州海力特生物科技有限公司 | A kind of method of lamination centrifugal filtration separation and Extraction excretion body |
| CN115961286B (en) * | 2022-12-02 | 2025-11-11 | 青岛双瑞海洋环境工程股份有限公司 | Low-driving potential aluminum alloy sacrificial anode for seawater cooling water system and preparation method thereof |
Family Cites Families (17)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US2930568A (en) * | 1954-01-11 | 1960-03-29 | Clarence M Rader | Hanger for electrolytic liquid treating device |
| NL288527A (en) * | 1963-02-04 | |||
| FR1399752A (en) * | 1964-04-04 | 1965-05-21 | Soc Gen Magnesium | New alloy based on aluminum and mercury and its application to the production of anodes |
| US3240688A (en) * | 1964-04-21 | 1966-03-15 | Olin Mathieson | Aluminum alloy electrode |
| US3379636A (en) * | 1964-07-23 | 1968-04-23 | Dow Chemical Co | Indium-gallium-aluminum alloys and galvanic anodes made therefrom |
| US3337333A (en) * | 1964-07-23 | 1967-08-22 | Dow Chemical Co | Aluminum alloys and galvanic anodes made therefrom |
| ES315697A1 (en) * | 1964-07-23 | 1966-03-16 | Dow Chemical Co | A procedure to produce anodos consumibles. (Machine-translation by Google Translate, not legally binding) |
| JPS4838285B1 (en) * | 1970-10-07 | 1973-11-16 | ||
| US3721618A (en) * | 1971-03-11 | 1973-03-20 | Dow Chemical Co | Aluminum sacrifical anode |
| US3870615A (en) * | 1971-12-30 | 1975-03-11 | Standard Brass & Mfg | Sacrificial anode |
| YU40575A (en) * | 1975-02-20 | 1982-02-25 | Inst Tehnickih Nauka Sanu | Alloy of aluminium with indium or gallium or thallium |
| FR2377455A1 (en) * | 1978-05-25 | 1978-08-11 | Petrocokino Denis | Sacrificial aluminium-zinc alloy anodes - for cathodic protection of metal structures in corrosive electrolytes |
| US4240829A (en) * | 1979-01-25 | 1980-12-23 | Dunaev Jury D | Aluminum-base alloy used as material for galvanic protector |
| FR2449730A1 (en) * | 1979-02-23 | 1980-09-19 | Inst Orch Kataliza | Aluminium-gallium-magnesium alloy - for cathodic protection of iron and steel immersed in water contg. low concn. of salts |
| JPS5858430B2 (en) * | 1980-02-26 | 1983-12-24 | 住友金属工業株式会社 | Corrosion prevention method for steel structures in marine environment |
| NZ224999A (en) * | 1987-06-16 | 1990-10-26 | Comalco Alu | Aluminium alloy suitable for sacrificial anodes |
| US5006214A (en) * | 1990-02-05 | 1991-04-09 | Burchnell Donald H | Cathodic protection apparatus |
-
1993
- 1993-10-29 FR FR9312916A patent/FR2713244B1/en not_active Expired - Lifetime
-
1994
- 1994-10-27 EP EP94402419A patent/EP0651075B1/en not_active Expired - Lifetime
- 1994-10-27 DE DE69418817T patent/DE69418817T2/en not_active Expired - Lifetime
- 1994-10-27 ES ES94402419T patent/ES2131652T3/en not_active Expired - Lifetime
- 1994-10-28 NO NO944110A patent/NO307661B1/en not_active IP Right Cessation
- 1994-10-28 US US08/331,119 patent/US5547560A/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| US5547560A (en) | 1996-08-20 |
| NO944110D0 (en) | 1994-10-28 |
| EP0651075A1 (en) | 1995-05-03 |
| FR2713244B1 (en) | 1996-01-12 |
| DE69418817D1 (en) | 1999-07-08 |
| NO307661B1 (en) | 2000-05-08 |
| FR2713244A1 (en) | 1995-06-09 |
| NO944110L (en) | 1995-05-02 |
| DE69418817T2 (en) | 1999-11-11 |
| ES2131652T3 (en) | 1999-08-01 |
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