JPH06329512A - Antifouling composition - Google Patents

Abstract

PURPOSE:To provide an antifouling composition sustainedly giving antifouling performance on marine organisms, excellent in durability, also free from toxicity, thus contributing to marine environmental protection. CONSTITUTION:At least the surface layer of the antifouling composition is constituted of a beryllium-copper alloy containing at least one kind of element selected from Pb, Fe, Zn, Sn, Al, Mn, Ni, Cr, Ti, Zr, Co, As, Sb and Si. The composition of this alloy is as follows: (1) Be: 0.01-15.0 atom % and (2) Be and the above at least one kind of element total <=50 atom %. On immersing this antifouling composition, an intermediate layer is formed between the copper- oxidized film and beryllium-oxidized film each developed on the surface layer of the beryllium-copper alloy matrix, resulting in favorable liberating effect for release layer.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an antifouling composition having a function of preventing adhesion of marine organisms such as barnacles, purple shellfish and algae.

[0002]

2. Description of the Related Art Marine structures in contact with seawater are constantly exposed to fouling due to the adhesion of marine life. Therefore, not only the appearance of the ordinary marine structure is impaired but also the functional structure is impaired. For example, in the case of a ship, the resistance increases due to the adhesion of sea life to the bottom surface of the hull and the like, and the propulsion speed of the hull decreases. Further, in the case of a thermal power plant, if marine organisms adhere to the seawater intake pit, the flow of seawater, which is a cooling medium, may be impaired, and power generation may have to be stopped.

For this reason, many techniques for preventing adhesion of marine organisms have been studied in the past. Among them, the technique for preventing adhesion of marine organisms, which has been put into practical use at present, is a marine structure using paint containing cuprous oxide or organotin. It is a method of applying to the contact surface with seawater.

[0004]

However, according to such a conventional antifouling method using a paint, even if the paint is applied thickly, the paint is easily peeled off, so that the life expectancy of a remarkable antifouling effect is It takes about one year, and complicated maintenance work is required to reapply it every year. In addition, the paint containing organic tin has a problem of toxicity, and its use on the viewpoint of environmental protection is not desirable because it may be deposited on seafood. More recently, cupro-nickel of 10% nickel-90% copper has been put into practical use, but it has a problem that it has excellent durability but does not have antifouling performance comparable to that of the above paint.

The object of the present invention is to solve the above-mentioned conventional problems, to provide excellent antifouling performance and durability, requiring no maintenance, and having no toxicity problem and antifouling composition. It is to provide a method for forming a peeling layer of a body.

[0006]

The antifouling composition of the first invention of the present invention for solving the above-mentioned problems is characterized by comprising a beryllium copper alloy and an additional element. The content ratio of beryllium in the beryllium copper alloy is preferably 0.01 to 15.0 atomic%. In addition, atomic% is the concentration represented by the number of atoms (Handbook of Metals-Edited by Japan Institute of Metals).

In order to smoothly proceed from the formation of the peeling layer, which is an oxide film, to the peeling on the surface of the beryllium copper alloy, at least one element selected from the group A, the group B or the group C is selected according to each purpose. Added. Of these, the additional elements involved in the peeling layer forming method are the A group and the B group. Group A: Pb, Fe, Zn, Sn, Al, Mn, Ni, C
r, Ti, Zr, Co, As, Sb, Si B group: Fe, As, Mn, Ni, Sb, Cr, Ti, Z
r, Mg, Co, P C group: Zn, Sn Atomic% of all elements selected from the A group, B group and C group
The lower limit of A is 0.01 atomic%, and A including beryllium is included.
The atomic% of all the elements selected from group B, group B and group C is 5
It shall be 0.0 atomic% or less. However, the upper limits of the content rates of the following additional elements are P, As, Sb: 2.0 wt% and Si: 5.0 wt%.

The purpose of adding each element, the method for forming the peeling layer, and the reasons for limiting the upper limit and the lower limit of the addition range are shown below. Beryllium (Be): 0.01 to 15.0 atomic% Be is added so that when the antifouling composition is immersed in seawater, Be is eluted to exert an antifouling effect, and the strength of the beryllium copper alloy is increased. This is because the properties such as corrosion resistance are improved, the heat treatment property, the manufacturability such as grain size adjustment, etc. are improved, and the moldability and the castability are improved. Be is 0.
If it is less than 01 atomic%, it is difficult to form a BeO layer on the beryllium copper alloy surface. When Be exceeds 15.0 atomic%,
BeO and Cu ₂ O are mixed on the surface of the beryllium copper alloy, and the layer structure does not become clear and the antifouling effect is not exhibited.

Group A: Pb, Fe, Zn, Sn, Al, M
At least one element selected from the group consisting of n, Ni, Cr, Ti, Zr, Co, As, Sb, and Si A is added to BeO formed on the surface of a beryllium copper alloy.
This is because an intermediate layer which is an oxide of the above element is formed between the layer and the Cu ₂ O layer to improve the release effect of the release layer.
When the addition range of the group A is less than 0.01 atomic%, Be
No intermediate layer is formed between the O layer and the Cu ₂ O layer. Also,
If the upper limit is exceeded, the proportion of Cu in the beryllium copper alloy will be low, and the antifouling performance will be reduced. If As and Sb exceed the upper limits, there is concern that the human body may be adversely affected when a beryllium copper alloy is produced. That is, there is a problem in hygiene. Also, with Si, the castability is significantly reduced.

Group B: Fe, As, Mn, Ni, Cr, T
The addition of at least one element selected from the group consisting of i, Zr, Mg, Co, Sb, and P B forms an intermetallic compound in a beryllium copper alloy,
This is because the elution amount of Cu is controlled by selecting the additive element. If the addition range is less than 0.01 atomic%, the elution amount of copper cannot be controlled even if an intermetallic compound is formed. If the upper limit is exceeded, the element A
For the same reason as the group, the antifouling performance deteriorates, and Sb also
For the same reason as the above-mentioned element A group, it is an upper limit in consideration of hygiene problems. This is because if P exceeds the upper limit, the material becomes brittle.

Group C: Zn, Sn The addition of at least one element selected from the group C is for strengthening the material of the beryllium copper alloy to provide it with erosion resistance and cavity resistance. If Zn and Sn are less than 0.01 atom%, the above-mentioned effects cannot be sufficiently exhibited. If it exceeds the upper limit, the antifouling performance is lowered for the same reason as that of the element A group.

The composition of the beryllium copper alloy used in the antifouling composition is, for example, Be: 0.2 to 1.0% by weight,
Co: 2.4 to 2.7 wt%, balance Cu and inevitable impurities, Be: 0.2 to 1.0 wt%, Ni: 1.4 to
2.2% by weight, balance Cu and inevitable impurities, Be:
1.0 to 2.0% by weight, Co: 0.2 to 0.6% by weight,
The balance Cu and unavoidable impurities, Be: 1.6 to 2.8.
% By weight, Co: 0.4 to 1.0% by weight, Si: 0.2 to
0.35% by weight, balance Cu and inevitable impurities.

In the method for forming a peeling layer of the present invention, a beryllium or copper oxide film and at least one element selected from Group A are added to the surface layer of a beryllium-copper alloy base material which comes into contact with seawater, and the intermediate layer is formed. By forming and forming at least one element selected from Group B, the amount of copper ions eluted from the exposed surface layer of the beryllium copper alloy base material into seawater according to the environment is controlled. Further, it is characterized by adding at least one or more elements selected from the group C to strengthen the material to obtain a beryllium copper alloy having erosion resistance and cavity resistance.

[0014]

It is generally known that copper has an antifouling property, and it is considered that copper ions exert a repellent effect of repelling marine life. However, even if copper is simply used in the marine structure, it is not possible to obtain a sufficient antifouling effect in practice. As a result of many years of experimental research conducted by the present inventor, it has been found that when a beryllium copper alloy is used in a marine structure, an extremely excellent antifouling effect can be obtained, as shown in Examples described later. The reason for this is that by adding a metal element that effectively forms an antifouling release layer to a beryllium copper alloy, the effect of copper ion elution is maintained for a long time,
It is presumed that it exerts a great repellent effect on marine life and also prevents the reproduction of marine life.

That is, the beryllium copper alloy has an effect of exhibiting an antifouling function and a continuous action of elution of copper ions. The effect of exhibiting the antifouling function and the sustained action of elution of copper ions are described in detail below. Effect of antifouling function Standard free energy of formation of beryllium and copper oxide is
It is known from the literature that Be <Cu. Therefore, beryllium oxidizes even at a very low oxygen potential, so that an internal oxide layer of BeO is formed on the beryllium copper alloy surface, for example, as shown in FIG. Since this BeO film is porous, copper elution is allowed to form Cu ₂ O + BeO on the surface. However, since the standard free energies of formation of the oxides of Cu and Be are too different from each other, they exist in a state closer to a metal in which an oxide is dispersed rather than a complete oxide layer. Therefore, in order to enhance the antifouling function by smoother peeling, at least one selected from the group A in which the standard energy of the oxide is larger than Be and smaller than Cu.
By adding more than one kind of element, for example, as shown in FIG. 1, the oxide of the additional element forms an intermediate layer on the outside of BeO and brings the BeO layer into a state close to the oxide layer. Antifouling function is demonstrated.

Sustaining action of copper ion elution The above-mentioned effect of exhibiting the antifouling function has a continuing action of eluting copper ions. That is, beryllium copper has an action of continuing the antifouling function without stopping. A dense surface oxide (Cu ₂ O) is formed on the surface of beryllium copper that comes into contact with seawater, but as shown in FIG. 1, the internal oxide of porous BeO is formed in the lower layer of the surface oxide. A film of matter is formed. Therefore, the elution of copper into seawater is maintained, and the volume of this film increases due to oxidation. When the volume increase of the film reaches a certain amount, the oxide film on the surface is separated from the porous internal oxide layer. Therefore, it is considered that the electrochemical action and the elution of copper are maintained for a long time.

Further, the continuous action of copper ion elution generated by beryllium copper will be explained as follows using the schematic diagram shown in FIG. 4 when comparing beryllium copper and cupro nickel. As shown in FIG. 4, when beryllium copper (BeCu) has a certain thickness of a corrosion product (oxide), the corrosion product is peeled off. Then, the surface of the beryllium copper alloy appears, and the thickness of the corrosion product increases as the corrosion progresses again. Then, the corrosion product is peeled off again when it reaches a certain thickness, which is repeated. On the other hand, the elution of ions decreases as the thickness of the corrosion product increases, which gradually decreases. However, when the corrosion products are peeled off as described above, the surface of the alloy appears and the amount of ion elution increases. Therefore, the increase and decrease of copper ion elution are repeated.

In the beryllium copper of the embodiment of the present invention, the elution of copper ions is sustained by the peeling of the oxide film. As a result, the amount of dirt attached to the surface of the beryllium copper is small, or hardly adheres. Furthermore, when at least one element selected from the group B that forms an intermetallic compound with Be is added to the beryllium copper alloy, the beryllium copper alloy with addition of them contains a large amount of Be because it forms an intermetallic compound with Be. Since the existing portion is formed and the portion is oxidized faster than the other portions, the interfacial area for reaction increases due to the unevenness. That is, depending on the additive element, C
The elution of u can be controlled.

On the other hand, as shown in FIG. 3, in the case of cupro-nickel (CuNi) of the comparative example, dense nickel oxide NiO ₂ or copper oxide Cu ₂ O is formed in the surface layer over a certain period of time. Thus, as shown in FIG. 4, the elution of copper ions is suppressed. The cause is considered to be the ionization tendency of Be, Ni, and Cu. It is known from the literature that the ionization tendency of each element is Be>Ni> Cu, indicating that the element on the left side is more likely to be eluted. In the case of cupro-nickel, it is considered that nickel (Ni) is preferentially eluted to form a local battery, which is due to the formation of a dense oxide on the surface as shown in FIG. Therefore, as shown in FIG. 4, in the case of cupro-nickel, the thickness of the corrosion product initially increases with time, but the growth rate of the corrosion product gradually decreases.
At the same time, the elution amount of copper ions gradually decreases. Moreover, with Cupro nickel, flaking of corrosion products does not occur as easily as with copper beryllium. Therefore, the elution amount of ions remains at a low level, and the antifouling effect decreases.

In terms of antifouling mechanism, it can be said that the beryllium copper alloy according to the present invention is different from the conventionally used antifouling composition. Further, the antifouling composition has a difference in atomic size from Cu so as to maintain a smooth peeling layer formation and peeling action in any environment in seawater. It is possible to strengthen the material by adding more than one kind.

Various practical beryllium copper alloys, such as 11 alloys having a beryllium content of 0.2 to 0.6% by weight and 25 alloys having a beryllium content of 1.8 to 2.0% by weight, etc. However, the beryllium content is preferably 1.6% by weight in terms of antifouling effect.
When the content of beryllium exceeds 2.8% by weight, beryllium does not form a solid solution in copper any more, so that the antifouling effect is excellent but the wrought workability is gradually reduced. Therefore, high beryllium copper is preferably manufactured by casting.

Further, it was confirmed that the beryllium copper alloy has no toxicity problem and has the same excellent durability in seawater as aluminum bronze and white copper. The shape of the antifouling composition of the present invention can be any shape other than a plate, a tube, etc. by casting, and thus various shapes can be selected according to the application. Further, the antifouling composition of the present invention can be made of a beryllium copper alloy as a whole, and can also be a clad material made of a beryllium copper alloy only in a portion in contact with seawater.

[0023]

EXAMPLES The present invention will be described in more detail below with reference to examples. (Example 1) The following is an experimental example using a beryllium copper alloy according to the present invention. In each experiment, beryllium copper alloys with different addition elements and addition amounts were prepared and immersed in seawater to evaluate their antifouling performance and corrosion resistance.

The antifouling performance was evaluated by observing the state of adhesion of shellfish and algae to the surface of the test piece dipped in seawater. ◎, which is inferior to ◎ when no biofouling is observed after 2 years, and which is 5% or less of the whole test piece after 2 years without biofouling after 2 years Less than 1%, the area where the bio-attached area was 50% or less of the whole test piece after 1 year was evaluated as Δ, and the area less than Δ was evaluated as x, and the results were entered in each experimental result table. The corrosion resistance was evaluated as shown below. A corrosion rate of 20 μm / year or less is ◎, a corrosion rate of 20 μm / year or more and 50 μm / year or less is ○, a corrosion rate of 50 μm / year or more and 100 μm / year or less is Δ, and a corrosion rate is 100 μm / year Those that showed local abnormal corrosion even if it was above or below ×
And

Experiment 1 A beryllium copper alloy was prepared by changing Al at 5.0 atomic% and Be in stages, and the balance being copper, and antifouling evaluation and corrosion resistance evaluation were performed. The results are shown in Tables 1 and 2.

[0026]

[Table 1]

[0027]

[Table 2] From this experiment, the amount of Be added is 2.0 to 1 at 5 atomic% Al.
It can be seen that 0.0 atom% is the most preferable condition. Similarly, similar experiments were conducted for other group A elements. Next, the amount of Be was kept constant at 10.0 atom%, and the amount of Al added was changed to perform an experiment. The results are shown in Table 3. It should be noted that, as a comparative example, the case where the addition is performed beyond the upper limit and the lower limit of the addition range is also described.

[0028]

[Table 3] In terms of corrosion resistance, good results have been obtained with an Al content of 10.0 atom% or more, but in view of the antifouling property, the Al content is preferably 10.0 atom%. Experiment 2 Subsequently, the standard production energy is Be <Al <Mn <C.
u and Mn, which are higher than Al and behave like Cu in terms of easiness of oxidation, were evaluated by changing their amounts stepwise. The results are shown in Table 4. The comparative example is a case where the upper limit and the lower limit of the addition range are exceeded. Further, among the elements A, Si and Fe were also tested.

[0029]

[Table 4] From this experiment, when Be10.0 atomic%, Mn3.0
It can be seen that atomic% is preferred. Experiment 3 Be 10.0 atomic%, Al 3.0 atomic%, element B
Evaluation experiments were conducted by adding P and Co. The results are shown in Table 5.

[0030]

[Table 5] Experiment 4 An experiment was conducted by changing the addition amounts of Sn and Zn of the element C. At this time, the content rate of other elements is Be: 10.0.
Atomic%, Al: 3.0 at%, P: 1.0 at%. The results are shown in Table 6.

[0031]

[Table 6] As can be seen from the above results, the addition elements and the addition amounts of the beryllium copper alloy according to the present invention require steady trial and error, and have been obtained by the inventor's many years of accumulated experimental research. (Example 2) A 0.1 mm-thick plate made of beryllium copper alloy (165 alloy) containing 1.6 to 1.8 wt% of Be was attached to the surface of a glass fiber boat outer plate, Even after more than two years, there was no noticeable adhesion of marine organisms, and during that time, it could be used without being washed once.

(Example 3) A 0.5 mm thick plate made of beryllium copper alloy (25 alloy) containing 1.8 to 2.0% Be was attached to the concrete surface of the intake pit of a thermal power plant. However, there is almost no adhesion of marine life,
There was no need to wash even after two years. If the concrete remains as it is, it is necessary to remove marine organisms every three months.

(Example 4) A high beryllium material was produced by casting. A tube having an outer diameter of 120 mm, a wall thickness of 10 mm, and a length of 300 mm was immersed in seawater, and a change in the radial surface of the tube was observed for a long period of time. The composition of the tube used here is Be: 2.2% by weight, Co: 0.72% by weight, Si: 0.29% by weight, balance Cu and inevitable impurities in the first tube, and the second tube For the tube No. 2, Be: 2.4 wt%, Co: 0.80 wt%, Si: 0.28 wt%, the balance Cu and inevitable impurities. As a result, no noticeable adhesion of marine organisms was observed in this tube after 2 years.

As described above, the propulsive energy can be saved particularly when the ship is used as in the above-mentioned embodiment.
Further, if it is applied to the water intake pit of the power plant, it is possible to exert a great economic effect such as eliminating the stoppage of the power plant. In addition to the above, the present invention has a wide range of uses such as exterior plates for submarines, exterior plates for marine power stations, netting piles for fish cages, aquaculture cages, and condensers for thermal power stations. It can contribute to the development of industry in a wide range of fields.

[0035]

As described above, according to the antifouling composition and the method for forming a peeling layer of the present invention, it is possible to prevent the adhesion of marine organisms for a long period of time, the durability is excellent, and the maintenance labor is simple. It has many excellent effects such as contributing to environmental protection without toxicity problems.

[Brief description of drawings]

FIG. 1 is a schematic view showing a state of an oxide film of a beryllium copper alloy according to an example of the present invention.

FIG. 2 is a schematic view showing a state of an oxide film of a beryllium copper alloy containing no additional element in a comparative example.

FIG. 3 is a schematic view showing a state of an oxide film of cupro nickel in a comparative example.

FIG. 4 is a schematic explanatory view comparing changes over time in copper ion elution amount and corrosion product thickness for beryllium copper and cupro nickel.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Mamoru Toriyao 1-20 Kitakanyama, Otaka-cho, Midori-ku, Nagoya-shi, Aichi Chubu Electric Power Co., Inc. Electric Power Technology Research Center (72) Inventor Morita Etsushihiro Midori-ku, Nagoya-shi, Aichi Takamachi Kitakanzan No.20-1 Chubu Electric Power Co., Inc. Electric Power Technology Research Institute (72) Inventor Mitsuhiro Sato 3-1,308 Higashiyama, Nisshin-cho, Aichi-gun, Aichi Prefecture (72) Inventor Mitsui Mitsui, Higashiura-cho, Chita-gun, Aichi Prefecture 8 of 2 (72) Inventor Keiji Nojiri 1-106, Shingu-cho, Handa City, Aichi Prefecture

Claims (6)

[Claims] 1. An antifouling composition comprising a beryllium copper alloy having a beryllium content of 0.01 to 15.0 atomic% and containing at least one element selected from the following group A. . Group A: Pb, Fe, Zn, Sn, Al, Mn, Ni, C
r, Ti, Zr, Co, As, Sb, Si 2. The antifouling composition according to claim 1, wherein the beryllium copper alloy contains at least one element selected from the group B below. Group B: Fe, As, Mn, Ni, Sb, Cr, Ti, Z
r, Mg, Co, P 3. The antifouling composition according to claim 1 or 2, wherein the beryllium copper alloy contains at least one element selected from the group C below. Group C: Zn, Sn 4. An antifouling composition for use in a portion that comes into contact with seawater, at least the surface layer of which comprises a beryllium copper alloy, and the beryllium copper alloy has a beryllium content of 0.01 to 15.0. An antifouling composition, which is in atomic%. 5. A beryllium copper alloy containing at least one metal element according to claim 1 to form an intermediate layer between the BeO layer and the Cu ₂ O layer formed on the beryllium copper alloy surface. A method for forming a release layer of a characteristic antifouling composition. 6. The gold according to claim 2 in a beryllium copper alloy.
Beryllium copper by adding one or more elements
It forms an intermetallic compound with Be in the alloy, and Cu ₂ O layer generation
Antifouling set characterized by controlling the speed of
Method for forming adult release layer.