JPH0335369B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention aims to provide a biofouling-resistant copper alloy to which shellfish or other aquatic animals and plants are extremely difficult to adhere to when placed in seawater, river water, or sewage. In general, copper alloys not only have superior corrosion resistance to seawater compared to iron-based materials, but even when left in seawater, living organisms such as shellfish and seaweed are less likely to adhere to them, and they also have excellent resistance to biological fouling. It exhibits superior effects compared to other metals. Among these, Cypronickel-based alloys have better biological fouling resistance than other copper alloys, so they are used in large quantities as outer panels for ships and as materials for fisheries. However, the composition of the Cypronickel alloys currently used in biofouling environments is determined with consideration to corrosion resistance, especially crushing corrosion resistance against high-velocity seawater, and it is not necessarily the best alloy composition for biofouling resistance. That is not possible. In other words, high nickel alloys such as 70/30 Cypronickel (JIS, C7150 alloy) are used when a high degree of corrosion resistance is required, but they are used in stationary or low-flow seawater environments where biological fouling is a problem. In this case, such corrosion resistance is not necessary and economically undesirable. Normally, in such usage environments, 90/10 Cypronickel (JIS.C7060 alloy), which is cheaper than 70/30 Cypronickel alloy, is used, but its resistance to biological fouling in still seawater is not sufficient. . In order to prevent marine life pollution, it is necessary for trace amounts of copper ions to be leached from the material side, but conventional alloys aimed at corrosion resistance have compositions that make it as difficult as possible for copper ions to be leached out. It is something that exists. The present invention has been made as a result of extensive research in view of the current situation, and has developed a copper alloy that has excellent biological fouling resistance and corrosion resistance. That is, the present invention is a biofouling-resistant copper alloy characterized in that (1) it contains 2.0 to 12.0 wt% of Ni and the balance is Cu. (2) Biological fouling resistance characterized by containing 2.0 to 12.0 wt% Ni and either or both of Fe 0.8 wt% or less and Mn 1.0 wt% or less, with the balance consisting of Cu. It is a copper alloy. The reason why the amount of Ni added is limited to 2.0 to 12.0 wt% in the present invention is that corrosion resistance is insufficient if it is less than 2.0 wt%. This is because corrosion resistance improves as the amount of Ni increases, but if it exceeds 12 wt%, resistance to biological fouling decreases and the price becomes high, making it impossible to put it into practical use. It is also known that the crushing corrosion resistance is improved by adding Fe, but the addition amount is 0.8wt%.
Exceeding this will inhibit the biofouling resistance of the Cu-Ni alloy. Furthermore, by adding Mn, castability and workability can be improved without impairing the biofouling resistance, but if the amount added exceeds 1.0 wt%, the biofouling resistance will decrease. The copper base metal of the alloy of the present invention contains impurities such as Sn, Pb, Zn, etc. contained in ordinary copper base metals, and deoxidizers such as Ti, Zr, Al, Si, Mg, etc. There is no problem as long as the total amount is 0.5wt% or less. Next, examples of the present invention will be described. Example Alloys having the compositions shown in Table 1 were melted and cast in the atmosphere using a magnesia crucible, and the resulting ingots were hot rolled and then cold rolled into plates with a thickness of 1 mm. This plate material was brightly annealed at a temperature of 700°C to obtain an alloy of the present invention and a comparative alloy. Samples of the alloy thus obtained were cut into shapes of 150 mm x 500 mm x 1 mm, and each sample was suspended vertically in seawater on a coast where ocean currents are relatively weak.
I left it for a month. The results are shown in Table 2.

【table】

[Table] As is clear from the above table, the alloy of the present invention exhibited excellent biological fouling resistance, with the area to which living things such as shellfish and seaweed were attached being extremely small compared to the total area, and no corrosion holes were observed. On the other hand, in Comparative Example Alloy No. 8, the area of bioadhesion was almost the same as that of the alloy of the present invention, but corrosion holes were observed. Furthermore, both Comparative Example Alloy No. 9 and the conventional alloy had a large biofouling area and were clearly inferior in biofouling resistance. As detailed above, the alloy of the present invention has excellent resistance to biological fouling and is therefore extremely useful for use in fishing equipment materials, structural materials for ships, structural materials for water supply and drainage equipment, and surface layer materials for cladding.

Claims (1)

[Claims] 1. A biofouling-resistant copper alloy characterized by containing 2.0 to 12.0 wt% of Ni and the balance being Cu. 2. A biofouling-resistant copper alloy containing 2.0 to 12.0 wt% Ni and one or both of Fe 0.8 wt% or less and Mn 1.0 wt% or less, with the remainder being Cu. .