JPH0380860B2 - - Google Patents

Description

[Detailed description of the invention]

(Industrial Field of Application) The present invention relates to a copper alloy suitable for automobile radiator fins, particularly a copper alloy for fins having excellent heat resistance and corrosion resistance. (Prior Art) Metal materials with excellent corrosion resistance, heat resistance, thermal conductivity, strength, workability, etc. are required for automobile radiator fins. Among these, corrosion resistance is extremely important because in recent years, the driving environment of automobiles has become subject to severe conditions for corrosion of radiator fins due to an increase in nitrogen oxides, sulfur oxides, chlorine, chlorine compounds, etc. in the atmosphere. It is a characteristic. In addition, heat resistance is a property that must also be considered in terms of strength so that it does not soften due to the heat applied when soldering to the radiator tube when assembling and processing the radiator.
is important. Therefore, in terms of heat resistance, a material that satisfies the condition of having a Vickers hardness of 100 or more after heating at 350°C for 5 minutes is considered suitable. Furthermore, thermal conductivity is still an important property, as there has been a strong desire to improve the heat dissipation per unit volume of the fin material as the weight of automobiles has become lighter in recent years. For this reason, conventional alloy materials used as radiator fin materials have been put into practical use by adding 1% or less or several percent of one or more of tin, phosphorus, silver, cadmium, zinc, etc. to copper. In addition, alloy materials of this type have also been proposed, as shown in Japanese Patent Publication No. 47-4228, Japanese Patent Publication No. 62-21061, or Japanese Patent Application Laid-Open No. 61-266543. (Problems to be Solved by the Invention) However, none of these alloy materials having the above structure can simultaneously satisfy the above properties. The present invention has been made based on the above circumstances, and has superior corrosion resistance than the copper-tin alloy currently most widely used as a fin material for radiators, and has a low heat dissipation property per unit area of the fin material. An object of the present invention is to provide a copper alloy for radiator fins whose thermal conductivity, which is an important property, is equal to or higher than that of the copper alloy described above, and which also has sufficient heat resistance required as a fin material. It is something. (Means for solving the problem) Therefore, as a result of intensive study, the present inventors found that tellurium is 0.005 to 0.025% by weight, zinc is 0.1 to 2.5% by weight, nickel is 0.005 to 0.5% by weight, and the balance is substantially It has been discovered that a copper alloy consisting of copper and accompanying impurities is extremely excellent as an alloy for radiator fins. (Function) As described above, the reason why tellurium is added in an amount of 0.005 to 0.025% by weight in the alloy of the present invention is that tellurium plays a role in imparting heat resistance, but if it is less than 0.005% by weight, the heat resistance is insufficient. On the other hand, if the content exceeds 0.025% by weight, the effect of improving heat resistance will not only be saturated, but also the workability of the alloy will deteriorate. Next, the amount of zinc added is set to 0.1 to 2.5% by weight because if it is less than 0.1% by weight, the corrosion resistance will not be improved sufficiently, whereas if it exceeds 2.5% by weight, the thermal conductivity of the alloy will decrease. Furthermore, although nickel works synergistically with zinc to improve corrosion resistance, the reason why the amount added is 0.005 to 0.5% by weight is because if it is less than 0.005% by weight, the improvement in corrosion resistance is not sufficient. This is because, if it exceeds this amount, the thermal conductivity of this alloy will decrease. In producing the alloy of the present invention, zinc may be added as a simple substance, tellurium and nickel may be added as a master alloy with copper, and if necessary, 0.01% by weight or less of phosphorus may be added as a deoxidizing agent. It's okay. Furthermore, the atmosphere for melting and casting operations does not need to be particularly limited, and any method such as atmospheric melting, vacuum melting, reduction, atmospheric melting using an inert gas, etc. may be employed. (Example) The alloy of the present invention will be explained below with reference to Examples. While covering the hot water surface with charcoal powder, electrolytic copper is melted in a graphite crucible under high frequency and atmospheric conditions, and phosphorus is added and deoxidized in the form of a copper-phosphorus alloy. After that, desired amounts of tellurium, zinc, and nickel are dissolved alone and with copper. It was added, melted and cast in the form of an alloy. The composition of the obtained ingot (thickness: 30 mm, width: 80 mm, length: 150 mm) was as shown in Table 1. After cutting the surface of these ingots by 2mm on each side,
A plate with a thickness of 26 mm was heated and hot rolled at 900°C, then intermediate annealing was performed once at 400°C for 1 hour in a nitrogen atmosphere, and the thickness was reduced by cold rolling with a reduction of 40%. An alloy plate of the present invention and a comparative alloy plate with a diameter of 0.3 mm were obtained. Plate pieces were suitably cut from the obtained plate material and used for measurement of thermal conductivity, heat resistance, and corrosion resistance. Next, thermal conductivity was evaluated by measuring electrical conductivity, which has a strong positive correlation.
In addition, to measure the heat resistance, we cut out a square piece of 20 mm on a side from the obtained plate material with a thickness of 0.3 mm, and measured the bath temperature.
This was done by measuring the Vickers hardness Hv of a sample that was immersed and heated for 5 minutes in a salt bath furnace with a weight ratio of NaNO ₂ and NaNO ₃ of 1:1 set at 350°C.
Furthermore, the corrosion resistance was measured from the obtained plate material with a width of 25 mm.
A test piece with a length of 90 mm was cut out and sprayed with saline solution at a concentration of 5% by weight at a temperature of 35°C for 1 hour, and then at a temperature of 50°C.
After placing it in a corrosive environment where one cycle is 60 cycles (60 days) of holding at 80% relative humidity for 23 hours, the generated corrosion products are removed.
This was done by measuring weight loss. The results obtained are shown in Table 1. As is clear from Table 1, the alloy of the present invention satisfies the characteristics required as an alloy for radiator fins in terms of electrical conductivity and heat resistance, and has greatly improved corrosion resistance compared to conventional materials. Among the comparative examples, No. 7 lacks heat resistance, Nos. 9 and 10 lack corrosion resistance, and No. 8 has low conductivity, all of which are inferior to the present alloy.

【table】

[Table] (Effects of the Invention) As explained in detail above, the alloy according to the present invention has excellent performance as an alloy for radiator fins in terms of thermal conductivity, heat resistance, and corrosion resistance.

[Claims]

1. A biofouling-resistant structure characterized by coating part or all of the surface of a structural member such as metal or synthetic resin with a biofouling-resistant copper alloy containing 2.0 to 12.0 wt% Ni and the balance Cu. parts. 2. A biofouling-resistant copper alloy consisting of 2.0 to 12.0 wt% Ni, one or both of these within the range of 1.0 wt% or less Fe and 1.0 wt% or less Mn, and the balance being Cu,
A structural component resistant to biological fouling, characterized in that a part or all of the surface of a structural component made of metal, synthetic resin, etc. is coated.