Radiating fin and radiating method using the radiating fin

ES 2 328 019 T3

DESCRIPTION

Radiator fins and radiation procedure using the radiator fin.

Technical field

The present invention relates to a thermal radiator fin, as defined in the preamble of claim 1, for a heating element of an electrical product, an electronic apparatus and the like and, in particular, to a thermal radiator fin with a radiator effect remarkably improved thermal radiation, and to a thermal radiation process that uses it. This thermal radiating fin is known, for example, from JP 10-118731.

Background of the technique

Various types of thermal radiators (thermal radiator fins) are used as means of thermal radiation in an electrical product or in an electronic device, such as a television, a computer, or a machine, a motor and a radiator of an automobile, various machinery and similar, to avoid the failure or the degradation of the functions after a thermal radiation. As a constituent material of a thermal radiator fin, a metallic material, such as aluminum or copper, having a high thermal conductance is generally used.

As a method to improve the thermal radiator effect of this radiator, various methods have been proposed to date. For example, as a method of increasing its heat radiation area, an alumite treatment or a jet treatment is adopted, and a method of increasing the number of fins (JP 11-238837 A), a method of bending an envelope of a thermal radiator fin to increase the speed and flow rate of cooling air passing through the thermal radiator fin (JP 10-242357A), a method for lowering the heat capacity of a thermal radiator fin (JP 10-116942 A) and the like.

In addition, to further enhance the effect of thermal radiation, there is an air cooling system to cool the air through ventilation with a combination of a thermal radiator fin and a fan, a water cooling system using cooling water , and a cooling method using a Peltier element on one side of a thermal radiator fin (JP 10-318624 A), and the like.

All of the conventional cooling procedures mentioned above have various problems. For example, in the process of increasing the number of fins to increase the specific surface area of ​​a thermal radiating fin, if the number of fins increases excessively, the air flow is blocked, causing degradation of the thermal radiating property. Furthermore, in the process of lowering the heat capacity of a thermal radiator fin, if the thickness of the fins is excessively reduced to reduce the heat capacity, the mechanical strength decreases and the heat radiator fin is likely to break.

The alumite treatment or the jet treatment has a problem that very small holes are plugged due to secular change, which causes a decrease in the heat radiating effect.

Although the above-mentioned air cooling system has a simple structure, since the thermal conductance between the air and the fins is small, it is necessary to increase the heat radiation area or increase the air flow rate by using a fan. Therefore, problems such as the increase in the size of the apparatus and the noise occur with the ventilation.

On the other hand, the water cooling system has a significant cooling effect, because the specific heat of water is large and the thermal conductance is high. However, the water cooling system requires a circulation system and a pump to circulate the water, and a radiator and a fan to radiate the heat into the open air, and its structure is complicated and the size of the appliance increases. Consequently, the cost and energy consumption of the apparatus increase, which is economically disadvantageous.

Since the cooling process employing a Peltier element requires a Peltier element, a thermal radiator fin and a fan, and the power consumption of the Peltier element is high, the process is economically disadvantageous.

Description of the invention

An object of the present invention is to eliminate the aforementioned disadvantages in the prior art, and to provide an inexpensive thermal radiator fin having a high cooling effect.

As a result of concentrated study efforts, the inventors completed the present invention based on the knowledge described below.

That is, as a consequence of the fact that the thermal conductance between air and a metal is small compared to the thermal conductance between water and a metal, it can be noted that the heat capacity of air is small compared to the heat capacity. of the water. In addition, air molecules adhere to a

ES 2 328 019 T3 metal surface of a thermal radiator fin due to physical adsorption without electron exchange or chemical adsorption with electron exchange and coat the metal surface, and these adsorption layers form a thermal insulating layer to prevent thermal radiation .

Chemical adsorption is caused by the formation of bonds, such as covalent bonds, electrostatic attraction, or the action of ion exchange, and the molecules are selectively adsorbed at a specific adsorption site to form a unimolecular adsorption layer that excludes the formation of a layer oxide or the like.

Furthermore, since physical adsorption is caused by condensation of molecules or a force similar to condensation due to Van der Waals forces, an electrostatic interaction, or the like, the molecules adhere uniformly to a complete interface, rather than to a specific site on the surface. Furthermore, a characteristic of physical adsorption is that it is a polymolecular layer adsorption.

The force of attraction of the molecules of a polymolecular adsorption layer to a surface (dispersion force) is greater in the first layer and decreases step by step in the second layer and subsequent layers. For example, in the case where molecules are adsorbed on a metal, although the adsorption force between the first layer and the metal is large, when a relatively large number of layers are deposited on the first layer, the same gas adheres to a gas to be adsorbed. At this point, the adsorption force is relatively small compared to the adsorption force between the first layer and the metal.

Therefore, when molecules in air with a small thermal conductance are adsorbed on the metal, the formation of a multilayer with the same molecules continues to advance on it. In addition, it is considered that this layer of molecules becomes an insulating layer as its thickness increases, and prevents thermal radiation from the metal. Therefore, it is considered that if the layer of gas molecules physically adsorbed on the metal surface is desorbed and removed, the effect of thermal radiation can be enhanced.

In this case, in general, in chemical adsorption, it takes time to cross an activation energy peak for adsorption, and the adsorption rate is low. On the other hand, in physical adsorption, which does not require activation energy for adsorption, its adsorption rate is high. Therefore, the molecules are first physically adsorbed onto the surface of the metal. Then, when enough energy is obtained to cross the peak of the activation energy, chemical adsorption occurs to discharge a large amount of energy. Thermal radiation due to chemical adsorption on the metal surface is 10 to 100 kcal / mol. Furthermore, the thermal radiation from physical adsorption is several kcal / mol or less, which is less than that from chemical adsorption. On the other hand, the adsorbed molecules are desorbed from the surface to return to space when the molecules receive the same energy as at the moment of adsorption, while remaining retained on the surface.

By the way, nitrogen, which exists in large volume in air, has little chemical activity and is physically adsorbed to the metal in many cases. On the other hand, oxygen, which has high chemical activity, is in many cases subjected to chemical adsorption that involves a specific chemical reaction with the metal, even at low pressure. Furthermore, its heat of adsorption always leads to thermal radiation.

From the issues discussed above, it is considered effective to cause chemical adsorption, which generates greater energy than the energy generated by physical adsorption, to desorb the physically adsorbed gas on the metal. More specifically, it is considered that if the chemical adsorption of oxygen is facilitated, the physically adsorbed molecules are desorbed and the effect of thermal radiation can be enhanced.

With respect to this point, the inventors have found that the ionization tendency of the metal plays an important role in the chemical adsorption of oxygen on the metal surface. That is, normally gaseous oxygen or water molecules are adsorbed on the surface of a metal (in the atmosphere, although the thickness of a layer of water generated on the surface of the metal differs depending on the state of humidity, the adsorbed water is measured with a thickness of 10 to 100 A and, in the humid atmosphere in which fine particles of water are deposited, from 10 A to 1 nm). The chemical adsorption of chemically active gaseous oxygen to the metal surface is extremely fast, and its oxidizing speed increases as the water layer increases its thickness (the oxidizing speed can even decrease when the thickness is 1 pm or more) . In addition, if there are water molecules on the surface of the metal, an ion exchange action occurs, and the greater the ionization tendency of the metal, the greater the rate of oxygen adsorption to the metal. In addition, since there are many pollutants in the atmosphere, such as sulfur dioxide, the adsorption of oxygen to the metal is further facilitated.

Herein, the ionization tendency of metal means the tendency of a simple metallic substance to become a cation in water, and changes of the metal in water are represented as MM '+ ne. Oxygen in air receives electrons and changes to an oxide anion, which is represented as follows:

1/2₂ (in the air) + H₂O (aqueous solution) + 2e (metal) = 2OH '(aqueous solution)

A standard electrode potential in the aforementioned reaction is calculated as +0.401 from the thermodynamic data. Therefore, the lower the standard electrode potential of the metal, the higher the

ES 2 328 019 T3 potential difference between metal and oxygen, easily causing an ionization reaction. That is, the greater the ionization tendency of the metal, the easier it will be for an ionization reaction to occur with oxygen.

From the point of view of an oxidation-reduction reaction, the ionization series establishes an order of ease to emit e- from a simple metallic substance, that is, a reducing power. Furthermore, oxygen is a substance with an extremely high oxidation power. Furthermore, the reaction of metal and oxygen is an exothermic reaction, which occurs even if the metal and oxygen are not in an aqueous environment.

From the reasons mentioned above, it is considered that by placing a metal with a large ionization tendency on the surface of a thermal radiating fin, the chemical adsorption of oxygen on the metal surface can be facilitated, whereby physically adsorbed molecules on the metal surface can be desorbed to enhance the effect of thermal radiation.

Then, examples of a factor for imparting influence to the thermal radiating effect include a difference between the heat capacity of a heat radiating fin and the heat capacity of air.

Then, considering a heat flux, thermal radiation from a high-temperature object is transmitted to the open air by convection or emission. So, in the case where the areas are identical, the heat transmitted by emission depends on the emissivity of the object, but the heat transmission by convection is greatly affected by the state of the fluid that comes into contact with the object.

The heat transmission in the case in which the temperature of an object is high and the heat is radiated to a fluid is represented by the following formula:

q = λ / L (Ti -T₂) = a (T₂ - To) where q is the heat flux (kcal / hm²), λ is the thermal conductivity of the object (kcal / ° Chm), L is the thickness of the object (m), Ti is the temperature of the object (° C), T₂ is the surface temperature of the object on the low-temperature side (° C), T_or is the temperature of the fluid (° C), and α is the thermal conductivity of the fluid (kcal / ° Chm).

It is evident from the previous formula that when the heat transmission of an object placed in a fluid of the same conditions occurs, a greater quantity of heat is radiated towards the free air the higher the thermal conductivity of the object and the lower it is. its thickness.

Furthermore, the calorific balance of a system, which includes the heat capacity, is represented by the following formula:

<img file="ES2328019T3_D0001.tif" />

where Q is the amount of heat supplied, θ is the internal temperature, θ₀ is the free air temperature, t is time, W is a constant of proportionality, and C is the heat capacity. Heat capacity is defined as follows:

C (heat capacity) = Q (amount of heat) / AT (temperature difference)

That is, AT is represented as AT = Q / C.

From the previous formula it is observed that if the quantity of heat supplied is constant, the thermal radiation towards the free air increases when the heat capacity is lower. Therefore, if an object with a small heat capacity is used for a thermal radiator plate, the internal heat accumulation decreases and the amount of thermal radiation emitted into the open air can increase.

Furthermore, the equilibrium temperature at the moment when objects with different heat capacities come into contact with each other is represented by the following formula:

T_and (equilibrium temperature) = (CpTi + C₂ T₂) / (C₁ + C₂)

ES 2 328 019 T3

From the above formula, it is observed that the equilibrium temperature is affected by the temperature of an object with a large heat capacity, and equilibrium occurs at a temperature close to the temperature of the object with a large heat capacity.

One reason why the thermal conductance between the air and the thermal radiator fin is small, compared to that between the water and the thermal radiator fin, is that the heat capacity of the air is small. Heat capacity is represented by C = V (volume, cm³) x D (density, g / cm³) xc (specific heat, cal / g ° C). In the same amount of water and air, water has a higher heat capacity because the specific heat and density of water are large compared to air, and the thermal conductance between the water and the thermal radiating fin becomes higher compared to the thermal conductance between air and thermal radiator fin.

That is, by increasing the amount of air contacted with the thermal radiator fin, the heat capacity of the air can increase, and the thermal conductance between the air and the thermal radiator fin can increase. Increasing the air flow rate to enhance its thermal radiation effect means removing trapped high temperature air in the vicinity of a thermal radiator plate and bringing the low temperature air into contact with the thermal radiator plate, thereby depriving heat. to the thermal radiator plate. However, this also means increasing the heat capacity of the air relative to the thermal radiator fin.

From the above description, it can be said, in other words, that the reduction of the heat capacity of the thermal radiator plate means the same as the increase of the heat capacity of the air with respect to the heat capacity of the thermal radiator plate. even if the amount of air that comes into contact with the thermal radiator fin is the same. Therefore, the amount of thermal radiation into the air increases if an object with a low heat capacity is used for the thermal radiator fin. Note that in the case where air with a small heat capacity is used as the cooling medium, the cooling effect is decreased compared to water with a large heat capacity, unless the air flow rate is increased.

Normally, since the heat resistance at the time when heat is transmitted from the surface of a metal to the air is greater than the heat resistance of a metal used as a heat radiating fin, the effect of heat radiation cannot be improved unless The heat resistance is reduced at the moment when the heat is transmitted from the metal surface to the air.

From the above description, the inventors considered and discovered, through experiments, that an improvement in the effect of thermal radiation can be made by coating the surface of a thermal radiating fin with an object with a small heat capacity to decrease the heat capacity. of the object put in contact with the air, compared with the heat capacity of the air and increasing the difference in the heat capacities.

As a result of repeated investigations based on the above knowledge, the inventors found that the effect of thermal radiation can be improved by coating the surface of a metal, which is to be a thermal radiating fin, with a metal that has a great tendency to ionization and also making the metallic cladding layer thin so that its heat capacity is small compared to that of the metal which is to be a thermal radiating fin, and contacting the coating layer with air, thereby completing the present invention.

Therefore, the present invention refers to a thermal radiating fin formed by a main body and a metallic coating layer stacked on the surface of the main body, characterized in that at least the tendency to ionization of the metallic material that constitutes the layer Metallic coating is greater than that of silver, and the layer thickness of the metallic coating layer is not greater than 5 μιη.

Furthermore, the present invention refers to a thermal radiating fin, characterized in that the metallic material that constitutes the metallic coating layer is selected from the group that includes copper, nickel, cobalt, chromium, zinc, manganese and alloys containing these metals. .

Furthermore, the present invention relates to a thermal radiating fin, characterized in that the metallic material that constitutes the metallic coating layer is selected from the group that includes nickel, chromium, zinc and alloys containing these metals.

Furthermore, the present invention relates to a thermal radiating fin according to any one of the previous descriptions, characterized in that the heat capacity of the metallic coating layer is less than the heat capacity of the main body.

Furthermore, the present invention relates to a thermal radiating fin according to any one of the previous descriptions, characterized in that the layer thickness of the metallic coating layer is from 0.03 to 10 pm.

Furthermore, the present invention relates to a thermal radiator fin according to any one of the previous descriptions, characterized in that the main body consists of aluminum.

The present invention relates to a thermal radiation process, characterized by radiating heat while the air acting as a cooling fluid is brought into contact with a surface of the thermal radiating fin according to any one of the previous descriptions.

ES 2 328 019 T3

The present invention will be described in detail below.

An embodiment of the present invention will be described below according to the accompanying drawings. Figures 1 and 2 are perspective views showing examples of a structure of a thermal radiator fin of the present invention. Figure 3 is a sectional view of the thermal radiator fins of Figures 1 and 2, in which Figure 3 (a) is a sectional view of the thermal radiator fin of Figure 1, and Figure 3 (b ) is a sectional view of the thermal radiator fin of Figure 2.

(1) Constituent material of the thermal radiator fin

The thermal radiating fin of the present invention (reference number 1 in figure 1 or 2) is made up of a main body (reference number 2 in figure 3) and a metallic coating layer (reference number 3 in figure 3) stacked on the surface of the main body.

The material forming the main body can be appropriately selected from metallic materials and their alloys, which are conventionally publicly known as materials for a thermal radiator fin. Examples of these materials include single metals, such as iron, aluminum, copper, nickel, platinum, silver, gold, tungsten, or zinc, and alloys, such as stainless steel, brass, bronze, chromium-nickel alloy, aluminum-silicon alloy, alloy aluminum-manganese, nickel-copper alloy, titanium-iron alloy or titanium-aluminum alloy, or the like. The material may also be provided with a protective film by galvanic vapor deposition or the like, or it may undergo a surface treatment, such as an oxidation treatment. Among these, aluminum, copper or the like are preferably used, in terms of economical cost, low weight properties, processability or the like.

The shape of the main body is not specifically limited, and is selected in various ways, such as plate-shaped and rod-shaped, depending on the application. Furthermore, its size and thickness are not specifically limited. For example, in the case where the main body is manufactured as a metal plate, the thickness of the metal plate may increase if it is used for a large product, such as a large appliance, or it may decrease if it is used for a large appliance. little. However, the thickness is preferably in the range of 0.01 to 10mm, and more preferably in the range of 0.1 to 8.0mm.

Although examples of shapes of this main body of a thermal radiator fin are shown in Figures 1 and 2, the shape is not limited to these. For example, the main body may have an arbitrary shape, such as a plate shape, a square shape, a circular shape, a tubular shape, a hemispherical shape, or a spherical shape, and one of its surfaces can be processed to be a surface. wavy, uneven surface, projected shaped surface, or the like.

(2) Metallic coating layer

In the present invention, a layer consisting of a metal with a higher ionization tendency than silver (metallic coating layer) is stacked in a thin layer on a surface of the main body of the aforementioned thermal radiating fin, preferably so that its heat capacity is small, compared to the heat capacity of the main body of the thermal radiator fin, to coat the main body of the thermal radiator fin.

The ionization trend referred to herein means the result obtained from the measurement of the potential difference between two poles, and the measurement value obtained by performing the measurement with a common oxidation-reduction potentiometer (electronic voltmeter) at room temperature is used as the ionization tendency. In addition, the numerical value calculated from the thermodynamic data is used if the measurement of the potential difference between the two poles is difficult.

For the metallic material that can be used for the metallic coating layer in the present invention, it is necessary to select a material with a tendency to ionization, which is obtained by such measurement, which is higher than that of silver. Furthermore, it is preferable to select a material with a heat capacity less than the heat capacity of the main body of the heat radiator fin.

More specifically, examples of metallic materials include copper, nickel, cobalt, chromium, iron, zinc, manganese, aluminum, and magnesium, the oxides of these metals, the alloys of these metals, and the like. Among these materials, if the ionization tendency is too high, the oxidation rate due to oxygen increases and the cladding metal changes to an oxide rapidly, and as a result, the decrease in the ionization tendency is also accelerated, which produces a decrease in the thermal radiator effect. Thus, more preferably, a material selected from the group consisting of copper, nickel, cobalt, chromium, zinc and manganese is employed, and the alloys containing these metals. Note that examples of alloys include nickel-ferrite, nickel-chromium, nickel-copper, nickel-zinc, nickel-copper-zinc, nickel-boron, and the like.

Among these, taking into consideration a high thermal radiation effect, a relatively low oxidation rate due to air, economic cost, processing properties and durability, examples of the most preferable materials include zinc, chromium, nickel or alloys. containing these metals. In addition,

Examples of the most preferable materials among these include nickel, which has the least tendency to ionization, has a low oxidation rate, and has excellent durability.

In the present invention, the metallic material constituting the main body of the thermal radiating fin and the metallic material constituting the metallic coating layer need not always be different materials. However, since the thermal radiating effect is further increased if the metallic cladding layer is formed so that its heat capacity is small compared to the heat capacity of the main body of the heat radiating fin, taking into consideration the combination with the material. metal of the main body of the thermal radiator fin, A material different from the metallic material constituting the main body of the thermal radiating fin may be selected as the metallic material constituting the metallic coating layer.

The metallic cladding layer may be stacked on the entire surface of the main body of the thermal radiator fin or it may be stacked only on a part of the surface of the main body. A location to be coated can be appropriately selected and the metallic layer stacked as required. For example, in the thermal radiator fin of the shape shown in Figure 1 or 2, it is not always necessary to stack the metallic coating layer on the bottom surface.

With regard to the thickness of the metallic coating layer (layer thickness), it is desirable to select this layer thickness so as to increase the difference between the heat capacities of the metallic coating layer and the air, to facilitate the chemical adsorption of the molecules in the air. More specifically, it is desirable that the layer thickness is set to a range of 0.1 to 5 µm, and particularly preferably 0.5 to 5 µm. If the layer thickness is too great, the thermal radiation from the main body of the thermal radiator fin is likely to be impeded. On the other hand, if the layer thickness is too small, since the amount of metal contained in the metallic cladding layer is small, the metallic cladding layer, which chemically adsorbs oxygen to enhance the effect of thermal radiation, changes with ease and speed to a rust. Therefore, a disadvantage can arise in that the metal contained in the metallic coating layer is almost completely lost and the effect of thermal radiation is diminished.

Note that the layer thickness referred to herein means, for example, assuming that the metallic cladding layers are formed on the top, the middle, and the bottom surface of a fin, obtaining an average layer thickness value of these three parts using a spesometer. The measurement of the layer thickness can be an arbitrary procedure and can be measured, for example, by a fluorescent X-ray apparatus or the like.

A stacking process (coating process) for the metallic coating layer in the present invention is not specifically limited and can be arbitrarily selected from the processes that are commonly employed to form a thin layer, for example, a liquid phase process. such as electrical coatings, non-electrical coatings, or hot dip coatings from a molten metal, physical vapor deposition (PVD), such as vacuum vapor deposition, ion plating, or cathodic erosion, a vapor phase process, such as thermal CVD, plasma CVD, or optical CVD. Furthermore, the metallic cladding layer can be stacked by arbitrarily combining these techniques.

Furthermore, the time to form the metallic cladding layer is also arbitrary. For example, the metallic cladding layer can be formed after processing a metallic material in various shapes to form the main body of a thermal radiating fin, or it can be processed in various shapes after being stacked on a sheet-shaped metallic material, stick shape or the like before processing. Therefore, coating can be done when required.

Furthermore, in Figures 1 and 2, the case is shown where the main body of the thermal radiating fin and the metallic cladding layer are a single body, respectively. However, in the present invention, the main body of the thermal radiator fin or the metallic cladding layer, or both, can be formed as a complex consisting of two or more types of materials. For example, the main body of the thermal radiating fin can be formed as a multilayer structure, and the metallic cladding layer can be formed as a multilayer structure and divided into a surface layer and an inner layer, each of which can be made of different materials. In this case, it is desirable to use the aforementioned metallic material, with a tendency to ionization greater than that of silver, for a layer that comes into contact with the air layer, and to set the layer thickness in a range 0.1 to 5 jum.

(3) Thermal radiation procedure

The thermal radiation process of the present invention is characterized in that the heat is radiated while the air acting as a cooling fluid is brought into contact with the surface of the thermal radiating fin of the present invention. Since the thermal radiator fin of the present invention has a metallic coating layer, which is stacked in a thin layer on its surface, so that its heat capacity is less than that of the main body of the thermal radiator fin, the heat capacity of the air increases relatively and the difference between the heat capacity of the air and the heat capacity of the thermal radiator fin widens. Therefore, the effect of thermal radiation, in the case of using air as the cooling fluid, can be remarkably improved.

ES 2 328 019 T3

Note that, in this case, the thermal radiation procedure can be used in conjunction with a means that has been conventionally adopted to facilitate thermal radiation, for example, a procedure for making a surface uneven, a procedure for enlarging the radiation area thermal, such as an alumite treatment or a jet treatment, a procedure to increase the number of fins, a method of bending an envelope of a thermal radiator fin to increase the speed and volume of the cooling air passing through the thermal radiator fin, a method of decreasing the heat capacity of a thermal radiator fin, and the like. Furthermore, it is possible to enlarge the specific surface of the metallic coating layer by applying a physical treatment or a chemical treatment, such as jet treatment, to the metallic coating layer to further enhance its thermal radiation effect. Furthermore, it is also possible to stack a catalyst or the like on the surface of the metallic coating layer to facilitate chemical adsorption.

Brief description of the drawings

Fig. 1 is a perspective view showing an example of the structure of a thermal radiator fin of the present invention.

Fig. 2 is a perspective view showing an example of the structure of a thermal radiator fin of the present invention.

Figure 3 shows sectional views of the thermal radiator fins of Figures 1 and 2, and Figure 3 (a) is a sectional view of the thermal radiator fin of Figure 1, and Figure 3 (b) is a Sectional view of the thermal radiator fin of Figure 2.

Fig. 4 is a schematic view showing a test apparatus of the first embodiment.

Fig. 5 is a schematic view showing a test apparatus of the second to the sixth embodiment.

Fig. 6 is a side view showing a cooling device used in a test apparatus of the seventh and eighth embodiments.

Fig. 7 is a schematic view showing a test apparatus of the seventh and eighth embodiments.

In the figures, the reference number 1 indicates a thermal radiator fin; 2, the main body of a thermal radiator fin; 3, a metallic coating layer; 4, a bakelite plate; 5, a heater; 6, an aluminum plate for temperature measurement; 7, a hole for temperature measurement; 8, a styrofoam board; 9, a fan; 10, a Peltier element; 11, a cooling surface; and 12, an input terminal, and the reference symbol "a" indicates the vertical dimension; "B", the horizontal dimension; "C", the height; "D", the height of the fin; "E", the thickness of the upper part of the fin; and "f", the thickness of the bottom of the fin.

Best way to carry out the invention

The present invention will now be described more specifically with reference to embodiments. However, the present invention is not limited only to these embodiments. Note that the thickness of the layer in these embodiments is an average value obtained by measuring the thickness of the layer in three parts, namely the top, the middle and the bottom surface of a fin, using a fluorescent X-ray apparatus. .

First realization

The inventors prepared aluminum thermal radiator fins (hereinafter simply referred to as "fins") having the shape shown in Figure 1, with a coating of Zn, Cr, Ni or Cu, respectively, coating the main body of an aluminum thermal radiating fin having a length of 100mm, a width of 100mm, and a height of 40mm, a fin height of 30mm, a fin thickness of 2mm at the top, and a 5mm at the bottom, and a weight of 480 g (in figure 1, a = 100 mm, b = 100 mm, c = 40 mm, d = 30 mm, e = 2 mm, and f = 5 mm); an identical thermal radiator fin with a methyl methacrylate-ethyl acrylate-styrene copolymer coating; and an identical thermal radiator fin that has not undergone any processing. Note that the layer thickness of the respective coating layers is shown in Table 1.

As shown in Figure 4, the Bakelite plate (in Figure 4, reference no. 4; same in the following), heater 5, aluminum plate for temperature measurement 6 with a thickness of 10mm, a length of 50mm and a width of 50mm with a hole for temperature measurement 7 open on one side, and the fin 1 were arranged on top of each other in order, and the fin 1 and the Bakelite plate 4 were screwed and closely adhered to each other to make a test apparatus. The test apparatus was then placed on the Styrofoam plate 8 with the Bakelite plate 4 on the bottom side. Heat radiation grease was applied between the aluminum plate 6 and the fin 1, and between the aluminum plate 6 and the heater 5, respectively.

As heater 5 a 100 V / 150 W heater was used, and an electrical power of 9.5 W (25 V / 0.38 A) was applied to heater 5 with a rectifier manufactured by Kikusui Kabushiki Kaisha to cause the heater

ES 2 328 019 T3 radiated heat, and the temperature at the time the heat radiation started was compared with the temperature after 90 minutes. The result is shown in table 1. Note that the ionization tendency in this case is large, with the order Zn> Cr> Ni> unprocessed aluminum fin> Cu.

TABLE 1

<td>Coating layer material (layer thickness)</td><td>Start temperature (° C)</td><td>Temperature after 90 minutes (° C)</td>

<td>Zn (1,455 pm)</td><td> 19,8</td><td> 41,8</td>

<td>Cr (1,467 pm)</td><td> 19,8</td><td> 42,3</td>

<td>Ni (1,513 pm)</td><td> 19,8</td><td> 42,5</td>

<td>Cu (1,499 pm)</td><td> 19,8</td><td> 43,5</td>

<td>MM (1,552 pm)</td><td> 19,8</td><td> 44,1</td>

<td>No treatment</td><td> 19,8</td><td> 44,9</td>

<td>Room temperature</td><td> 19,8</td><td> 20,1</td>

<td colspan="3">Note: MM, methyl methacrylate-ethyl acrylate-styrene copolymer</td>

From the result mentioned above, it is observed that the temperature after 90 minutes has the order Zn &lt;Cr &lt;Ni &lt;Cu &lt;MM &lt;unprocessed aluminum fin, and the temperature falls between 1.4 ° C and 3.1 ° C if an object with low heat capacity compared with the unprocessed aluminum fin is stacked, and the heat radiation effect is enhanced. In addition, it is observed that the temperature of Cu, Ni, Cr or Zn, with a great tendency to ionization compared to the chemically inactive methyl methacrylate-ethyl acrylate-styrene copolymer, falls between 0.6 ° C and 2, 3 ° C, and when the tendency to ionization increases, the effect of thermal radiation is improved.

Second realization

As in the first embodiment, identical aluminum thermal radiator fins are prepared with a coating of Zn, Cr, Ni or Cu, by coating the main body of an aluminum thermal radiator fin having a length of 100 mm, a width of 100 mm. , and a height of 40mm, a fin height of 30mm, a fin thickness of 2mm at the top and 5mm at the bottom, and a weight of 480g; with a methyl methacrylate-ethyl acrylate-styrene copolymer coating; and without submitting to any processing. Note that the layer thickness of the respective coating layers is shown in Table 2.

As shown in figure 5, bakelite plate 4, heater 5, aluminum plate for temperature measurement 6 with a thickness of 10mm, a length of 50mm, and a width of 50mm with a hole for temperature measurement 7 open on one side, and the fin 1 were arranged on top of each other in order, and the fin 1 and Bakelite plate 4 were fastened with screws and closely adhered to each other to make an apparatus of test. The test apparatus was then placed on the Styrofoam plate 8 with the Bakelite plate 4 on the bottom side. Then a cooling fan 9 (with a length of 80 mm and a width of 80 mm; manufactured by Sanyo Denki Co., Ltd .; number of revolutions 2,900 rpm, 12 V / 0.13 A; flow rate of air = 1.03 m³/ m) to the top of the fin on the upper side for cooling. Heat radiation grease was applied between the aluminum plate 6 and the fin 1, and between the aluminum plate 6 and the heater 5, respectively.

A 100 V / 150 W heater was used as heater 5, and an electrical power of 84.75 W (75 V / 1.13 A) was applied to heater 5 with a rectifier manufactured by Kikusui Kabushiki Kaisha to cause the heater heat was radiated, and the temperature at the time the heat radiation started was compared with the temperature after 90 minutes. The result is shown in table 2. Note that the ionization tendency in this case is large, with the order Zn> Cr> Ni> unprocessed aluminum fin> Cu.

ES 2 328 019 T3

TABLE 2

<td>Coating layer material (layer thickness)</td><td>Start temperature (° C)</td><td>Temperature after 90 minutes (° C)</td>

<td>Zn (1,455 pm)</td><td> 18,1</td><td> 53,8</td>

<td>Cr (1,467 pm)</td><td> 18,1</td><td> 54,3</td>

<td>Ni (1,513 pm)</td><td> 18,1</td><td> 54,4</td>

<td>Cu (1,499 pm)</td><td> 18,1</td><td> 54,7</td>

<td>MM (1,552 pm)</td><td> 18,1</td><td> 56,9</td>

<td>No treatment</td><td> 18,1</td><td> 57,5</td>

<td>Room temperature</td><td> 18,1</td><td> 18,4</td>

<td colspan="3">Note: MM, methyl methacrylate-ethyl acrylate-styrene copolymer</td>

From the above-mentioned result, it is seen that the temperature after 90 minutes also has the order Zn &lt;Cr &lt;Ni &lt;Cu &lt;MM &lt;unprocessed aluminum fin even if cooled with a fan, and the temperature falls between 0, 6 ° C and 3.7 ° C if an object with low heat capacity compared with unprocessed aluminum fin is stacked, and the heat radiation effect is enhanced. In addition, it is observed that the temperature of Cu, Ni, Cr or Zn, with a great tendency to ionization compared to the chemically inactive methyl methacrylate-ethyl acrylate-styrene copolymer, falls between 2.2 ° C and 3, 1 ° C, and the thermal radiation effect of the coated thermal radiating fin is enhanced in order to high the ionization tendency by ventilation using a fan.

Third realization

Identical aluminum thermal radiator fins, similar to those used in the second embodiment, are prepared with a coating of Zn, Cr, Ni, Cu and MM on the main body of an aluminum thermal radiator fin; and without submitting to any processing. Note that the layer thickness of the respective coating layers is shown in Table 3.

The bakelite plate 4, the heater 5, the aluminum plate for temperature measurement 6 and the fin 1 were arranged one above the other to make a test apparatus similar to that made in the second embodiment. Then, the fin 1 and the bakelite plate 4 were screwed and closely adhered to each other, and the test apparatus was placed on the styrofoam plate 8 with the bakelite plate 4 on the bottom side. Then a cooling fan 9, similar to that used in the second embodiment (with a length of 80mm and a width of 80mm; manufactured by Sanyo Denki Co., Ltd.) was fitted to the top of the fin.

As heater 5, a 100 V / 150 W heater was used and, without changing the applied electrical power of 84.75 W (75 V / 1.13 A), the temperature of the central aluminum part was compared at the time of that the thermal radiation started with the temperature after 90 minutes, under the respective conditions that the number of revolutions of the fan 9 was changed to 1800 rpm (flow rate: 0.92 m³/ m), 2900 rpm (flow rate: 1.03 m³/ m) and 3400 rpm (flow: 1.20 m³/ m). The result is shown in table 3. Note that the ionization tendency in this case is large, with the order Zn> Cr> Ni> unprocessed aluminum fin> Cu.

ES 2 328 019 T3

TABLE 3

<td>Type / no. Of revolutions</td><td colspan="2">1800 rpm</td><td colspan="2">2900 rpm</td><td colspan="2">3400 rpm</td>

<td>Layer material coating (thickness of layer-pm)</td><td>Start temperature (° C)</td><td>Temperature after 90 minutes (° C)</td><td>Start temperature (° C)</td><td>Temperature after 90 minutes (° C)</td><td>Start temperature (° C)</td><td>Temperature after 90 minutes (° C)</td>

<td>Zn (1,455)</td><td> 17,3</td><td> 67,6</td><td> 16,9</td><td> 53,8</td><td> 17,4</td><td> 50,1</td>

<td>Cr (1,467)</td><td> 17,3</td><td> 67,9</td><td> 16,9</td><td> 54,3</td><td> 17,4</td><td> 50,7</td>

<td>Ni (1,513)</td><td> 17,3</td><td> 68</td><td> 16,9</td><td> 54,4</td><td> 17,4</td><td> 50,9</td>

<td>Cu (1,499)</td><td> 17,3</td><td> 68,3</td><td> 16,9</td><td> 54,7</td><td> 17,4</td><td> 51,3</td>

<td>MM (1,552)</td><td> 17,3</td><td> 70</td><td> 16,9</td><td> 56,9</td><td> 17,4</td><td> 54,1</td>

<td>No treatment</td><td> 17,3</td><td> 70,2</td><td> 16,9</td><td> 57,5</td><td> 17,4</td><td> 54,2</td>

<td colspan="7">Note: MM, methyl methacrylate-ethyl acrylate-styrene copolymer</td>

From the above-mentioned result, it is observed that the temperature after 90 minutes also has the order Zn &lt;Cr &lt;Ni &lt;Cu &lt;MM &lt;unprocessed aluminum fin even if the number of revolutions of the fan is changed, and the temperature drops between 0.2 ° C and 2.6 ° C in the case of 1800 rpm, between 0.6 ° C and 3.7 ° C in the case of 2900 rpm, and between 0.1 ° C and 4.1 ° C in the case of 3400 rpm, if an object with low heat capacity compared to the unprocessed aluminum fin is stacked, and the effect of heat radiation is enhanced. In addition, it is observed that the temperature of Cu, Ni, Cr or Zn, with a great tendency to ionization compared to the chemically inactive methyl methacrylate-ethyl acrylate-styrene copolymer, falls between 1.7 ° C and 2, 4 ° C in the case of 1800 rpm, between 2.2 ° C and 3.1 ° C in the case of 2900 rpm, and between 2.8 ° C and 4.0 ° C in the case of 3400 rpm, and the thermal radiation effect of the coated thermal radiating fin is improved in order to high the ionization tendency by increasing the number of revolutions of the fan.

Fourth realization

Identical aluminum thermal radiator fins, similar to those used in the third embodiment, are prepared with a coating of Zn, Cr, Ni, Cu and MM on the main body of an aluminum thermal radiator fin; and without submitting to any processing. Note that the layer thickness of the respective coating layers is shown in Table 4.

The bakelite plate 4, the heater 5, the aluminum plate for temperature measurement 6 and the fin 1 were arranged one above the other to make a test apparatus which is similar to that manufactured in the third embodiment. Then, the fin 1 and the bakelite plate 4 were screwed and closely adhered to each other, and the test apparatus was placed on the styrofoam plate 8 with the bakelite plate 4 on the bottom side. A cooling fan 9, similar to that used in the third embodiment (with a length of 80mm and a width of 80mm; manufactured by Sanyo Denki Co., Ltd.) was then fitted to the top of the fin.

A 100 V / 150 W heater was used and, while maintaining fan speed 9 at 2900 rpm (flow rate: 1.03 m³/ m), the temperature at the time the thermal radiation started was compared with the temperature after 90 minutes, under the respective conditions that the electrical power was changed to 37.5 W, 84.7 W and 150 W. The result is shown in table 4. Note that the ionization tendency in this case is large, with the order Zn> Cr> Ni> unprocessed aluminum fin> Cu.

ES 2 328 019 T3

TABLE 4

<td>Type / electrical power applied</td><td colspan="2">37.5 W</td><td colspan="2">84.75 W</td><td colspan="2">150 W</td>

<td>Layer material coating (thickness of layer-pm)</td><td>Start temperature (° C)</td><td>Temperature after 90 minutes (° C)</td><td>Start temperature (° C)</td><td>Temperature after 90 minutes (° C)</td><td>Start temperature (° C)</td><td>Temperature after 90 minutes (° C)</td>

<td>Zn (1,455)</td><td> 17,5</td><td> 33,2</td><td> 16,9</td><td> 53,8</td><td> 17,1</td><td> 86,2</td>

<td>Cr (1,467)</td><td> 17,5</td><td> 33,3</td><td> 16,9</td><td> 54,3</td><td> 17,1</td><td> 86,7</td>

<td>Ni (1,513)</td><td> 17,5</td><td> 33,4</td><td> 16,9</td><td> 54,4</td><td> 17,1</td><td> 86,7</td>

<td>Cu (1,499)</td><td> 17,5</td><td> 33,5</td><td> 16,9</td><td> 54,7</td><td> 17,1</td><td> 87,1</td>

<td>MM (1,552)</td><td> 17,5</td><td> 35,1</td><td> 16,9</td><td> 56,9</td><td> 17,1</td><td> 89,9</td>

<td>No treatment</td><td> 17,5</td><td> 35,4</td><td> 16,9</td><td> 57,5</td><td> 17,1</td><td> 90,4</td>

<td colspan="7">Note: MM, methyl methacrylate-ethyl acrylate-styrene copolymer</td>

From the result mentioned above, it is observed that the temperature after 90 minutes also has the order Zn &lt;Cr &lt;Ni &lt;Cu &lt;MM &lt;unprocessed aluminum fin even if the applied electrical power is changed, and the temperature falls between 0 , 3 ° C and 1.2 ° C in the case of 37.5 W, between 0.6 ° C and 3.7 ° C in the case of 84.75 W, and between 0.5 ° C and 4, 2 ° C in the case of 150 W, and the heat radiation effect is enhanced by stacking an object with low heat capacity compared to the unprocessed aluminum fin. Furthermore, it is observed that the temperature of Cu, Ni, Cr or Zn, with a great tendency to ionization compared to the chemically inactive ethyl methyl acrylate methacrylate-styrene copolymer, falls between 1.6 ° C and 1.9 ° C in the case of 37.5 W, between 2.2 ° C and 3.1 ° C in the case of 84.75 W, and between 2.8 ° C and 3.7 ° C in the case of 150 W , and the thermal radiation effect of the coated thermal radiating fin is improved in order to increase the ionization tendency by increasing the applied electrical power.

Fifth realization

The same aluminum fins of the first embodiment are used, with Zn stacked on them with a thickness of 0.037 pm, 0.106 pm, 0.503 pm, 1.455 pm, 2.883 pm, 3.787 pm, 4.993 pm, 6.112 pm, 7.568 pm, and 10.231 pm, respectively, to compare their respective temperatures after 90 minutes with the same procedure as in the second embodiment. The result is shown in table 5.

ES 2 328 019 T3

TABLE 5

<td>Zinc layer thickness</td><td>Start temperature (° C)</td><td>Temperature after 90 minutes (° C)</td>

<td>0.037 pm</td><td> 19,5</td><td> 57,3</td>

<td>0.106 pm</td><td> 19,5</td><td> 56,3</td>

<td>0.503 pm</td><td> 19,5</td><td> 53,8</td>

<td>1,455 pm</td><td> 19,5</td><td> 53,1</td>

<td>2,883 pm</td><td> 19,5</td><td> 54,3</td>

<td>3,787 pm</td><td> 19,5</td><td> 54,8</td>

<td>4,993 pm</td><td> 19,5</td><td> 55,3</td>

<td>6,112 pm</td><td> 19,5</td><td> 56,9</td>

<td>7,568 pm</td><td> 19,5</td><td> 57,4</td>

<td>10,231 pm</td><td> 19,5</td><td> 57,8</td>

<td>No treatment</td><td> 19,5</td><td> 58,1</td>

<td>Room temperature</td><td> 19,5</td><td> 19,9</td>

From the above-mentioned result, it is observed that the improvement in the effect of thermal radiation is remarkable when the thickness of the zinc is in the range of 0.037 pm to 10 pm, it is more remarkable when the thickness is in the range of 0.1 pm to 7.5 pm, and in particular when the thickness is in the range of 0.5 pm to 5 pm.

Sixth realization

The same aluminum fins of the first embodiment are used, with Ni stacked on them with a thickness of 0.031 pm, 0.587 pm, 0.998 pm, 1.486 pm, 2.999 pm, 3.893 pm, 4.875 pm, 5.669 pm, 7.665 pm, and 10.026 pm, respectively, to compare their respective temperatures after 90 minutes with the same procedure as in the second embodiment. The result is shown in table 6.

TABLE 6

<td></td><td>Start temperature (° C)</td><td>Temperature after 90 minutes (° C)</td>

<td>0.031 pm</td><td> 19,8</td><td> 57,1</td>

<td>0.587 pm</td><td> 19,8</td><td> 56,6</td>

<td>0.998 pm</td><td> 19,8</td><td> 54,8</td>

<td>1,486 pm</td><td> 19,8</td><td> 53,5</td>

<td>2,999 pm</td><td> 19,8</td><td> 54,1</td>

<td>3,893 pm</td><td> 19,8</td><td> 54,9</td>

<td>4,875 pm</td><td> 19,8</td><td> 56,2</td>

<td>5,669 pm</td><td> 19,8</td><td> 56,8</td>

<td>7,665 pm</td><td> 19,8</td><td> 57,3</td>

<td>10,026 pm</td><td> 19,8</td><td> 58,1</td>

<td>No treatment</td><td> 19,8</td><td> 58,2</td>

<td>Room temperature</td><td> 19,8</td><td> 20,1</td>

ES 2 328 019 T3

From the result mentioned above, it is observed that the improvement in the effect of thermal radiation is remarkable when the thickness of nickel is in the range of 0.03 μm to 10 jum, it is more remarkable when the thickness is in the range of 0 , 5 pm to 7.5 jum, and in particular when the thickness is in the range of 0.5 pm to 6 jum.

Seventh realization

A thermal radiating fin with the shape shown in figure 2 was used, with Zn stacked on it with a thickness of 0.034 jum, 0.098 jum, 0.532, um, 1.612, um, 3.661 jum, 5.053 jum, 6.022, um, 7.889 jum, and 10,088 jum, respectively, on the main body of an aluminum thermal radiator fin with a length of 100 mm, a width of 100 mm and a height of 40 mm, with a number of fins of 625, a height of the 34mm fin and 2mm x 2mm fin thickness.

A cooling device (manufactured by Frigester Kabushiki Kaisha, F44-HS) was used, in which the thermal radiating fin 1 is arranged with the Peltier element 10 subjected to the aforementioned treatment, and a cooling fan 9 (with a length of 100 mm and a width of 100 mm; the number of revolutions is 3600 rpm; 12 V / 0.175 A) is arranged in order, as shown in figure 6.

The thermal radiator fin and Peltier element were closely adhered by thermal radiation grease. Then, as shown in Figure 7, the cooling device was arranged so that the cooling surface 11 (portion of the Peltier element; temperature measurement point) was at the top and the thermal radiating fin was was at the bottom to rotate the fan, a voltage of 12 V was applied to the Peltier element 10, and the temperatures on the cooling surface were compared after 90 minutes. The result is shown in table 7.

TABLE 7

<td></td><td>Start temperature (° C)</td><td>Temperature after 90 minutes (° C)</td>

<td>0.034 pm</td><td> 22,8</td><td> -14,3</td>

<td>0.098 pm</td><td> 22,8</td><td> -16,8</td>

<td>0.532 pm</td><td> 22,8</td><td> -17,5</td>

<td>1,612 pm</td><td> 22,8</td><td> -18,2</td>

<td>3,661 pm</td><td> 22,8</td><td> -16,9</td>

<td>5,053 pm</td><td> 22,8</td><td> -16,0</td>

<td>6.022 pm</td><td> 22,8</td><td> -15,2</td>

<td>7,889 pm</td><td> 22,8</td><td> -14,7</td>

<td>9,975 pm</td><td> 22,8</td><td> -14,4</td>

<td>No treatment</td><td> 22,8</td><td> -14,1</td>

<td>Room temperature</td><td> 22,8</td><td> 22,4</td>

From the result mentioned above, it is observed that the reduction in the temperature on the cooling surface is significant, and that the improvement in the effect of thermal radiation is remarkable when the thickness of the zinc is in the range of 0.03 pm to 10 jum is most noticeable when the thickness is in the range of 0.03 pm to 8 jum, and in particular when the thickness is in the range of 0.1 pm to 5 jum.

Eighth realization

A test apparatus was manufactured using the Peltier element in the same way as in the seventh embodiment, except that aluminum thermal radiating fins were used (one provided with a metallic coating layer and the other without any processing). , which are the same as those used in the first

ES 2 328 019 T3 embodiment. The temperatures in the center of the aluminum plate fitted on the cooling side were compared at the time when voltages of 7.5 V and 10 V were applied, and the number of revolutions was changed to 1800 rpm, 2900 rpm and 3400 rpm. The result is shown in table 8.

TABLE 8

<td>number of revolutions</td><td colspan="2">1800 rpm</td><td colspan="2">2900 rpm</td><td colspan="2">3400 rpm</td>

<td>Type / voltage</td><td>7.5V</td><td>10 V</td><td>7.5V</td><td>10 V</td><td>7.5V</td><td>10 V</td>

<td>Zn (1,455 pm)</td><td> 1,4</td><td> 0,5</td><td> 0,5</td><td> -0,5</td><td> 0,1</td><td> -1,1</td>

<td>Cr (1,467 pm)</td><td> 2,1</td><td> 1,3</td><td> 1,5</td><td> 0,6</td><td> 0,6</td><td> -0,3</td>

<td>Ni (1,513 _Mm)</td><td> 2,2</td><td> 1,5</td><td> 1,7</td><td> 0,8</td><td> 0,7</td><td> -0,1</td>

<td>Cu (1,499 μΓη)</td><td> 2,5</td><td> 1,7</td><td> 1,9</td><td> 0,9</td><td> 1,3</td><td> 0,6</td>

<td>MM (1,552 pm)</td><td> 4,1</td><td> 3,2</td><td> 3,3</td><td> 2,8</td><td> 2,7</td><td> 2,3</td>

<td>No treatment</td><td> 5,8</td><td> 5,4</td><td> 3,5</td><td> 3,1</td><td> 3,6</td><td> 6,0</td>

<td>Room temperature</td><td> 20,1</td><td> 20,0</td><td> 20,2</td><td> 20,3</td><td> 20,0</td><td> 20,2</td>

<td colspan="7">Note: MM, methyl methacrylate-ethyl acrylate-styrene copolymer</td>

From the previous result it is observed that, even if the applied voltage and the number of revolutions of the cooling fan are changed, the effect of thermal radiation is improved, and the temperature on the cooling surface decreases by coating the surface with an object that have a great tendency to ionization.

Industrial applicability

Since the thermal radiator fin is provided with a metallic coating layer consisting of a metallic material with a great tendency to ionization, the chemical adsorption of oxygen in air to a surface of the thermal radiator fin is facilitated, and the molecules Physically adsorbed on the surface they desorb to improve the effect of thermal radiation significantly. In addition, since the thermal radiator fin has the metallic coating layer stacked in thin layer, so that its heat capacity is less than that of the main body of the thermal radiator fin, the heat capacity of the air increases relatively, the difference is widened. between the heat capacity of the air and the heat capacity of the thermal radiator fin, and the effect of heat radiation is further enhanced in the case where air is used as the cooling fluid.

According to the thermal radiation method using the thermal radiator fin of the present invention, since air is used as the cooling fluid, a high thermal radiation effect can be obtained without installing a circulation system and an apparatus, such as a pump such as in a water cooling system employing a cooling liquid such as water, and a compact, light weight and inexpensive cooling device can be provided. In addition, since the efficiency of thermal radiation is better than conventional air cooling system, problems such as the size of the apparatus and noise can be eliminated with ventilation.

The thermal radiating fin of the present invention can be effectively used not only in a display apparatus, such as a television, computer or plasma monitor, in an electrical product / electronic apparatus, such as a refrigerator or a machine, and in various mechanical devices, such as a motor or a radiator of a car, in a heat exchanger, in a nuclear reactor, and in a generator, but also in switches, in a heating element of a small integrated circuit, as an IC chip, or in electronic devices and the like.