Process and device for feeding, into an electronic tubes and mercury sending composite material

Abstract

The invention relates to a composite material, i.e. a combination of materials, for producing a device that combines the functions of a getter and a mercury emitter, as well as a device made of such a material, and a method for introducing mercury into an electron tube. The mercury emitter composite material of the invention comprises a mercury emitter intermetallic compound A, which comprises mercury and a second metal, which is titanium, zirconium or a mixture thereof. It further comprises an intermetallic compound forming a component B, which comprises copper, tin and one or more rare earth metals (REE).The intermetallic compound Ti3Hg constituting component A and component B are an alloy which are within the polygon defined by the following points within the triangular diagram indicating the components: a) Cu 63 wt% - Sn 36.5 wt% - MM 0.5 wt% b) Cu 63 wt% - Sn 10 wt% - MM 27 wt%c) Cu 30 wt% - Sn 10 wt% - MM 60 wt% d) Cu 3 wt% - Sn 37 wt% - MM 60 wt% e) Cu 3 wt% - Sn 96.5 wt% - MM 0.5 wt%. The device according to the invention made from such a material is inserted into the electron tube in the form of a tablet (10) during the process according to the invention, for example, and then after the tube is closed, the device is heated to a temperature between 600-900 °C for 10-60 s to remove mercury. ŕ.

Description

The invention relates to a composite material, i.e. a combination of materials, for making a device that combines the functions of a getter and a mercury emitter, as well as to a device made of such a material and a method for introducing mercury into an electron tube. Small amounts of mercury are used in electron tubes, such as mercury arc rectifiers, lasers, various displays, such as alphanumeric displays, but especially in fluorescent tubes. The precise dosage of mercury in these devices is particularly important for the quality achieved, but also for environmental reasons. In fact, the high toxicity of this element causes a serious problem due to environmental pollution when such mercury-containing devices have to be disposed of as waste at the end of their service life or after accidental breakage. These environmental problems require that the smallest possible amount of mercury suitable for the operation of the tubes be used. These considerations have recently become part of legislation, and international legislation is aimed at setting the maximum amount of mercury that can be used in the manufacture of such devices. For example, in the case of standard fluorescent tubes, the total amount of mercury used is recommended to be no more than 10 mg per tube. Mercury can be added to fluorescent tubes in liquid form. However, the use of liquid mercury causes problems in fluorescent tube manufacturing facilities, primarily due to storage and handling, as the vapor pressure is high even at room temperature. Secondly, there is a common drawback that adding mercury to tubes in liquid form is very difficult to achieve in precise and repeatable quantities, since the amount to be added is in the order of microliters, and therefore the amount added is usually larger than necessary. Taking these shortcomings into account has led to the development of various methods that deliver mercury in a different form than the liquid free form. Some prior art solutions have used capsules containing liquid mercury. Methods for this are described, for example, in US Patents 4,823,047 and 4,754,193, which describe capsules made of metal. US Patents 4,182,971 and 4,278,908 describe mercury containers made of glass. After the tube is sealed, the mercury is released by heat treatment, which causes the container to break. These methods have some general drawbacks. First, the preparation of the capsules and their installation inside the tube can be complicated, especially when they have to be inserted into small tubes.Secondly, it is worth mentioning that breaking the capsule, especially if it is made of glass, results in the production of debris, which compromises the quality of the tube to such an extent that, to eliminate this, US patent specification 4,335,326 proposes the use of a structure in which the capsule containing the mercury is located inside another capsule, the latter serving to collect the debris. A further drawback is that the release of mercury is often very violent, which can potentially damage the internal structure of the tube. Finally, such systems have the drawback of containing the mercury in liquid form, and therefore do not fully solve the problem of accurate and repeatable dosing of a few mg of mercury. US 4,808,136 and EP 568,317 patent applications describe the use of tablets or small balls made of porous material and impregnated with mercury, from which the mercury is released by heating after the lamp is closed. However, these known methods require complicated operations to load the mercury into the tablet and at the same time the amount of mercury released is difficult to reproduce. It is also known to use mercury amalgams for similar purposes, for example amalgams formed with indium, bismuth or zinc. However, these amalgams generally have the disadvantage of having a low melting point and a high vapor pressure of mercury at low temperatures. For example, the zinc amalgams described in the brochure of APL Engineered Materials Inc. have a vapor pressure of approximately 90% of the vapor pressure of liquid mercury at 43°C. Consequently, such amalgams have difficulty withstanding the heat treatments to which the lamps into which the amalgam is introduced are subjected during manufacture. These problems are overcome by the solution described in US patent specification 3,657,589, which relates to an intermetallic compound containing mercury, having the general formula TixZryHg, where the values ​​of x and y can vary between 0 and 13, the sum of x and y (x+y) can vary between 3 and 13, and the value of z is 1 or 2. These compounds have the property that the initial temperature of mercury release can be varied, but all are considered stable at temperatures of about 500 °C in both atmospheric and evacuated environments, and as a result they are well suited for use in the assembly operations of electron tubes, while the mercury release devices can reach temperatures of up to about 600 °C. After the tube is sealed, the mercury is released from the above compounds during an activation operation, which is generally carried out by heating the material to a temperature between 750 and 900 °C for a period of about 30 s. The heating can be achieved by laser irradiation or by induction heating of a metal holder of the mercury release compound.The Ti3Hg compound manufactured by the applicant of the present application and marketed under the name St 505 proves to be particularly advantageous, especially since the St 505 compound is sold in the form of powder pressed into an annular container or in the form of pills or tablets pressed from the powder under the name STAHGSORB, or in the form of a powder applied in a layer on a metal strip under the name GEMEDIS. The various advantages of these materials over previous solutions are as follows: HU 221 281 B1 - as mentioned above, the risk of mercury evaporation during the production of the tube, when temperatures of up to 350-400 °C can be avoided; - as described in the above-referenced US 3,657,589 patent, a getter material can be easily added to the mercury-releasing compound, the purpose of which is to chemically absorb various gases, such as CO, CO2, O2, H2, H2O, which would otherwise interfere with the operation of the tube, and this getter can be activated together with it by heat treatment to release the mercury; - the amount of mercury released is easily controlled and reproducible. Despite their good chemical-physical characteristics and their very simple application, these materials have the disadvantage that the mercury contained in them cannot be completely released during the activation treatment. In practice, during the manufacturing process of mercury-containing electron tubes, the tube sealing operation (for example, the sealing of fluorescent tubes by melting) is carried out by glass fusion or frit sealing, i.e. by welding two pre-formed glass parts with a paste made of low-melting glass. During these operations, the mercury-releasing device can heat up to a temperature of about 600 °C due to indirect heating. During this operation, the device is affected by gases and vapors escaping from the molten glass, as well as by the air present in most industrial operations.Under these conditions, the mercury-releasing material undergoes surface oxidation, which ultimately results in less than about 40% of the total mercury released during activation. For example, in the case of circular compact fluorescent lamps, the mercury-releasing material is heated to about 600 °C due to indirect heating during the closing and bending of the tube. In this case, the amount that can be released during the activation process is only about 20% of the total mercury content of the device. The mercury not released during the activation process is then released slowly and gradually over the lifetime of the tube. This characteristic, combined with the fact that the tube must obviously operate from the very beginning of its life, leads to the fact that at least twice as much mercury must be introduced into the device as would theoretically be necessary. To overcome these problems, EP-A 091297 proposes the addition of Ni or Cup to Ti3Hg or Zr3Hg compounds. According to this document, the addition of Ni and Cu to the mercury-releasing compound results in the melting of the material thus obtained, which facilitates the release of almost the entire amount of mercury within a few seconds. The melting takes place at the eutectic point of the Ni-Ti, Ni-Zr, Cu-Ti and Cu-Zr systems, which temperature is in the range from approximately 880 °C for the composition Cu 66%-Ti 34% to 1280 °C for the composition Ni 81%-Ti 19%, although the document incorrectly gives a temperature of 770 °C for the composition Ni 4%-Ti 96% (the compositions are given in atomic percentages). This document recognizes that the mercury-containing compound is altered during pipe processing operations and therefore requires protection.To this end, it proposes to enclose the powder in a container made of steel, copper or nickel sheet, which is burst by the pressure created by the mercury vapor inside the container during activation. This solution is not entirely satisfactory: in practice, as in the case of processes based on the use of capsules, the mercury bursts very violently and can damage parts of the tube, and the manufacture of the container is very complicated, since it requires welding of small metal parts. Furthermore, this document does not contain experimental data that would support the claims regarding the good mercury release capacity of the combinations. Finally, the means provided in this document, unlike the solution according to the referenced US 3,657,589 patent, do not allow the incorporation of a getter material, although its presence is necessary for the correct operation of the lamps. A similar solution is described in the patent description with registration number HU 215849, which describes the use of Cu-Si alloys for the release of mercury from Ti3Hg amalgam, while the patent description with registration number HU 215491 describes the use of alloys containing copper and a second element as an auxiliary compound, where the second element is tin, indium or silver. These solutions are also unsatisfactory in the sense that mercury release and getter effect are required simultaneously in lamps. Based on the above, the aim of the invention is to further develop the combination of materials with which mercury can be added to electron tubes, and which makes it possible to overcome one or more of the shortcomings of previous solutions. The object of the invention is primarily to provide an improved composite material for releasing mercury, which is capable of releasing more than 60% of the mercury during the activation step, even after partial oxidation, and thereby capable of reducing the total amount of mercury used. A further aim of the invention is to create a composite material whose residual part after activation for mercury release has a getter effect. A further aim of the invention is to develop a mercury-releasing device comprising the composite material according to the invention. A further object of the invention is to develop a method for feeding mercury into an electron tube using the device according to the invention, which requires this element. The aim of the invention has been achieved by creating a mercury-releasing composite material comprising: - component A formed by an intermetallic compound that releases mercury, - contains component B formed by an auxiliary alloy or intermetallic compound, where component A is a second metal containing mercury and titanium, zirconium or mixtures thereof, component B is composed of HU 221 281 Bl contains copper, tin and one or more rare earth metals. According to the invention, the intermetallic compound Ti3Hg constituting component A and component B are alloys which are within the polygon defined by the following points within the triangular diagram indicating the components: a) Cu 63 wt% - Sn 36.5 wt% - MM 0.5 wt0 / » b) Cu 63 wt% - Sn 10 wt% - MM 27 wt% c) Cu 30 wt% - Sn 10 wt% - MM 60 wt% d) Cu 3 wt% - Sn 37 wt% - MM 60 wt0 / » e) Cu 3 wt% - Sn 96.5 wt% - MM 0.5 wt0 / », where MM denotes a mixture of rare earth metals, which is referred to in the field as “misch metal”. Its composition also depends on the place of origin, and since they are chemically very similar to each other, there is no need to separate them. Its composition is given similarly by different sources. According to the “Metals Handbook” published by the American Society for Metals (US, Ohio, Metals Park), the composition of misch metal is 45-50 wt% Ce, 20-38 wt% La, 12-19 wt% Nd, 4-6 wt% Pr, 1-8 wt% other rare earth metals. The total rare earth metal content is usually at least 90 wt%. According to the Römps Chemie Lexikon (Kosmos Verlag, Stuttgart), it contains approximately 50-60% Ce, 25-30% La, 15-17% Nd, and 4-6% Pr. According to the Encyclopedia Britannica, its composition is similar, but it is stated to be 50% Ce, 25% La, 15% Nd, and 10% other rare earths and iron. The invention will be described in more detail below with reference to the exemplary embodiment shown in the accompanying drawing. In the drawing: Figure 1 is a perspective view of one embodiment of the mercury delivery device according to the invention, Figures 2 and 2a are a top view and a section of another embodiment of the mercury delivery device according to the invention, Figures 3, 3a and 3b are a top view and a section taken along the line III-III of a further possible embodiment of the mercury delivery device according to the invention, Figure 4 is a ternary diagram showing the alloys according to the invention. The composite material of the invention, hereinafter referred to as mercury dispenser, has as its component A an intermetallic compound of the formula TixZryHgz, as described in US Patent 3,657,589, the details of which are incorporated herein by reference. Of these materials, Zr3Hg and especially Ti3Hg are preferred. Component B of the composite material according to the invention promotes the release of mercury from component A and is hereinafter referred to as the auxiliary material. This component B is a metallic alloy or an intermetallic compound comprising copper, tin and one or more rare earth metals. A mixture of rare earth metals is considered advantageous over a single element, since these metals have similar chemical properties and, at the same time, their separation from each other is difficult and expensive, on the other hand, by using a mixture of rare earth metals, the same results can be achieved within the scope of the present invention as if the individual elements were used separately. A mixture of rare earth metals is also known in the art as a “misch metal” and this mixture is hereinafter referred to as MM both in the description and in our claims. The weight ratio of copper, tin and MM can vary over a wide range, but advantageous results are obtained with compositions as illustrated in the triangular diagram of Figure 4, which fall within the polygon defined by the following points: a) Cu 63 wt% - Sn 36.5 wt% - MM 0.5 wt0 / » b) Cu 63 wt% - Sn 10 wt% - MM 27 wt0 / » c) Cu 30 wt% - Sn 10 wt% - MM 60 wt0 / » d) Cu 3 wt% - Sn 37 wt% - MM 60 wt0 / » e) Cu 3 wt% - Sn 96.5 wt% - MM 0.5 wt0 / ). If the proportion of copper in the alloy is greater than 63% by weight, a high melting point is achieved and very high temperatures may be required for activation. Conversely, if the proportion of copper is less than about 3% by weight, the melting point of the alloy will be too low, with the risk of forming a low-viscosity liquid phase at temperatures ranging from about 600 to 800°C, temperatures which are often encountered in lamp manufacturing. If the MM concentration is greater than 60% by weight, the alloy becomes excessively reactive and can cause violent reactions both during lamp manufacturing and during the activation step. Finally, if the proportion of tin is less than 10% by weight, the melting point of the alloy becomes high. Particularly advantageous results have been achieved within the above limits with compositions whose proportions fall within the polygon defined by the following points within the triangular diagram of Figure 4: a) Cu 63 wt% - Sn 36.5 wt% - MM 0.5 wt0 / » b) Cu 63 wt% - Sn 10 wt% - MM 27 wt0 / » c) Cu 50 wt% - Sn 10 wt% - MM 40 wt% d) Cu 30 wt% - Sn 30 wt% - MM 40 wt% e) Cu 30 wt% - Sn 69.5 wt% - MM 0.5 wt0 / ». We have found an alloy composition in which the proportions are as follows to be particularly advantageous: Cu 40 wt% - Sn 30 wt% - MM 30 wt0 / », HU 221 281 Β1 which composition corresponds to point i) of the triangular diagram in Figure 4. Within the composite material according to the invention, the weight ratio of components A and B may vary within wide limits, but is generally in the range of 20:1 and 1:20, and preferably in the range of 10:1 and 1:5. Components A and B of the composite material of the invention may be used in different physical forms and are not necessarily the same for the two components, for example component B may be used as a coating on a metal substrate and component A may be applied by rolling onto component B. However, the best results are obtained when both components are present in the form of fine powders, in which the particle size is less than 250 pm, and preferably between 100-125 pm. The invention also relates to mercury-releasing devices made using a composite material comprising components A and B as described above. As already mentioned, the composite materials according to the invention have the advantage over previous systems that they do not require mechanical protection from the environment and therefore do not require the use of this composite material in a closed container. Consequently, the mercury-releasing devices according to the invention can be manufactured in a wide variety of geometric shapes and the components A and B of the composite material need not be applied without a support, i.e. not placed on a support, which support should otherwise be made of metal. For the correct operation of certain types of electron tubes requiring the use of mercury-releasing devices, the presence of a getter material is also necessary, which removes traces of certain gases, such as CO, CO2, O2 gases and water vapor. This requirement exists, for example, in the case of fluorescent tubes. An important advantage of the composite material according to the invention is that the material remaining after the evaporation of the mercury has a getter effect.The amount of gas that can be trapped by this residue and the rate of trapping is sufficient to create a vacuum of sufficient magnitude for many applications. In order to increase the gas trapping rate and capability of the device according to the invention, it is obviously possible to add an additional C component, which has a getter effect, the methods of which are described in US 3,657,589. It is obvious that in this case the amount of C getter component is smaller than in the case of previously used devices for the same purpose. Examples of getter materials include metals such as titanium, zirconium, tantalum, niobium, vanadium and mixtures or alloys thereof with other metals such as nickel, iron, aluminum and the like, and the alloy has a composition ratio of Zr 84% / Al 16%, which is marketed by the applicant of the present application under the name St 101, or intermetallic compounds such as Zr2Fe and Zr2Ni, which are marketed under the names St 198 and St 199.The getter material is activated by the same heat treatment that releases the mercury in the interior of the tube. The getter component C may be present in various physical forms, but is preferably used in the form of a finely divided powder, in which the particle size is between 250 pm, and preferably between 100-125 pm. The ratio of the components, based on the combined ratio of components A and B to the getter component C, is generally between 10:1 and 1:10, preferably between 5:1 and 1:2. Some possible embodiments of the devices according to the invention are described below with reference to the figures. A first possible embodiment of the mercury delivery device according to the invention can be simply formed as a tablet 10, which can be formed by compressing the material of components A and B (and optionally C) without support, which can be simply formed into a cylindrical or rectangular shape for ease of manufacture, the latter being illustrated in Figure 1. In a version supplemented with a carrier, the device according to the invention can be designed as a ring 20 according to Figure 2, which is shown in a top view in Figure 2 and in a section taken along the line II-II in Figure 2a. In this case, the device has a carrier 21, which is provided with a toroidal channel, and in which the material of the components A and B (and possibly C) is located. The carrier can generally be made of metal, preferably nickel-plated steel. Another variant is shown in Figure 3, which shows a version of the device according to the invention 30 in the form of a strip in top view. Figures 3a and 3b show a section taken along the line III—III of the strip 30. In this case, the device according to the invention has a strip-shaped carrier 31, which can preferably be made of nickel-plated steel, and on which the material of the components A and B (and optionally C) is applied by cold pressing (rolling). In this case, if the presence of the getter component C is also required, the components A, B and C can be mixed and rolled onto one or both sides of the strip 30 (Figure 3a), or the components A and B can be rolled onto one side of the strip 30 and the getter component C onto the other side of the strip 30 (see Figure 3b). The invention further provides a method for introducing mercury into electron tubes using the devices described above. In the process, the mercury-releasing composite material as described above is placed inside the tube in the form of the above-described tablets 10, rings 20 or strips 30, and then the mercury is released by heating it. The heating step is carried out by any suitable means, for example, by irradiation, high-frequency inductive heating or by passing an electric current through the substrate, in which case the substrate is formed with a high electrical resistance. During heating, the composite material is heated to a temperature at which the mercury is released, which temperature is between 600-900 ° C and the heating time is between 10-60 s. At temperatures below 600 °C, almost no mercury is released, while at temperatures above 900 °C there is a risk of harmful gases being produced by the release of gases from certain parts of the electron tube in the vicinity of the device, or by the formation of metal vapors. HU 221 281 B1 The invention will be described in the following by way of examples. These non-limiting examples are merely embodiments that illustrate to the skilled person how the invention can be put into practice and what are considered to be the best options for its implementation. Examples 1 and 9 show the preparation of mercury releasers and auxiliaries, and Examples 3-6 show tests that demonstrate mercury release following heat treatment simulating tube sealing. In the following examples, all metals used to prepare the alloys and compounds are at least 99.5% pure by weight. Unless otherwise indicated, the percentages given are by weight. Example 1 This example illustrates the synthesis of mercury-releasing Ti3Hg. 143.7 g of titanium is placed in a steel cradle and degassed in a furnace at 700 °C for 30 minutes at a pressure of 10-6 mbar. After cooling the titanium powder in an inert gas, 200.6 g of mercury is added to the cradle using a mercury tube. The cradle is then closed and heated to a temperature of approximately 750 °C for about three hours. After cooling, the product is ground until a powder that cannot be sieved through a standard sieve of 120 pm is obtained. The material obtained in this way has an essentially Ti3Hg composition, which can be confirmed by powder diffraction analysis. Example 2 This example relates to the preparation of a co-alloy which forms part of the combinations according to the invention. 40 g Cu, 30 g Sn and 30 g MM are placed in an aluminum crucible in powder form and placed in an induction vacuum furnace. The rare earth MM mixture contains approximately 50% cerium, 30% lanthanum, 15% neodymium and the remainder other rare earths. This mixture is heated to a temperature of approximately 900 °C and held at this temperature for approximately five minutes to homogenize it, and then finally cast into steel to form a casting. Each casting is ground in a knife mill and sieved in the same way as in Example 1. The composition of the alloy thus obtained is Cu 40 wt% - Sn 30 wt% - MM 30 wt%, which corresponds to the composition according to point i in Figure 4. Example 3 This example relates to the preparation of a co-alloy which forms part of the combinations according to the invention. The procedure of Example 2 is repeated using 60 g of Cu, 30 g of Sn and 10 g of MM powder metal. The composition of the alloy thus obtained is as follows: Cu 60 wt% - Sn 30 wt% - MM 10 wt% and this corresponds to point 1 of the diagram in Figure 4. Examples 4-9 Examples 4-9 illustrate tests of the mercury release rate after heat treatment in air. This heat treatment mimics the conditions of fritting, which is used to seal the tube (hereinafter referred to as sealing). Examples 4-7 are comparative examples showing mercury release after fritting using only a mercury releasing component (Example 4) and then the same component mixed with only copper, tin and the aforementioned St 101 getter alloy (Examples 5-7). A similar comparative test using a mixture of Ti3Hg and MM powder was not feasible due to the excessive reactivity of the mixture. To simulate sealing, 100 mg of each powder mixture was applied either to a ring-shaped holder as shown in Figure 2 or to a tape similar to that shown in Figure 3 and each was subjected to the following heat treatment in air: - heating from room temperature to 450 °C in approximately 5 s; - constant temperature holding at 450 °C for 60 s; - cooling from 450 °C to 350 °C in approximately 2 s; - maintaining a constant temperature of 350 °C for 30 s; - spontaneous cooling to room temperature in about 2 minutes. The mercury release of the heat-treated samples was then investigated by heating the samples in a vacuum chamber to 850 °C for 30 s. The amount of mercury remaining in the mercury-releasing device was then measured using the Volhart complexometric titration method. The results of the measurements are included in Table 1, which contains the mercury-releasing component A, the assisting component B (in the case of examples 8 and 9, the symbols i or 1 indicate the composition of the Cu-Sn-MM alloy indicated in the diagram of Figure 4), and the ratio between the masses of component A and component B, as well as the mercury release, which refers to the released mercury to the total amount of mercury in the device. Comparative studies are marked with an asterisk. Table 1 Pclda- serial number ABA / B Hg release wt% 4* Ti3Hg - - 35.2 5* Ti3Hg Cu 7 / 3 34.0 6* Ti3Hg Sn 5 / 1 25.0 7* Ti3Hg St 101 1 / 1 22.4 8 Ti3Hg Cu-Sn-MM (i) 2 / 1 80.0 9 Ti3Hg Cu-Sn-MM (1) 2 / 1 87.0 Examples 10-14 Examples 10-14 illustrate the performance of the composite material of the invention as a getter material after mercury release, compared to some comparative compositions. HU 221 281 B1 To carry out the tests, we simulated the fritting conditions to which the materials are exposed when bending and sealing a circular compact fluorescent lamp, which, in accordance with the above description, represent higher stress than in the case of straight fluorescent lamps. The materials with the compositions given in the examples were subjected to the following heat treatment in air: - heating from room temperature to 600 °C in approximately 10 s; - heat holding at 600 °C for 15 s; - spontaneous cooling to room temperature in about 2 minutes. The mercury release test (activation) was performed on the samples after simulating the frit sealing. The fritted samples were placed in a 1 l vacuum chamber and heated to 850 °C under vacuum for 10 s and held at this temperature for 20 s. The getter capacity of the residual material was measured after activation. This measurement was performed by introducing enough hydrogen into the vacuum chamber to achieve a pressure of 0.1 mbar at 30 °C and measuring the time it took for the pressure to drop to 0.01 mbar. The pressure was measured using a capacitive pressure gauge. The results of the tests are summarized in Table 2, which shows the composition of the sample and the rate of hydrogen absorption at 30 °C. The column “Sample composition” in the table shows the mass ratio of the composite materials in percent. Comparative combinations are marked with *. Table 2 Sample number Sample composition H2 absorption rate [cm3 / s] 10* Ti3Hg not measurable 11* Ti3Hg: 50 wt% 7.2 St 10: 50 wt% 12 Ti3Hg: 60 wt% _ 6.9 Cu-Sn-MM (i) 40 wt% 13 Ti3Hg: 60 wt% 3.5 Cu-Sn-MM (1) 40 wt% 14 Ti3Hg: 30 wt% 15.3 Cu-Sn-MM (i) 20 wt% St 101 50 wt% It can be seen from the data in Table 1 that the alloy according to the invention containing the auxiliary material can release more than 80% mercury during the activation step even after frit sealing at a temperature of 450 °C in air, thereby enabling the reduction of the total amount of mercury introduced into the electron tubes. In addition, the data in Table 2 illustrate that the material remaining after the release of mercury has a getter effect: in fact, after the release of mercury, the composite material contains only Ti3Hg, then no getter effect is observed, the sample according to Example 13 has a significant hydrogen absorption rate without the addition of a getter. In addition, the hydrogen absorption capacity of the sample according to Example 12 is comparable to that of the sample according to Example 11, which is actually a combination of a mercury release material with a getter, which is widely used in lamp production. If a getter material is added to the composition of Example 12, the mercury binding rate increases approximately twice as much as in Example 11, while the proportion of getter material is the same. The combination according to the invention, i.e. its compositional properties, allow for the addition of very small additional amounts of getter material, or even the omission, while maintaining the operability of the device. The composite material according to the invention, when supplemented with an auxiliary material, offers another important advantage, which is the possibility of carrying out the activation operation in a shorter time or at a lower temperature compared to the materials used previously. In fact, to achieve an activation time that is also acceptable in practice, Ti3Hg alone requires activation at a temperature of about 900 °C, whereas the composition according to the invention allows the operation time and the size of the production line for the lamps to be reduced, and in both cases double the power is achieved, since on the one hand less contamination is produced inside the tube due to the outgassing of the materials contained therein, and on the other hand by reducing the energy required for activation.

Claims

PATENT CLAIMS 1. A mercury-releasing composite material comprising - component A formed by a mercury-releasing intermetallic compound, - component B formed by an auxiliary alloy or intermetallic compound, wherein component A comprises mercury and a second metal comprising titanium, zirconium or mixtures thereof, component B comprises copper, tin and one or more rare earth metals, characterised in that the intermetallic compound Ti3Hg forming component A and component B are alloys which are within the polygon defined by the following points within the triangular diagram indicating the components: a) Cu 63 wt% - Sn 36.5 wt% - MM 0.5 wt% b) Cu 63 wt% - Sn 10 wt% - MM 27 wt% c) Cu 30 wt% - Sn 10 wt% - MM 60 wt% d) Cu 3 wt% - Sn 37 wt% - MM 60 wt% e) Cu 3 wt% - Sn 96.5 wt% - MM 0.5 wt%. HU 221 281 Bl 2. The mercury-releasing composite material according to claim 1, characterized in that the auxiliary component B is an alloy that is within the polygon defined by the following points within the triangular diagram indicating the components: a) Cu 63 wt% - Sn 36.5 wt% - MM 0.5 wt% b) Cu 63 wt% - Sn 10 wt% - MM 27 wt% c) Cu 50 wt% - Sn 10 wt% - MM 40 wt% d) Cu 30 wt% - Sn 30 wt% - MM 40 wt% e) Cu 30 wt% - Sn 69.5 wt% - MM 0.5 wt%.

3. The mercury-releasing composite material according to claim 2, characterized in that the auxiliary component B is an alloy containing 40 wt% Cu - 30 wt% Sn - 30 wt% MM.

4. The mercury-releasing composite material according to claim 2, characterized in that the auxiliary component B is an alloy containing 60 wt% Cu - 30 wt% Sn - 10 wt% MM, 5. The mercury-releasing composite material according to claim 1, characterized in that the weight ratio of components A and B is in the range of 20:1 to 1:

20.

6. The mercury-releasing composite material according to claim 5, characterized in that the weight ratio of components A and B is in the range of 10:1 to 1:

5.

7. A mercury-releasing device comprising a mercury-releasing composite material according to claim 1.

8. A mercury delivery device according to claim 7, characterized in that components A and B are in powder form.

9. A mercury delivery device according to claim 8, characterized in that it comprises a tablet (10) compressed from a powder containing components A and B.

10. A mercury delivery device according to claim 8, characterized in that components A and B are placed in a metal support (21) provided with a toroidal channel.

11. A mercury delivery device according to claim 8, characterized in that the composition containing components A and B is rolled onto the surface of a strip-shaped support (31).

12. The mercury releasing device according to claim 7, characterized in that it also contains a getter C component.

13. A mercury delivery device according to claim 12, characterized in that the getter component C comprises titanium, zirconium, tantalum, niobium, vanadium or mixtures thereof or alloys thereof with nickel, iron or aluminum.

14. The mercury-releasing device according to claim 13, characterized in that the getter component C is an alloy containing 84 wt% Zr and 16 wt% Al.

15. The mercury release device of claim 13, wherein the getter component C is Zr2Fe.

16. The mercury release device of claim 13, wherein the getter component C is Zr2Ni.

17. The mercury release device of claim 12, wherein the mercury release component A, the helper component B, and the getter component C are in powder form.

18. A mercury delivery device according to claim 17, characterized in that the powdered components A, B and C are compressed into a tablet (10).

19. A mercury delivery device according to claim 17, characterized in that components A, B and C are placed in a metal carrier (21) provided with a toroidal channel.

20. A mercury delivery device according to claim 17, characterized in that components A and B are rolled onto one surface of a strip-shaped support (30), and getter component C is rolled onto the opposite side of the same strip (30).

21. A mercury delivery device according to claim 17, characterized in that components A, B and C are rolled onto a single surface of a support in the form of a tape (30).

22. The mercury delivery device of claim 13, wherein the weight ratio between the combined weight of components A and B and the weight of getter component C is in the range of 10:1 to 1:

10.

23. A mercury delivery device according to claim 22, characterized in that the weight ratio between the combined weight of components A and B and the weight of getter component C is in the range of 5:1 and 1:

2.

24. The mercury release device of claim 17, wherein the mercury release material, the auxiliary material and the getter are in powder form with a particle size of less than 250 µm.

25. A mercury release device according to claim 24, characterized in that the mercury release material, the auxiliary material and the getter are in powder form, the particle size of which is in the range of 10-125 µm.

26. A method for introducing mercury into the interior of electron tubes, characterized in that a device according to any one of claims 9-25 is placed in the open tube, and after closing the tube, the device is heated to a temperature between 600-900 °C for 10-60 s to remove mercury.

27. The method of claim 26, characterized in that the device is placed in a straight fluorescent tube.

28. The method of claim 26, characterized in that the device is placed in a circular compact fluorescent lamp.