RU108447U1 - AMORPHIC BAND SOLDER BASED ON ZIRCONIUM - Google Patents

Abstract

 1. Amorphous zirconium-based tape solder for brazing products from niobium and its alloys, made in the form of a flexible tape of an amorphous structure from an alloy based on zirconium containing niobium, characterized in that the width of the tape is selected in accordance with the width of the grooves on the joined products in the range 1.0-40 mm, the tape thickness is selected in the range of 25-60 microns, while the solder additionally contains nickel in the following ratio of components, wt.%:! Niobium 17-21 Nickel 7.5-15 Zircon The rest! 2. The solder according to claim 1, characterized in that it is made in the form of a flexible tape with a width of 1.1-3 mm, a thickness of 25-35 microns. ! 3. The solder according to claim 2, characterized in that the width and thickness of the flexible tape is selected with the possibility of placing it in the grooves on the connected products in the form of coaxially connected cylindrical parts of the collector assembly of the nuclear power channel of a nuclear reactor with the possibility of soldering without melting the solder of the technological channels. !four. The solder according to claim 1, characterized in that it is made in the form of a roll of a flexible tape made by ultrafast quenching from a liquid metal melt at a rate of 104-106 ° C / s to obtain an amorphous alloy structure. ! 5. The solder according to claim 1, characterized in that the zirconium-based alloy additionally contains iron in the following ratio of components, wt.%:! Niobium 17-21 Nickel 7.5-15 Iron 6-9 Zircon The rest! 6. The solder according to claim 1, characterized in that the zirconium-based alloy additionally contains iron and beryllium in the following ratio of components, wt.%:! Niobium 17-21 Nickel 7.5-15 Iron 6-9 Beryllium 0.1-2.0 Zircon The rest! 7. The solder according to claim 1, characterized in that in

Description

The utility model relates to soldering, to developing the optimal form of release and composition of solder used for soldering products from niobium and its alloys.

The utility model may find application, for example, in the manufacture by soldering of energy-intensive units for the needs of nuclear energy.

Of the methods for producing permanent joints, welding and soldering were widely developed. However, in some cases, welding is not technologically feasible. In particular, in the manufacture of the collector assembly of an electric generating channel (EGC) of a nuclear reactor, the only feasible connection technology is high-temperature brazing, which is carried out at temperatures significantly lower than welding. These bonding methods involve heating the materials to be bonded. However, irreversible structural transformations can occur as a result of welding, which will lead to degradation of the properties of materials and compounds in general. The use of a particular joining method depends on a number of factors, including structural features of materials, dimensions and shape of the product, conditions for further operation, economic costs, technological feasibility of the joining process, optimality, etc. In many cases, welding and brazing are mutually complementary. However, when creating unique products, the most favorable methods are soldering due to the characteristics of this process.

Soldering, as a method of obtaining permanent joints, creates the opportunity to obtain durable and high-quality joints in hidden and inaccessible places of structures; the possibility of manufacturing thin-walled products with a high density of soldered joints; the ability to connect dissimilar materials and parts with a large difference in thicknesses.

Soldering has a number of significant advantages over welding due to:

- the ability to connect parts without melting the base metal, without violating the geometric dimensions of the product, in any combination of metals;

- the formation of the connection almost simultaneously on all contact surfaces, and not sequentially, as in welding;

- obtaining a high-quality seam when connecting parts in various spatial positions;

- the possibility of combining soldering and heat treatment using the same heating equipment.

These advantages made it possible to successfully apply soldering in the technology of creating nuclear energy propulsion systems (NPPs) based on thermionic converter reactors (TRP). The key component of the TRP is the power generating channel (EGC), the design of which is disclosed in the prior art, for example, in patent RU 2102813.

In the process of modernizing the design of the collector package of EHCs, it turned out that the previously used solder 60% Pd-40% Ni (T _pl = 1237 ° C) for soldering coaxially connected collector elements from an alloy based on niobium NbTs-1 (Nb-1% Zr) turned out to be unacceptable due to the high melting point, since at a temperature above 1175 ° C, a eutectic reaction occurs between Ni and Nb: Ж↔Ni ₃ Nb + Ni ₆ Nb ₇ with a content of 40.5 at.% Nb. As a result of the eutectic reaction, the materials of the collector pack (NBC-1) are melted, which leads to a violation of the geometry of the structure and degradation of the operational characteristics of the EGC as a whole.

Therefore, the task arose to develop a solder for soldering materials of a collector package made of the NbTs-1 alloy in the form of a tape with a melting point below 1175 ° C, that is, below the eutectic formation temperature as a result of interaction with the niobium elements that make up the solder.

Hard operating modes of the collector EGC package include powerful heat and particle (neutron) fluxes from the side of nuclear fuel. This imposes severe restrictions on the choice of solders planned for use. The solder must withstand the operating conditions of the EGC and meet the following requirements:

- be compatible with solderable materials, namely with niobium and its alloys;

- brittle intermetallic compounds should not form in soldered seams;

- have a melting point and soldering temperature below the temperature of the eutectic reaction of niobium to prevent the formation of a eutectic reaction of components of the solder with the base metal, to preserve the geometric dimensions of the product and the mechanical properties of the brazed materials;

- provide high thermal conductivity and high heat resistance of soldered joints;

- do not contain copper and metals with high vapor pressure, due to the possibility of their evaporation during heating of soldered joints and adsorption of metal vapors on insulators;

- solder components should not have a high neutron capture cross section and (or) form long-lived radioactive nuclides with strong gamma radiation;

- to be made in the form of flexible tapes.

The prior art solder for soldering molybdenum and niobium containing zirconium as the main component in the following ratio of components (in wt.%):

Vanadium 20-40;

Titanium 10-20;

Tantalum 10-20;

Silicon 0.5-2;

Hafnium 5-10;

Aluminum 0.5-2;

Zirconium - the rest.

This solder is available in the form of a powder composition and has a soldering temperature of 1600-1650 ° C. (USSR Author's Certificate No. 633694, published November 25, 1978). This solder has a too high melting point and, in addition, the powder form of the release of this solder is very inconvenient for soldering products of complex configuration, in particular for soldering tubular products, in addition, the powder solder does not exclude the presence of non-solders, pores, and fusion of small holes.

Zirconium-based solders are known, which can be made both in the form of powder alloys and in the form of a tape. (See patents RU 2009240 dated 03.15.1994 and RU 2009241 dated 15.03.1994). However, the tape of these alloys is fragile, which does not allow winding and securing it on cylindrical parts. In addition, these solders are preferably used for joining products from zirconium and are not intended for soldering products from niobium and its alloys.

Recently, amorphous and microcrystalline tape solders with a thickness of 20-80 μm obtained by ultrafast quenching from liquid metal melt at a rate of 10 ⁴ -10 ⁶ ° C / s have been widely used. Due to their unique properties, such solders are used in the brazing of copper and copper alloys, nickel and its alloys, corrosion-resistant steels, titanium and its alloys, zirconium, beryllium, refractory metals, in particular, niobium, hard alloys, oxide ceramics, graphite and etc.

However, to date, the physicochemical and technological features of quick-hardened solders (BPZ) have not been sufficiently studied. There is the possibility of optimizing the composition and development of new tape BZP, improving the properties of solders and technological modes of soldering modern materials.

Closest to the claimed utility model is an amorphous strip solder based on zirconium, known from the description of patent RU2252848, published on 05.27.2005. The specified solder is intended for soldering elements of fuel assemblies of nuclear reactors, mainly in the manufacture of spacer grids formed from tube blanks. The alloy contains components in the following ratio, wt.%:

Iron 4.0-6.0,

Beryllium more than 3.0-4.0,

Niobium 0.9-1.1,

Copper 4.0-8.0,

Tin 1.0-3.0,

Chrome 0.2-1.0,

Bismuth + arsenic 0.0001-0.0018,

Sulfur 0.0001-0.0015,

Zirconium and the inevitable impurities are the rest. Additionally, the alloy may contain germanium in an amount of 0.25-2.5 wt.%.

This solder in its composition contains copper from 4 to 8 percent, which is unacceptable for soldering the structural elements of the power generating channels (EHC) of the reactor of a thermionic nuclear power plant.

EGC, in which the use of solder is planned, is a device containing many compounds of the type: conductor-dielectric, for example, metal (conductor) - ceramic (dielectric). The experience of the developers of EGCs suggests that when copper is used as a component of solder, it diffuses to the dielectric region, and it gradually loses its dielectric properties and becomes a conductor. Therefore, the EGC developers ruled out any possibility of using copper as an alloying additive in the solders used in the manufacture of this device.

The utility model solves the problem of obtaining solder based on zirconium in the form of a flexible strip of amorphous structure suitable for soldering coaxially connected products from niobium alloys without melting with solder of the technological channels of the product, since by adjusting the technological parameters of the ultrafast hardening process, it is possible to strictly fix the thickness and width of the tape, thereby ensure the optimal amount of solder in the gap during soldering, which makes it possible to simplify the assembly, improve the accuracy of manufacturing the product and allows you to ku thin-walled materials without the melting of small holes.

The technical result is to simplify the assembly, increase its accuracy, as well as increase the operational characteristics of the soldered product by improving heat transfer conditions.

Also the technical result is to improve the quality of the solder joint, reducing the number of defects.

To solve this problem, an amorphous zirconium-based tape solder for brazing products from niobium and its alloys, made in the form of a flexible tape of an amorphous structure from a zirconium-based alloy containing niobium, is claimed. The width of the tape is selected in accordance with the width of the grooves on the joined products in the range of 1.0-40 mm, the thickness of the tape is selected in the range of 25-60 microns, while the solder additionally contains nickel in the following ratio of components (in wt.%): Niobium 17- 21; nickel 7.5-15; zirconium - the rest. Preferably, a narrow solder strip is made with a width of 1.1-3 mm and a thickness of 25-35 microns. The specified width and thickness of the product are selected to enable flexible solder tape to be placed in the grooves on the coaxially connected cylindrical parts of the collector assembly of the nuclear power channel of the nuclear reactor with the possibility of soldering without melting the solder of the technological channels.

For shipment to consumers, the flexible solder tape is rolled up (of unlimited length), made by ultrafast quenching from liquid metal melt at a speed of 10 ⁴ -10 ⁶ deg./s to obtain an amorphous alloy structure. (The length of the tape in a roll is determined by the needs of the customer and the performance of the equipment).

The amorphous structure of the tape solder ensures its uniform phase state, obtaining a narrow interval between the melting and solidification temperatures with its high adhesive and capillary activity.

When the thickness of the solder tape is more than 60 μm, the amorphous structure of the solder does not form due to a decrease in the cooling rate due to the bulkiness of the tape. With a tape thickness of less than 25 μm, structural defects occur due to discontinuity, as well as uneven thickness.

Since the tape solder of this composition is intended to be inserted into the grooves of the parts to be connected, the minimum width of the tape should be less than the width of the grooves. The width of the grooves on the cylindrical parts to be connected to the collector assembly of the nuclear power channel of the nuclear reactor is 1.4 mm, and the width of the disk on which the tape is made is 50 mm, that is, it is convenient to obtain a tape with a width of 30-40 mm on existing equipment. Attempts to cut a wide tape into narrow strips lead to a change in its structure and the loss of expensive solder material. Therefore, the lower boundary of the interval (1.0-3.0 mm) of the width of the cast amorphous zirconium-based solder strip obtained as part of the development of this utility model is an improvement in the technology of soldered assembly of nuclear reactors.

On the other hand, when assembling products of a different configuration, for example, when soldering flat parts, it is more technologically advanced to use a wide solder tape (40 mm), indicated as the upper limit of the width range of the claimed tape solder.

To improve the quality of the brazed joint, the declared solder in the composition of the alloy based on zirconium may additionally contain iron in the following ratio of components (in wt.%): Niobium 17-21; nickel 7.5-15; iron 6-9; zirconium - the rest.

In another embodiment, the claimed solder in the composition of the alloy based on zirconium may additionally contain beryllium in the following ratio of components (in wt.%): Niobium 17-21; nickel 7.5-15; iron 6-9; beryllium 0.1-2.0; zirconium - the rest.

In addition, to ensure the high quality of the brazed joint obtained using the claimed solder, the composition of the zirconium-based alloy additionally limits the content of inevitable (harmful) impurities of bismuth, arsenic and sulfur in the following ratio of components (in wt.%):

Niobium 17-21;

Nickel 7.5-15;

Iron 6-9

Beryllium 0.1-2.0

The total content of bismuth and arsenic is 0.0001-0.0018

Sulfur 0.0001-0.0015

Zirconium - the rest.

The optimal choice of solder components is confirmed by an analysis of the phase diagram of the state of the Zr-Nb system, which at high temperatures is characterized by the mutual solubility of Nb and Zr, both in liquid and in solid state. At a concentration of 21.7 at.% Nb, the liquidus temperature decreases to 1740 ° C. With a decrease in temperature in the concentration range of 19-91 at.% Nb, the solid solution (βZr, Nb) separates into two isomorphic phases (βZr) and (Nb). The critical point of the delamination curve corresponds to a temperature of 988 ° C at a concentration of 60 at.% Nb. At a temperature of 610 ° C and a concentration of 17.5 at.% Nb, the monotectoid reaction (βZr, Nb) = (αZr) + (Nb) occurs. The solubility of Nb in αZr is: 6.5 at.% At 610 ° C; 1.1 at.% At 600 ° C; 0.68 at.% At 620 ° C. The solubility of αZr in (Nb) in the monotectoid reaction is 91 at.%. At high cooling rates, the phase (βZr, Nb) can be partially or fully preserved at 20 ° C, and metastable phases can be formed differently.

It can be seen from the Zr-Nb state diagram that the ratio of Zr- (10-30)% Nb components is most suitable as the basis for solder, since at these concentrations the largest decrease in the melting temperature is achieved.

To further reduce the temperature, Ni, Fe, Co, Be are most suitable as depressants, since these elements with Zr form eutectics melting at temperatures of 960 ° С (at.% Ni), 928 ° С (at.% Fe), 940 ° C (at.% Co) and 950 ° C (at.% Be), respectively. The use of Co is excluded due to the formation of radioactive nuclides with strong gamma radiation under neutron irradiation.

The utility model is illustrated by figures 1-5 and examples.

Figure 1 shows the installation diagram for obtaining an amorphous tape solder.

Figure 2 shows the appearance of the product: "amorphous tape solder based on zirconium."

Figure 3 shows the assembly diagram of the product from two coaxial brazing cylinders.

Figure 4 shows a characteristic curve of the soldering regime of samples of niobium alloy.

5 shows photographs of the structure of a soldered joint.

The claimed solder was used to solder the structural elements of the electricity generating channels (EHC) of the reactor of a thermionic nuclear power plant (NPP). The power-generating channel is structurally a cylindrical assembly of serially connected similar type of power-generating elements (EGE), enclosed in a common housing. Each power generating element consists of a thermionic converter, a fuel core and a switching jumper connecting it to neighboring EGEs. The thermionic converter consists of two thin coaxially arranged cylindrical electrodes separated by an interelectrode gap, which is filled with cesium vapor in the working state. EGC has high energy efficiency. The temperature of the emitter 3 of the EHC is ~ 1800 K in the nominal mode, and the specific electric power is ~ 2 W / cm ² , increasing to ~ 2100 K in the forced mode, while the specific electric power increases to ~ 5 W / cm ² (the degree of forcing - 2.5). All soldered joints must reliably maintain strength under specified operating conditions.

For the manufacture of a collector package, EGCs obtained an amorphous strip solder using ultrafast quenching technology from a melt to a rotating disk-cooler at a speed of 10 ⁴ ... 10 ⁶ ° C / s. The high cooling rate allows solders to be obtained at room temperature with the structure of a supercooled liquid in which the elements are evenly distributed throughout the volume, which gives advantages to amorphous solder over crystalline solder in the process of melting and interaction of the melt with soldered materials. The application of this technology makes it possible to obtain convenient to use flexible tapes from hard-deformed ingots that have a whole range of advantages over their crystalline counterparts obtained by traditional methods: they have a uniform phase state, are characterized by narrow melting and solidification intervals, and high adhesive and capillary activity. All this allows to improve the quality of soldering, to reduce the number of defects in soldered joints, to reduce the degree of formation of intermetallic compounds in the joints.

The ingots for the manufacture of tape solder were smelted in an MIFI-9 arc furnace in an argon medium. The MIFI-9 furnace with a tungsten non-consumable electrode is designed for smelting refractory metals and alloys.

As the charge materials used:

- zirconium metal iodide, TU 95-46-76;

- niobium electron beam remelting;

- Nickel cathode H0 or H1 (GOST 849-70);

- hot-pressed beryllium with a purity of 99.98%;

- armco iron;

To simplify the process of uniform distribution of alloying components in the ingot, pre-melted more fusible ligatures were used as charge materials. So beryllium and niobium were introduced as ligatures: Zr-5 wt.% Be, Zr-50 wt.% Nb. The mixture was loaded onto a water-cooled under and subjected to fusion. After each remelting, the ingot was turned over and the transfer procedure was repeated. The number of such remelts was in the range of 6-20, depending on the chemical composition of the alloy. For one technological cycle received two homogeneous ingots of 100 grams.

The chemical composition of the ingots was determined by X-ray microanalysis using an INCA 350 x-act energy dispersive spectrometer (Oxford Instruments).

Obtaining alloys-solders in the form of flexible tapes was carried out by the method of ultrafast quenching on a rotating disk-cooler on the modernized Crystal-702 installation, the scheme of which is shown in Fig. 1. This setup allows to obtain alloys-solders with a melting point up to 1600 ° C (depending on the crucible material) in an amorphous or nanocrystalline state by melt quenching with cooling rates of ~ 10 ⁴ -10 ⁶ K / s to obtain flexible tapes. The maximum amount of tape obtained per one technological cycle was 0.3–0.5 kg.

In accordance with figure 1, the installation diagram Crystal-702 contains a control panel 1; high frequency generator 2; inert gas cylinder 3; gas inlet system 4; control device 5; potentiometer 6 (KSP-4); the housing of the vacuum chamber 7; quartz crucible 8; thermocouple 9; high frequency inductor 10; melt 11; quenching copper disk 12; tape stripper 13; vacuum system 14 with a VT-2A thermocouple vacuum gauge; unit 15 vacuum AVZ-20D; tape receiver 16; tape 17 received solder.

Preliminarily melted in a MIFI-9 arc furnace, ingots of solder alloys were placed in a quartz crucible 8 having a nozzle. The crucible 8 with ingots was placed inside the high-frequency inductor 10. By high-frequency currents using the high-frequency generator 2 and inductor 10, the ingots were heated to the required temperature, depending on the chemical composition of the alloy. The solder melt under the influence of an inert gas (helium) ejection pressure supplied through a gas inlet system 4 was supplied through a nozzle of a crucible 8 to a rapidly rotating quenching copper disk 12 with a width of 50 mm and a diameter of 300 mm. In this case, the surface area of the melt in contact with the disk 12 increased many times and, accordingly, a high rate of heat removal from the melt to the disk 12 was achieved. Almost instantaneous solidification of the melt occurred. The solidified melt of the solder is separated from the disk 12 under the influence of thermal stresses and centrifugal force or cut off with the help of a tape stripper 13. Then, the (rapidly quenched) amorphous tape 17 of the solder fell into the tape receiver 16. The process of manufacturing rapidly quenched amorphous tapes was carried out in a controlled helium gas medium created using vacuum system 14 and inert gas inlet system 4.

In the process of manufacturing rapidly quenched tapes, a number of technological parameters were simultaneously taken into account and regulated, such as the heating rate, the temperature of the melt filling process, the excess gas pressure in the crucible, the speed of the quenching disk, the nozzle-disk distance, the gas medium and its pressure, and nozzle width , the mass of the molten ingot and others. The width of the solder ribbon was controlled by the length of the crucible nozzle. The thickness of the solder ribbon was changed by a number of parameters: excess gas pressure during injection of the melt, speed of rotation of the quenching disk, melt viscosity, casting temperature, nozzle-disk distance, etc.

The appearance of the finished product corresponding to the claimed utility model is shown in figure 2, which shows two rolls of amorphous flexible zirconium-based solder flax.

Tested samples of the obtained tape solder. The conditions and test results are presented in examples 1-3.

Example 1

Samples of amorphous strip solder based on zirconium were prepared containing (in wt.%): 19% niobium and 15% nickel. The solidus temperature for samples of this composition is 1000 ° C, the liquidus temperature is 1080 ° C, and the solder melting range is 80 ° C.

The solder is made in the form of a roll of flexible tape, as shown in figure 2, and is used to solder the prototypes of the collector package of the EHC from the NbTs-1 alloy. The NbTs-1 alloy contains 1 wt.% Zirconium, the rest is niobium and inevitable impurities.

Assembly layout of the collector node EGC is presented in figure 3. View a) shows a cross-section of an external cylindrical element of a node made of the NBTs-1 alloy. View b) shows a section of the inner cylindrical element of a given unit made of the NBTs-1 alloy. The inner cylindrical element of the collector assembly of the EGC contains transverse grooves 18 for accommodating the tape solder and longitudinal grooves 19, which are technological channels designed to remove gases during the operation of the EGC. For the normal functioning of the collector assembly of the EGC, the solder should in no case melt the technological channels. View c) shows the prototype EGC assembly in the assembly for the soldering process.

In the manufacture of prototype EGC assemblies, the solder 20 was wound into grooves 18 specially made for it. The number of turns when laying the solder tape in the grooves 18 depended on the depth of the groove and the gap between the cylinders. In this example, the transverse grooves 18 are 1.4 mm wide and 0.15 mm deep. The surface of the samples was subjected to grinding and polishing. On average, the thickness of the wound solder was about 150 microns.

Figure 4 shows a characteristic curve of heating samples for soldering. Distinctive features consisted only in temperatures and holding times, which varied from 900 to 1200 ° C and from 2 to 30 minutes, respectively.

The samples were heated by soldering on average at a speed of 15 degrees. C / s For uniform heating of samples and prototypes over 200 degrees, isothermal aging was carried out to the solder solidus temperature, then heating was continued to the soldering temperature, at which aging was also carried out.

Photographs confirming the quality structure of the obtained soldered connection are shown in Fig.6.

Figure 5 a) and b) shows the results of metallographic studies and X-ray microanalysis of the soldered joint NBc1-NBc1 with Zr-19% Nb-15% Ni solder at a temperature of 1200 ° C, with a holding time of 5 min. In the photo (a), the technological channel is clearly visible, preserved after soldering without melting and geometry disruption, which ensures the release of gaseous fission products during the operation of the collector pack. It should also be noted that during the formation of the brazed joint, areas with a chemical composition similar to the base metal are formed (see Fig. 5 b)), which is associated with the diffusion of the components of the solder Zr and Ni in the brazed material and crystallization of the melt with a chemical composition close to the composition of the base metal.

To study the flow of solder into the gap, the welded cylinders were cut lengthwise and the corresponding studies were carried out.

A comparative soldering of the prototypes of the EGC collector package from the NbTs-1 alloy of Zr-19Nb-15Ni alloy and a solder known in the art containing 60 wt.% Pd and 40 wt.% Ni was performed, as a result of which zirconium-based solder demonstrated the possibility of obtaining products without fusion of technological channels, which was not achieved when using solder based on palladium.

Example 2

Samples of amorphous zirconium-based strip solder were prepared, containing: 19 mass% Nb, 15 mass% Ni, 1 mass% Be and Zr - the rest.

The solidus temperature for samples of this composition is 846 ° C, the liquidus temperature is 924 ° C, the melting interval of the solder is 78 ° C.

The solder is made in the form of a roll of flexible tape, as shown in figure 2, and is used to solder the prototypes of the collector package of the EHC from the NbTs-1 alloy.

Obtained, as in example 1, the solder joint has a high strength sufficient for reliable operation under operating conditions of the collector package of the EGC, including the effects of thermal and neutron fluxes from the side of nuclear fuel. The resulting solder is perfectly compatible with niobium and its alloys; there are no brittle intermetallic compounds in soldered seams; the solder provides high thermal conductivity and heat resistance of soldered joints. The solder does not contain copper and other metals with high vapor pressure and does not pose a threat of evaporation of components during heating of soldered joints with the adsorption of metal vapors on insulators. Among the solder components, there are no elements having a high neutron capture cross section that form long-lived radioactive nuclides with strong γ-radiation.

Example 3

As in example 1, samples were prepared of amorphous zirconium-based strip solder containing: 19 wt.% Nb, 7.5 wt.% Ni, 7.5 wt.% Fe and Zr and the inevitable impurities - the rest. The quantitative content of the inevitable impurities of bismuth arsenic and sulfur was strictly controlled so that the total content of bismuth and arsenic was in the range of 0.0001-0.0018 wt.%, And the sulfur content was 0.0001-0.0015 wt.%.

The solidus temperature for the samples of tape solder of the specified composition is 968 ° C, the liquidus temperature is 1002 ° C, the melting interval of the solder was 34 ° C.

The solder was made in the form of a roll of flexible tape with a width of 1.0-40 mm and a thickness of 25-60 microns, as shown in figure 2, and used for soldering products from alloy BH2. The BH2 alloy contains 3.8-5.2 wt.% Molybdenum, not more than 0.05 carbon, not more than 0.03 oxygen, not more than 0.04 nitrogen, the rest is niobium and inevitable impurities.

The above examples 1-3 confirm that the amorphous zirconium-based tape solder containing the components in accordance with the claimed formula is suitable for soldering materials of the collector package of niobium-based alloys. All samples of the obtained amorphous tape solder had a melting point below 1175 ° C, that is, below the melting temperature of eutectics formed as a result of interaction with the niobium elements that make up the solder. The claimed tape solder allows you to choose the width of the tape, so that it is convenient to place it in the grooves on coaxially connected products from niobium alloys without fusing the solder technological channels. By adjusting the technological parameters of the ultrafast hardening process, it is possible to strictly fix the thickness and width of the tapes, thereby ensuring the optimal amount of solder in the gap during soldering, which makes it possible to reduce the chemical erosion of the base metal, and allows the soldering of thin-walled materials without melting small holes.

Examples 1-3 confirmed the increase in the operational characteristics of the solder by ensuring a homogeneous phase state of the amorphous alloy, obtaining a narrow interval between the melting point and solidification of the solder with high adhesive and capillary activity during brazing, which provides better wetting and faster diffusion of alloying elements of the solder into the base metal products.

Examples 1-3 confirmed the uniform melting of the solder throughout the volume, the formation during solidification of a continuous and uniform in structure soldered seam.

Thus, the claimed amorphous tape solder based on zirconium provides an increase in the quality of soldering, reducing the number of defects of the soldered joint, reducing the content of intermetallic compounds in the brazed joint.

Claims (7)

1. Amorphous zirconium-based tape solder for brazing products from niobium and its alloys, made in the form of a flexible tape of an amorphous structure from an alloy based on zirconium containing niobium, characterized in that the width of the tape is selected in accordance with the width of the grooves on the joined products in the range 1.0-40 mm, the tape thickness is selected in the range of 25-60 μm, while the solder additionally contains nickel in the following ratio of components, wt.%: Niobium 17-21 Nickel 7.5-15 Zirconium Rest 2. The solder according to claim 1, characterized in that it is made in the form of a flexible tape with a width of 1.1-3 mm, a thickness of 25-35 microns. 3. The solder according to claim 2, characterized in that the width and thickness of the flexible tape is selected with the possibility of placing it in the grooves on the connected products in the form of coaxially connected cylindrical parts of the collector assembly of the nuclear power channel of a nuclear reactor with the possibility of soldering without melting the solder of the technological channels. 4. The solder according to claim 1, characterized in that it is made in the form of a roll of a flexible tape made by ultrafast quenching from a liquid metal melt at a rate of 10 ⁴ -10 ⁶ ° C / s to obtain an amorphous alloy structure. 5. The solder according to claim 1, characterized in that the zirconium-based alloy additionally contains iron in the following ratio of components, wt.%: Niobium 17-21 Nickel 7.5-15 Iron 6-9 Zirconium Rest 6. The solder according to claim 1, characterized in that the zirconium-based alloy additionally contains iron and beryllium in the following ratio of components, wt.%: Niobium 17-21 Nickel 7.5-15 Iron 6-9 Beryllium 0.1-2.0 Zirconium Rest 7. The solder according to claim 1, characterized in that the composition of the zirconium-based alloy is further limited by the content of inevitable impurities: bismuth, arsenic and sulfur in the following ratio of components, wt.%: Niobium 17-21 Nickel 7.5-15 Iron 6-9 Beryllium 0.1-2.0 The total content of bismuth and arsenic 0.0001-0.0018 Sulfur 0.0001-0.0015 Zirconium Rest