Flame-retardant titanium-based filler metal, and preparation method and application thereof

Abstract

This invention discloses a flame-retardant titanium-based brazing filler metal, its preparation method, and its application, belonging to the field of titanium-based brazing filler metal technology. The flame-retardant titanium-based brazing filler metal mainly consists of the following components by mass percentage: Zr: 30%–40%, Cu: 22%–34%, Al: 0.5%–1%, Cr: 0.5%–2%, V: 0%–1%, with Ti as the balance. Titanium-zirconium-copper brazing filler metal, pure aluminum, and copper-chromium alloys are vacuum-melted according to the above proportions to obtain alloy ingots. Then, powder is prepared using an aerosol method to obtain flame-retardant titanium-based brazing filler metal powder with antioxidant and flame-retardant properties. This process for preparing the flame-retardant titanium-based brazing filler metal is simple, has low production costs, and is suitable for large-scale production, which is of great significance for improving the flame-retardant performance of aero-engine blade tip coatings.

Description

Technical Field

[0001] This invention belongs to the field of titanium-based brazing filler metal technology, specifically relating to a flame-retardant titanium-based brazing filler metal, its preparation method, and its application. Background Technology

[0002] Titanium alloys, due to their advantages such as low density, good heat resistance, good corrosion resistance, and high mechanical strength, have been widely used in the manufacture of advanced aero-engine components such as compressor casings, rotor disks, rotor blades, stator blades, and fan blades to reduce engine weight and improve thrust-to-weight ratio. However, with the increase in engine inlet temperature and gas pressure, the service environment of the engine compressor and turbine blades becomes more severe, especially the blade tips. Due to transient loads or maneuvering overloads during flight, the radial clearance of the turbine blade tips often decreases suddenly. The blade tips come into contact with the casing, causing interference friction and a rapid temperature rise within a short period of time, reaching the melting point of titanium alloys. This can trigger titanium fire, causing the coating or even the substrate to fail.

[0003] The current main method for addressing titanium fire is to prepare a wear-resistant coating on the blade tip surface. This prevents direct friction between the blade and the casing during wear, instead consuming the wear-resistant coating on the blade and the wear-prone coating on the casing. However, this method has a major drawback: the coating may fail due to environmental factors during service, exposing the titanium alloy substrate and potentially triggering titanium fire during scraping. Furthermore, most existing blade tip coatings only possess certain high-temperature oxidation and corrosion resistance properties, without significant breakthroughs in flame retardancy. Summary of the Invention

[0004] In order to overcome the shortcomings of the prior art, the purpose of this invention is to provide a flame-retardant titanium-based brazing filler metal, its preparation method and application, and to solve the problem of titanium fire caused by interference friction at turbine blade tips.

[0005] To achieve the above objectives, the present invention employs the following technical solution:

[0006] This invention discloses a flame-retardant titanium-based solder, which, by mass percentage, comprises Zr: 30%–40%, Cu: 22%–34%, Al: 0.5%–1%, Cr: 0.5%–2%, with Ti as the balance.

[0007] Preferably, it also includes V with a mass percentage of ≤1%.

[0008] Preferably, the flame-retardant titanium-based solder has a particle size of 50–100 μm.

[0009] Preferably, the sphericity of the flame-retardant titanium-based solder is ≥90%.

[0010] This invention also discloses a method for preparing the above-mentioned flame-retardant titanium-based solder, the steps of which are as follows:

[0011] 1) Titanium zirconium copper brazing filler metal, pure aluminum, and copper chromium alloy are used as raw materials for brazing filler metal alloy. Each raw material is weighed accurately according to the proportion, and the mass of each component is accurate to 0.1% of its component.

[0012] 2) Melt the raw materials weighed in step 1), keep them at a constant temperature, and obtain titanium alloy ingots;

[0013] 3) Re-weigh and inspect the titanium alloy ingot obtained in step 2). If the quality of the alloy ingot deviates from that of the alloy raw material before melting by less than 1%, it is considered a qualified ingot; if it deviates by more than 1%, it is considered a substandard ingot.

[0014] 4) The qualified ingots from step 3) are crushed and powdered to obtain titanium alloy powder;

[0015] 5) The titanium alloy powder obtained in step 4) is sieved to obtain flame-retardant titanium-based brazing filler metal.

[0016] Preferably, in step 1), the purity of the raw material is 99.9%.

[0017] Preferably, in step 1), pure vanadium is also added to the raw materials.

[0018] Preferably, in step 2), the melting conditions are: vacuum melting under argon protection, melting temperature of 1500℃, and vacuum degree > 10. -3 pa.

[0019] Preferably, in step 4), the specific steps of crushing and grinding are as follows: using a gas atomization method, the qualified ingot is ground under a gas pressure of 25-35 bar and an airflow of 20-25 m. 3 Crushing and pulverizing are performed under the following conditions: gas temperature: 0℃, atomization rate: 0.4~1.0Kg / min, and oxygen partial pressure in the atomization atmosphere is below 10ppm or 0.01%.

[0020] This invention also discloses the application of the aforementioned flame-retardant titanium-based brazing filler metal in the brazing of flame-retardant titanium alloys, and in the preparation of a wear-resistant coating with flame-retardant properties for the tips of aero-engine blades.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] This invention provides a flame-retardant titanium-based brazing filler metal, using a TiZrCu alloy as the matrix, which has the advantages of low melting point and low brittleness. The reinforcing element Al is added in elemental form to improve the brazing filler metal's oxidation resistance and corrosion resistance. Titanium and zirconium are infinitely soluble, and Cr is added in the form of a CuCr master alloy, which can improve the brazing filler metal's oxidation resistance and flame-retardant properties. The Cr element in the flame-retardant titanium alloy diffuses outward and reacts with oxygen to form Cr2O3, which has a higher density than TiO2. Ti atoms have difficulty diffusing outward through Cr2O3 to react with oxygen, increasing the density of the combustion surface and inhibiting oxygen diffusion. By adding appropriate amounts of Al and Cr to the TiZrCu matrix to improve the oxidation resistance and flame-retardant properties of the flame-retardant brazing filler metal, the resulting flame-retardant titanium-based brazing filler metal also has a low melting point of 992℃. Therefore, this flame-retardant titanium-based brazing filler metal can protect the blade substrate and is suitable for brazing flame-retardant titanium alloys and preparing wear-resistant coatings with flame-retardant properties for the tips of aero-engine blades. It can be used as an alloy coating for engine blade tips on various titanium alloy substrates.

[0023] Furthermore, the addition of V element to the flame-retardant titanium-based solder allows the V element in the flame-retardant titanium alloy to diffuse outward and react with oxygen to form V2O5, which has a higher density than TiO2. This makes it difficult for Ti atoms to diffuse outward through V2O5 and react with oxygen, thereby increasing the density of the combustion surface and inhibiting oxygen diffusion. This further improves the oxidation resistance and flame-retardant properties of the solder.

[0024] This invention provides a method for preparing flame-retardant titanium-based brazing filler metal. The prepared titanium-based brazing filler metal powder has uniform quality and extremely low impurity content. The brazing filler metal melting and powder preparation processes are carried out in a vacuum atmosphere, and the oxygen content in the powder is controllable and low, resulting in superior process performance. At the same time, the production cost is low, the preparation method is simple, and it is suitable for large-scale production. This method is of great significance for improving the flame-retardant performance of aero-engine blade tips. Detailed Implementation

[0025] The present invention will now be described in further detail:

[0026] The present invention provides a flame-retardant titanium-based brazing filler metal, which, by mass percentage (wt%), comprises Zr: 30%–40%, Cu: 22%–34%, Al: 0.5%–1%, Cr: 0.5%–2%, V: 0%–1%, and Ti as the balance.

[0027] The present invention provides a method for preparing a flame-retardant titanium-based solder, comprising the following steps:

[0028] (1) Ingredients:

[0029] Titanium-zirconium copper brazing filler metal, pure aluminum, and copper-chromium alloy are used as raw materials for the brazing filler metal alloy. The purity of the raw materials is 99.9%. Each raw material is weighed precisely according to the proportion, and the mass of each component is accurate to 0.1% of its component. Furthermore, pure vanadium can also be added to the raw materials.

[0030] (2) Melting and alloying:

[0031] The alloy raw materials prepared in step (1) are vacuum melted using a melting equipment under argon protection at a melting temperature of 1500℃ and a vacuum degree of 10. -3 Above Pa; after melting, continue to hold under argon protection for 1 to 6 hours to ensure the uniformity of the alloy composition, and then pour into a graphite mold to obtain a titanium alloy ingot;

[0032] The smelting equipment is a vacuum induction heating furnace, and the preferred holding time is 1 hour.

[0033] (3) Re-inspection of smelted alloy ingots:

[0034] The titanium alloy ingot obtained in step (2) is re-weighed and inspected. If the quality of the alloy ingot deviates from that of the alloy raw material before melting by less than 1%, it is a qualified ingot; if it deviates from that of the alloy raw material before melting by more than 1%, it is an unqualified ingot.

[0035] (4) Crushing and grinding of alloy ingots:

[0036] The alloy ingot that passed inspection in step (3) is atomized to obtain alloy powder.

[0037] In the gas atomization method, the gas pressure is 25–35 bar, and the airflow is 20–25 m. 3 / min, gas temperature: 0℃, atomization rate: 0.4~1.0Kg / min, oxygen partial pressure in atomizing atmosphere: less than or equal to 10ppm or 0.01%;

[0038] (5) Sieving of brazing filler metal powder:

[0039] The brazing filler metal powder prepared by the aerosol method in step (4) is sieved and classified using a target sieve. The powder that passes through the sieve is the qualified finished brazing filler metal powder. The particle size of the screened powder is 50-100μm and the sphericity is ≥90%.

[0040] Example 1

[0041] A flame-retardant titanium-based solder, comprising, by weight percentage: Zr: 36%, Cu: 25%, Al: 1%, Cr: 0.5%, and Ti: 37.5%.

[0042] The preparation method of the flame-retardant titanium-based solder includes the following steps:

[0043] (1) Ingredients:

[0044] A certain composition of titanium zirconium copper brazing filler metal, as well as pure aluminum and copper chromium alloy, are used as raw materials for the brazing filler metal alloy. The purity of each raw material is 99.99%. Each raw material is weighed precisely according to the proportion, and the mass of each component is accurate to 0.1% of its component.

[0045] (2) Induction melting alloying:

[0046] The alloy raw materials prepared in step (1) are vacuum melted in a vacuum induction heating furnace under argon protection at a melting temperature of 1500℃ and a vacuum degree of 2×10⁻⁶. -3 After melting, the alloy is held at a constant temperature under argon gas for 1 hour to ensure the uniformity of the alloy composition. Then, it is poured into a graphite mold to obtain a titanium alloy ingot.

[0047] (3) Re-inspection of smelted alloy ingots:

[0048] The titanium alloy ingot obtained in step (2) is re-weighed and inspected. If the quality of the alloy ingot deviates from that of the alloy raw material before melting by less than 1%, it is a qualified ingot; if it deviates from that of the alloy raw material before melting by more than 1%, it is an unqualified ingot.

[0049] (4) Crushing and grinding of alloy ingots:

[0050] The alloy ingot that passed inspection in step (3) was atomized to obtain alloy powder, wherein the oxygen partial pressure in the atomizing atmosphere was 10 ppm; the relevant parameters were: gas pressure: 35 bar, gas flow: 25 m 3 / min, gas temperature: 0℃, atomization rate: 1.0Kg / min.

[0051] (5) Sieving of brazing filler metal powder:

[0052] The brazing filler metal powder prepared by the aerosol method in step (4) is sieved and classified using a target sieve. The powder that passes through the sieve is the qualified finished brazing filler metal powder. The particle size of the screened powder is 50-100μm.

[0053] Example 2

[0054] A flame-retardant titanium-based solder, comprising, by weight percentage: Zr: 36%, Cu: 25%, Al: 1%, Cr: 1%, and Ti: 37%.

[0055] The method for preparing the titanium-based solder includes the following steps:

[0056] (1) Ingredients:

[0057] A certain composition of titanium zirconium copper brazing filler metal, as well as pure aluminum and copper chromium alloy, are used as raw materials for the brazing filler metal alloy. The purity of each raw material is 99.99%. Each raw material is weighed precisely according to the proportion, and the mass of each component is accurate to 0.1% of its component.

[0058] (2) Induction melting alloying:

[0059] The alloy raw materials prepared in step (1) are vacuum melted in a vacuum induction heating furnace under argon protection at a melting temperature of 1500℃ and a vacuum degree of 10. -1 After melting, the alloy is held at a constant temperature under argon gas for 1 hour to ensure the uniformity of the alloy composition. Then, it is poured into a graphite mold to obtain a titanium alloy ingot.

[0060] (3) Re-inspection of smelted alloy ingots:

[0061] The titanium alloy ingot obtained in step (2) is re-weighed and inspected. If the quality of the alloy ingot deviates from that of the alloy raw material before melting by less than 1%, it is a qualified ingot; if it deviates from that of the alloy raw material before melting by more than 1%, it is an unqualified ingot.

[0062] (4) Crushing and grinding of alloy ingots:

[0063] The alloy ingot that passed inspection in step (3) was atomized to obtain alloy powder, wherein the oxygen partial pressure in the atomizing atmosphere was 10 ppm; the relevant parameters were: gas pressure: 28 bar, gas flow: 25 m. 3 / min, gas temperature: 0℃, atomization rate: 0.8Kg / min.

[0064] (5) Sieving of brazing filler metal powder:

[0065] The brazing filler metal powder prepared by the aerosol method in step (4) is sieved and classified using a target sieve. The powder that passes through the sieve is the qualified finished brazing filler metal powder. The particle size of the screened powder is 50-100μm.

[0066] Example 3

[0067] A flame-retardant titanium-based solder, comprising, by weight percentage: Zr: 36%, Cu: 25%, Al: 1%, Cr: 1.5%, and Ti: 36.5%.

[0068] The method for preparing the titanium-based solder includes the following steps:

[0069] (1) Ingredients:

[0070] A certain composition of titanium zirconium copper brazing filler metal, as well as pure aluminum and copper chromium alloy, are used as raw materials for the brazing filler metal alloy. The purity of each raw material is 99.99%. Each raw material is weighed precisely according to the proportion, and the mass of each component is accurate to 0.1% of its component.

[0071] (2) Induction melting alloying:

[0072] The alloy raw materials prepared in step (1) are vacuum melted using an induction melting device under argon protection at a melting temperature of 1500℃ and a vacuum degree of 10. -2 After melting, the alloy is held at a constant temperature under argon protection for 6 hours to ensure the uniformity of the alloy composition. Then, it is poured into a graphite mold to obtain a titanium alloy ingot.

[0073] (3) Re-inspection of smelted alloy ingots:

[0074] The titanium alloy ingot obtained in step (2) is re-weighed and inspected. If the quality of the alloy ingot deviates from that of the alloy raw material before melting by less than 1%, it is a qualified ingot; if it deviates from that of the alloy raw material before melting by more than 1%, it is an unqualified ingot.

[0075] (4) Crushing and grinding of alloy ingots:

[0076] The alloy ingot that passed inspection in step (3) was atomized to obtain alloy powder, wherein the oxygen partial pressure of the atomizing atmosphere was 10 ppm; the relevant parameters were: gas pressure: 26 bar, gas flow: 20 m. 3 / min, gas temperature: 0℃, atomization rate: 0.6Kg / min.

[0077] (5) Sieving of brazing filler metal powder:

[0078] The brazing filler metal powder prepared by the aerosol method in step (4) is sieved and classified using a target sieve. The powder that passes through the sieve is the qualified finished brazing filler metal powder. The particle size of the screened powder is 50-100μm.

[0079] Example 4

[0080] A flame-retardant titanium-based solder, comprising, by weight percentage: Zr: 36%, Cu: 25%, Al: 1%, Cr: 2%, and Ti: 36%.

[0081] The method for preparing the titanium-based solder includes the following steps:

[0082] (1) Ingredients:

[0083] A certain composition of titanium zirconium copper brazing filler metal, as well as pure aluminum and copper chromium alloy, are used as raw materials for the brazing filler metal alloy. The purity of each raw material is 99.99%. Each raw material is weighed precisely according to the proportion, and the mass of each component is accurate to 0.1% of its component.

[0084] (2) Induction melting alloying:

[0085] The alloy raw materials prepared in step (1) are vacuum melted using an induction melting device under argon protection at a melting temperature of 1500℃ and a vacuum degree of 10. -2 After melting, the alloy is held at a constant temperature under argon gas for 1 hour to ensure the uniformity of the alloy composition. Then, it is poured into a graphite mold to obtain a titanium alloy ingot.

[0086] (3) Re-inspection of smelted alloy ingots:

[0087] The titanium alloy ingot obtained in step (2) is re-weighed and inspected. If the quality of the alloy ingot deviates from that of the alloy raw material before melting by less than 1%, it is a qualified ingot; if it deviates from that of the alloy raw material before melting by more than 1%, it is an unqualified ingot.

[0088] (4) Crushing and grinding of alloy ingots:

[0089] The alloy ingot that passed inspection in step (3) was atomized to obtain alloy powder, wherein the oxygen partial pressure in the atomizing atmosphere was 10 ppm; the relevant parameters were: gas pressure: 25 bar, gas flow: 25 m. 3 / min, gas temperature: 0℃, atomization rate: 0.4Kg / min.

[0090] (5) Sieving of brazing filler metal powder:

[0091] The solder powder prepared by the aerosol method in step (4) is sieved and classified using a target sieve. The powder that passes through the sieve is the qualified finished solder powder. The particle size of the sieved powder is 50-100μm and the liquidus temperature is 992℃, which is the liquidus temperature of Ti-36Zr-25Cu-Al-2Cr.

[0092] The solidus and liquidus lines of the flame-retardant titanium-based solders obtained in Examples 1 to 4 are shown in Table 1:

[0093] Table 1 shows the melting temperature range of the titanium-based solders obtained in the examples.

[0094] Experimental Example <![CDATA[Solidus temperature T s (°C)]]> <![CDATA[Liquidus temperature T1 (°C)]]> ΔT (°C) Experimental Example 1 899 1020 121 Experiment Example 2 896 1010 114 Experimental Example 3 892 1000 108 Experiment Example 4 890 992 102

[0095] As can be seen from Table 1, the flame-retardant titanium-based solder obtained by this method has a low melting point of 992℃.

[0096] Example 5

[0097] A flame-retardant titanium-based solder, comprising, by weight percentage: Zr: 30%, Cu: 28%, Al: 0.5%, Cr: 1%, V: 1%, and Ti: 39.5%.

[0098] The method for preparing the titanium-based solder includes the following steps:

[0099] (1) Ingredients:

[0100] A titanium-zirconium-copper brazing filler metal of a certain composition, as well as pure aluminum, pure vanadium, and copper-chromium alloy, are used as raw materials for the brazing filler metal alloy. The purity of each raw material is 99.99%. Each raw material is weighed precisely according to the proportion, and the mass of each component is accurate to 0.1% of its component.

[0101] (2) Induction melting alloying:

[0102] The alloy raw materials prepared in step (1) are vacuum melted using an induction melting device under argon protection at a melting temperature of 1500℃ and a vacuum degree of 10. -2 After melting, the alloy is held at a constant temperature for 3 hours under argon protection to ensure the uniformity of the alloy composition. Then, it is poured into a graphite mold to obtain a titanium alloy ingot.

[0103] (3) Re-inspection of smelted alloy ingots:

[0104] The titanium alloy ingot obtained in step (2) is re-weighed and inspected. If the quality of the alloy ingot deviates from that of the alloy raw material before melting by less than 1%, it is a qualified ingot; if it deviates from that of the alloy raw material before melting by more than 1%, it is an unqualified ingot.

[0105] (4) Crushing and grinding of alloy ingots:

[0106] The alloy ingot that passed inspection in step (3) was atomized to obtain alloy powder, wherein the oxygen partial pressure of the atomizing atmosphere was 10 ppm; the relevant parameters were: gas pressure: 25 bar, gas flow: 20 m. 3 / min, gas temperature: 0℃, atomization rate: 0.4Kg / min.

[0107] (5) Sieving of brazing filler metal powder:

[0108] The brazing filler metal powder prepared by the aerosol method in step (4) is sieved and classified using a target sieve. The powder that passes through the sieve is the qualified finished brazing filler metal powder. The particle size of the screened powder is 50-100μm.

[0109] Example 6

[0110] A flame-retardant titanium-based solder comprises, by weight percentage: Zr: 32%, Cu: 22%, Al: 0.8%, Cr: 1%, V: 0.5%, and Ti: 43.7%.

[0111] The method for preparing the titanium-based solder includes the following steps:

[0112] (1) Ingredients:

[0113] A titanium-zirconium-copper brazing filler metal of a certain composition, as well as pure aluminum, pure vanadium, and copper-chromium alloy, are used as raw materials for the brazing filler metal alloy. The purity of each raw material is 99.99%. Each raw material is weighed precisely according to the proportion, and the mass of each component is accurate to 0.1% of its component.

[0114] (2) Induction melting alloying:

[0115] The alloy raw materials prepared in step (1) are vacuum melted using an induction melting device under argon protection at a melting temperature of 1500℃ and a vacuum degree of 10. -1 After melting, the alloy is held at a constant temperature under argon gas for 5 hours to ensure the uniformity of the alloy composition. Then, it is poured into a graphite mold to obtain a titanium alloy ingot.

[0116] (3) Re-inspection of smelted alloy ingots:

[0117] The titanium alloy ingot obtained in step (2) is re-weighed and inspected. If the quality of the alloy ingot deviates from that of the alloy raw material before melting by less than 1%, it is a qualified ingot; if it deviates from that of the alloy raw material before melting by more than 1%, it is an unqualified ingot.

[0118] (4) Crushing and grinding of alloy ingots:

[0119] The alloy ingot that passed inspection in step (3) was atomized to obtain alloy powder, wherein the oxygen partial pressure in the atomizing atmosphere was 10 ppm; the relevant parameters were: gas pressure: 28 bar, gas flow: 24 m. 3 / min, gas temperature: 0℃, atomization rate: 0.8Kg / min.

[0120] (5) Sieving of brazing filler metal powder:

[0121] The brazing filler metal powder prepared by the aerosol method in step (4) is sieved and classified using a target sieve. The powder that passes through the sieve is the qualified finished brazing filler metal powder. The particle size of the screened powder is 50-100μm.

[0122] Example 7

[0123] A flame-retardant titanium-based solder comprises, by weight percentage: Zr: 40%, Cu: 34%, Al: 0.8%, Cr: 0.5%, V: 0.2%, and Ti: 24.5%.

[0124] The method for preparing the titanium-based solder includes the following steps:

[0125] (1) Ingredients:

[0126] A titanium-zirconium-copper brazing filler metal of a certain composition, as well as pure aluminum, pure vanadium, and copper-chromium alloy, are used as raw materials for the brazing filler metal alloy. The purity of each raw material is 99.99%. Each raw material is weighed precisely according to the proportion, and the mass of each component is accurate to 0.1% of its component.

[0127] (2) Induction melting alloying:

[0128] The alloy raw materials prepared in step (1) are vacuum melted using an induction melting device under argon protection at a melting temperature of 1500℃ and a vacuum degree of 10. -2 After melting, the alloy is held at a constant temperature under argon gas for 2 hours to ensure the uniformity of the alloy composition. Then, it is poured into a graphite mold to obtain a titanium alloy ingot.

[0129] (3) Re-inspection of smelted alloy ingots:

[0130] The titanium alloy ingot obtained in step (2) is re-weighed and inspected. If the quality of the alloy ingot deviates from that of the alloy raw material before melting by less than 1%, it is a qualified ingot; if it deviates from that of the alloy raw material before melting by more than 1%, it is an unqualified ingot.

[0131] (4) Crushing and grinding of alloy ingots:

[0132] The alloy ingot that passed inspection in step (3) was atomized to obtain alloy powder, wherein the oxygen partial pressure of the atomizing atmosphere was 10 ppm; the relevant parameters were: gas pressure: 25 bar, gas flow: 20 m. 3 / min, gas temperature: 0℃, atomization rate: 0.4Kg / min.

[0133] (5) Sieving of brazing filler metal powder:

[0134] The brazing filler metal powder prepared by the aerosol method in step (4) is sieved and classified using a target sieve. The powder that passes through the sieve is the qualified finished brazing filler metal powder. The particle size of the screened powder is 50-100μm.

[0135] The above content is only for illustrating the technical concept of the present invention and should not be construed as limiting the scope of protection of the present invention. Any modifications made to the technical solution based on the technical concept proposed in this invention shall fall within the scope of protection of the claims of this invention.

Claims

1. A flame-retardant titanium-based solder, characterized in that, The composition by mass percentage includes Zr: 30%~40%, Cu: 22%~34%, Al: 0.5%~1%, Cr: 0.5%~2%, and Ti as the balance; the flame-retardant titanium-based brazing filler metal has a particle size of 50~100 µm and a sphericity ≥90%.

2. The flame-retardant titanium-based solder as described in claim 1, characterized in that, It also includes V with a mass percentage ≤1%.

3. The method for preparing a flame-retardant titanium-based solder according to claim 1 or 2, characterized in that, The steps are as follows: 1) Titanium-zirconium copper brazing filler metal, pure aluminum, and copper-chromium alloy are used as raw materials for the brazing filler metal alloy. Each raw material is weighed precisely according to the proportion, and the mass of each component is accurate to 0.1% of its component. 2) Melt the raw materials weighed in step 1), hold them at a constant temperature, and obtain titanium alloy ingots; 3) Re-weigh and inspect the titanium alloy ingot obtained in step 2). If the quality of the alloy ingot deviates from that of the alloy raw material before melting by less than 1%, it is considered a qualified ingot; if it deviates by more than 1%, it is considered a substandard ingot. 4) The qualified ingots from step 3) are crushed and powdered to obtain titanium alloy powder; 5) The titanium alloy powder obtained in step 4) is sieved to obtain flame-retardant titanium-based brazing filler metal.

4. The method as described in claim 3, characterized in that, In step 1), the purity of the raw material is 99.9%.

5. The method as described in claim 3, characterized in that, In step 1), pure vanadium is also added to the raw materials.

6. The method as described in claim 3, characterized in that, In step 2), the melting conditions are: vacuum melting under argon protection, melting temperature of 1500 ℃, and vacuum degree > 10. -3 pa.

7. The method as described in claim 3, characterized in that, In step 4), the specific steps for crushing and grinding are as follows: Using a gas atomization method, the qualified ingot is ground at a gas pressure of 25~35 bar and an airflow of 20~25 m³ / h. 3 Crushing and pulverizing are performed under the following conditions: gas temperature: 0 ℃, atomization rate: 0.4~1.0 Kg / min, and oxygen partial pressure in the atomization atmosphere is below 10 ppm or 0.01%.

8. The application of the flame-retardant titanium-based brazing filler metal according to claim 1 or 2 in the brazing of flame-retardant titanium alloys and in the preparation of a wear-resistant coating with flame-retardant properties for the tip of aero-engine blades.