CN114477768A - A kind of lead-free low melting point sealing glass doped with fusible metal alloy and preparation method thereof - Google Patents

Abstract

The invention relates to a lead-free low-melting-point sealing glass doped with fusible metal alloy and a preparation method thereof, wherein the glass comprises the following components by weight percent, 60-85% of the lead-free low-melting-point sealing glass; 8 to 20 percent of low expansion filler; 7 to 20 percent of fusible metal alloy. The expansion coefficient of the lead-free low-melting-point sealing glass is matched with that of platinum group glass, the sealing temperature is less than or equal to 420 ℃, the chemical stability is good, the sealing strength is high, and the preparation is easy. The invention can flexibly adjust the proportion of each component according to different characteristic index requirements, optimize the glass formula and meet the specific requirements of the market on the lead-free low-melting-point sealing glass.

Description

A kind of lead-free low melting point sealing glass doped with fusible metal alloy and preparation method thereof

technical field

The invention relates to the technical field of glass material preparation, in particular to a lead-free low melting point sealing glass doped with a fusible metal alloy and a preparation method.

Background technique

As a kind of sealing material, low melting point sealing glass has a wide field of application. With the development of modern science and technology, especially the rapid progress of vacuum electronics technology, optoelectronic technology, microelectronic semiconductor technology, laser and infrared technology, electric light source, industrial testing and other fields, the miniaturization of devices and the precision of structural components have continued to With the improvement of electronic components, there are more and more types of electronic components, and the shapes of products are becoming more and more complex. As a result, the requirements for low melting point sealing glass are becoming more and more stringent, requiring a wide range of application fields, and at the same time, it has strong pertinence and special index requirements.

Among the low melting point sealing glass, the lead-containing sealing glass has a series of characteristics such as low softening temperature, stable electrical properties and good chemical stability. It has a wide range of uses in the sealing of various electronic components. The PbO-B ₂ O ₃ -ZnO-SiO ₂ glass system is often used in the preparation of lead-containing sealing glass at home and abroad, but the PbO content in most commercial sealing glasses is even as high as 70% or more. Serious harm to the environment and humans. At the same time, a large number of discarded electronic components cannot be disposed of harmlessly, and lead ions will gradually dissolve when eroded by rainwater and the atmosphere, resulting in serious pollution of soil and groundwater quality, and a serious threat to the human living environment. Therefore, the application of lead-containing materials in the world is more and more strictly restricted. Although the application of lead-containing low-melting sealing glass is strictly limited, in addition to being unfriendly to the environment, lead-containing low-melting sealing glass has almost all physical and chemical properties superior to lead-free low-melting sealing glass. For the low melting point sealing glass field, the urgent research and development task is to make the low melting point sealing glass lead-free and replace the lead-containing low melting point sealing glass. At present, the research and development trend of low-melting sealing glass has changed to lead-free, low-temperature, and practical. If lead-free low-melting sealing glass is to completely replace lead-containing low-melting sealing glass, it must meet these "three modernizations" at the same time. harsh requirements. At present, the research on lead-free low melting point sealing glass mainly focuses on phosphate glass system, vanadate glass system, bismuth glass system, borosilicate glass system and so on. Among them, bismuthate glass has attracted attention because it can be sealed at low temperature, has high sealing strength, and has good chemical stability. R&D institutions at home and abroad have issued relevant patents in the above research fields.

The US patent for invention US2006/01058981 discloses a low melting point sealing glass component, in terms of mass percentage, the glass components are 70%-90% Bi ₂ O ₃ , 10%-35% ZnO, 10%-35% % of B ₂ O ₃ , 0.1% to 5% of Al ₂ O ₃ , 0.1% to 5% of CeO ₂ , 0% to 5% of CuO, 0% to 0.2% of Fe ₂ O ₃ , of which CuO+Fe The content of ₂ O ₃ is 0.05% to 5%, and the glass of this component does not crystallize at the sealing temperature. The disadvantage of this system glass is that the sealing temperature of the glass is obvious due to the addition of a large amount of Al ₂ O ₃ to the glass. improve.

Japanese Patent Laid-Open No. 2006143480 discloses a Bi ₂ O ₃ -B ₂ O ₃ series glass component and a sealing material using the component, which is basically free of lead, and its components in terms of mole percentage are: 35%～ 60% Bi ₂ O ₃ , 10%-35% B ₂ O ₃ , 0.1%-5% WO ₃ . The sealing material using this component contains 40% to 90% by volume of the base glass component and 60% to 10% of the low-expansion refractory filler. The disadvantage of this system glass is that its thermal expansion coefficient is too high. Before adding low-expansion refractory filler, its value is above 110×10 ^-7 /℃, and it is easy to crystallize during the sealing process.

Invention patent CN 101602573A of China Institute of Jiliang discloses a bismuthate low melting point sealing glass material, which adopts -Bi ₂ O ₃ -ZnO--B ₂ O ₃ -Sb ₂ O ₃ glass system, wherein the mass percentage is : 71% to 91% of Bi ₂ O ₃ , 2% to 20% of ZnO, 5% to 25% of B ₂ O ₃ , and 0.5% to 5% of Sb ₂ O ₃ . It also includes 0% to 3% of BaO, 0% to 3% of SrO, 0% to 3% of CuO, and 0% to ₃ % of TeO. The prepared lead-free bismuthate glass has an expansion coefficient of (95.6～104.9)×10 ^-7 /°C, which is used for sealing at 480～500°C. The sealing temperature of this kind of glass is too high, which limits its practical use. .

The existing lead-free low-melting glass sealing glass has various performance defects, such as high sealing temperature, easy crystallization of glass, poor chemical stability, and narrow scope of practical application.

SUMMARY OF THE INVENTION

The main purpose of the present invention is to provide a lead-free low-melting-point seal doped with fusible metal alloys, which is easy to prepare and has an expansion coefficient matched with platinum group glass, a sealing temperature ≤ 420° C., good chemical stability, high sealing strength, and easy preparation. Connect the glass.

For achieving the above object, the technical scheme adopted in the present invention is as follows:

The invention provides a lead-free low melting point sealing glass doped with a fusible metal alloy, which comprises the following components by weight: 60% to 85% of the lead-free low melting point sealing glass; 8% to 85% of the low expansion filler 20%; fusible metal alloys 7% to 20%.

The invention also provides a preparation method of lead-free low melting point sealing glass powder doped with fusible metal alloy:

It includes the following steps:

Step 1: According to the weight percentage of each component, weigh each raw material, and after fully mixing, it becomes a batch material, and the raw material is an oxide or a corresponding compound;

Step 2: preheat the silicon molybdenum rod electric furnace to 900-1100°C;

Step 3: Put the batch material of Step 1 into a corundum crucible, and then put it into a resistance furnace with a furnace temperature of 200°C-250°C for preheating;

Step 4: put the preheated batch in step 3 into a silicon molybdenum rod electric furnace for glass melting for 1 to 3 hours;

Step 5: The molten glass in step 4 is poured into a tablet press to be pressed into thin glass sheets, and stored after cooling;

Step 6: Put the flake glass prepared in Step 5 into a ball-milling jar for ball-milling;

Step 7: sieve and store the ball-milled glass powder in step 6 with the required screen to obtain lead-free basic glass powder;

Step 8: Separately sieve the lead-free basic glass powder, low-expansion filler powder, and bismuth-tin metal alloy powder, and sieve them with a 200-mesh to 240-mesh sieve. The high-speed mixer is fully homogenized and mixed at 80-95 r/min and the mixing time is 80-90 minutes. Glass composite.

By the above-mentioned technical scheme, the present invention has at least the following advantages:

1. The original lead-free low melting point sealing glass has one or more of the following performance defects (1) the glass is easy to crystallize, (2) the sealing temperature is high, (3) the sealing strength is low , (4) poor chemical stability, (5) low sealing air tightness. If lead-free low melting point sealing glass occupies one or more items, its application scope will be limited. The lead-free low-melting-point sealing glass prepared by the present invention is used as the basic glass in the composite body. Through the optimized design of components, various performance indicators are basically taken into account. Under lead-free conditions, the low-melting point sealing glass has stable structure and glass forming Wide, low sealing temperature, high sealing strength, good chemical stability, to ensure the air tightness of sealing components.

2. In the present invention, as the low-expansion filler powder in the composite body, the bismuth niobate filler has excellent low-expansion performance. When it is mixed into the base glass powder, the sealing temperature of the composite powder is not significantly increased, and at the same time, it is greatly reduced. The expansion coefficient of the composite powder also significantly improves the chemical stability of the composite powder.

3. In the present invention, as the fusible bismuth-tin metal alloy powder in the composite, its function is to not significantly increase the expansion of the composite powder after it is uniformly mixed into the base glass powder and the low-expansion filler powder At the same time, the sealing temperature of the composite powder is greatly reduced, and the sealing temperature of the glass is controlled to be less than or equal to 420 °C, which can release the residual stress after the sealing of the device and ensure the sealing air tightness of the sealing components.

The above description is only an overview of the technical solution of the present invention. In order to understand the technical means of the present invention more clearly, and to implement according to the content of the description, the preferred embodiments of the present invention are described in detail below.

Detailed ways

In order to further illustrate the technical means and effects adopted by the present invention to achieve the predetermined purpose of the invention, the following preferred embodiments, the specific embodiments, structures, features and effects of the present invention, are described in detail as follows. In the following description, different "an embodiment" or "embodiments" do not necessarily refer to the same embodiment. Furthermore, the particular features, structures, or characteristics in one or more embodiments may be combined in any suitable form.

The invention provides a lead-free low-melting-point sealing glass doped with a fusible metal alloy, which comprises the following components by weight: 60%-85% of the lead-free low-melting point sealing glass; 8%-20% of the low-expansion filler %; 7% to 20% of fusible metal alloys.

The present invention consists of three parts mixing and homogenizing. The first part is composed of lead-free low-melting base glass, and its function is to select the base glass powder with excellent comprehensive performance indicators. The second part is composed of low-expansion filler powder, and its function is to mix it into the base glass powder, without significantly increasing the sealing temperature of the composite powder, and at the same time greatly reducing the expansion coefficient of the composite powder. The third part is composed of a fusible metal alloy, and its function is to mix it into the above two powders, without significantly increasing the expansion coefficient of the composite powder, and at the same time greatly reducing the sealing temperature of the composite powder, which can release the device seal. The residual stress after the connection ensures the airtightness of the components.

The expansion coefficient of the lead-free low melting point sealing glass of the invention matches that of the platinum group glass, the sealing temperature is less than or equal to 420 DEG C, the chemical stability is good, the sealing strength is high, and the preparation is easy. The invention can flexibly adjust the ratio of each component according to different characteristic index requirements, optimize the glass formula, and meet the specific requirements of the market for lead-free and low melting point sealing glass.

Further, the lead-free low-melting base glass is based on the Bi ₂ O ₃ -ZnO-B ₂ O ₃ -P ₂ O ₅ glass system, and the lead-free low-melting sealing glass is prepared as the base glass, wherein no The lead low melting point sealing glass includes the following components by weight: 55%-87% Bi ₂ O ₃ , 5%-20% B ₂ O ₃ , 5%-20% ZnO, 1%-10% % P ₂ O ₅ .

In the glass system of the present invention, Bi ₂ O ₃ , B ₂ O ₃ , ZnO, and P ₂ O ₅ are used as glass network formers to function as the basic framework of the glass network. The high content of Bi ₂ O ₃ ensures the low softening temperature of the glass, and the moderate content of P ₂ O ₅ helps to lower the softening temperature of the glass and reduce the tendency of the glass to crystallize without significantly reducing the chemical stability of the glass. An appropriate amount of B ₂ O ₃ can stabilize the glass network and keep the viscosity stable during the glass melting process. Although ZnO is an intermediate oxide, under the condition of sufficient free oxygen, zinc-oxygen tetrahedron is formed into the glass network.

Further, the lead-free low-melting base glass further contains the following glass performance modifiers by weight: 0.5%-6% SiO ₂ , 0.1%-6% Al ₂ O ₃ , 0.1%-5% BaO, 0.1% to 5% SrO.

In the glass system of the present invention, SiO ₂ , Al ₂ O ₃ , BaO, and SrO are glass structure modifiers. BaO and SrO can not only strengthen the glass network, but also provide free oxygen as intermediate oxides to help SiO ₂ and Al ₂ O ₃ repair the broken network of the glass system.

Further, the lead-free low-melting base glass also contains the following glass performance modifiers by weight: 0.5%-8% Sb ₂ O ₃ , 0.1%-6% CuO, 0.1%-6% Fe ₂ O ₃ , 0.1% to 6% of Co ₂ O ₃ , 0.1% to 6% of MnO ₂ , 0.2% to 6% of La ₂ O ₃ , and 0.2% to 6% of CeO ₂ .

In the glass system of the present invention, CuO, Fe ₂ O ₃ , Sb ₂ O ₃ , Co ₂ O ₃ , MnO ₂ , La ₂ O ₃ and CeO ₂ are glass performance modifiers, and CuO, Fe ₂ O ₃ , Co ₂ O ₃ It can not only adjust the color of the glass, but also improve the wettability of the sealing material and the chemical stability of the base glass, which is beneficial to the sealing process. MnO ₂ , Sb ₂ O ₃ , La ₂ O ₃ , CeO ₂ can improve the electrical properties of the glass, especially the volume resistance and surface resistance.

Preferably, the lead-free low-melting base glass contains the following components by weight: 70%-85% Bi ₂ O ₃ , 5%-15% B ₂ O ₃ , 5%-15% ZnO, 1%-6% P ₂ O ₅ , 0.5%-4% SiO ₂ , 0.1%-4% Al ₂ O ₃ , 0.1%-4.5% BaO, 0.1%-3% SrO, 0.5% %～5% of Sb ₂ O ₃ , 0.1% to 5% of CuO, 0.1% to 4% of Fe ₂ O ₃ , 0.1% to 2% of Co ₂ O ₃ , 0.1% to 2% of MnO ₂ , 0.2 %～3% La ₂ O ₃ , 0.2%～3% CeO ₂ .

Further, the low-expansion filler is selected from at least one of aluminum titanate, eucryptite, cordierite, zircon, bismuth niobate, zinc silicate and quartz glass, and the expansion coefficient of the low-expansion filler ranges from At (-110～60)×10 ^-7 /°C.

The lead-free basic glass powder prepared by the invention has lower sealing temperature, better chemical stability and suitable expansion coefficient. However, in order to expand its application range and obtain more excellent physical and chemical properties, the present invention mixes filler powder with low expansion coefficient into the lead-free glass powder, and the filler powder must all pass through 200-240 mesh screens. In the lead-free low melting point sealing glass composite doped with fusible metal alloy, the weight percentage of the filler is preferably in the range of 8% to 20%.

Further, the fusible metal alloy is a bismuth-tin metal alloy.

The mass percentage of bismuth in the bismuth-tin metal alloy is 20%-80%, and the mass percentage of tin is 80%-20%.

In the present invention, in preparing a lead-free low melting point sealing glass composite doped with fusible metal alloy, the composite body also includes bismuth-tin metal alloy powder, and the bismuth-tin metal alloy powder must pass through 200-240 mesh The mesh sieve does not significantly increase the expansion coefficient of the composite powder after it is incorporated, and at the same time greatly reduces the sealing temperature of the composite powder. The bismuth-tin metal alloy powder preferably ranges from 7% to 20% by weight in the lead-free low melting point sealing glass composite doped with the fusible metal alloy.

The present invention also provides a preparation method of the above-mentioned lead-free low melting point sealing glass doped with fusible metal alloy, comprising the following steps:

Step 1: According to the weight percentage of each component, weigh each raw material, and after fully mixing, it becomes a batch material, and the raw material is an oxide or a corresponding compound;

Step 2: preheat the silicon molybdenum rod electric furnace to 900-1100°C;

Step 3: put the batching material in step 1 into a corundum crucible, and then put it into a resistance furnace with a furnace temperature of 200°C to 250°C for preheating for 30 to 60 minutes;

Step 4: put the preheated batch in step 3 into a silicon molybdenum rod electric furnace for glass melting for 1 to 3 hours;

Step 5: The molten glass in step 4 is poured into a tablet press to be pressed into thin glass sheets, and stored after cooling;

Step 6: Put the flake glass prepared in Step 5 into a ball-milling jar for ball-milling;

Step 7: sieve and store the ball-milled glass powder in step 6 with the required screen to obtain lead-free basic glass powder;

Step 8: Separately sieve the lead-free basic glass powder, low-expansion filler powder, and bismuth-tin metal alloy powder, and sieve them with a 200-mesh to 240-mesh sieve. The high-speed mixer is fully homogenized and mixed at 80-95 r/min and the mixing time is 80-90 minutes. Glass composite.

The preparation method provided by the invention not only has a simple and practical process, but also can prepare a lead-free low-melting point sealing glass doped with a fusible metal alloy, which is environmentally friendly, large-scale production, and excellent in various performance indicators. The method not only makes the manufacturing process of the glass powder simple and feasible, but also does not pollute the environment in the manufacturing process of the whole process.

The present invention will be described in further detail below in conjunction with specific embodiments.

Examples 1 to 7 are specific examples of preparing a lead-free low melting point sealing glass doped with a fusible metal alloy of the present invention. Each example weighs a total of about 150 grams of corresponding raw materials according to the weight percentage of each component, that is, about 150 grams of lead-free low-melting sealing glass in total. The implementation results and performance data of each example are shown in Table 1.

The technological process of a kind of lead-free low melting point sealing glass doped with fusible metal alloy prepared by the present invention is carried out according to the following steps:

Step 1: Accurately weigh the oxide or the corresponding compound according to the chemical composition and weight percentage of the lead-free low melting point sealing glass, and mix thoroughly: 70%-90% Bi ₂ O ₃ , 5%-15% B ₂ O ₃ , 5%～15% ZnO, 1%～6% P ₂ O ₅ , 0.5%～4% SiO ₂ , 0.1%～4% Al ₂ O ₃ , 0.1%～4.5% BaO, 0.1%～3% SrO, 0.5%～5% Sb ₂ O ₃ , 0.1%～5% CuO, 0.1%～4% Fe ₂ O ₃ , 0.1%～2% Co ₂ O ₃ , 0.1%-2% MnO ₂ , 0.2%-3% La ₂ O ₃ , 0.2%-3% CeO ₂ .

Step 2: preheat the silicon molybdenum rod electric furnace to 900-1100°C.

Step 3: Put the batch material of Step 1 into a corundum crucible, and then put it into a resistance furnace with a furnace temperature of 200°C to 250°C for preheating for 30-60 minutes.

Step 4: Put the preheated batch in step 3 into a silicon molybdenum rod electric furnace for glass melting for 1 to 3 hours.

Step 5: The molten glass in step 4 is poured into a tablet press to be pressed into thin glass sheets, and stored after cooling.

Step 6: Put the flake glass prepared in Step 5 into a ball-milling jar for ball-milling.

Step 7: Sieve the ball-milled glass powder in Step 6 with a 200-mesh to 240-mesh sieve, and store the sieved glass powder.

Step 8: Select one or more combinations of the following low-expansion filler powders that pass through 200-mesh to 240-mesh sieves, and the fillers are aluminum titanate, eucryptite, cordierite, zircon, bismuth niobate, One or more combinations of zinc silicate and quartz glass, and the expansion coefficient of the filler is in the range of (-110 to 60)×10-7/°C.

Step 9: Select the following fusible bismuth-tin metal alloy powder that passes through a 200-mesh-240-mesh sieve, and its weight percentages are 20% to 80% of bismuth and 80% to 20% of tin.

Step 10: The lead-free basic glass powder prepared in step 7, the low-expansion filler powder selected in step 8, and the fusible bismuth-tin metal alloy powder selected in step 9 are 60% to 85% by weight of the lead-free basic glass powder. %, the weight percentage of low-expansion filler powder is 8% to 20%, and the weight percentage of fusible bismuth-tin metal alloy powder is 7% to 20%, accurately weighed and mixed, and put into a high-speed mixer Fully homogenized and mixed at a mixing time of 80 to 95 rpm and a mixing time of 80 to 90 minutes. The powder after homogenization and mixing is a lead-free low melting point sealing glass composite doped with a fusible metal alloy.

For the glass samples of Examples 1 to 7, the performance testing methods are as follows:

1. Expansion coefficient: adopt Chinese electronics industry standard SJ/T 11036-96;

2. Softening temperature: adopt Chinese electronics industry standard SJ/T11038-96;

3. Sealing temperature: adopt Chinese electronic industry standard SJ/T11038-96;

4. The diameter of the flow column: adopt the standard SJ-3232.3-89 of the Ministry of Machinery and Electronics Industry of China;

5. Water resistance chemical stability test: The water resistance test of glass was carried out in distilled water at 90°C, and the glass sample ground to 10×10×10mm was placed in a water bath at 90°C in distilled water for 24 hours, and weighed after drying. Weight loss in grams per square centimeter.

The invention can adjust the expansion coefficient and the sealing temperature by adjusting the components of the glass powder, the type and content of the filler, and the ratio of the bismuth-tin alloy, so as to adapt to the sealing between various glasses, ceramics, metals and alloys. Connection and welding.

Table 1 Chemical composition and performance data of each embodiment

As shown in Table 1, a lead-free low melting point sealing glass doped with a fusible metal alloy of the present invention has a glass transition temperature of 335°C to 375°C, and an average thermal expansion coefficient of 25°C to 300°C in (83.38～ 95.34)×10 ^-7 /℃, no crystallization during the sealing process, it can be sealed in the range of 420℃～460℃. The invention solves the problems of low melting point sealing glass with stable structure, wide glass formation range, low sealing temperature, high sealing strength, good chemical stability and ensuring the airtightness of sealing components under lead-free conditions.

The above are only preferred embodiments of the present invention, and are not intended to limit the present invention in any form. Although the present invention has been disclosed above with preferred embodiments, it is not intended to limit the present invention. Technical personnel, within the scope of the technical solution of the present invention, can make some changes or modifications to equivalent embodiments of equivalent changes by using the technical content disclosed above, but any content that does not depart from the technical solution of the present invention, according to the present invention Any simple modifications, equivalent changes and modifications made to the above embodiments still fall within the scope of the technical solutions of the present invention.

Claims (10)

1. A lead-free low-melting-point sealing glass doped with a fusible metal alloy, characterized in that: it comprises the following components by weight: 60%～85% of lead-free low-melting-point base glass; 8% of low-expansion filler ~ 20%; fusible metal alloys 7% ~ 20%. 2 . The lead-free low-melting point sealing glass doped with fusible metal alloy according to claim 1 , wherein the lead-free low-melting point base glass is made of Bi ₂ O ₃ -ZnO-B ₂ O ₃ - 2 . Based on the P ₂ O ₅ glass system, the prepared lead-free low-melting sealing glass is used as the base glass, wherein the lead-free low-melting sealing glass includes the following components by weight: 55% to 87% Bi ₂ O ₃ , 5%～20% B ₂ O ₃ , 5%～20% ZnO, 1%～10% P ₂ O ₅ . 3. The lead-free low-melting-point sealing glass of doped fusible metal alloy according to claim 2, is characterized in that, described lead-free low-melting-point base glass also contains the glass performance modifier of following weight percentage: 0.5%～6% SiO ₂ , 0.1%～6% Al ₂ O ₃ , 0.1%～5% BaO, 0.1%～5% SrO. 4. The lead-free low-melting-point sealing glass of doped fusible metal alloy according to claim 3, is characterized in that, described lead-free low-melting-point base glass also contains the glass performance modifier of following weight percentage: 0.5%-8% Sb ₂ O ₃ , 0.1%-6% CuO, 0.1%-6% Fe ₂ O ₃ , 0.1%-6% Co ₂ O ₃ , 0.1%-6% MnO ₂ , 0.2%-6% La ₂ O ₃ , 0.2%-6% CeO ₂ . 5 . The lead-free low-melting-point sealing glass doped with a fusible metal alloy according to claim 4 , wherein the lead-free low-melting-point base glass contains the following components by weight: 70%～ 85% Bi ₂ O ₃ , 5%-15% B ₂ O ₃ , 5%-15% ZnO, 1%-6% P ₂ O ₅ , 0.5%-4% SiO ₂ , 0.1%- 4% of Al ₂ O ₃ , 0.1% to 4.5% of BaO, 0.1% to 3% of SrO, 0.5% to 5% of Sb ₂ O ₃ , 0.1% to 5% of CuO, 0.1% to 4% of Fe ₂ O ₃ , 0.1%-2% Co ₂ O ₃ , 0.1%-2% MnO ₂ , 0.2%-3% La ₂ O ₃ , 0.2%-3% CeO ₂ . 6. The lead-free low melting point sealing glass doped with a fusible metal alloy according to any one of claims 1 to 5, wherein the low expansion filler is selected from aluminum titanate, eucryptite, cordierite , at least one of zircon, bismuth ^niobate , zinc silicate and quartz glass. 7 . The lead-free low melting point sealing glass doped with a fusible metal alloy according to claim 6 , wherein the fusible metal alloy is a bismuth-tin metal alloy. 8 . 8 . The lead-free low melting point sealing glass doped with a fusible metal alloy according to claim 7 , wherein the mass percentage of bismuth in the bismuth-tin metal alloy is 20% to 80%, and the mass percentage of tin The percentage is 80% to 20%. 9. A preparation method of lead-free low melting point sealing glass doped with fusible metal alloy according to any one of claims 1-8, characterized in that, comprising the steps of: Step 1: According to the weight percentage of each component, weigh each raw material, and after fully mixing, it becomes a batch material, and the raw material is an oxide or a corresponding compound; Step 2: preheat the silicon molybdenum rod electric furnace to 900-1100°C; Step 3: put the batch material in step 1 into a corundum crucible, and then put it into a resistance furnace with a furnace temperature of 200 ℃ ~ 250 ℃ to preheat; Step 4: put the preheated batch in step 3 into a silicon molybdenum rod electric furnace for glass melting for 1 to 3 hours; Step 5: The molten glass in step 4 is poured into a tablet press to be pressed into thin glass sheets, and stored after cooling; Step 6: Put the flake glass prepared in Step 5 into a ball-milling jar for ball-milling; Step 7: sieve and store the ball-milled glass powder in step 6 with the required screen to obtain lead-free basic glass powder; Step 8: Separately sieve the lead-free basic glass powder, low-expansion filler powder, and bismuth-tin metal alloy powder, and sieve them with a 200-mesh to 240-mesh sieve. The high-speed mixer is fully homogenized and mixed at 80-95 r/min and the mixing time is 80-90 minutes. Glass composite. 10. The preparation method according to claim 9, wherein the preheating time is 30-60 minutes.