Lead-free alkali-free tungsten-containing low-temperature sealing glass and preparation method thereof

Abstract

The invention provides lead-free alkali-free tungsten-containing low-temperature sealing glass and a preparation method thereof. The sealing glass is prepared from the following components in parts by mass: 20 to 50 parts of phosphorus pentoxide, 10 to 20 parts of diboron trioxide, 20 to 50 parts of stannous chloride, 0 to 10 parts of zinc oxide, 5 to 20 parts of titanium dioxide and 10 to 30 parts of tungsten trioxide. The preparation method comprises the following steps: by taking phosphorus pentoxide, ammonium dihydrogen phosphate, boric acid, stannous oxide, stannous chloride, zinc oxide, titanium dioxide and tungsten trioxide as raw materials, calculating the mass percent of the raw materials according to the mole percent of each component of the sealing glass, weighing the raw materials, uniformly mixing, putting into a corundum crucible, and melting at 500-600 DEG C; the molten glass liquid is subjected to casting molding or water quenching and then ground into powder, and the powder is sieved by a 200-mesh sieve; the sealing glass material does not contain alkali metal, lead, cadmium, thallium and other toxic and harmful substances, is low in sealing temperature, does not crystallize, has excellent chemical stability, and is especially suitable for sealing of electronic components, and the lowest sealing temperature can reach 330 DEG C.

Description

Technical Field

[0001] The present invention relates to a lead-free, alkali-free, tungsten-containing low-temperature sealing glass, and in particular to an alkali-free, lead-free, tungsten-containing low-temperature sealing glass widely used in instruments and electronic components such as communication, measurement, transmission, and display, and a preparation method thereof. Background Art

[0002] The glass composition disclosed in US Patent No. 20230314969 is composed of SnO 30% to 80%, B2O3 45% to 81%, NaO 1% to 7%, ZnO 0.1% to 9%, Al2O3 0.1% to 5%, Li2O 0.1% to 2%, TiO2 0.5% to 6%, ZrO2 0.1% to 6%, and BaO 4% to 25%. The softening temperature of the glass in this system is 370 to 525°C, and the thermal expansion coefficient is 90 to 110×10 -7 / ℃, the melting temperature of glass is 480~510℃.

[0003] U.S. Patent No. 20230124925 discloses a method for forming low-melting-point glass fibers, comprising providing a glass raw material comprising low-melting-point glass and melting and spinning the glass raw material to produce glass fibers, wherein the glass fibers have a glass transition temperature less than or equal to about 120% of the glass transition temperature of the glass raw material. The glass of the system comprises, by weight, Sn 59% to 89%, P 0% to 13%, F 0% to 12%, O 6% to 25%, with Sn + P + O + F being at least about 75%, and a transition temperature of 100 to 400°C.

[0004] Chinese Patent No. 202210196815.6 discloses a lead-free, low-melting-point sealing glass doped with a fusible metal alloy and its preparation method. The glass comprises the following components by weight: 55% to 87% Bi2O3, 5% to 20% B2O3, 5% to 20% ZnO, and 1% to 10% P2O5. The glass has an expansion coefficient that matches that of platinum-group glasses, a sealing temperature of ≤420°C, good chemical stability, high sealing strength, and is easy to prepare.

[0005] Japanese Patent Application Laid-Open No. 2006143480 discloses a Bi2O3-B2O3 glass composition and a sealing material using this composition. This composition is essentially lead-free and consists, by mole percentage, of 35% to 60% Bi2O3, 10% to 35% B2O3, and 0.1% to 5% WO3. The sealing material using this composition contains 40% to 90% by volume of the base glass component and 60% to 10% of a low-expansion refractory filler. A disadvantage of this glass system is its high coefficient of thermal expansion, which is approximately 110×10-10°C before the addition of the low-expansion refractory filler.-7 / ℃ and it is easy to crystallize during the sealing process.

[0006] Chinese patent CN 109455940A discloses a soft, lead-free, low-temperature sealing glass and its preparation method. Its components, calculated by weight percentage, are: phosphorus pentoxide 40%-65%, silicon dioxide 0.1%-5%, zinc oxide 20%-40%, sodium oxide 3%-13%, potassium oxide 3%-13%, aluminum oxide 1%-15%, cerium dioxide 1%-5%, and colorants 0%-3% (such as chromium oxide, iron oxide, etc.). The low-temperature sealing glass prepared by the present invention has a thermal expansion coefficient of 12-16×10 -6 / ℃ soft glass, the sealing temperature is only 450-550℃, suitable for aluminum alloy sealing with extremely low working temperature. Because of its soft texture and high wettability, the thermal expansion coefficient is between Kovar alloy and aluminum alloy, which can well match the sealing between Kovar alloy and aluminum alloy.

[0007] The current lead-free low-temperature sealing glass belongs to the phosphate system, and its chemical stability is poor, which limits the sealing application field and sealing effect of the glass. Summary of the Invention

[0008] The technical problem to be solved by the present invention is to provide a lead-free, alkali-free, tungsten-containing low-temperature sealing glass and a preparation method thereof, so as to make up for the deficiencies or defects of the existing technology and meet the needs of production and life.

[0009] In order to solve the above technical problems, one of the technical solutions adopted by the present invention is: a lead-free, alkali-free, tungsten-containing low-temperature sealing glass, the components and contents of which are as follows by mass:

[0010]

[0011] The second technical solution adopted by the present invention is: a lead-free, alkali-free, tungsten-containing low-temperature sealing glass and a preparation method thereof, comprising the following steps:

[0012] (1) Raw materials for introducing oxides: phosphorus pentoxide is introduced from ammonium dihydrogen phosphate, boron oxide is introduced from boric acid, and the remaining components are introduced from their respective oxides. According to the composition range of the sealing glass in molar percentage, the glass formula is determined, the weight percentage of the glass is calculated, and then weighed and mixed evenly.

[0013] (2) Select a corundum crucible and melt it in a silicon carbon rod electric furnace at a temperature of 550-750°C for 0.5-1 hour;

[0014] (3) Casting the molten glass liquid, and promptly placing the glass sample into the annealing furnace for annealing at a temperature of 150-200°C, keeping it warm for 1 hour, and then cooling it with the furnace;

[0015] (4) The annealed glass is processed and shaped according to the test requirements.

[0016] The beneficial effects of the present invention are as follows: the lead-free, alkali-free, tungsten-containing low-temperature sealing glass of the present invention does not contain lead oxide and alkali metals, thereby reducing the need for adding tungsten oxide and optimizing the glass composition ratio, further lowering the transition temperature and softening temperature of the glass system, and thus lowering the glass sealing temperature. The softening temperature is within the range of 100°C to 260°C, and the sealing temperature is within the range of 330°C to 400°C, meeting the low-temperature sealing requirements of electronic components. According to the national standard SJT 11035-1996, the glass's water resistance and chemical stability reach Level 1, expanding its scope of application and being widely used for connecting, sealing, and sealing various glass, ceramic, and metal parts. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is the thermal expansion curve of Example 1 of the lead-free, alkali-free, tungsten-containing low-temperature sealing glass. The transition temperature and softening temperature of the sample are 86°C and 104°C respectively, and the sealing temperature is 330°C. DETAILED DESCRIPTION

[0018] The present invention will be further described in detail below with reference to specific embodiments.

[0019] According to the above-mentioned lead-free low-melting-point sealing glass composition range, the glass formula is determined, the weight percentage of the glass is calculated for batching, the glass is melted, formed and ground according to the above-mentioned glass processing and preparation method, and the processed samples are tested.

[0020] The glass composition (weight percentage) of the embodiment is shown in Table 1 below:

[0021] 1 2 3 4 5 6 <![CDATA[P2O5]]> 40 30 20 45 30 30 <![CDATA[B2O3]]> 10 20 10 15 5 5 <![CDATA[SnCl2]]> 30 40 35 30 40 50 <![CDATA[TiO2]]> 5 0 5 0 5 5 ZnO 5 0 10 0 10 0 <![CDATA[WO3]]> 10 10 20 10 10 10

[0022] Example 1

[0023] The ingredients were prepared according to the composition in Table 1. Due to the high bulk resistivity requirements for the glass, alkali metal oxides were excluded from the formulation. The glass mixture was placed in a corundum crucible and melted in a silicon carbon rod electric furnace. The temperature was rapidly raised to 500°C and held for 30 minutes. The melted glass was formed in a preheated mold and quickly annealed in a muffle furnace at 100°C for one hour before cooling in the furnace. The annealed samples were ground and analyzed for performance.

[0024] Example 2

[0025] The ingredients were prepared according to the composition in Table 1, increasing the stannous chloride content and reducing the titanium dioxide content to lower the glass transition temperature and softening temperature. The glass mixture was placed in a corundum crucible and melted in a silicon carbon rod electric furnace, rapidly heating to 500°C and holding for 30 minutes. The melted glass was formed in a preheated mold and quickly annealed in a muffle furnace at 100°C for one hour before cooling in the furnace. The annealed samples were ground and analyzed for performance.

[0026] Example 3

[0027] The glass was prepared according to the composition in Table 1, with the proportion of tungsten trioxide increased to a certain extent. The glass mixture was placed in a corundum crucible and melted in a silicon carbide furnace. The temperature was rapidly raised to 500°C and held for 30 minutes. The melted glass was formed in a preheated mold and quickly annealed in a muffle furnace at 100°C for one hour before cooling with the furnace. The annealed samples were ground and analyzed for performance.

[0028] Example 4

[0029] The glass-forming properties of the sample were improved by mixing the ingredients according to the composition in Table 1 and increasing the proportions of phosphorus pentoxide and boron oxide. The glass mixture was placed in a corundum crucible and melted in a silicon carbide furnace. The temperature was rapidly raised to 500°C and held for 30 minutes. The melted glass was formed in a preheated mold and quickly annealed in a muffle furnace at 100°C for one hour before cooling in the furnace. The annealed samples were ground and analyzed for performance.

[0030] Example 5

[0031] By mixing the ingredients according to the composition in Table 1 and increasing the zinc oxide content, the glass's thermal expansion coefficient can be reduced, improving its thermal stability. The glass mixture was placed in a corundum crucible and melted in a silicon-carbon rod electric furnace. The temperature was rapidly raised to 500°C and held for 30 minutes. The melted glass was formed in a preheated mold and quickly annealed in a muffle furnace at 100°C for one hour before cooling in the furnace. The annealed samples were ground and analyzed for performance.

[0032] Example 6

[0033] The ingredients were prepared according to the composition in Table 1, increasing the stannous chloride content in the glass components and lowering the sealing temperature. The glass mixture was placed in a corundum crucible and melted in a silicon carbon rod electric furnace, rapidly heating to 500°C and holding for 30 minutes. The melted glass was formed in a preheated mold and quickly annealed in a muffle furnace at 100°C for one hour before cooling in the furnace. The annealed samples were ground and analyzed for performance.

Claims

1. A lead-free, alkali-free, tungsten-containing low-temperature sealing glass and a preparation method thereof, characterized by: Its components and contents are calculated by mass as follows:

2. A lead-free, alkali-free, tungsten-containing low-temperature sealing glass and its preparation method, characterized in that The specific steps are as follows: (1) Introducing raw materials for oxides: phosphorus pentoxide is introduced from ammonium dihydrogen phosphate, boron oxide is introduced from boric acid, and the remaining components are introduced from their respective oxides. Based on the molar percentage composition range of the sealing glass, the glass formula is determined, the weight percentage of the glass is calculated, and then the materials are weighed and mixed uniformly; (2) Select a corundum crucible and melt it in a silicon carbon rod electric furnace; (3) Casting the molten glass liquid and promptly placing the glass sample into an annealing furnace for annealing; (4) The annealed glass is processed and shaped according to the test requirements.

3. The sealing glass material according to claim 1, wherein The components of the prepared sealing glass do not contain lead.

4. The sealing glass material according to claim 1, wherein The components of the prepared sealing glass do not contain alkali metal oxides.

5. The sealing glass material according to claim 1, wherein The softening temperature of the prepared sealing glass is between 100 and 260°C.

6. The sealing glass material according to claim 1, wherein: The sealing temperature of the prepared sealing glass is between 330 and 400°C.

7. The preparation method according to claim 2, characterized in that In step (1), phosphorus pentoxide is introduced from ammonium dihydrogen phosphate, which improves the chemical stability of the glass.

8. The preparation method according to claim 2, characterized in that The melting temperature in step (2) is 550-750° C. and the temperature is kept for 0.5-1 hour.

9. The preparation method according to claim 2, characterized in that In step (3), the annealing temperature is 150-200° C., and the mixture is kept at this temperature for 2 hours and then cooled in the furnace.

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