Glass sintering base with high pressure-bearing performance and excellent thermal shock resistance and preparation method thereof

Abstract

The invention discloses a glass sintering base with high pressure-bearing performance and excellent thermal shock resistance and a preparation method thereof.The glass sintering base comprises a shell, a lead and glass ceramic beads, a plurality of sealing through holes are formed in the shell, the glass ceramic beads are fixed in the sealing through holes, and the middle of the lead is inserted into the glass ceramic beads; the glass beads and the glass ceramic beads are sintered into a whole in an auxiliary manner through a sintering tool and then are fixed in the sealing through holes; the glass ceramic beads are made of a lead-free crystal type glass material, and the system of the lead-free glass material is SiO2-B2O3-Al2O3-Dy2O3. Glass microcracks caused by difference of thermal expansion coefficients in the preparation process of the glass sintering base are reduced through tool design; the glass material is optimized into crystalline glass, so that the mechanical property and the chemical stability of the glass are enhanced, and the thermal shock resistance of the sealing assembly is further improved.

Description

Technical Field

[0001] The present invention relates to the technical field of sensors, and particularly to a glass sintered base with high pressure bearing performance and excellent thermal shock resistance and a preparation method thereof. Background Art

[0002] A pressure sensor can convert the measured pressure into an electrical signal and is widely used in various industrial automatic control environments, including various fields such as aerospace, military defense, automotive electronics, railway transportation, industrial manufacturing, and the Internet of Things. The pressure sensor often operates at low or high temperatures during work. Its main component, the glass sintered base of the pressure sensor, is a glass-metal seal assembly. Under the working conditions of stress and alternating temperature, the glass is prone to creep, the sealing interface fails, and leakage occurs in the sintered base seal, resulting in the failure of the sensor operation.

[0003] For example, the invention application with the application number CN202210313752.8 discloses a temperature and pressure composite sensor based on welded sealing of a metal glass sintered base, including a housing component, a signal transmission structure, and a sealing structure; the housing component is connected to an electrical connector, and a temperature probe is provided at the lower end of the housing component; the signal transmission structure includes a sintered base and a ceramic circuit board, and a pressure sensing component and a temperature sensing component are connected to the ceramic circuit board. The temperature sensing component extends downward into the temperature probe; a metal pin penetrates through the sintered base, and both ends of the metal pin are respectively connected to the ceramic circuit board and the electrical connector; the sealing structure includes a sealing hole and a vitreous body, and the metal pin is located in the sealing hole and is sintered and sealed in the sealing hole by means of the vitreous body.

[0004] For example, the utility model with the application number 201120039738.0 discloses a glass-ceramic sealed base for a pressure sensor, including a housing and leads connected to the housing. A group of sintering holes are provided on the housing, and a lead is provided in each sintering hole. The neck of one end of the lead is sealed in the sintering hole of the housing by glass-ceramic, and the end head above the neck of the lead is exposed outside the glass-ceramic.

[0005] The preparation process of the glass sintered base requires the assistance of tooling. There are differences in the thermal expansion coefficients between the conventional graphite tooling and those of metals and glass, and the structural design of the tooling also affects the sealing effect of the glass sintered base. At the same time, the commonly used glass sealing materials for the glass sintered base are mostly non-crystalline glass materials, and cracks are prone to propagate due to creep of micro-cracks during use, resulting in poor sealing. Summary of the Invention

[0006] Aiming at the deficiencies of the prior art, the purpose of the present invention is to provide a crystalline glass material, a glass sintered base and a preparation method thereof with high pressure-bearing performance and excellent thermal shock resistance. By tooling design, the glass microcracks caused by the difference in thermal expansion coefficient during the preparation of the glass sintered base are reduced; by optimizing the glass material into a crystalline glass, the mechanical properties and chemical stability of the glass are enhanced, thereby improving the thermal shock resistance of the sealing component.

[0007] The technical solution adopted by the present invention to solve the technical problem is: a glass sintered base with high pressure-bearing performance and excellent thermal shock resistance, including a housing, leads and microcrystalline glass beads. A number of sealing through holes are provided in the housing, the microcrystalline glass beads are fixed in the sealing through holes, the middle part of the lead is inserted into the microcrystalline glass beads, and after being sintered into one body with the microcrystalline glass beads by the assistance of a sintering tooling, it is fixed in the sealing through hole; the microcrystalline glass beads are a lead-free crystalline glass material, and the system of this lead-free glass material is SiO2-B2O3-Al2O3-Dy2O3.

[0008] Further, the lead-free crystalline glass material contains the following components by weight percentage: silicon dioxide 25.95-30.98%, boron oxide 31.57-37.70%, aluminum oxide 12.88-16.01%, sodium oxide 2.43-3.26%, zirconium oxide 2.59-5.44%, magnesium oxide 1.70-1.98%, calcium oxide 4.13-4.40%, dysprosium oxide 5.89-10.98%, titanium dioxide 0.88-1.23%.

[0009] Further, the housing is any one of 316L stainless steel or 304L stainless steel; the lead is nickel-iron alloy Alloy52 or iron-nickel constant expansion alloy 4J50.

[0010] Further, the thermal expansion coefficient of the sintering tooling matches the thermal expansion coefficient of the housing, and the material of the sintering tooling is 316L stainless steel or 304L stainless steel.

[0011] A preparation method of a glass sintered base with high pressure-bearing performance and excellent thermal shock resistance includes the following steps:

[0012] S1. Place the housing in a vacuum furnace for vacuum annealing, and the annealing temperature is 700-1050°C; place the lead in a pre-oxidation furnace for alloy pre-oxidation, and the pre-oxidation temperature is 550-640°C;

[0013] S2. Ultrasonically clean the housing, leads and microcrystalline glass beads with deionized water and absolute ethanol for 10-15 minutes each, and place them in an oven at 100-120°C for drying > 4 hours;

[0014] S3. Assemble the glass ceramic beads, leads, and the housing into the sintering tooling in sequence; place them together with the sintering tooling into a nitrogen atmosphere bell jar furnace for sealing. The sintering temperature is 900 - 930 °C, and the sintering time is 15 - 30 min. After sintering, cool it in the furnace to room temperature to obtain the sealed component;

[0015] S4. Conduct surface treatment on the sealed component to remove the oxide layer;

[0016] S5. Conduct electroplating treatment on the sealed component, electroplate gold on the leads to obtain the glass sintered base;

[0017] S6. Conduct various performance tests on the sealed component, including insulation resistance, helium leak rate, and thermal shock resistance.

[0018] Performance test results: All key dimensions of the sealed component meet the requirements; the appearance of the housing is uniform and there is no obvious oxide layer; the glass surface is smooth without impurities, bubbles, or cracks; the insulation resistance of the sealed component is ≥500 MΩ@1000 Vdc; the helium leak rate is ≤1x10 -9 Pa·m 3 / s; after the sealed component undergoes a thermal shock cycle of -54 °C to 150 °C ≥48 h (holding at -54 °C for 2 h and 150 °C for 2 h) under a pressure of 15 Mpa, the helium leak rate is ≤1x10 -9 Pa·m 3 / s.

[0019] Furthermore, the preparation of the glass ceramic beads includes the following steps:

[0020] S21. Weigh each component of the glass material by weight percentage and mix them evenly with a mixer;

[0021] S22. Melt at a high temperature of 1450 - 1650 °C for 40 - 70 min to obtain a clarified glass solution. Quench the glass solution with water to obtain glass slag, and dry it in an oven at 100 °C for >4 hours;

[0022] S23. Place the glass slag in a planetary ball mill for crushing to obtain glass powder; the particle size D50 of the glass powder is between 20 - 30 μm;

[0023] S24. During the water quenching process in S22, cast regular rectangular glass rods separately, conduct grinding and polishing, and then test the intrinsic thermal properties of the glass material, including thermal expansion coefficient, softening temperature, and glass transition temperature;

[0024] S25. Pulp the glass powder in S23 to obtain glass slurry;

[0025] S26. Granulate the glass paste in S25 using spray granulation technology, and control the inlet and outlet temperatures and the feeding speed to obtain granulated powder with a particle size of 80 - 200 mesh.

[0026] S27. Automatically form the granulated powder in S26 into green blanks of glass beads, then carry out debinding and vitrification to obtain fired blanks of glass-ceramic beads with appropriate inner and outer diameters and weights.

[0027] Further, in step S25, the pulping process is specifically as follows: Add an appropriate amount of deionized water into a ball mill tank, then add an appropriate amount of glass powder, and then add a certain amount of dispersant, and ball mill for 30 - 40 minutes to obtain a mixed solution. Finally, add an appropriate amount of binder and ball mill for another 30 - 40 minutes to obtain a uniformly mixed glass paste.

[0028] Further, in step S23, the glass transition temperature T g of the glass powder is 585 - 601 °C, and the softening temperature T f of the glass powder is 660 - 671 °C.

[0029] Further, in step S26, the inlet temperature is 200 - 250 °C, the outlet temperature is 80 - 95 °C; the feeding speed is 1.5 - 2.5 rpm; in step S27, the inner diameter of the fired blank of glass-ceramic beads is 0.6 - 0.8 mm, and the outer diameter is 2.5 - 2.7 mm.

[0030] The beneficial effects of the present invention are as follows: Compared with the prior art, in a glass sintered base with high pressure-bearing performance and excellent thermal shock resistance and its preparation method provided by the present invention, the SiO2 - B2O3 - Al2O3 - Dy2O3 series crystalline glass material, in which magnesium oxide (MgO), zirconium oxide (ZrO2), and titanium oxide (TiO2) are matrix reinforcing phases of the crystalline glass material; Dy2O3 in the glass material helps the melting and clarification of the glass. At low temperatures, it can form a denser structure, improve the strength and toughness of the glass, and enhance the impact resistance of the glass material; improve the creep resistance under pressure of the glass material, and can meet the requirement that the high and low temperature cycles are greater than 48 h under pressure conditions.

[0031] The sintering tooling is optimized from the commonly used graphite tooling in the prior art to 316L stainless steel or 304L stainless steel tooling with a matched coefficient of thermal expansion; firstly, it synchronizes the expansion and contraction of metal parts during the sintering process, reduces the residual stress generated due to uneven thermal field after sintering, and further prevents the occurrence of glass microcracks; secondly, it is optimized from an integral tooling with high processing difficulty to a split tooling that is easier to process and has an increased service life.

[0032] The conventional test method for the pressure-bearing property of the glass sintered base is carried out at the target temperature, while the test of the present invention is carried out throughout the process from low temperature to high temperature, that is, heating, heat preservation, and cooling. Loads are applied in each stage to test the creep resistance of the glass and observe the reliability of the sealing at the glass-metal sealing interface during this process. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 It is a schematic structural diagram of the glass sintered base provided by the present invention.

[0034] Figure 2 It is a schematic structural diagram of the glass sintered base and the sintering tooling in the present invention.

[0035] Figure 3 It is a schematic cross-sectional structural diagram after the glass sintered base and the sintering tooling in the present invention are assembled.

[0036] Figure 4 It is an XRD diagram of the crystalline glass material obtained in Example 1 of the present invention.

[0037] Among them, 1 - outer shell; 2 - lead; 3 - glass ceramic bead; 4 - sintering tooling; 5 - sealing through hole. DETAILED DESCRIPTION OF THE INVENTION

[0038] The present invention will be further described below through specific examples. However, these examples are only used to illustrate the present invention and not to limit the scope of the present invention.

[0039] As Figures 1 to 4 shown, a glass sintered base with high pressure-bearing performance and excellent thermal shock resistance includes an outer shell, leads, and glass ceramic beads. A number of sealing through holes are provided in the outer shell. The glass ceramic beads are fixed in the sealing through holes. The middle part of the lead is inserted into the glass ceramic beads, and after being sintered into one body with the glass ceramic beads with the assistance of a sintering tooling, it is fixed in the sealing through holes. The glass ceramic beads are a lead-free crystalline glass material, and the system of this lead-free glass material is SiO2 - B2O3 - Al2O3 - Dy2O3.

[0040] The lead-free crystalline glass material includes the following components by weight percentage: silica 25.95 - 30.98%, boron oxide 31.57 - 37.70%, alumina 12.88 - 16.01%, sodium oxide 2.43 - 3.26%, zirconium oxide 2.59 - 5.44%, magnesium oxide 1.70 - 1.98%, calcium oxide 4.13 - 4.40%, dysprosium oxide 5.89 - 10.98%, and titanium dioxide 0.88 - 1.23%.

[0041] The outer shell is any one of 316L stainless steel or 304L stainless steel; the lead wire is nickel-iron alloy Alloy52 or iron-nickel constant expansion alloy 4J50. The thermal expansion coefficient of the sintering tooling matches that of the outer shell, and the material of the sintering tooling is 316L stainless steel or 304L stainless steel.

[0042] A preparation method of a glass sintered base with high pressure-bearing performance and excellent thermal shock resistance includes the following steps:

[0043] S1. Place the outer shell in a vacuum furnace for vacuum annealing, and the annealing temperature is 700-1050 °C; place the lead wire in a pre-oxidation furnace for alloy pre-oxidation, and the pre-oxidation temperature is 550-640 °C;

[0044] S2. Ultrasonically clean the outer shell, lead wire and glass ceramic beads with deionized water and anhydrous ethanol for 10-15 min each, and place them in an oven at 100-120 °C for drying for more than 4 h;

[0045] S3. Assemble the glass ceramic beads, lead wire and outer shell into the sintering tooling in sequence; place them together with the sintering tooling in a nitrogen atmosphere bell jar furnace for sealing, the sintering temperature is 900-930 °C, the sintering time is 15-30 min, and after sintering, cool them to room temperature with the furnace to obtain a sealed component;

[0046] S4. Perform surface treatment on the sealed component to remove the oxide layer;

[0047] S5. Perform electroplating treatment on the sealed component, electroplate gold on the lead wire, and obtain a glass sintered base;

[0048] S6. Perform various performance tests on the sealed component, including insulation resistance, helium leakage rate, and thermal shock resistance.

[0049] Performance test results: All key dimensions of the sealed component meet the requirements; the appearance of the outer shell is uniform and there is no obvious oxide layer; the glass surface is smooth without impurities, bubbles and cracks; the insulation resistance of the sealed component is ≥500 MΩ@1000 Vdc; the helium leakage rate is ≤1x10 -9 Pa·m 3 / s; after the sealed component undergoes a thermal shock cycle of -54 °C to 150 °C for ≥48 h (insulated at -54 °C for 2 h and at 150 °C for 2 h) under a pressure of 15 Mpa, the helium leakage rate is ≤1x10 -9 Pa·m 3 / s.

[0050] Among them, the preparation of the glass ceramic beads used in S2 includes the following steps:

[0051] S21. Weigh each component of the glass material by weight percentage and mix them evenly with a mixer;

[0052] S22. Melting at a high temperature of 1450 - 1650 °C for 40 - 70 min to obtain a clarified glass solution, quenching the glass solution with water to obtain glass slag, and drying it in an oven at 100 °C for more than 4 hours;

[0053] S23. Place the glass slag in a planetary ball mill for crushing to obtain glass powder; the particle size D50 of the glass powder is between 20 - 30 μm; the glass transition temperature T of the glass powder g is 585 - 601 °C, and the softening temperature T of the glass powder f is 660 - 671 °C;

[0054] S24. During the water quenching process in S22, regularly cast rectangular glass rods, after grinding and polishing, test the intrinsic thermal and mechanical properties of the glass material, including the coefficient of thermal expansion, softening temperature, glass transition temperature, and fracture toughness;

[0055] S25. Pulverize the glass powder in S23 to obtain a glass slurry; the pulping process is specifically as follows: add an appropriate amount of deionized water to the ball mill tank, add an appropriate amount of glass powder, and then add a certain amount of dispersant. The dispersant is a conventional aqueous dispersant; ball mill for 30 - 40 min to obtain a mixed solution, and finally add an appropriate amount of binder. The binder is polyethylene glycol 6000 (PEG); ball mill for 30 - 40 min for the second time to obtain a uniformly mixed glass slurry;

[0056] S26. Granulate the glass slurry in S25 using spray granulation technology, control the inlet temperature at 200 - 250 °C, the outlet temperature at 80 - 95 °C, and the feeding speed at 1.5 - 2.5 rpm to obtain granulated powder with a particle size of 80 - 200 mesh;

[0057] S27. Automatically form the granulated powder in S26 into a green body of glass beads, then carry out debinding and vitrification to obtain a fired body of microcrystalline glass beads with an inner diameter of 0.6 - 0.8 mm and an outer diameter of 2.5 - 2.7 mm.

[0058] The following is a list of the compositions (by weight percentage) of the lead - free crystalline glass materials used in two specific examples (Example 1 and Example 2):

[0059] consist of <![CDATA[SiO2]]> <![CDATA[B2O3]]> <![CDATA[Al2O3]]> <![CDATA[Na2O]]> <![CDATA[ZrO2]]> MgO CaO <![CDATA[Dy2O3]]> <![CDATA[TiO2]]> Sum (wt.%) Example 1 30.98 37.70 12.88 3.26 2.59 1.70 4.13 5.89 0.88 100.00 Example 2 25.95 31.57 16.01 2.43 5.44 1.98 4.40 10.98 1.23 100.00

[0060] The performance test results of the lead - free crystalline glass materials obtained in the above - mentioned Example 1 and Example 2 are as follows:

[0061]

[0062] The performance test results of the sealing components prepared from the lead-free crystalline glass materials obtained in the above-mentioned Example 1 and Example 2 are as follows:

[0063] Test items Insulation resistance Helium leak rate Thermal shock resistance Example 1 > 500 MΩ @ 1000 V <![CDATA[≤1x10 -9 Pa·m 3 / s]]> ≤48h Example 2 > 500 MΩ @ 1000 V <![CDATA[≤1x10 -9 Pa·m 3 / s]]> ＞48h

[0064] The above embodiments are only used to illustrate the present invention and are not intended to limit the present invention. Those of ordinary skill in the relevant technical field can also make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, all equivalent technical solutions also belong to the scope of the present invention. The patent protection scope of the present invention shall be defined by the claims.

Claims

1. A glass sintered base with high pressure-bearing performance and excellent thermal shock resistance, characterized in that: It includes a housing, leads and a glass-ceramic bead. A number of sealing through-holes are provided inside the housing. The glass-ceramic bead is fixed in the sealing through-hole. The middle part of the lead is inserted into the glass-ceramic bead, and after being sintered into one body with the glass-ceramic bead with the assistance of a sintering tooling, it is fixed in the sealing through-hole. The glass-ceramic bead is a lead-free crystalline glass material, and the system of this lead-free glass material is SiO2 - B2O3 - Al2O3 - Dy2O3.

2. The glass sintered base with high pressure bearing performance and excellent thermal shock resistance according to claim 1, characterized in that: The lead-free crystalline glass material contains the following components by weight percentage: silicon dioxide 25.95 - 30.98%, boron oxide 31.57 - 37.70%, aluminum oxide 12.88 - 16.01%, sodium oxide 2.43 - 3.26%, zirconium oxide 2.59 - 5.44%, magnesium oxide 1.70 - 1.98%, calcium oxide 4.13 - 4.40%, dysprosium oxide 5.89 - 10.98%, titanium dioxide 0.88 - 1.23%.

3. A glass sintered base with high pressure resistance and excellent thermal shock resistance as described in claim 1, characterized in that: The housing is any one of 316L stainless steel or 304L stainless steel; the lead is nickel-iron alloy Alloy52 or iron-nickel constant expansion alloy 4J50.

4. A glass sintered base with high pressure bearing performance and excellent thermal shock resistance as described in claim 1, characterized in that: The thermal expansion coefficient of the sintering tooling matches that of the housing, and the material of the sintering tooling is 316L stainless steel or 304L stainless steel.

5. The preparation method of a glass sintered base with high pressure bearing performance and excellent thermal shock resistance according to any one of claims 1 to 4, characterized in that, It includes the following steps: S1. Place the housing in a vacuum furnace for vacuum annealing, and the annealing temperature is 700 - 1050 °C; place the lead in a pre-oxidation furnace for alloy pre-oxidation, and the pre-oxidation temperature is 550 - 640 °C. S2. Ultrasonically clean the housing, leads and glass-ceramic bead with deionized water and absolute ethanol for 10 - 15 min each, and place them in an oven at 100 - 120 °C for drying > 4 h. S3. Assemble the glass-ceramic bead, lead and housing into the sintering tooling in sequence; place them together with the sintering tooling in a nitrogen atmosphere bell furnace for sealing. The sintering temperature is 900 - 930 °C, and the sintering time is 15 - 30 min. After sintering, cool it to room temperature with the furnace to obtain a sealed component. S4. Perform surface treatment on the sealed component to remove the oxide layer. S5. Perform electroplating treatment on the sealed component, and electroplate gold on the lead to obtain a glass sintered base. S6. Perform various performance tests on the sealed component, including insulation resistance, helium leakage rate, and thermal shock resistance.

6. The preparation method of a glass sintered base with high pressure bearing performance and excellent thermal shock resistance according to claim 1, characterized in that, The preparation of the glass-ceramic bead includes the following steps: S21. Weigh each component of the glass material by weight percentage and mix them evenly with a mixer. S22. Melt at a high temperature of 1450 - 1650 °C for 40 - 70 min to obtain a clear glass solution. Quench the glass solution with water to obtain glass slag, and dry it in an oven at 100 °C for > 4 hours. S23. Place the glass slag in a planetary ball mill for crushing to obtain glass powder; the particle size D50 of the glass powder is between 20 - 30 μm. S24. During the water quenching process in S22, cast regular cuboid glass rods separately, perform grinding and polishing, and then test the intrinsic thermal properties of the glass material, including thermal expansion coefficient, softening temperature, and glass transition temperature. S25. Make a slurry of the glass powder in S23 to obtain a glass slurry. S26. Granulate the glass paste in S25 using spray granulation technology, and control the inlet and outlet temperatures and the feeding speed to obtain granulated powder with a particle size of 80 - 200 mesh. S27. Automatically form the granulated powder in S26 into green blanks of glass beads, then carry out debinding and vitrification to obtain sintered blanks of glass-ceramic beads with appropriate inner and outer diameters and weights.

7. The preparation method of a glass sintered base with high pressure-bearing performance and excellent thermal shock resistance as described in claim 6, characterized in that: In step S25, the pulping process is specifically as follows: Add an appropriate amount of deionized water into a ball mill tank, then add an appropriate amount of glass powder, and further add a certain amount of dispersant. Ball mill for 30 - 40 minutes to obtain a mixed solution, and finally add an appropriate amount of binder and ball mill for another 30 - 40 minutes to obtain a uniformly mixed glass paste.

8. The preparation method of a glass sintered base with high pressure bearing performance and excellent thermal shock resistance as described in claim 6, characterized in that: In step S23, the glass transition temperature T of the glass powder g is 585 to 601 °C, and the softening temperature T of the glass powder f is 660 to 671 °C.

9. The preparation method of a glass sintered base with high pressure bearing performance and excellent thermal shock resistance according to claim 6, characterized in that: In step S26, the temperature at the feeding port is 200 - 250 °C, and the temperature at the discharging port is 80 - 95 °C; the feeding speed is 1.5 - 2.5 rpm; in step S27, the inner diameter of the sintered blank of glass-ceramic beads is 0.6 - 0.8 mm, and the outer diameter is 2.5 - 2.7 mm.

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