阅读说明：本技术 一种热电偶用封装玻璃及其制备和封装方法 (Packaging glass for thermocouple and preparation and packaging methods thereof ) 是由 钱学富 彭艳 缪鑫涛 韩滨 于 2021-07-02 设计创作，主要内容包括：本发明公开了一种热电偶用封装玻璃,P2O5在玻璃中具有成核作用,配合K-2O和MgO可以提高Li-2O-ZnO-SiO-2系微晶玻璃线膨胀系数,使封接玻璃的线膨胀系数为116-130×10～(-7)/℃(室温-300℃),与高温合金GH3039、镍铬合金和镍硅合金接近,可用于三种金属封接；B-2O-3、MgO和Al-2O-3联合使用具有降低玻璃与金属润湿角的作用,提高玻璃与金属的结合力,使封接玻璃在最高350℃温度下使用后泄漏率低于1×10～(-10)Pa·m3/s,绝缘电阻可达∞,同时,封接后产品具有很高的机械强度,能够通过GJB150.16A规定的振动试验；本发明中还加入了BaO,该成分具有调节玻璃软化温度,保证热电偶的镍铬-镍硅材料在经过玻璃封接后内部原子不会发生无序排列,使玻璃封接后热电偶的精度能够满足GB/T 16839.2规定的±0.004|t|℃的要求。(The invention discloses a packaging glass for a thermocouple, wherein P2O5 has a nucleation effect in the glass and is matched with K 2 O and MgO can increase Li 2 O‑ZnO‑SiO 2 The linear expansion coefficient of the glass ceramics is set to be 116-130 x 10 ‑7 The temperature is approximate to the high-temperature alloy GH3039, the nickel-chromium alloy and the nickel-silicon alloy at room temperature of-300 ℃, and the sealing material can be used for sealing three metals; b is 2 O 3 MgO and Al 2 O 3 The combined use has the effects of reducing the wetting angle of glass and metal, improving the bonding force of the glass and the metal, and ensuring that the leakage rate of the sealing glass is lower than 1 multiplied by 10 after the sealing glass is used at the temperature of 350 ℃ at most ‑10 Pa.m 3/s, insulation resistance up toInfinity, and the sealed product has high mechanical strength and can pass the vibration test specified by GJB150.16A; BaO is added in the invention, and the component can adjust the softening temperature of glass, so that the disordered arrangement of internal atoms of the nickel-chromium-nickel-silicon material of the thermocouple can be avoided after the glass sealing, and the precision of the thermocouple after the glass sealing can meet the requirement of +/-0.004T DEG C specified in GB/T16839.2.)

1. The packaging glass for the thermocouple is characterized by comprising the following components in parts by weight: SiO 2₂：50-60wt％，ZnO：10-12wt％，Li₂O：8-9wt％，Al₂O₃：5-7wt％，B₂O₃：5-7wt％，K₂O：4-5wt％，MgO：4-5wt％，P₂O₅：1-3wt％，BaO：0.5-2wt％。

2. The sealing glass for a thermocouple according to claim 1, characterized in that it comprises the following components in parts by weight: SiO 2₂：55.3wt％，ZnO：10.3wt％，Li₂O：8.6wt％，Al₂O₃：6.0wt％，B₂O₃：6.7wt％，K₂O：4.8wt％，MgO：4.9wt％，P₂O₅：1.9wt％，BaO：1.5wt％。

3. A method for producing the sealing glass for a thermocouple according to claim 1 or 2, characterized in that: (1) mixing all the components on a ball mill for 7-9h to form a mixture, heating the mixture at 1480-1520 ℃ for 5-7h, then quickly cooling, and grinding after quick cooling to ensure that the particle size is less than or equal to 75 micrometers to obtain glass powder; (2) mixing the glass powder and the high-purity paraffin according to the mass ratio of 25-35:1, stirring and mixing at 70-90 ℃, then performing dry pressing molding, and performing structural heat preservation and dewaxing to obtain a glass blank.

4. A method for sealing a sealing glass for a thermocouple according to claim 1 or 2, comprising: assembling the high-temperature alloy GH3039 shell, the nickel-chromium wire core, the nickel-silicon wire core and the glass blank, then preserving the heat for 30-50min at the temperature of 1020-.

Technical Field

The invention relates to the technical field of glass, in particular to packaging glass for a thermocouple and a preparation method and a packaging method thereof.

Background

The working environment of the high-temperature section of the modern aeroengine is severe, and the gas temperature of the modern aeroengine is mainly measured by an armored thermocouple. Insulation resistance is an important index of the armored thermocouple, and shunt errors can be introduced into temperature measurement due to the reduction of the insulation resistance, so that the test precision of the armored thermocouple is influenced, and therefore, the sealing of the output end of the armored thermocouple is particularly important.

The sealing material at the output end of the armored thermocouple depends on the temperature of the use environment, and can be sealed by silicon rubber and epoxy resin when the temperature is lower than 300 ℃, and sealed by glass when the temperature is higher than 300 ℃. The aviation armored thermocouple has high requirement on the corrosion resistance of a shell material, so that the traditional kovar alloy suitable for glass sealing cannot be used, the aviation armored thermocouple shell generally uses a high-temperature alloy GH3039 (the linear expansion coefficient is 132 multiplied by 10 < -7 >/DEG C, the room temperature is 300 ℃ below zero), the inner wire core is a nickel-chromium wire and a nickel-silicon wire (the linear expansion coefficient is 135 multiplied by 10 < -7 >/DEG C, the room temperature is 300 ℃ below zero), tests prove that the air tightness of the aviation armored thermocouple can meet the use requirement only when the air tightness reaches 1 multiplied by 10 < -10 > m < -3 >/s under the high-temperature and high-humidity environment of an aeroengine, and the insulation of the armored thermocouple can be reduced only when the traditional glass sealing is used, wherein the air tightness reaches 1 multiplied by 10 < -9 > m < -3 >/s, or even lower. In addition, if the glass sealing temperature can not reach the maximum service temperature of the thermocouple, the precision of the thermocouple is ultra-poor after sealing, and the requirement of +/-0.004T DEG C specified by GB/T16839.2 can not be met.

Li₂O-ZnO-SiO₂The glass is an important sealing material in glass packaging, and people are increasingly researching the glass, for example, Chinese patent document CN104529164A discloses devitrification type high-expansion glass powder, a preparation method and an application thereof, which comprises the following steps: 30-60 wt% SiO₂、10-30wt％ZnO、5-15wt％Li₂O、0-5wt％Al₂O₃、2-12wt％B₂O₃、0-8wt％K₂O、0-10wt％Na₂O、0-10wt％P₂O₅And 0-10 wt% NiO, Fe₂O₃And/or Cr₂O₃The sum of the weight fractions of the components is 100 percent. However, in the above-mentioned documents, Li is adjusted₂O-ZnO-SiO₂Is a glass composition formula, which has an expansion coefficient of 130-^-7In the range of/° c, enabling it to be sealed in high expansion metal devices. However, when it is applied to a sheathed thermocouple, its accuracy exceeds the national standard requirements and the leakage rate is relatively high.

Disclosure of Invention

In order to solve the technical problem, the invention provides packaging glass for a thermocouple, which comprises the following components in parts by weight: SiO 2₂：50-60wt％，ZnO：10-12wt％，Li₂O：8-9wt％，Al₂O₃：5-7wt％，B₂O₃：5-7wt％，K₂O：4-5wt％，MgO：4-5wt％，P₂O₅：1-3wt％，BaO：0.5-2wt％。

Further, the paint comprises the following components in parts by weight: SiO 2₂：55.3wt％，ZnO：10.3wt％，Li₂O：8.6wt％，Al₂O₃：6.0wt％，B₂O₃：6.7wt％，K₂O：4.8wt％，MgO：4.9wt％，P₂O₅：1.9wt％，BaO：1.5wt％。

The invention also provides a preparation method of the packaging glass for the thermocouple, which comprises the following steps: (1) mixing the components on a ball mill for 7-9h to form a mixture, heating the mixture at 1480-1520 ℃ for 5-7h, then quickly cooling, and grinding after quick cooling to ensure that the particle size is less than or equal to 75 micrometers to obtain glass powder; (2) mixing glass powder and high-purity paraffin according to the mass ratio of 25-35:1, stirring and mixing at 70-90 ℃, then performing dry pressing molding, and performing structural heat preservation and dewaxing to obtain a glass blank; as for the molding structure, without particular limitation, a cylindrical band having two or 4 holes is preferable; as for the rapid cooling, that is, the cooling process, there is no particular limitation, and natural cooling with air may be specifically employed.

The invention also provides a method for encapsulating the glass for the thermocouple, which comprises the steps of assembling the high-temperature alloy GH3039 shell, the nickel-chromium wire core, the nickel-silicon wire core and the glass blank, then preserving the heat for 30-50min at the temperature of 1020-.

Compared with the prior art, the technical scheme of the invention has the following advantages:

(1) the P2O5 in the packaging glass for the thermocouple has the nucleation effect in the glass and is matched with K₂O and MgO can increase Li₂O-ZnO-SiO₂The linear expansion coefficient of the glass ceramics is set to be 116-130 x 10^-7The temperature is approximate to the high-temperature alloy GH3039, the nickel-chromium alloy and the nickel-silicon alloy at room temperature of-300 ℃, and the sealing material can be used for sealing three metals; b is₂O₃MgO and Al₂O₃The combined use has the effects of reducing the wetting angle of glass and metal, improving the bonding force of the glass and the metal, and ensuring that the leakage rate of the sealing glass is lower than 1 multiplied by 10 after the sealing glass is used at the temperature of 350 ℃ at most^-10Pa.m 3/s, the insulation resistance can reach infinity, and simultaneously, the sealed product has very high mechanical strength and can pass a vibration test specified by GJB150.16A; BaO is added, the softening temperature of the glass is adjusted, the disordered arrangement of atoms in the nickel-chromium-nickel-silicon material of the thermocouple can be guaranteed after the glass sealing, the precision of the thermocouple after the glass sealing can meet the requirement of +/-0.004T DEG C specified by GB/T16839.2, and the precision error is plus or minus 4 degrees taking 1000 ℃ as an example.

(2) According to the preparation method and the packaging method of the packaging glass for the thermocouple, disclosed by the invention, when the glass blank prepared from the glass raw materials is used for preparing the thermocouple, the mechanical strength is high, the leakage rate is low, and the precision meets the national standard requirement.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings needed to be used in the embodiments will be briefly described below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and it is obvious for those skilled in the art to derive other drawings without creative efforts.

FIG. 1 is a diagram of the packaging effect of the present invention;

Detailed Description

The present invention now will be described more fully hereinafter with reference to the accompanying drawings, in which some, but not all embodiments of the invention are shown. The embodiments in the present invention, other embodiments obtained by persons skilled in the art without any inventive work, belong to the protection scope of the present invention.

Example 1

1) Weighing the following components in parts by weight: SiO 2₂：55.3wt％，ZnO：10.3wt％，Li₂O：8.6wt％，Al₂O₃：6.0wt％，B₂O₃：6.7wt％，K₂O：4.8wt％，MgO：4.9wt％，P₂O₅：1.9wt％，BaO：1.5wt％；

2) Mixing the components on a ball mill for 8 hours, heating the mixture in a crucible at 1495 ℃ for 6 hours, then cooling the mixture by air, naturally cooling the mixture, and then grinding the mixture to obtain glass powder with the particle size of 75 microns at most;

3) mixing the glass powder with the high-purity paraffin wax slices (mass ratio is 30:1), stirring and mixing at 80 ℃, then performing dry pressing and molding, and then performing heat preservation at 610 ℃ for 4 hours to remove wax to prepare a glass blank;

4) and (3) deoiling and cleaning the shell, the nickel-chromium wire core and the nickel-silicon wire core, then placing the shell, the nickel-chromium wire core and the nickel-silicon wire core in a common box furnace at 700 ℃, preserving heat for 10min, and then taking out for air cooling.

d) Assembling the shell, the nickel-chromium wire core, the nickel-silicon wire core and the glass blank, then filling nitrogen into a vacuum furnace, maintaining the temperature of 1055 ℃ for 40min, cooling along with the furnace, and taking out to obtain the thermocouple.

Example 2

1) Weighing the following components in parts by weight: SiO 2₂：50wt％，ZnO：12wt％，Li₂O：9wt％，Al₂O₃：7wt％，B₂O₃：7wt％，K₂O：5wt％，MgO：5wt％，P₂O₅：3wt％，BaO：2wt％；

2) Mixing the components on a ball mill for 7 hours, heating the mixture in a crucible at the temperature of 1480 ℃ for 5 hours, then cooling the mixture with air, and grinding the mixture after natural cooling to obtain glass powder with the particle size of 75 microns at most;

3) mixing glass powder and high-purity paraffin wax slices (mass ratio is 25:1), stirring and mixing at 70 ℃, then performing dry pressing and molding, and then performing heat preservation at 610 ℃ for 4 hours to remove wax to prepare a glass blank;

4) and (3) deoiling and cleaning the shell, the nickel-chromium wire core and the nickel-silicon wire core, then placing the shell, the nickel-chromium wire core and the nickel-silicon wire core in a common box furnace at 700 ℃, preserving heat for 10min, and then taking out for air cooling.

d) And assembling the shell, the nickel-chromium wire core, the nickel-silicon wire core and the glass blank, then filling nitrogen into a vacuum furnace, maintaining the temperature at 1020 ℃ for 30min, cooling along with the furnace, and taking out to obtain the thermocouple.

Example 3

1) Weighing the following components in parts by weight: SiO 2₂：60wt％，ZnO：10wt％，Li₂O：8.5wt％，Al₂O₃：5wt％，B₂O₃：5.5wt％，K₂O：4wt％，MgO：5wt％，P₂O₅：1.5wt％，BaO：0.5wt％；

2) Mixing the components on a ball mill for 9h, heating the mixture in a crucible at 1520 ℃ for 6h, then cooling the mixture by air, and grinding the mixture after natural cooling to obtain glass powder with the particle size of 75 microns at most;

3) mixing glass powder and high-purity paraffin wax slices (mass ratio is 35:1), stirring and mixing at 90 ℃, then performing dry pressing and molding, and then performing heat preservation at 610 ℃ for 4 hours to remove wax to prepare a glass blank;

4) and (3) deoiling and cleaning the shell, the nickel-chromium wire core and the nickel-silicon wire core, then placing the shell, the nickel-chromium wire core and the nickel-silicon wire core in a common box furnace at 700 ℃, preserving heat for 10min, and then taking out for air cooling.

d) And assembling the shell, the nickel-chromium wire core, the nickel-silicon wire core and the glass blank, then filling nitrogen into a vacuum furnace, maintaining the temperature at 1070 ℃ for 50min, cooling along with the furnace, and taking out to obtain the thermocouple.

Example 4

1) Weighing the following components in parts by weight: SiO 2₂：59wt％，ZnO：11wt％，Li₂O：8wt％，Al₂O₃：6wt％，B₂O₃：5wt％，K₂O：4.5wt％，MgO：4.5wt％，P₂O₅：1wt％，BaO：1wt％；

2) Mixing the components on a ball mill for 8 hours, heating the mixture in a crucible at 1495 ℃ for 5 hours, then cooling the mixture with air, and grinding the mixture after natural cooling to obtain glass powder with the particle size of 75 microns at most;

3) mixing the glass powder with the high-purity paraffin wax slices (mass ratio is 30:1), stirring and mixing at 80 ℃, then performing dry pressing and molding, and then performing heat preservation at 610 ℃ for 4 hours to remove wax to prepare a glass blank;

4) and (3) deoiling and cleaning the shell, the nickel-chromium wire core and the nickel-silicon wire core, then placing the shell, the nickel-chromium wire core and the nickel-silicon wire core in a common box furnace at 700 ℃, preserving heat for 10min, and then taking out for air cooling.

d) Assembling the shell, the nickel-chromium wire core, the nickel-silicon wire core and the glass blank, then filling nitrogen into a vacuum furnace, maintaining the temperature of 1055 ℃ for 40min, cooling along with the furnace, and taking out to obtain the thermocouple.

Comparative example 1

1) Weighing the following components in parts by weight: SiO 2₂：56.8wt％，ZnO：10.3wt％，Li₂O：8.6wt％，Al₂O₃：6.0wt％，B₂O₃：6.7wt％，K₂O：4.8wt％，MgO：4.9wt％，P₂O₅：1.9wt％；

2) Mixing the components on a ball mill for 8 hours, heating the mixture in a crucible at 1495 ℃ for 6 hours, then cooling the mixture with air, and grinding the mixture after natural cooling to obtain glass powder with the particle size of 75 microns at most;

3) mixing the glass powder with the high-purity paraffin wax slices (mass ratio is 30:1), stirring and mixing at 80 ℃, then performing dry pressing and molding, and then performing heat preservation at 610 ℃ for 4 hours to remove wax to prepare a glass blank;

4) and (3) deoiling and cleaning the shell, the nickel-chromium wire core and the nickel-silicon wire core, then placing the shell, the nickel-chromium wire core and the nickel-silicon wire core in a common box furnace at 700 ℃, preserving heat for 10min, and then taking out for air cooling.

d) Assembling the shell, the nickel-chromium wire core, the nickel-silicon wire core and the glass blank, then filling nitrogen into a vacuum furnace, maintaining the temperature of 1055 ℃ for 40min, cooling along with the furnace, and taking out to obtain the thermocouple.

Comparative example 2

1) Weighing the following components in parts by weight: SiO 2₂：55wt％，ZnO：13wt％，Li₂O：11wt％，Al₂O₃：2wt％，B₂O₃：4wt％，Na₂O：6wt％，P₂O₅：4wt％，Fe₂O₃：5wt％；

2) The components are fully and uniformly mixed and then are put into a crucible, a crucible cover is added, and the temperature is kept for 2 hours in a 1480-DEG silicon-molybdenum rod electric furnace;

3) then, rolling, crushing, drying and ball-milling the melted glass liquid to form particles with the particle size of 50 particles at most;

4) and (3) deoiling and cleaning the shell, the nickel-chromium wire core and the nickel-silicon wire core, then placing the shell, the nickel-chromium wire core and the nickel-silicon wire core in a common box furnace at 700 ℃, preserving heat for 10min, and then taking out for air cooling.

5) Assembling the shell, the nickel-chromium wire core, the nickel-silicon wire core and the glass particle powder, preserving heat for 40min at 1055 ℃ in a vacuum nitrogen protection furnace, and cooling along with the furnace; and finally, carrying out heat treatment at 671 ℃ for 3.5 h.

Test example 1

The surface effect observation of the thermocouple obtained in example 1 shows that the glass is tightly combined with the wire core and the shell, the unshelling phenomenon does not occur, and the formed glass has no air holes and a smooth surface.

Test example 2

The thermocouples obtained in examples 1 to 4 and comparative examples 1 to 2 were subjected to a test of thermal expansion coefficient, leak rate, and thermocouple accuracy. The specific method comprises the following steps: the thermal expansion coefficient is tested according to the method specified in GB/T1697-2015; the leak rate was tested according to the method specified in section 1008 of GJB 1217; thermocouple accuracy was tested according to the method specified in section 6.3 of JB/T8205-1999.

Wherein the thermal expansion coefficient results, leakage rate results and accuracy results are shown in Table 1

In conclusion, through the tests, compared with the comparative example 1, the results of the 3 tests are that the effect of the thermocouple obtained by the invention is far better than that of the comparative example 1; in comparative example 2, although the thermal expansion coefficient was substantially the same as the result of the present invention, the effect was far less excellent in terms of leakage rate and accuracy than that of the thermocouple obtained by the present invention.

It should be understood that the above examples are only for clarity of illustration and are not intended to limit the embodiments. Other variations and modifications will be apparent to persons skilled in the art in light of the above description. And are neither required nor exhaustive of all embodiments. And obvious variations or modifications therefrom are within the scope of the invention.