阅读说明：本技术 一种高温压力传感器及其制备方法 (High-temperature pressure sensor and preparation method thereof ) 是由 李晨 熊继军 贾鹏宇 孙博山 于 2020-11-25 设计创作，主要内容包括：本发明涉及高温压力传感器技术领域,公开了一种高温压力传感器及其制备方法,包括：包括相互连接的传感器头和转换电路板,所述传感器头包括：封装外壳,敏感微结构,设置在空腔内；前卡环,设置在空腔内的前端,对敏感微结构的前端进行限位；后卡环,设置在空腔的后端,对敏感微结构的后端进行限位；转换电路板,设置在套筒外壳内；高温丝管壳,一端通过连接部与封装外壳连接,另一端与套筒外壳连接；高温丝,穿过高温丝管壳,一端伸入封装外壳内与敏感微结构连接,另一端伸入套筒外壳内与转换电路板连接,这种高温压力传感器及其制备方法,实现了压力传感器在-40℃—1000℃全温区高精度动态测量。(The invention relates to the technical field of high-temperature pressure sensors, and discloses a high-temperature pressure sensor and a preparation method thereof, wherein the preparation method comprises the following steps: including sensor head and the switching circuit board of interconnect, the sensor head includes: the packaging shell is provided with a sensitive microstructure which is arranged in the cavity; the front clamping ring is arranged at the front end in the cavity and used for limiting the front end of the sensitive microstructure; the rear clamping ring is arranged at the rear end of the cavity and used for limiting the rear end of the sensitive microstructure; the conversion circuit board is arranged in the sleeve shell; one end of the high-temperature wire tube shell is connected with the packaging shell through a connecting part, and the other end of the high-temperature wire tube shell is connected with the sleeve shell; the high-temperature wire penetrates through the high-temperature wire tube shell, one end of the high-temperature wire extends into the packaging shell to be connected with the sensitive microstructure, and the other end of the high-temperature wire extends into the sleeve shell to be connected with the conversion circuit board.)

1. A high temperature pressure sensor, comprising: a sensor head and a converter circuit board connected to each other, the sensor head comprising:

the packaging structure comprises a packaging shell (1), wherein a cavity (2) is arranged in the packaging shell, one end of the cavity (2) is provided with an airflow channel (13), and the other end of the cavity is provided with a connecting part (14);

a sensitive microstructure (7) arranged in the cavity (2);

the front clamping ring (6) is arranged at the front end in the cavity (2) and used for limiting the front end of the sensitive microstructure (7);

the rear clamping ring (8) is arranged at the rear end of the cavity (2) and used for limiting the rear end of the sensitive microstructure (7);

the conversion circuit board (5) is arranged in the sleeve shell (4) and is used for converting the pressure signal received by the sensitive microstructure (7) into an electric signal;

one end of the high-temperature wire tube shell (3) is connected with the packaging shell (1) through a connecting part (14), and the other end of the high-temperature wire tube shell is connected with the sleeve shell (4);

and the high-temperature wire (10) penetrates through the high-temperature wire tube shell (3), one end of the high-temperature wire extends into the packaging shell (1) to be connected with the sensitive microstructure (7), and the other end of the high-temperature wire extends into the sleeve shell (4) to be connected with the conversion circuit board (5).

2. The high-temperature pressure sensor according to claim 1, wherein the package housing (1) is made of nickel-based superalloy, the gas flow channel (13) includes a threaded through hole and a tapered through hole, the tapered through hole is close to the sensitive microstructure (7), the threaded through hole and the tapered through hole are coaxial, so that gas can be introduced to distribute pressure evenly on the surface of the sensitive microstructure (7), a ceramic column (11) is arranged inside the high-temperature wire tube housing (3), the ceramic column (11) is provided with a fine hole (12) along a length direction, and the high-temperature wire (10) penetrates through the ceramic column (11) through the fine hole (12).

3. A high-temperature pressure sensor according to claim 1, characterized in that the sensitive microstructure (7) comprises: a first layer (701), a second layer (702), and a third layer (703) that are sintered as one body;

a first layer (701) having two concentric square capacitor plates printed on the inner surface;

a second layer (702) arranged between the first layer (701) and the third layer (703), wherein a square cavity (711) is arranged in the center;

and a square capacitor is printed on the inner surface of the third layer (703), and a nickel-chromium and nickel-silicon thermocouple film is sputtered on the outer surface of the third layer by magnetron sputtering.

4. A high temperature pressure sensor according to claim 3, wherein the conductive film of the concentric square capacitor plates is a platinum film (706), a silicon dioxide film (707) is sputtered on the capacitor plates of the first layer (701) as an overload protection film, and the conductive film of the square capacitors of the third layer (703) is a square platinum film (708).

5. The high-temperature pressure sensor according to claim 1, wherein the pores (9) between the high-temperature wire (10) and the sensitive microstructure (7) are sealed by glass cement, and the pores between the sensitive microstructure (7) and the package housing (1) are sealed by high-temperature welding.

6. A high-temperature pressure sensor according to claim 1, wherein the sensitive microstructure (7) is plated with nickel and gold on both its upper and lower surfaces.

7. A method for making a high temperature pressure sensor as claimed in any of claims 1 to 6, comprising the steps of:

s1, preparing a sensitive microstructure (7);

s2, the sensitive microstructure (7) is arranged in the packaging shell (1);

s3, snap ring structures with round threads at the periphery and square clamping grooves (15) in the middle are arranged at the front and the back of a cavity (2) in a packaging shell (1), a front snap ring (6) is screwed into the packaging shell (1), the front end of a sensitive microstructure (7) is limited, and threads of the front snap ring (6) are sealed by a thread locking agent;

s4, placing the sensitive microstructure (7) in a notch of the square clamping groove (15), and sealing a gap between the sensitive microstructure (7) and the periphery of the notch for the first time by using glass cement;

s5, placing the sensitive microstructure (7) and the packaging shell (1) into a muffle furnace for sintering, wherein the set temperature of the muffle furnace is 800 ℃, the heat preservation time is 60 minutes, and then testing the sealing airtightness between the sensitive microstructure (7) and the packaging shell (1);

s6, clamping the head of the high-temperature wire (10) by using a pair of tweezers, and enabling the high-temperature wire (10) to penetrate through the fine hole (12) of the ceramic column (11) at a constant speed;

s7, screwing in a rear snap ring (8) to lock and fix the rear end of the sensitive microstructure (7), and sealing the inner side and the outer side of the rear snap ring (8) for the second time by using glass cement;

s8, putting the material into a muffle furnace for re-sintering, setting the temperature to be 800 ℃, keeping the temperature for 40 minutes, and then testing the sealing property between the sensitive microstructure (7) and the packaging shell (1) to finish the preparation of the sensor head;

s9, packaging the high-temperature wire (10) and the ceramic column (11) connected with the sensitive microstructure (7) by a nickel-based high-temperature alloy thin tube;

s10, welding the high-temperature wire (10) and the conversion circuit board (5);

s11, after welding, encapsulating and fixing the conversion circuit board (5) in the sleeve shell (4) by epoxy ethylene glue prepared according to a proportion;

and S12, finally drying for 1 hour by using a high-low temperature test chamber to finish the packaging of the high-temperature pressure sensor.

8. The method for preparing a high-temperature pressure sensor according to claim 7, wherein the step S1 of preparing the sensitive microstructure (7) comprises the steps of:

s101, placing the tape-cast raw porcelain tape into a slicing machine to slice according to the designed substrate size;

s102, putting the cut green ceramic chip into a punching machine for punching, and punching a counter bore (709) and a through hole;

s103, placing the punched green ceramic chips into a laminating machine for lamination, and then placing the green ceramic chips and a steel plate into a vacuum bag for compaction treatment;

s104, laminating the sensitive microstructure (7) in a laminating machine to finish the manufacture of a first layer (701), a second layer (702) and a third layer (703) of the sensitive microstructure;

s105, screen-printing a designed central square, a peripheral annular square platinum film and conducting circuits thereof on the upper surface of the first layer (701) of the green ceramic chip, wherein the conducting circuits respectively point to two sides of the square green ceramic chip, and the second layer (702) is used as a cavity isolating layer and is not processed;

s106, screen printing a square platinum polar plate and a conducting circuit thereof on the lower surface of the third layer (703) of the green ceramic chip;

s107, after printing is finished, putting the printed product into a high-low temperature test chamber for primary curing treatment, setting the temperature at 120 ℃, and drying for 10 minutes;

s108, embedding the high-temperature wire (10) into the counter bore (709), after the position is adjusted, filling the hole by using a micropore filling machine, electrically interconnecting the high-temperature wire and the conducting circuit, and drying again;

s109, fixing the position of the high-temperature wire, and putting the first layer (701) into a magnetron sputtering furnace with argon atmosphere to sputter a layer of silicon dioxide film (707) on the upper surface of the annular platinum plate;

s110, placing the laminated second layer (702) in the middle, aligning and laminating the first layer (701) to the third layer (703), and then performing hot isostatic pressing;

s111, putting the integral structure into a high-temperature furnace for sintering;

and S112, taking the sintered sensitive microstructure (7) as a substrate, and co-sputtering the nickel-chromium/nickel-silicon multi-target thermocouple film.

9. The method according to claim 8, wherein the sputtering target for sputtering the silicon dioxide thin film (707) in step S109 is a silicon target, and a gas mass flow ratio in the chamber during sputtering is O₂/(O₂And the + Ar) is 5/(5+200), the air pressure is constant to be 2Pa, and the overload insulating layer is taken out after sputtering for 40 minutes to finish the preparation of the overload insulating layer.

10. The method for manufacturing a high temperature pressure sensor according to claim 8, wherein in step S112, a thermocouple thin film is sputtered under a nichrome target, the manufactured ceramic pattern plate is covered on the surface of the substrate, the sputtering power is 200W, and the sputtering time is 50 minutes; covering the other ceramic pattern plate on the surface of the substrate, and sputtering the nickel-silicon film, wherein the sputtering power is 150W, and the sputtering time is 50 minutes; the atmosphere in the chamber is argon, the pressure is 2.5Pa, and the ceramic pattern plates are two-pole patterns of the thermocouple respectively.

Technical Field

The invention relates to the technical field of high-temperature pressure sensors, in particular to a high-temperature pressure sensor and a preparation method thereof.

Background

The high-temperature pressure sensor is used for measuring the pressure of various gases and liquids in a high-temperature environment, and has wide application prospect in the fields of civil industry and national defense and military industry. For example, the pressure measuring device can be used for measuring the pressure in a smelting tower and the pressure of a high-temperature oil well for civil use; the pressure sensor is used for measuring the pressure of heat-resistant cavities and surface parts of aeroengines and the like in military. The measurement of the pressure parameter under the high-temperature working condition is a key technology bottleneck restricting the development and operation processes of large-scale equipment such as advanced engines in the fields of aviation and aerospace, and how to realize accurate in-situ measurement of the pressure under the high-temperature working condition is a hotspot of future sensor research.

Although the existing high-temperature pressure sensor based on different principles and different materials solves the measurement problem under partial high-temperature working conditions, a plurality of defects still exist. For example, the silicon piezoresistive SOI high-temperature pressure sensor has the defect that the sensor is difficult to work in a high-temperature environment for a long time due to leakage current; the piezoresistive sensor based on SiC has the defects of large temperature drift and poor dynamic performance of the sensor due to the limitation of temperature on ohmic contact; the optical fiber type high-temperature pressure sensor is easily influenced by other non-measured physical quantities, and further influences the testing precision. The ceramic material has the characteristics of high temperature resistance, corrosion resistance, high mechanical strength, zero creep deformation and the like. Thus, ceramic-based high temperature pressure sensors offer a number of advantages not available with other types of sensors. The patent provides a high-temperature pressure sensor and a preparation method thereof, and the prepared sensor has the characteristics of strong corrosion resistance and strong overload resistance and can perform high-precision dynamic measurement on in-situ pressure parameters in a full temperature range of-40 ℃ to 1000 ℃.

Disclosure of Invention

The invention provides a high-temperature pressure sensor and a preparation method thereof, aiming at overcoming the defects of large temperature drift, poor dynamic performance and difficulty in working in a high-temperature environment for a long time of various sensors and ensuring that the sensor can accurately measure the pressure in the high-temperature environment in situ, the invention adopts a temperature and pressure integrated sensitive microstructure, a unique high-temperature signal transmission mode, a packaging structure and a temperature compensation system to realize the high-precision dynamic measurement of the pressure sensor in a full-temperature region of-40 ℃ to 1000 ℃.

The invention provides a high-temperature pressure sensor, which comprises a sensor head and a conversion circuit board which are connected with each other, wherein the sensor head comprises:

the packaging shell is internally provided with a cavity, one end of the cavity is provided with an airflow channel, and the other end of the cavity is provided with a connecting part;

the sensitive microstructure is arranged in the cavity;

the front clamping ring is arranged at the front end in the cavity and used for limiting the front end of the sensitive microstructure;

the rear clamping ring is arranged at the rear end of the cavity and used for limiting the rear end of the sensitive microstructure;

the conversion circuit board is arranged in the sleeve shell and used for converting the pressure signal received by the sensitive microstructure into an electric signal;

one end of the high-temperature wire tube shell is connected with the packaging shell through a connecting part, and the other end of the high-temperature wire tube shell is connected with the sleeve shell;

and the high-temperature wire penetrates through the high-temperature wire tube shell, one end of the high-temperature wire extends into the packaging shell to be connected with the sensitive microstructure, and the other end of the high-temperature wire extends into the sleeve shell to be connected with the conversion circuit board.

The packaging shell is made of nickel-based high-temperature alloy, the airflow channel comprises a threaded through hole and a conical through hole, the conical through hole is close to the sensitive microstructure, the threaded through hole and the conical through hole are coaxial, gas can be conveniently introduced to evenly distribute pressure on the surface of the sensitive microstructure, a ceramic column is arranged inside the high-temperature wire tube shell, a fine hole is formed in the ceramic column in the length direction, and the high-temperature wire penetrates through the ceramic column through the fine hole.

The sensitive microstructure comprises: sintering the first layer, the second layer and the third layer into a whole;

a first layer, wherein two concentric square capacitor plates are printed on the inner surface;

the second layer is arranged between the first layer and the third layer, and a square cavity is arranged in the middle of the second layer;

a square capacitor is printed on the inner surface of the third layer, and a nickel-chromium and nickel-silicon thermocouple film is sputtered on the outer surface of the third layer through magnetron sputtering;

the conductive film of the concentric square capacitor plate is a concentric platinum film, a layer of silicon dioxide film is sputtered on the capacitor plate of the first layer to serve as an overload protection film, and the conductive film of the square capacitor of the third layer is a square platinum film.

And the pores between the high-temperature wires and the sensitive microstructures are sealed by adopting glass cement, and the pores between the sensitive microstructures and the packaging shell are sealed by adopting high-temperature welding.

And performing nickel-gold electroplating treatment on the upper surface and the lower surface of the sensitive microstructure.

A preparation method of a high-temperature pressure sensor comprises the following steps:

s1, preparing a sensitive microstructure;

s2, the sensitive microstructure is arranged in the packaging shell;

s3, snap ring structures with round threads at the periphery and square clamping grooves in the middle are arranged at the front and the back of a cavity in the packaging shell, the front snap ring is screwed into the packaging shell to limit the front end of the sensitive microstructure, and the threads of the front snap ring are sealed by a thread locking agent;

s4, placing the sensitive microstructure in a notch of the square clamping groove, and sealing a gap between the sensitive microstructure and the periphery of the notch for the first time by using glass cement;

s5, placing the sensitive microstructure and the packaging shell into a muffle furnace for sintering, wherein the set temperature of the muffle furnace is 800 ℃, the heat preservation time is 60 minutes, and then testing the air tightness of the seal between the sensitive microstructure and the packaging shell;

s6, clamping the head of the high-temperature wire by using a pair of tweezers, and enabling the high-temperature wire to penetrate through the fine holes of the ceramic column at a constant speed;

s7, screwing in the rear snap ring to lock and fix the rear end of the sensitive microstructure, and sealing the inner side and the outer side of the rear snap ring for the second time by using glass cement;

s8, placing the material into a muffle furnace for re-sintering, setting the temperature to be 800 ℃, keeping the temperature for 40 minutes, and then testing the sealing property between the sensitive microstructure and the packaging shell to finish the preparation of the sensor head;

s9, packaging the high-temperature wire and the ceramic column connected with the sensitive microstructure by using a nickel-based high-temperature alloy thin tube;

s10, welding the high-temperature wire and the conversion circuit board;

s11, after welding, encapsulating and fixing the conversion circuit board in the sleeve shell by epoxy ethylene glue prepared according to a proportion;

and S12, finally drying for 1 hour by using a high-low temperature test chamber to finish the packaging of the high-temperature pressure sensor.

The step S1 of preparing the sensitive microstructure includes the following steps:

s101, placing the tape-cast raw porcelain tape into a slicing machine to slice according to the designed substrate size;

s102, putting the cut green ceramic chip into a punching machine for punching, and punching a counter sink and a through hole;

s103, placing the punched green ceramic chips into a laminating machine for lamination, and then placing the green ceramic chips and a steel plate into a vacuum bag for compaction treatment;

s104, laminating the sensitive microstructure in a laminating machine to finish the manufacture of a first layer, a second layer and a third layer of the sensitive microstructure;

s105, silk-screen printing a designed central square, a peripheral annular square platinum film and conducting circuits of the central square and the peripheral annular square platinum films on the upper surface of the first layer of the green ceramic chip, wherein the conducting circuits respectively point to two sides of the square green ceramic chip, and the second layer is used as a cavity isolating layer and is not processed;

s106, screen printing a square platinum polar plate and a conducting circuit thereof on the lower surface of the third layer of green ceramic chip;

s107, after printing is finished, putting the printed product into a high-low temperature test chamber for primary curing treatment, setting the temperature at 120 ℃, and drying for 10 minutes;

s108, embedding the high-temperature wire into the counter bore, adjusting the position, filling the pores by using a micropore filling machine to electrically interconnect the high-temperature wire and the conduction circuit, and drying again;

s109, fixing the position of the high-temperature wire, and placing the first layer into a magnetron sputtering furnace with argon atmosphere to sputter a layer of silicon dioxide film on the upper surface of the annular platinum plate;

s110, placing the laminated second layer in the middle, aligning and laminating the first layer to the third layer, and then carrying out hot isostatic pressing;

s111, putting the integral structure into a high-temperature furnace for sintering;

and S112, taking the sintered sensitive microstructure as a substrate, and co-sputtering the thermocouple film by using the nickel chromium/nickel silicon multi-target.

The sputtering target material for sputtering the silicon dioxide film in the step S109 is a silicon target, and the gas mass flow ratio in the chamber in the sputtering process is O₂/(O₂And the + Ar) is 5/(5+200), the air pressure is constant to be 2Pa, and the overload insulating layer is taken out after sputtering for 40 minutes to finish the preparation of the overload insulating layer.

In the step S112, firstly, sputtering a thermocouple film under a nichrome target, covering the surface of a substrate with the manufactured ceramic pattern plate, wherein the sputtering power is 200W, and the sputtering time is 50 minutes; covering the other ceramic pattern plate on the surface of the substrate, and sputtering the nickel-silicon film, wherein the sputtering power is 150W, and the sputtering time is 50 minutes; the atmosphere in the chamber is argon, the pressure is 2.5Pa, and the ceramic pattern plates are two-pole patterns of the thermocouple respectively.

Compared with the prior art, the invention has the beneficial effects that:

the invention enables the sensor to accurately measure the pressure in a high-temperature environment, and the high-precision dynamic measurement of the pressure sensor in a full-temperature area of-40-1000 ℃ is realized by adopting a temperature and pressure integrated sensitive microstructure, a unique high-temperature signal transmission mode and a packaging structure.

Drawings

Fig. 1 is a schematic structural diagram of layers in a sensitive microstructure of a high-temperature pressure sensor according to the present invention.

Fig. 1(a) is a schematic structural diagram of a first layer in a sensitive microstructure of a high-temperature pressure sensor according to the present invention.

Fig. 1(b) is a schematic diagram of a second layer structure in a sensitive microstructure of a high-temperature pressure sensor provided by the invention.

Fig. 1(c) is a schematic structural diagram of an upper surface of a third layer in a sensitive microstructure of a high-temperature pressure sensor provided by the invention.

Fig. 1(d) is a schematic structural diagram of a lower surface of a third layer in a sensitive microstructure of a high-temperature pressure sensor according to the present invention.

Fig. 2 is a schematic view of an overall structure of a sensitive microstructure in a high-temperature pressure sensor according to the present invention.

Fig. 3 is a schematic perspective view of a high-temperature pressure sensor head according to the present invention.

Fig. 4 is a schematic diagram of a package structure of a high temperature pressure sensor head according to the present invention.

Fig. 5 is a schematic view of an overall structure of a high-temperature pressure sensor according to the present invention.

Fig. 6 is a schematic diagram of a rear-end signal processing circuit of a high-temperature pressure sensor according to the present invention.

Description of reference numerals:

1-packaging shell, 2-cavity, 3-high temperature wire tube shell, 4-sleeve shell, 5-conversion circuit board, 6-front snap ring, 7-sensitive microstructure, 701-first layer, 702-second layer, 703-third layer, 704-nickel/chromium film, 705-nickel/silicon film, 706-concentric platinum film, 707-silicon dioxide film, 708-square platinum film, 709-counter sink hole, 710-high temperature wire through hole, 711-square cavity, 8-rear snap ring, 9-pore, 10-high temperature wire, 11-ceramic column, 12-pore, 13-airflow channel, 14-connecting part, 15-square clamping groove.

Detailed Description

An embodiment of the present invention will be described in detail below with reference to fig. 1-6, but it should be understood that the scope of the present invention is not limited to the embodiment.

The invention provides a high-temperature pressure sensor, which comprises a sensor head and a conversion circuit board which are connected with each other, wherein the sensor head comprises:

the packaging structure comprises a packaging shell 1, wherein a cavity 2 is arranged in the packaging shell, one end of the cavity 2 is provided with an airflow channel 13, and the other end of the cavity is provided with a connecting part 14;

the sensitive microstructure 7 is arranged in the cavity 2;

the front clamping ring 6 is arranged at the front end in the cavity 2 and used for limiting the front end of the sensitive microstructure 7;

the rear clamping ring 8 is arranged at the rear end of the cavity 2 and used for limiting the rear end of the sensitive microstructure 7;

the conversion circuit board 5 is arranged in the sleeve shell 4 and is used for converting the pressure signal received by the sensitive microstructure 7 into an electric signal;

one end of the high-temperature wire tube shell 3 is connected with the packaging shell 1 through a connecting part 14, and the other end of the high-temperature wire tube shell is connected with the sleeve shell 4;

and the high-temperature wire 10 penetrates through the high-temperature wire tube shell 3, one end of the high-temperature wire extends into the packaging shell 1 to be connected with the sensitive microstructure 7, and the other end of the high-temperature wire extends into the sleeve shell 4 to be connected with the conversion circuit board 5.

The packaging shell 1 is made of nickel-based high-temperature alloy, the airflow channel 13 comprises a thread through hole and a conical through hole, the conical through hole is close to the sensitive micro structure 7, the thread through hole and the conical through hole are coaxial, gas can be conveniently introduced to evenly distribute pressure on the surface of the sensitive micro structure 7, the ceramic column 11 is arranged inside the high-temperature wire tube shell 3, the ceramic column 11 is provided with a fine hole 12 along the length direction, and the high-temperature wire 10 penetrates through the ceramic column 11 through the fine hole 12.

The sensitive microstructure 7 comprises: a first layer 701, a second layer 702, and a third layer 703 which are sintered as one body;

a first layer 701 having two concentric square capacitor plates printed on the inner surface thereof;

a second layer 702 disposed between the first layer 701 and the third layer 703, and having a square cavity 711 in the center;

a square capacitor is printed on the inner surface of the third layer 703, and a nickel-chromium and nickel-silicon thermocouple film is sputtered on the outer surface of the third layer by magnetron sputtering;

the conductive film of the concentric square capacitor plate is a concentric platinum film 706, a silicon dioxide film 707 is sputtered on the capacitor plate of the first layer 701 to serve as an overload protection film, and the conductive film of the square capacitor of the third layer 703 is a square platinum film 708.

And the pore 9 between the high-temperature wire 10 and the sensitive microstructure 7 is sealed by adopting glass cement, and the pore between the sensitive microstructure 7 and the packaging shell 1 is sealed by adopting high-temperature welding.

And the upper surface and the lower surface of the sensitive microstructure 7 are both subjected to nickel-gold electroplating treatment.

The preparation method of the high-temperature pressure sensor is characterized by comprising the following steps of:

s1, preparing a sensitive microstructure 7;

s2, the sensitive microstructure 7 is arranged in the packaging shell 1;

s3, arranging clamp ring structures with round threads at the periphery and square clamping grooves 15 in the middle at the front and the back of a cavity 2 in a packaging shell 1, screwing a front clamp ring 6 into the packaging shell 1, limiting the front end of a sensitive microstructure 7, and sealing the threads of the front clamp ring 6 by using a thread locking agent;

s4, placing the sensitive microstructure 7 in a notch of the square clamping groove 15, and sealing a gap between the sensitive microstructure 7 and the periphery of the notch for the first time by using glass cement;

s5, placing the sensitive microstructure 7 and the packaging shell 1 into a muffle furnace for sintering, wherein the set temperature of the muffle furnace is 800 ℃, the heat preservation time is 60 minutes, and then testing the air tightness of the seal between the sensitive microstructure 7 and the packaging shell 1;

s6, clamping the head of the high-temperature wire 10 by using a pair of tweezers, and enabling the high-temperature wire 10 to penetrate through the fine holes 12 of the ceramic column 11 at a constant speed;

s7, screwing in the rear snap ring 8 to lock and fix the rear end of the sensitive microstructure 7, and sealing the inner side and the outer side of the rear snap ring 8 for the second time by using glass cement;

s8, placing the material into a muffle furnace for re-sintering, setting the temperature to be 800 ℃, keeping the temperature for 40 minutes, and then testing the sealing property between the sensitive microstructure 7 and the packaging shell 1 to finish the preparation of the sensor head;

s9, packaging the high-temperature wire 10 and the ceramic column 11 connected with the sensitive microstructure 7 by a nickel-based high-temperature alloy thin tube;

s10, welding the high-temperature wire 10 and the conversion circuit board 5;

s11, after welding, encapsulating and fixing the conversion circuit board 5 in the sleeve shell 4 by epoxy ethylene glue prepared according to a proportion;

and S12, finally drying for 1 hour by using a high-low temperature test chamber to finish the packaging of the high-temperature pressure sensor.

The step S1 of preparing the sensitive microstructure 7 includes the following steps:

s101, placing the tape-cast raw porcelain tape into a slicing machine to slice according to the designed substrate size;

s102, putting the cut green ceramic chip into a punching machine for punching, and punching a counter bore 709 and a through hole;

s103, placing the punched green ceramic chips into a laminating machine for lamination, and then placing the green ceramic chips and a steel plate into a vacuum bag for compaction treatment;

s104, laminating the sensitive microstructure 7 in a laminating machine to complete the manufacture of a first layer 701, a second layer 702 and a third layer 703 of the sensitive microstructure 7;

s105, screen-printing a designed central square, a peripheral annular square platinum film and conducting circuits of the central square and the peripheral annular square platinum films on the upper surface of the first layer 701 of the green ceramic chip, wherein the conducting circuits respectively point to two sides of the square green ceramic chip, and the second layer 702 is used as a cavity isolating layer and is not processed;

s106, screen printing a square platinum polar plate and a conducting circuit thereof on the lower surface of the third layer 703 green ceramic chip;

s107, after printing is finished, putting the printed product into a high-low temperature test chamber for primary curing treatment, setting the temperature at 120 ℃, and drying for 10 minutes;

s108, embedding the high-temperature wire 10 into the counter bore 709, adjusting the position, filling the hole with a micropore filling machine to electrically interconnect the high-temperature wire and the conduction circuit, and drying again;

s109, fixing the position of the high-temperature wire, placing the first layer 701 into a magnetron sputtering furnace with an argon atmosphere, and sputtering a layer of silicon dioxide film 707 on the upper surface of the annular platinum pole plate;

s110, placing the laminated second layer 702 in the middle, aligning and laminating the first layer 701 to the third layer 703, and then performing hot isostatic pressing;

s111, putting the integral structure into a high-temperature furnace for sintering;

and S112, taking the sintered sensitive microstructure 7 as a substrate, and co-sputtering the thermocouple film by using nickel chromium/nickel silicon multi-target.

The sputtering target material for sputtering the silicon dioxide film 707 in the step S109 is a silicon target, and the gas mass flow ratio in the chamber during sputtering is O₂/(O₂And the + Ar) is 5/(5+200), the air pressure is constant to be 2Pa, and the overload insulating layer is taken out after sputtering for 40 minutes to finish the preparation of the overload insulating layer.

In the step S112, firstly, sputtering a thermocouple film under a nichrome target, covering the surface of a substrate with the manufactured ceramic pattern plate, wherein the sputtering power is 200W, and the sputtering time is 50 minutes; covering the other ceramic pattern plate on the surface of the substrate, and sputtering the nickel-silicon film, wherein the sputtering power is 150W, and the sputtering time is 50 minutes; the atmosphere in the chamber is argon, the pressure is 2.5Pa, and the ceramic pattern plates are two-pole patterns of the thermocouple respectively.

A full-temperature-zone high-precision high-frequency-response dynamic pressure sensor comprises sensitive microstructure design preparation, thin-film thermocouple design preparation, signal shielding prevention design, high-temperature signal transmission design, overload resistance design, polishing and thinning process, high-temperature sealing technology and temperature compensation technology; the sensitive microstructure is a laminated structure assembled by a high-temperature co-fired ceramic technology and comprises three layers. The first layer 701 is a green ceramic chip with two concentric square capacitor plates printed on the upper surface, the second layer 702 is a square green ceramic chip with a cavity in the middle, and the third layer 703 is a green ceramic chip with a square capacitor printed on the lower surface and a thin film thermocouple with the upper surface subjected to magnetron sputtering; the signal anti-shielding design is that nickel and gold are electroplated on the surface of the sensitive microstructure after the sensitive microstructure is prepared to form a protective cover so as to prevent electromagnetic shielding; the high-temperature signal transmission is designed to transmit signals to a circuit board at the rear end through a high-temperature wire coated with a heat-insulating ceramic thin tube, as shown in figure 5, the high temperature at the head of the sensor is isolated from the circuit board at the rear end; the overload resistance design is that a layer of silicon dioxide film 707 is subjected to magnetron sputtering on the surface of the first layer 701 of the polar plate to prevent the upper and lower polar plates of the capacitor from contacting when the sensor sensing diaphragm bears the pressure of an overrange, so that the sensor is prevented from short-circuit failure; the polishing and thinning process is to change the thickness of the sensitive microstructure 7 through the polishing process to realize the required sensor measuring range on the basis of the preparation of the sensitive microstructure; the high-temperature sealing technology comprises HTCC co-firing sealing of the sensitive microstructure, pore sealing between the high-temperature wire and the sensitive microstructure through high-temperature welding and pore sealing between the sensitive microstructure and a sensor shell; the temperature compensation is realized by integrating a thermocouple and a sensor sensitive microstructure, and the thermocouple measures the real-time temperature of the sensitive microstructure part so as to perform temperature compensation on the test data at a sensor data acquisition end, so as to obtain accurate pressure test data of a full-temperature region of-40 ℃ to 1000 ℃.

The whole sensitive microstructure 7 of the sensor is made of the same material and is co-fired with the high-temperature wire to form a sealed whole, and the sensitive microstructure is integrally sintered and formed, so that the sealing performance of the sensitive microstructure can be ensured, and lead welding is not needed.

Meanwhile, the sensitive microstructures of the integrated thermocouple film and the capacitor plate film can simultaneously measure the temperature and pressure parameters of the high-temperature region in situ, and the pressure sensor with the pressure parameters subjected to rear-end temperature compensation can be applied to the accurate measurement of the pressure of the full-temperature region at-40 ℃ to 1000 ℃.

The HTCC technology is used for co-firing an integrated laminated structure at the high temperature of 1500-1600 ℃, so that the high-temperature-resistant high-temperature-compensation high-temperature-resistant high-power-consumption high-power-. The edge of a first layer 701 of the sensitive microstructure is provided with three countersunk punch holes for penetrating through a high-temperature wire, a pore is filled with platinum slurry by using a micropore filling machine, the high-temperature wire and an upper surface capacitance plate are electrically interconnected, and the other edge of the first layer 701 is provided with two adjacent through holes in a laser punching mode for penetrating through the high-temperature wire connected with a thermocouple film, as shown in the attached drawing 1 a; punching micropores with the same size at the positions of the second layer 702 and the third layer 703 corresponding to the structure of the first layer 701 by using a punching machine, as shown in fig. 1(b), 1(c) and 1 (d); the sensitive microstructure is formed by sequentially aligning, laminating and laminating a first layer 701, a second layer 702 and a third layer 703 structure from bottom to top, and then co-firing the whole structure at 1500-1600 ℃ to form an integrated structure. After the sensitive microstructure and the high-temperature wire are sintered and molded, a nickel-chromium/nickel-silicon thermocouple film is sputtered on the upper surface of the sensitive microstructure through magnetron sputtering, and a thermocouple covered at the front end of the sensitive microstructure can measure the temperature of the head of the sensor in situ, so that high-precision temperature compensation at the rear end is facilitated.

Printing a ring square platinum film with the outer side length of 9mm and the inner side length of 7mm on the upper surface of a first layer 701 of raw porcelain sheet, and then printing a ring square platinum film on the upper surface of the first layer 701 of raw porcelain sheetThe inside of the film is printed with 5.6 multiplied by 5.6mm²The interval distance between the square platinum film and the square platinum film is 0.5mm, so that the compensation effect of the peripheral capacitor is ensured; the middle of the second layer 702 of the green ceramic chip is a square cavity 8 structure, and the lower surface of the third layer 703 of the green ceramic chip is printed with 9 multiplied by 9mm²Square platinum film 708 with dimensions of 11X 11mm²。

The signal shielding design is that nickel and gold are electroplated on the surface of the sensitive microstructure to form a protective cover after the sensitive microstructure is prepared, so that the sensor failure caused by the interference of other external electromagnetic signals when the high-temperature pressure sensor works under various complex working conditions can be avoided.

The high-temperature signal transmission design is that capacitance signal and temperature signal transmit through high-temperature wire 10, and the high-temperature wire periphery cladding has adiabatic ceramic post 11 simultaneously, and the cooperation design of both has greatly blocked the heat of sensitive microstructure 7 front end and has passed through sensor encapsulation shell to the circuit board transmission, just so can make the sensor realize the pressure accurate measurement under high temperature and even super high temperature.

The overload resistance design is that a layer of silicon dioxide insulating film is formed on the surface of the first 701 polar plate in a magnetron sputtering mode, the thickness of the silicon dioxide insulating film is 30-50 mu m, and the size of the silicon dioxide insulating film is just the size of a ring-shaped polar plate.

The high-temperature sealing technology is to seal the sensitive microstructure multilayer structure through HTCC high-temperature co-firing, and seal the wire penetrating pore of the integrated structure, the sensitive microstructure 7 and the pore between the packaging shell 1 by adopting high-temperature welding, so that the sealing performance of the sensor under positive pressure and negative pressure is ensured, the pressure sensing and testing sensitivity of the sensor is greatly improved, and the in-situ dynamic testing precision can be improved.

The temperature compensation system is an integrated body of a thermocouple and a sensor sensitive microstructure, the thermocouple detects synchronous temperature sensed by the sensor sensitive microstructure, then the output temperature is transmitted to the acquisition module for temperature compensation, the output of the sensor after temperature compensation is a real-time accurate pressure value, and then the sensor can realize high-precision dynamic measurement of in-situ pressure parameters in a full temperature zone range of-40 ℃ to 1000 ℃.

The invention discloses a high-temperature pressure sensor and a preparation method thereof, wherein the high-temperature pressure sensor comprises a sensitive microstructure design, a thin-film thermocouple design, a signal shielding prevention design, a high-temperature signal transmission design, an overload prevention design, a polishing and thinning process, a high-temperature sealing process and a temperature compensation method; the sensitive microstructure comprises three layers of green ceramic chips, a thin film capacitor polar plate screen-printed on the surface of the green ceramic chips, and a thin film thermocouple formed by magnetron sputtering; the signal anti-shielding design is that nickel and gold are electroplated on the surface of the sensitive microstructure after the sensitive microstructure is prepared to form a protective cover; the signal transmission is designed in such a way that a signal is transmitted to a circuit board at the rear end through a high-temperature wire coated with a heat-insulating ceramic thin tube so as to isolate high temperature; the overload resistance design is realized by performing radio frequency magnetron sputtering on a layer of silicon dioxide film on the surface of the first 701 polar plate; the polishing and thinning process can change the thickness of the sensitive microstructure to realize the required sensor measuring range on the basis of completing the preparation of the sensitive microstructure; the high-temperature sealing technology comprises the steps of sealing the sensitive microstructure, sealing the high-temperature wire hole, sealing the sensitive microstructure and the sensor shell and the like by high-temperature welding; the temperature compensation method comprises integration of a thermocouple and a sensitive microstructure of a sensor, a rear-end acquisition circuit, a temperature compensation function and the like. The full-temperature-zone high-precision pressure sensing device has the characteristics of corrosion resistance, good dynamic performance, overload resistance of 4-5 FS, impact resistance and capability of realizing high-precision dynamic measurement of in-situ pressure parameters in a full-temperature zone range of-40-1000 ℃.

The sensitive microstructure of the sensor is an HTCC sintering integrated structure, a polar plate conductive film adopts metal platinum with high melting point, difficult oxidation and good adhesion, two concentric square capacitor polar plates are printed on the upper surface of a first layer 701 of the structure, a second layer 702 is a square with a cavity in the middle, a third layer 703 is a square capacitor printed on the lower surface, and a nickel/chromium film 704 or a nickel/silicon film 705 thermocouple is sputtered on the upper surface through magnetron sputtering; the packaging of the sensor adopts a slender tubular structure which is beneficial to heat dissipation, high-temperature wires, a capacitor plate and a thermocouple are welded and sealed at high temperature, and then high-temperature signals are transmitted through a pipeline of a ceramic column, and the special packaging structure can isolate high temperature from a circuit board and quickly dissipate heat; a layer of silicon dioxide film 707 is sputtered on the surface of the first layer 701 of electrode plate to prevent the upper and lower electrode plates of the capacitor from contacting when the sensing diaphragm of the sensor bears the pressure of an overrange, so that the sensor is prevented from short-circuit failure, as shown in fig. 3; the sensitive microstructure is sealed by a high-temperature co-fired ceramic process, the pores between the high-temperature wire and the sensitive microstructure are sealed by glass cement, and the pores between the sensitive microstructure and the sensor shell are sealed by a high-temperature welding process; the temperature compensation system of the sensor is integrated of a thermocouple and a sensitive microstructure of the sensor, the thermocouple measures the temperature synchronous with the sensitive microstructure of the sensor, then the output temperature is transmitted to the acquisition module for temperature compensation, the output of the sensor after temperature compensation is a real-time accurate pressure value, and then the sensor can realize high-precision dynamic measurement of in-situ pressure parameters in a full temperature zone range of-40 ℃ to 1000 ℃. The specific implementation method can be divided into the following three parts of design and preparation:

a. preparation of sensitive microstructures

Firstly, placing the tape-cast raw ceramic tape into a slicing machine for slicing, cutting out the designed size of a substrate, placing a certain number of raw ceramic chips into a perforating machine for punching, placing the punched raw ceramic chips into a laminating machine for laminating, then placing the laminated raw ceramic chips and a steel plate into a vacuum bag for compressing, and then placing the laminated raw ceramic chips into a laminating machine for laminating, thereby completing the manufacture of the raw ceramic chips with the three-layer sensitive microstructure.

Silk-screen printing is carried out on the upper surface of the first layer 701 of the green ceramic chip to form a designed concentric annular square platinum film and guide paths thereof, wherein the guide paths point to two sides of the square green ceramic chip respectively, the slurry is firstly coated on the edge of a silk screen plate graph during silk-screen printing, and then a scraper plate and a screen plate form an angle of 45 degrees to move uniformly along the silk screen plate, so that the printing of the graphs of the first layer 701 and the third layer 703 is completed. And (3) after printing is finished, putting the printed product into a high-low temperature test box for primary curing treatment, setting the temperature at 120 ℃, and drying for 10 minutes. Then, the high-temperature wire is embedded into the three counter bores 709, after the positions are adjusted, the three holes are filled by a micropore filling machine, so that the high-temperature wire and the pole plate are electrically interconnected, and the drying treatment is carried out again, as shown in the attached drawing 1 a; the position of the high-temperature wire is fixed,putting the first layer 701 structure into a magnetron sputtering furnace with argon atmosphere to sputter a silicon dioxide film, wherein the sputtering target is a silicon target, and the gas mass flow ratio O in the cavity in the sputtering process₂/(O₂The + Ar) is 5/(5+200), the air pressure is constant to be 2Pa, the sample is taken out after sputtering for 40 minutes, and the preparation of the overload insulating layer is finished, so that the first layer 701 and the third layer 703 of the sensitive microstructure are finished; the laminated structure of the second layer 702, as shown in fig. 1b, is placed in the middle position, the first layer 701 to the third layer 703 are laminated in a position from bottom to top, hot isostatic pressing is then performed, and finally the whole structure is sintered in a high temperature furnace. Taking a co-fired sensitive microstructure as a substrate, and carrying out nickel-chromium/nickel-silicon multi-target co-sputtering under the condition of respectively controlling the sputtering power of a nickel-chromium target and the sputtering power of a nickel-silicon target. Firstly, sputtering a thermocouple film under a nichrome target, covering the surface of a substrate with a manufactured ceramic pattern plate, wherein the sputtering power is 200W, and the sputtering time is 50 minutes; covering the other ceramic pattern plate on the surface of the substrate, and sputtering the nickel-silicon film, wherein the sputtering power is 150W, and the sputtering time is 50 minutes; the atmosphere in the chamber was argon, the pressure was 2.5Pa, the ceramic pattern plates were bipolar patterns of thermocouples, and the final sputtering pattern was as shown in FIG. 1 (d). After the microstructure is prepared, in order to prevent the sensor from being interfered by external electromagnetic signals when signals are output, nickel and gold electroplating treatment is carried out on the upper surface and the lower surface of the sensitive microstructure.

b. Structural design and packaging of sensor prototype

The structure of the sensor prototype is shown in figure 5, a packaging shell 1 is made of nickel-based high-temperature alloy, a threaded through hole is formed in a front cover of the packaging shell, a conical through hole is formed in the through hole close to a sensitive microstructure, and the pressure is uniformly distributed on the surface of the sensitive microstructure by introducing gas. The middle is a round cavity, and the front and the back are both provided with snap ring structures with the peripheries being round threads and the middle being a square clamping groove 15.

During packaging, the front clamping ring 6 is screwed into the packaging shell 1, the front end of the sensitive microstructure 7 is limited, and a thread locking agent is used for sealing threads; placing the square sensitive microstructure in a notch of a square clamping groove 15, sealing a gap between the sensitive microstructure 7 and the periphery of the notch for the first time by using glass cement, then placing the sensitive microstructure and the shell into a muffle furnace for sintering, setting the temperature to be 800 ℃, preserving heat for 1 hour, and then verifying whether the sealing air tightness is good or not on a pressure tank; then, threading the high-temperature wire 10, clamping the head of the high-temperature wire 10 by using tweezers, and threading the high-temperature wire into the fine hole 12 of the ceramic column 11 at a constant speed, wherein the positions of the three high-temperature wires 10 connected with the capacitor plate in the ceramic column 11 should be as follows: the public polar plate is placed in the middle, and two lower polar plate capacitances are distributed on the two symmetrical sides, so that the initial values of the two capacitances are equal to each other. Then screwing in the clamp ring 8 to be locked and fixed, sealing the inner side and the outer side of the clamp ring for the second time by using glass cement, sintering the clamp ring in a muffle furnace at the set temperature of 800 ℃, preserving heat for 40 minutes, testing good tightness on a pressure tank, and completing the preparation of the sensor head; the high-temperature wire 10 and the ceramic column 11 connected with the sensitive microstructure 7 are packaged by a nickel-based high-temperature alloy thin tube, and then the output capacitances of the three high-temperature wires 10 are corrected at the tail end of a packaging tube shell, so that the initial values of the two capacitances are the same, the sensitivity of the sensor can be effectively improved, the nonlinear error of output is reduced, the dynamic response characteristic is improved, and the temperature drift influence is reduced. And finally, welding the three output differential high-temperature wires with a circuit board, welding the two output thermocouple wires with a temperature converter, filling and fixing the conversion circuit board 5 by epoxy ethylene glue prepared according to a proportion after welding is finished, improving the vibration resistance of the sensor, and drying the high-low temperature test chamber for 1 hour to finish the packaging of a sample machine of the sensor.

c. Implementation of peripheral high-precision circuit

As shown in fig. 6, temperature compensation is required in the test result of the pressure due to the temperature drift phenomenon in the measurement of the pressure in the high temperature environment. The specific implementation method comprises the following steps: the current signals output by the conversion circuit board 5 and the temperature converter are connected into the same signal acquisition module, and the signal acquisition module integrates the functions of acquisition and conversion of pressure and temperature signals of the sensitive microstructure. The acquisition module completes the demodulation, amplification and temperature compensation of signals, and then transfers the signals to Labview-based graphical language for real-time storage and display of measured data and real-time display of pressure and temperature change curves after various processing conversions.

The peripheral high-precision circuit of the sensor utilizes a thermocouple integrated with a sensitive microstructure to measure and output the temperature in real time, the thermocouple measures the temperature synchronous with the sensitive microstructure of the sensor, and then the real-time temperature value is transmitted to a signal acquisition module to compensate the temperature, namely, the output data of the sensor is firstly tested under a single temperature variable to obtain a change curve of the output of the sensor along with the temperature, a function of the output along with the temperature change is written into an acquisition card of a converter, and the actual data measured in a temperature and pressure composite test environment and a temperature drift function are the real pressure output of the sensor.

The above disclosure is only for a few specific embodiments of the present invention, however, the present invention is not limited to the above embodiments, and any variations that can be made by those skilled in the art are intended to fall within the scope of the present invention.