Preparation method of metal oxide modified WO3-based gas sensor

Abstract

The invention belongs to the technical field of MEMS gas sensors, and particularly relates to a preparation method of a metal oxide modified WO3-based gas sensor. Comprising the following steps: step 1, weighing a proper amount of crystallized ammonium paratungstate (H42N10O42W12. XH2O), putting the weighed crystallized ammonium paratungstate in a sintering vessel, putting the sintering vessel in a high-temperature sintering furnace, and carrying out temperature programming; step 2, adding water into a product obtained in the step 1 to prepare a suspension, and loading the suspension onto an MEMS chip; 3, placing the chip in the step 2 in a high-temperature sintering furnace, and carrying out temperature programming; 4, placing the chip annealed in the step 3 in a magnetron sputtering instrument, and sputtering a metal oxide on the surface of the material; step 5, packaging the chip in the step 4 into an MEMS sensor through an MEMS packaging process; through cooperation of all the steps, the precious metal modified WO3 gas sensor prepared by the method is high in sensitivity, fast in response and good in stability on gas released when a cable is heated, and can be used for detecting the early stage of a fire disaster to achieve the purpose of early warning of the cable fire disaster.

Description

Technical Field

[0001] The present invention belongs to the technical field of MEMS gas sensors, and specifically relates to a metal oxide modified WO 3 Method for preparing a gas sensor based on nanostructured carbon foam. Background Art

[0002] With the rapid development of the economy, the demand for power construction is also increasing, and the application of power cables is extremely extensive. As the application of power cables expands, the fires caused by them are also increasing. The occurrence of cable fire accidents has the hazards of burning cables and equipment, resulting in direct power outages, long repair time, delayed production, and serious impact on the production progress, efficiency and economic benefits of enterprises.

[0003] The main causes of power cable fire accidents are cable damage, poor contact, cable short circuit and line overload. These reasons will cause the cable to overheat, which will then cause a fire. Power cable fires are mainly divided into three stages: the first stage is the early stage of the fire, when the cable core conductor heats up, and the heat accumulates in abnormal parts, forming a local temperature rise and releasing organic gases; the second stage is the early stage of the fire, when the cable is in a smoldering state, accompanied by a large amount of smoke; the third stage is the late stage of the fire, when a large amount of open flames and thick smoke appear in the cable, and the fire spreads rapidly. Power cable materials are mainly polymer materials, such as polyvinyl chloride, cross-linked polyethylene, etc., which will release a large amount of gas when the temperature is too high or a fire occurs.

[0004] The existing MEMS gas sensors have low sensitivity to the gas released by the cable sheath when heated, and are difficult to be applied in cable fire warning. The MEMS gas sensors with high sensitivity, fast response and good stability to the gas released by the cable when heated have been developed and can be used to detect the early stage of fire and achieve the purpose of cable fire warning. Summary of the invention

[0005] The purpose of the present invention is to overcome the shortcomings of the prior art and provide a metal oxide modified WO with high sensitivity, fast response and good stability to the gas released when the cable is heated. 3 Method for preparing a gas sensor based on nanostructured carbon foam.

[0006] The object of the present invention is achieved by: a metal oxide modified WO 3 A method for preparing a gas sensor comprising the following steps: Step 1: Weigh an appropriate amount of crystalline ammonium paratungstate (H 42 N 10 O 42 W 12 ·xH 2 O) placing the sintering dish in a high-temperature sintering furnace and performing a temperature increase program; Step 2, adding water to the product obtained in step 1 to prepare a suspension, and loading it onto the MEMS chip; Step 3, placing the chip in step 2 in a high-temperature sintering furnace and performing programmed temperature increase; Step 4, placing the chip annealed in step 3 in a magnetron sputtering device to sputter metal oxide on the surface of the material; Step 5: Use the MEMS packaging process to package the chip in step 4 into a MEMS sensor.

[0007] For better effect, the material in step 1 is placed in a high-temperature sintering furnace and programmed to heat up at a rate of 3°C / min.

[0008] For better effect, the step 1 is placed in a high temperature sintering furnace and programmed to heat up to 600° C. at a heating rate of 3° C. / min, and then sintered at 600° C. for 2 h.

[0009] For better effect, the product obtained in step 1 is added with water to prepare a suspension, which is then loaded onto the MEMS chip, specifically, the prepared suspension is loaded onto the interdigital electrode region of the MEMS chip.

[0010] For better effect, in step 3, the chip in step 2 is placed in a high-temperature sintering furnace and programmed to heat up at a rate of 1°C / min.

[0011] For better effect, in step 3, the chip in step 2 is placed in a high-temperature sintering furnace and programmed to heat up to 500° C. at a heating rate of 1° C. / min, and then sintered at 500° C. for 2 hours.

[0012] For better effect, in step 3, the chip in step 2 is placed in a high-temperature sintering furnace, programmed to heat up, sintered at 500° C. for 2 hours, and then cooled naturally.

[0013] For better effect, in step 4, the chip annealed in step 3 is placed in a magnetron sputtering device to sputter metal oxide on the surface of the material, and the power is set to 60W during sputtering.

[0014] For better effect, in step 4, the chip annealed in step 3 is placed in a magnetron sputtering device to sputter metal oxide on the surface of the material, and the sputtering time is set to 20-40s.

[0015] For better effect, in step 4, the chip annealed in step 3 is placed in a magnetron sputtering device to sputter metal oxide on the surface of the material, and the sputtered metal oxide is In 2 O 3 , ZnO or TiO 2 .

[0016] Beneficial effects of the present invention: A metal oxide modified WO 3 The preparation method of the gas sensor comprises the steps of: 1. weighing an appropriate amount of crystalline ammonium paratungstate (H 42 N 10 O 42 W 12 ·xH 2 O) in a sintering dish, placed in a high-temperature sintering furnace, and programmed temperature rise; step 2, adding water to the product obtained in step 1 to prepare a suspension, and loading it onto a MEMS chip; step 3, placing the chip in step 2 in a high-temperature sintering furnace, and programmed temperature rise; step 4, placing the annealed chip in step 3 in a magnetron sputtering instrument, and sputtering metal oxide on the surface of the material; step 5, packaging the chip in step 4 into a MEMS sensor through a MEMS packaging process; through the coordination of each step, the metal oxide prepared by the present invention modifies WO 3 The gas sensor has high sensitivity to the gas released when the cable is heated, fast response and good stability. It can be used to detect the early stage of fire and achieve the purpose of cable fire early warning. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 The present invention is a metal oxide modified WO 3 Schematic diagram of the process of preparing the gas sensor.

[0018] Figure 2 The present invention is a metal oxide modified WO 3 Preparation method of WO-based gas sensor 3 and In under different sputtering time 2 O 3 / WO 3 Schematic diagram of the sensor's response curve to gas released from YJV22 cable at different heating temperatures.

[0019] Figure 3 The present invention is a metal oxide modified WO 3 Preparation method of WO-based gas sensor 3 And ZnO / WO under different sputtering time 3 Schematic diagram of the sensor's response curve to gas released from YJV22 cable at different heating temperatures.

[0020] Figure 4 The present invention is a metal oxide modified WO 3 Preparation method of WO-based gas sensor 3 and TiO under different sputtering times 2 / WO 3Schematic diagram of the sensor's response curve to gas released from YJV22 cable at different heating temperatures.

[0021] Figure 5 The present invention is a metal oxide modified WO 3 Schematic diagram of the comparison of response curves of different sensors to gas released from YJV22 cable at different heating temperatures in the preparation method of the base gas sensor. DETAILED DESCRIPTION

[0022] The present invention will be further described below in conjunction with the accompanying drawings.

[0023] It should be understood that the specific embodiments described herein are only used to explain the present invention, and are not used to limit the present invention.

[0024] The following will be combined with the drawings in the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0025] The present invention is based on WO 3 Based gas sensor, providing a metal oxide modified WO 3 A method for preparing a gas sensor comprises the following steps: Step 1: Weigh an appropriate amount of crystalline ammonium paratungstate (H 42 N 10 O 42 W 12 ·xH 2 O) placing the sintering dish in a high-temperature sintering furnace and performing a temperature increase program; Step 2, adding water to the product obtained in step 1 to prepare a suspension, and loading it onto the MEMS chip; Step 3, placing the chip in step 2 in a high-temperature sintering furnace and performing programmed temperature increase; Step 4, placing the chip annealed in step 3 in a magnetron sputtering device to sputter metal oxide on the surface of the material; Step 5: Use the MEMS packaging process to package the chip in step 4 into a MEMS sensor.

[0026] For better effect, in one embodiment, the step 1 is placed in a high temperature sintering furnace and programmed to heat up at a rate of 3° C. / min.

[0027] For better effect, in one embodiment, the step 1 is placed in a high temperature sintering furnace and programmed to heat up to 600° C. at a heating rate of 3° C. / min, and then sintered at 600° C. for 2 h.

[0028] For better effect, in one embodiment, the product obtained in step 1 is added with water to prepare a suspension, which is then loaded onto the MEMS chip, specifically, the prepared suspension is loaded onto the interdigital electrode region of the MEMS chip.

[0029] For better effect, in one embodiment, in step 3, the chip in step 2 is placed in a high-temperature sintering furnace and programmed to heat up at a rate of 1° C. / min.

[0030] For better effect, in one embodiment, in step 3, the chip in step 2 is placed in a high-temperature sintering furnace, programmed to heat up to 500°C at a heating rate of 1°C / min, and then sintered at 500°C for 2h.

[0031] For better effect, in one embodiment, in step 3, the chip in step 2 is placed in a high-temperature sintering furnace, programmed to increase the temperature, sintered at 500° C. for 2 hours, and then cooled naturally.

[0032] For better effect, in one embodiment, in step 4, the chip annealed in step 3 is placed in a magnetron sputtering device to sputter metal oxide on the surface of the material, and the power is set to 60W during sputtering.

[0033] For better effect, in one embodiment, in step 4, the chip annealed in step 3 is placed in a magnetron sputtering device to sputter metal oxide on the surface of the material, and the sputtering time is set to 20-40s.

[0034] For better effect, in one embodiment, in step 4, the chip annealed in step 3 is placed in a magnetron sputtering device to sputter metal oxide on the surface of the material, and the sputtered metal oxide is In 2 O 3 , ZnO or TiO 2 .

[0035] In combination with the above, the present invention provides a metal oxide modified WO 3 A specific embodiment of the method for preparing the gas sensor comprises the following steps: Step 1: Weigh an appropriate amount of crystalline ammonium paratungstate (H 42 N 10 O 42 W 12 ·xH 2O) Place the sintering dish in a high-temperature sintering furnace, use programmed temperature increase, heating rate of 3°C / min, and sinter at 600°C for 2h; Step 2, adding water to the product obtained in step 1 to prepare a suspension, and loading the suspension into the interdigital electrode region of the MEMS chip; Step 3: Place the chip in step 2 in a high-temperature sintering furnace, use programmed heating, heating rate 1°C / min, sinter at 500°C for 2h, and cool naturally; Step 4: Place the chip annealed in step 3 in a magnetron sputtering instrument, set the power to 60W, and sputter metal oxide In on the surface of the material. 2 O 3 , the sputtering time is set to 20~40s; Step 5: Use the MEMS packaging process to package the chip in step 4 into a MEMS sensor.

[0036] The present invention discloses a metal oxide modified WO 3 Another specific embodiment of the method for preparing the base gas sensor includes the following steps: Step 1: Weigh an appropriate amount of crystalline ammonium paratungstate (H 42 N 10 O 42 W 12 ·xH 2 O) Place the sintering dish in a high-temperature sintering furnace, use programmed temperature increase, heating rate of 3°C / min, and sinter at 600°C for 2h; Step 2, adding water to the product obtained in step 1 to prepare a suspension, and loading the suspension into the interdigital electrode region of the MEMS chip; Step 3: Place the chip in step 2 in a high-temperature sintering furnace, use programmed heating, heating rate 1°C / min, sinter at 500°C for 2h, and cool naturally; Step 4, placing the chip annealed in step 3 in a magnetron sputtering instrument, setting the power to 60 W, sputtering metal oxide ZnO on the surface of the material, and setting the sputtering time to 20-40 s; Step 5: Use the MEMS packaging process to package the chip in step 4 into a MEMS sensor.

[0037] The present invention discloses a metal oxide modified WO 3 Another specific embodiment of the method for preparing the base gas sensor includes the following steps: Step 1: Weigh an appropriate amount of crystalline ammonium paratungstate (H 42 N 10 O 42 W 12 ·xH 2O) Place the sintering dish in a high-temperature sintering furnace, use programmed temperature increase, heating rate of 3°C / min, and sinter at 600°C for 2h; Step 2, adding water to the product obtained in step 1 to prepare a suspension, and loading the suspension into the interdigital electrode region of the MEMS chip; Step 3: Place the chip in step 2 in a high-temperature sintering furnace, use programmed heating, heating rate 1°C / min, sinter at 500°C for 2h, and cool naturally; Step 4: Place the chip annealed in step 3 in a magnetron sputtering instrument, set the power to 60W, and sputter the metal oxide TiO on the surface of the material. 2 , the sputtering time is set to 20~40s; Step 5: Use the MEMS packaging process to package the chip in step 4 into a MEMS sensor.

[0038] For WO prepared by the present invention 3 Gas sensors such as Figure 2 (WO 3 and In under different sputtering time 2 O 3 / WO 3 The sensor's response curve to the gas released by the YJV22 cable at different heating temperatures is shown in the figure, where R0 is the resistance of the sensor in the air; Rs is the resistance of the sensor under the target gas; the sensitivity of the sensor to the gas S=Rs / R0. The smaller the value, the higher the sensitivity of the sensor to the gas; 20In 2 O 3 / WO 3 Indicates the magnetron sputtering power of 60W 2 O 3 Target 20s, and the rest are similar; Figure 1 It can be seen that pure WO 3 The sensor is less sensitive to the gas released by YJV22 cable at different heating temperatures, while the surface sputtering In 2 O 3 The sensor sensitivity is relatively pure WO 3 Improved, including 20In 2 O 3 / WO 3 The sensitivity is the highest, and with the increase of sputtering time, the sensitivity shows a decreasing trend.

[0039] like Figure 3 (WO 3 And ZnO / WO under different sputtering time 3 The sensor response curve to the gas released by YJV22 cable at different heating temperatures is shown in the figure. Figure 3 It can be seen that pure WO3 The sensor has a lower sensitivity to the gas released by YJV22 cable at different heating temperatures. The sensor with surface sputtered ZnO is more sensitive than pure WO 3 Improved, among which 40ZnO / WO 3 、80ZnO / WO 3 、160ZnO / WO 3 The sensor sensitivity is comparable and has the greatest improvement. 3 , when the sputtering time exceeds 40s, the improvement of sensitivity is not obvious.

[0040] like Figure 4 (WO 3 and TiO under different sputtering times 2 / WO 3 The sensor response curve to the gas released by YJV22 cable at different heating temperatures is shown in the figure. Figure 4 It can be seen that pure / WO 3 The sensor has low sensitivity to the gas released by YJV22 cable at different heating temperatures. 2 The sensor sensitivity is relatively pure / WO 3 Improved, among which 20TiO 2 / / WO 3 The sensitivity is the highest, and with the increase of sputtering time, the sensitivity shows a decreasing trend.

[0041] like Figure 5 (Comparison of the response curves of different sensors to the gas released by YJV22 cable at different heating temperatures) Figure 5 It can be seen that WO 3 Surface sputtering ZnO has the best sensitivity improvement, while TiO 2 Worst.

[0042] In summary, a metal oxide modified WO of the present invention 3 The preparation method of the gas sensor comprises the steps of: 1. weighing an appropriate amount of crystalline ammonium paratungstate (H 42 N 10 O 42 W 12 ·xH 2O) in a sintering dish, placed in a high-temperature sintering furnace, and programmed temperature rise; step 2, adding water to the product obtained in step 1 to prepare a suspension, and loading it onto a MEMS chip; step 3, placing the chip in step 2 in a high-temperature sintering furnace, and programmed temperature rise; step 4, placing the annealed chip in step 3 in a magnetron sputtering instrument, and sputtering metal oxide on the surface of the material; step 5, packaging the chip in step 4 into a MEMS sensor through a MEMS packaging process; through the coordination of each step, the metal oxide prepared by the present invention modifies WO 3 The gas sensor has high sensitivity to the gas released when the cable is heated, fast response and good stability. It can be used to detect the early stage of fire and achieve the purpose of cable fire early warning.

[0043] In the description of this specification, the description with reference to the terms "one embodiment", "example", "specific example", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0044] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments, and the above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, and these changes and improvements all fall within the scope of the present invention to be protected.

Claims

1. A method for preparing a metal oxide modified WO3-based gas sensor, characterized in that: It includes the following steps: Step 1: Weigh an appropriate amount of crystalline ammonium paratungstate (H 42 N 10 O 42 W 12 xH2O) in a sintering dish, placed in a high-temperature sintering furnace, and programmed to heat; Step 2, adding water to the product obtained in step 1 to prepare a suspension, and loading it onto the MEMS chip; Step 3, placing the chip in step 2 in a high-temperature sintering furnace and performing programmed temperature increase; Step 4, placing the chip annealed in step 3 in a magnetron sputtering device to sputter metal oxide on the surface of the material; Step 5: Use the MEMS packaging process to package the chip in step 4 into a MEMS sensor.

2. The method for preparing a metal oxide modified WO3-based gas sensor according to claim 1, characterized in that: The step 1 is placed in a high temperature sintering furnace and programmed to heat up at a rate of 3° C. / min.

3. The method for preparing a metal oxide modified WO3-based gas sensor according to claim 2, characterized in that: The step 1 is placed in a high temperature sintering furnace and programmed to heat up to 600° C. at a heating rate of 3° C. / min, and then sintered at 600° C. for 2 hours.

4. The method for preparing a metal oxide modified WO3-based gas sensor according to claim 1, characterized in that: The product obtained in step 1 is added with water to prepare a suspension, and then loaded onto the MEMS chip. Specifically, the prepared suspension is loaded onto the interdigital electrode region of the MEMS chip.

5. The method for preparing a metal oxide modified WO3-based gas sensor according to claim 1, characterized in that: In the step 3, the chip in step 2 is placed in a high-temperature sintering furnace and programmed to heat up at a rate of 1°C / min.

6. The method for preparing a metal oxide modified WO3-based gas sensor according to claim 5, characterized in that: In the step 3, the chip in step 2 is placed in a high-temperature sintering furnace, programmed to heat up to 500° C. at a heating rate of 1° C. / min, and then sintered at 500° C. for 2 hours.

7. The method for preparing a metal oxide modified WO3-based gas sensor according to claim 6, characterized in that: In the step 3, the chip in step 2 is placed in a high-temperature sintering furnace, programmed to increase the temperature, sintered at 500° C. for 2 hours, and then cooled naturally.

8. The method for preparing a metal oxide modified WO3-based gas sensor according to claim 1, characterized in that: In the step 4, the chip annealed in the step 3 is placed in a magnetron sputtering device to sputter metal oxide on the surface of the material, and the power is set to 60W during the sputtering.

9. The method for preparing a metal oxide modified WO3-based gas sensor according to claim 8, characterized in that: In the step 4, the chip annealed in the step 3 is placed in a magnetron sputtering device to sputter metal oxide on the surface of the material, and the sputtering time is set to 20-40s.

10. The method for preparing a metal oxide modified WO3-based gas sensor according to claim 9, characterized in that: In the step 4, the chip annealed in the step 3 is placed in a magnetron sputtering device to sputter metal oxide on the surface of the material, and the sputtered metal oxide is In2O3, ZnO or TiO2.

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