阅读说明：本技术 一种球形尖端微纳热电偶探针及其制备方法 (Spherical tip micro-nano thermocouple probe and preparation method thereof ) 是由 顾宁 安远 毛伟 陈�峰 于 2021-08-31 设计创作，主要内容包括：本发明公开了一种球形尖端微纳热电偶探针及其制备方法。该热电偶探针主要由同轴四层结构组成：基极为微纳尖端呈球形的钨探针,介质层为绝缘层,外极为铂,最外层为疏水层。使用时通过将不同尺寸的球形尖端微纳热电偶探针应用于待测部位,可以测量表面积10-50μm2球形区域的温度。和目前报导的微纳热电偶相比,本发明的球形尖端微纳热电偶探针具有制备形貌均一性好、无热滞后、温度-热电曲线线性特性强、热电重复性和稳定性高、塞贝克系数均一性好的特性。本发明在形貌稳定性提高的同时,测定微纳尺度温度数据过程的稳定性也得到了提高。(The invention discloses a spherical tip micro-nano thermocouple probe and a preparation method thereof. The thermocouple probe mainly comprises a coaxial four-layer structure: the base is a tungsten probe with a micro-nano tip in a spherical shape, the dielectric layer is an insulating layer, the outer layer is platinum, and the outermost layer is a hydrophobic layer. When the temperature measuring device is used, the spherical tip micro-nano thermocouple probes with different sizes are applied to a part to be measured, and the temperature of an 2 spherical area with the surface area of 10-50 mu m can be measured. Compared with the currently reported micro-nano thermocouple, the spherical tip micro-nano thermocouple probe has the characteristics of good uniformity of preparation appearance, no thermal hysteresis, strong linear characteristic of temperature-thermoelectric curve, high thermoelectric repeatability and stability and good uniformity of Seebeck coefficient. According to the invention, the stability of the shape is improved, and the stability of the process of measuring the micro-nano scale temperature data is also improved.)

1. The micro-nano thermocouple probe with the spherical tip is characterized by comprising four coaxial layers, wherein a base electrode is tungsten, a dielectric layer is an insulating layer, an outer electrode is platinum, and the outermost layer is a hydrophobic layer.

2. The spherical tip micro-nano thermocouple probe according to claim 1, wherein the tip of the tungsten probe of the base is spherical.

3. The preparation method of the spherical-tip micro-nano thermocouple probe according to claim 1, which is characterized by comprising the following steps:

(1) using a corrosive solution, taking the tungsten rod as an anode, and carrying out electrochemical corrosion, wherein the tungsten rod at the position is corroded into a needle shape due to the high corrosion speed of a gas-liquid interface;

(2) wrapping the tip direction of the corroded tungsten rod with an insulating solution for multiple times to cover the tip direction with an insulating layer;

(3) ionizing air by the electric arc of the point discharge to generate high temperature, evaporating the insulating layer of the point and melting the tungsten needle point into a spherical shape;

(4) sputtering a platinum target on the insulating layer to obtain a platinum layer only with the tip in contact with tungsten;

(5) and coating a hydrophobic layer in the tip direction of the platinum layer to make the surface of the probe hydrophobic, thereby obtaining a final product.

4. The preparation method of the spherical-tip micro-nano thermocouple probe according to claim 3, wherein in the step (1), the diameter of the tungsten rod is 0.1-0.5mm, the corrosion solution is sodium hydroxide, the concentration is 0.5-5mol/L, the corrosion voltage is 3-10V, and the action time is 2-20 min.

5. The preparation method of the spherical-tip micro-nano thermocouple probe according to claim 3, wherein in the step (1), the radius of curvature of the needle-shaped tungsten tip is 1-8 nm.

6. The preparation method of the spherical-tip micro-nano thermocouple probe according to claim 3, wherein in the step (2), the insulating solution is polyurethane dissolved in tetrahydrofuran, and the concentration is 90-150 g/L.

7. The preparation method of the spherical-tip micro-nano thermocouple probe according to claim 3, wherein in the step (2), the wrapping times are 1-3 times, each time the probe is wrapped at different heights, and the probe is repeatedly soaked and lifted 1-10 times in each wrapping until the front end of the probe is completely wrapped.

8. The method for preparing the micro-nano thermocouple probe with the spherical tip as claimed in claim 3, wherein in the step (3), the humidity condition is 20% -80%, the voltage applied by the tip discharge is 200-1500V, the number of arc generation is 1-5, and the surface area of the tungsten tip melted to be spherical is 10-50 μm²。

9. The preparation method of the spherical-tip micro-nano thermocouple probe according to claim 3, wherein in the step (4), the thickness of the sputtered platinum film is 80-130 nm.

10. The preparation method of the spherical-tip micro-nano thermocouple probe according to claim 3, wherein in the step (5), the surface drying time after the hydrophobic layer is immersed is 2-48 h.

Technical Field

The invention belongs to the field of micro-nano scale temperature sensors, and particularly relates to a spherical tip micro-nano thermocouple probe and a preparation method thereof.

Background

The temperature change can reflect the change of energy, and a series of problems can be solved by measuring the temperature of the micro-nano scale. The liquid drop evaporation experiment is an important experimental means for acquiring liquid drop information, and is an important experimental method in the fields of fire and fire fighting, explosion research, energy research and the like. In a droplet suspension method experiment of a droplet evaporation experiment, the internal temperature of a droplet is not easy to measure, a micro temperature measuring structure is required to measure the temperature, and compared with a traditional macro thermocouple, the micro-nano thermocouple has the advantages of small size (the thickness is in the order of mum), light weight, small thermal capacity, quick response, small interference to the measured environment, high precision, high sensitivity and the like, and accords with the development trend of technical miniaturization, integration, array and intelligence of a temperature sensor, so that the micro-nano thermocouple probe with simple preparation, good uniformity and high temperature measuring precision can well solve the temperature measuring problem in the droplet evaporation experiment.

The seebeck effect is generated by two different conductors in a temperature gradient, namely, the difference of the temperatures of two contact ends generates a potential difference, and the potential difference can be used for measuring the temperature. At present, a platinum-platinum rhodium type thermocouple (S type) is prepared by welding, the thermocouple is easy to damage and has insufficient rigidity, and the shape of the thermocouple is not suitable for measuring the temperature of liquid drops; the platinum/gold micro thermocouple is prepared by a glass micropipettor, the base of the thermocouple is a glass tube, the heat capacity of a temperature measuring junction is larger than that of metal, and the temperature sensitivity is lower; the thermocouple manufactured by using the silicon-based micro-electro-mechanical system technology is used for preparing a temperature measuring junction by using an ion beam etching method, preparing the temperature measuring junction by using electrochemical corrosion, preparing the temperature measuring junction by using an electron beam lithography method, preparing the temperature measuring junction on a cantilever by combining the lithography method and the corrosion method and the like, and the methods are high in cost.

Disclosure of Invention

The purpose of the invention is as follows: the invention aims to provide a spherical tip micro-nano thermocouple probe with good morphology uniformity, no thermal hysteresis, strong temperature-thermoelectric curve linear characteristic, high thermoelectric repeatability and stability and good seebeck coefficient uniformity and a preparation method thereof.

The technical scheme is as follows: the spherical tip micro-nano thermocouple probe comprises four coaxial layers, wherein a base electrode is tungsten, a dielectric layer is an insulating layer, an outer electrode is platinum, and an outermost layer is a hydrophobic layer.

Further, the tungsten probe tip of the base is spherical.

The invention discloses a preparation method of a spherical tip micro-nano thermocouple probe, which comprises the following steps:

(1) using a corrosive solution, taking the tungsten rod as an anode, and carrying out electrochemical corrosion, wherein the tungsten rod at the position is corroded into a needle shape due to the high corrosion speed of a gas-liquid interface;

(2) wrapping the tip direction of the corroded tungsten rod with an insulating solution for multiple times to cover the tip direction with an insulating layer;

(3) ionizing air by the electric arc of the point discharge to generate high temperature, evaporating the insulating layer of the point and melting the tungsten needle point into a spherical shape;

(4) sputtering a platinum target on the insulating layer to obtain a platinum layer only with the tip in contact with tungsten;

(5) and coating a hydrophobic layer in the tip direction of the platinum layer to make the surface of the probe hydrophobic, thereby obtaining a final product.

Further, in the step (1), the diameter of the tungsten rod is 0.1-0.5mm, the corrosion solution is sodium hydroxide, the concentration is 0.5-5mol/L, the corrosion voltage is 3-10V, and the action time is 2-20 min.

Further, in the step (1), the radius of curvature of the needle-shaped tungsten tip is 1-8 nm.

Further, in the step (2), the insulating solution is polyurethane dissolved in tetrahydrofuran, and the concentration is 90-150 g/L.

Further, in the step (2), the wrapping times are 1-3 times, each time the front end is wrapped at different heights, and the front end is repeatedly soaked and lifted 1-10 times in each wrapping until the front end is completely wrapped.

Further, in the step (3), the humidity condition is 20% -80%, the applied voltage of point discharge is 200-²。

Further, in the step (4), the thickness of the sputtered platinum film is 80-130 nm.

Further, in the step (5), the surface drying time after the hydrophobic layer is immersed is 2-48 h.

Has the advantages that: compared with the prior art, the invention has the following remarkable advantages:

(1) controlling the shape of the thermocoupleIs prepared at 10-50 μm²And the temperature measurement of the micro-nano scale spherical area can be realized.

(2) The thermocouple prepared by the method has the advantages of good appearance uniformity, no thermal hysteresis, strong temperature-thermoelectric curve linear characteristic, high thermoelectric repeatability and stability and good uniformity of Seebeck coefficient.

(3) The thermocouple prepared by the invention has stable data and high precision in the temperature measurement process.

Drawings

Fig. 1 is a schematic view of a spherical tip micro-nano thermocouple probe prepared in example 1;

FIG. 2 is an electron microscope image of the spherical-tip micro-nano thermocouple probe prepared in example 1;

fig. 3 is a seebeck coefficient calibration curve of the spherical-tip micro-nano thermocouple probe prepared in example 1;

fig. 4 is a time-temperature curve of the spherical-tip micro-nano thermocouple probe prepared in example 1 for measuring the internal temperature of a water droplet.

Detailed Description

The technical scheme of the invention is further explained by combining the attached drawings.

Example 1

A preparation method of a spherical tip micro-nano thermocouple probe for measuring temperature of water drops is shown in figure 1 and comprises the following steps:

(1) putting a tungsten rod with the surface cleaned, the diameter of 0.3mm and the length of 70mm into 3mol/L sodium hydroxide solution, and performing electrochemical corrosion by taking the tungsten rod as an anode to obtain a tip with the curvature radius of 2nm-5 nm;

(2) placing the tungsten probe with the tip into a tetrahydrofuran solution containing 100g/L of polyurethane, and slowly lifting to obtain a tungsten probe wrapped at the rear end; placing the probe tip of the tungsten probe wrapped at the rear end into a tetrahydrofuran solution containing 100g/L of polyurethane and slowly lifting the probe tip to obtain a tungsten probe completely wrapped at the front end and the rear end;

(3) taking the completely wrapped tungsten probe as one electrode of point discharge, taking an electrode as the other electrode of the point discharge, applying 500V voltage to enable the two electrodes to slowly approach until electric arcs appear, puncturing an insulating layer, generating a high-temperature evaporation insulating layer, and melting the tip of the tungsten probe into a spherical shape to obtain the tungsten probe with a spherical tip;

(4) sputtering a layer of platinum on the lower part of the tungsten probe insulating layer with the spherical tip to obtain one electrode connected with the thermocouple tungsten platinum;

(5) wrapping the sputtered probe with a layer of Teflon to make the surface hydrophobic, and obtaining the temperature probe with the hydrophobic surface

(6) The probe is connected with another probe which is put into an ice-water mixture and a voltage detection system, so that the voltage of a probe part can be measured, and the temperature of the probe part can be calculated.

As shown in FIG. 2, the micro-nano thermocouple with spherical tip prepared in one experiment shows that the surface area of the tungsten tip which is melted to be spherical is 10-50 μm under an electron microscope²。

As shown in fig. 3, the prepared spherical-tip micro-nano thermocouple probe has good uniformity and stable property, and the error of 10 times of repeated calibration is small.

As shown in fig. 4, the difference between the sample temperature and the ambient temperature in one experiment is detected.

Example 2

A preparation method of a spherical tip micro-nano thermocouple probe for measuring temperature of water drops comprises the following steps:

(1) putting a tungsten rod with the surface cleaned, the diameter of 0.3mm and the length of 70mm into 3mol/L sodium hydroxide solution, and performing electrochemical corrosion by taking the tungsten rod as an anode to obtain a tip with the curvature radius of 2nm-5 nm;

(2) placing the tungsten probe with the tip into a tetrahydrofuran solution containing 100g/L of polyurethane, and slowly lifting to obtain a tungsten probe wrapped at the rear end; placing the probe tip of the tungsten probe wrapped at the rear end into a tetrahydrofuran solution containing 100g/L of polyurethane and slowly lifting the probe tip to obtain a tungsten probe completely wrapped at the front end and the rear end;

(3) taking the completely wrapped tungsten probe as one electrode of point discharge, taking an electrode as the other electrode of the point discharge, applying 600V voltage to enable the two electrodes to slowly approach until electric arcs appear, puncturing an insulating layer, generating a high-temperature evaporation insulating layer, and melting the tip of the tungsten probe into a spherical shape to obtain the tungsten probe with a spherical tip;

(4) sputtering a layer of platinum on the lower part of the tungsten probe insulating layer with the spherical tip to obtain one electrode connected with the thermocouple tungsten platinum;

(5) wrapping the sputtered probe with a layer of Teflon to make the surface hydrophobic, and obtaining the temperature probe with the hydrophobic surface

(6) The probe is connected with another probe which is put into an ice-water mixture and a voltage detection system, so that the voltage of a probe part can be measured, and the temperature of the probe part can be calculated.

The tungsten rod with the hole opened by the voltage of 600V has repeatability on the experimental result, the appearance of the obtained tungsten probe is the same as that of the tungsten rod with the hole opened by the voltage of 500V, and the Seebeck coefficient obtained by 10 times of repeated calibration is similar to that of the tungsten rod with the hole opened by the voltage of 500V.