A high-precision nickel-chromium-silicon-nickel-silicon-magnesium galvanic wire for automobiles and its preparation method

Abstract

The present invention relates to a high-precision nickel-chromium-silicon-nickel-silicon-magnesium galvanic wire for automobiles and a preparation method thereof, belonging to the field of thermocouple technology. The galvanic wire comprises an alloy galvanic wire, the surface of which is vapor-deposited with a silicon film, and a heat-resistant protective layer is cured on the outside of the silicon film. The heat-resistant protective layer is formed by compounding a heat-resistant protective glue and a curing agent and then baking and finalizing the mixture. The heat-resistant protective glue is made of parachlorophenol as a raw material, and is grafted with a silane coupling agent KH550 in an anhydrous environment to introduce siloxane groups. The silane coupling agent KH550 is then used to condense with ultrafine diamond powder in an alkaline alcohol-water environment, and then polymerized with a phenol and formaldehyde solution to form a phenolic resin-based adhesive. This ensures that the ultrafine diamond powder has good compatibility with the resin matrix and exerts a stable strengthening effect through covalent bond connection. In addition, after curing, a resin-ultrafine diamond powder heat conduction network is formed. Compared with conventional phenolic coatings, the heat conduction and heat dissipation performance is better, avoiding the introduction of the coating to form heat enrichment and cause measurement errors.

Description

Technical Field

[0001] The present invention belongs to the technical field of thermocouples, and in particular relates to a high-precision nickel-chromium-silicon-nickel-silicon-magnesium thermocouple wire for vehicles and a preparation method thereof. Background Art

[0002] Nickel-chromium-silicon-nickel-silicon-magnesium thermocouple is a low-cost metal thermocouple and is the latest internationally standardized thermocouple. The nominal chemical composition of its positive electrode is: Ni:Cr:Si≈84.4:14.2:1.4, and the nominal chemical composition of the negative electrode (NN) is: Ni:Si:Mg≈95.5:4.4:0.1. Its operating temperature range is -200-1300℃. It has the advantages of large thermoelectromotive force, high sensitivity, better stability and uniformity, strong oxidation resistance, and is not affected by short-range ordering. Its comprehensive performance is better than that of K-type thermocouple.

[0003] However, nickel-chromium-silicon-nickel-silicon-magnesium thermocouples cannot be used directly at high temperatures in sulfur, reducing, or alternating reducing and oxidizing atmospheres, or in vacuum. They are also not recommended for use in weakly oxidizing atmospheres, significantly limiting their application. With the development of the automotive industry, the demand for thermocouples is increasing. While traditional precious metal thermocouples offer high precision, their cost remains high. Therefore, this application aims to modify existing nickel-chromium-silicon-nickel-silicon-magnesium thermocouples and develop high-precision automotive nickel-chromium-silicon-nickel-silicon-magnesium thermocouple wires. Summary of the Invention

[0004] In order to solve the technical problems mentioned in the background technology, the purpose of the present invention is to provide a high-precision nickel-chromium-silicon-nickel-silicon-magnesium inductive wire for automobiles and a preparation method thereof.

[0005] The purpose of the present invention can be achieved through the following technical solutions:

[0006] A high-precision nickel-chromium-silicon-nickel-silicon-magnesium galvanic wire for automotive use comprises an alloy galvanic wire having a silicon film deposited on its surface and a heat-resistant protective layer cured on the outside of the silicon film. The silicon film has an extremely high density and can isolate the alloy galvanic wire from the test environment, effectively preventing the influence of environmental factors on the galvanic wire. The heat-resistant protective layer has stable heat resistance and heat dissipation capabilities, compensating for the defects of the thin silicon film and poor mechanical properties, protecting the silicon film, and stably performing an insulating function. The heat-resistant protective layer is formed by compounding a heat-resistant protective adhesive and a curing agent and then baking and finalizing them. The heat-resistant protective adhesive is prepared by the following method:

[0007] Step A1: preheating and dissolving parachlorophenol, anhydrous ethanol, and triethylamine under nitrogen protection, maintaining the temperature at 45-52° C., stirring at 180-240 rpm, and slowly adding silane coupling agent KH550. The total reaction time is 5-6 hours to obtain a phenol-modified coupling agent.

[0008] Furthermore, the usage ratio of p-chlorophenol, silane coupling agent KH550, triethylamine and anhydrous ethanol is 0.1 mol: 0.11-0.12 mol: 2.5-3.5 mL: 100-150 mL.

[0009] Step A2: Mix ultrafine diamond powder, phenol-modified coupling agent, and ethanol solution, add potassium hydroxide to adjust the pH to 9.5, and ultrasonically disperse at 40 kHz for 1-1.5 hours. Then, centrifuge and freeze-dry the bottom precipitate to obtain a modified coupling filler;

[0010] Furthermore, the usage ratio of the ultrafine diamond powder, the phenol-modified coupling agent and the ethanol solution is 10 g: 15-20 g: 180-250 mL, and the concentration of the ethanol solution is 40%.

[0011] Step A3: Ultrasonic dispersion of the modified coupling filler and formaldehyde solution, heating to 45-50°C under nitrogen protection, adding phenol and ammonia solution and stirring to mix, then continuing to heat to 80°C for a primary reaction until the GT reaches 180s, then switching to vacuum dehydration until the viscosity reaches 6 Pa·s, adding anhydrous ethanol (0.2 times the mass of the reaction substrate), and conducting a secondary reaction at 70°C until the GT reaches 140s. Anhydrous ethanol is again used to adjust the viscosity to 4 Pa·s to obtain a heat-resistant protective adhesive;

[0012] Furthermore, the usage ratio of the modified coupling filler, phenol, formaldehyde and ammonia water is 10-20 g: 0.4-0.6 mol: 1-1.2 mol: 30-40 mL, the concentration of the formaldehyde solution is 37%, and the concentration of the ammonia water is 25%.

[0013] Furthermore, the curing agent is an oligomer of resorcinol and formaldehyde.

[0014] A method for preparing a high-precision nickel-chromium-silicon-nickel-silicon-magnesium galvanic wire for automobiles comprises the following steps:

[0015] Step S1: vacuum evaporating a silicon film with a thickness of 0.2-0.3 μm on the surface of an alloy galvanic wire, then washing it with an alkaline ethanol solution and drying it with hot air to produce a silicon-coated wire;

[0016] Step S2: Evenly mix the heat-resistant protective adhesive and the curing agent, vacuum-degassing the adhesive, immersing the silicon-coated wire in the adhesive, leveling the adhesive, preheating the adhesive, and placing the adhesive in a baking oven. The baking process is set as follows: the first-stage baking temperature is 180-200°C, and the baking time is 20-30 minutes; the second-stage baking temperature is 190-240°C, and the baking time is 12-18 minutes; the third-stage baking temperature is 160-180°C, and the baking time is 10-15 minutes. The adhesive is cured to form a heat-resistant protective layer, and the adhesive is cooled to room temperature to produce a high-precision nickel-chromium-silicon-nickel-silicon-magnesium galvanic wire for automobiles.

[0017] Furthermore, the amount of curing agent used is 1.2-1.6 wt%.

[0018] Beneficial effects of the present invention:

[0019] The present invention prepares a nickel-chromium-silicon-nickel-silicon-magnesium galvanic wire with a composite structure. A very thin silicon film is evaporated on the surface of the alloy galvanic wire. The extremely high density of the silicon film isolates the alloy galvanic wire from the detection environment, effectively preventing the influence of environmental factors on the galvanic wire. A heat-resistant protective layer is formed on the surface of the silicon film by baking and curing with a heat-resistant protective glue and a curing agent to protect the silicon film and prevent the extremely thin silicon film from being damaged during assembly and use. The heat-resistant protective glue is made of parachlorophenol and is cured by a silane coupling agent KH55. 0 is grafted and modified in an anhydrous environment to introduce siloxane groups. It is then condensed with ultrafine diamond powder in an alkaline alcohol-water environment and polymerized with phenol and formaldehyde solution to form a phenolic resin-based adhesive. This makes the ultrafine diamond powder compatible with the resin matrix and exerts a stable strengthening effect through covalent bond connection. In addition, after curing, a resin-ultrafine diamond powder thermal conductivity network is formed. Compared with conventional phenolic coatings, it has better thermal conductivity and heat dissipation performance, avoiding the introduction of heat enrichment caused by the coating and causing measurement errors. DETAILED DESCRIPTION

[0020] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described 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 making any creative efforts shall fall within the scope of protection of the present invention.

[0021] Example 1

[0022] This embodiment prepares a high-precision nickel-chromium-silicon-nickel-silicon-magnesium galvanic wire for automotive use. The specific implementation process is as follows:

[0023] 1) Preparation of heat-resistant protective adhesive

[0024] a1. Add parachlorophenol, anhydrous ethanol and triethylamine to a reactor, introduce high-purity nitrogen until a stable airflow is discharged, so that the reactor is in a nitrogen protective atmosphere, preheat with electric heating, stir at 240 rpm until completely dissolved, then maintain a constant temperature at 52° C., set the stirring rate to 240 rpm, slowly add silane coupling agent KH550 within 1 hour, and continue to stir the reaction at a constant temperature. The overall addition reaction time is controlled to be 5 hours, and the reaction is subjected to vacuum rotary evaporation to remove the solvent and low-boiling substances mainly composed of anhydrous ethanol to obtain a phenol-modified coupling agent, wherein the amount ratio of parachlorophenol, silane coupling agent KH550, triethylamine and anhydrous ethanol is 0.1 mol:0.12 mol:3.5 mL:150 mL.

[0025] a2. Ultrafine diamond powder (fineness of 600 mesh, the same raw materials are used in the following examples), a phenol-modified coupling agent and a 40% ethanol solution were added to a reactor, potassium hydroxide was added to adjust the pH to 9.5, and ultrasonic dispersion was carried out at 40 kHz for 1 hour. The bottom precipitate was then centrifuged and freeze-dried to obtain a modified coupling filler, wherein the amount ratio of the ultrafine diamond powder, the phenol-modified coupling agent and the ethanol solution was 10 g: 20 g: 250 mL.

[0026] a3. The modified coupling filler and a 37% formaldehyde solution were added to a reactor, and ultrasonic dispersion was applied at 40 kHz for 10 minutes. High-purity nitrogen was introduced again for protection, and the temperature was raised to 50°C. Phenol and ammonia water were added and mechanically stirred at 240 rpm for 30 minutes. The temperature was then raised to 80°C for a primary reaction until the GT reached 180 seconds. The mixture was then vacuum dehydrated until the viscosity reached 6 Pa·s. Anhydrous ethanol (0.2 times the mass of the reaction substrate) was added, and a secondary reaction was carried out at 70°C until the GT reached 140 seconds. The viscosity was adjusted to 4 Pa·s with anhydrous ethanol to obtain a heat-resistant protective adhesive. The amount ratio of the modified coupling filler, phenol, formaldehyde, and ammonia water was 20 g:0.4 mol:1.2 mol:40 mL.

[0027] 2) Preparation of high-precision galvanic wire

[0028] s1. Take the alloy galvanic wire (nickel-chromium-silicon-nickel-silicon-magnesium galvanic wire, sold by Jiangyin Chengxin Alloy Material Co., Ltd.) and place it in a vacuum evaporation machine. Set the vacuum degree to no more than 5*10 -5 Torr, the evaporation current was 220A, the evaporation current curve was set, the silicon film thickness was controlled to be 0.2μm, a 60% ethanol solution was used, sodium carbonate was added to adjust the pH value to 9.0, the silicon-coated wire was cooled to room temperature, placed in the above alkaline ethanol solution for cleaning, then rinsed with water, and dried with hot air to obtain the silicon-coated wire;

[0029] s2. Take heat-resistant protective glue, add 1.6wt% of curing agent (oligomer of resorcinol and formaldehyde, provided by Zhejiang Annuo Chemical Co., Ltd.), stir and mix at high speed at 600rpm for 5min, then vacuum degassing for 5min, immerse the silicon-coated wire in the degassing glue, take it out and level it naturally at room temperature for 15min, after leveling, use a high-frequency heating furnace to quickly preheat it to 150℃, then pass through a tunnel heating furnace and undergo three-stage baking and curing, wherein the first baking temperature is 200℃ and the baking time is 20min, the second baking temperature is 240℃ and the baking time is 12min, the third baking temperature is 180℃ and the baking time is 10min, and then air-cooled to room temperature to obtain high-precision nickel-chromium-silicon-nickel-silicon-magnesium galvanic wire for automobiles.

[0030] Example 2

[0031] This embodiment prepares a high-precision nickel-chromium-silicon-nickel-silicon-magnesium galvanic wire for automotive use. The specific implementation process is as follows:

[0032] 1) Preparation of heat-resistant protective adhesive

[0033] a1. Add parachlorophenol, anhydrous ethanol and triethylamine to a reactor, introduce high-purity nitrogen until a stable airflow is discharged, so that the reactor is in a nitrogen protective atmosphere, preheat with electric heating, stir at 240 rpm until completely dissolved, then maintain a constant temperature at 45° C., set the stirring rate to 180 rpm, slowly add silane coupling agent KH550 within 1 hour, and continue to stir the reaction at a constant temperature. The overall addition reaction time is controlled to be 6 hours, and the reaction is subjected to vacuum rotary evaporation to remove the solvent and low-boiling substances mainly composed of anhydrous ethanol to obtain a phenol-modified coupling agent, wherein the amount ratio of parachlorophenol, silane coupling agent KH550, triethylamine and anhydrous ethanol is 0.1 mol:0.11 mol:2.5 mL:100 mL.

[0034] a2. Ultrafine diamond powder, phenol-modified coupling agent and 40% ethanol solution were added to a reactor, potassium hydroxide was added to adjust the pH to 9.5, and ultrasonic dispersion was performed at 40 kHz for 1.5 h. The bottom precipitate was then centrifuged and freeze-dried to obtain a modified coupling filler, wherein the amount ratio of ultrafine diamond powder, phenol-modified coupling agent and ethanol solution was 10 g:15 g:180 mL.

[0035] a3. Add the modified coupling filler and a 37% formaldehyde solution into a reactor, apply 40 kHz ultrasonic dispersion for 10 minutes, introduce high-purity nitrogen protection again, raise the temperature to 45°C, add phenol and ammonia water, and apply mechanical stirring at 240 rpm for 30 minutes. Then continue to raise the temperature to 80°C for a primary reaction until the GT reaches 180s. Then switch to vacuum dehydration until the viscosity reaches 6 Pa·s. Add anhydrous ethanol in an amount 0.2 times the mass of the reaction substrate, and carry out a secondary reaction at 70°C until the GT reaches 140s. Adjust the viscosity to 4 Pa·s with anhydrous ethanol again to obtain a heat-resistant protective adhesive. The amount ratio of modified coupling filler, phenol, formaldehyde, and ammonia water is 10g:0.6mol:1mol:30mL.

[0036] 2) Preparation of high-precision galvanic wire

[0037] s1. Place the alloy galvanic wire in a vacuum deposition machine and set the vacuum degree to no higher than 5*10 -5 Torr, the evaporation current was 240A, the evaporation current curve was set, the silicon film thickness was controlled to be 0.3μm, a 60% ethanol solution was used, sodium carbonate was added to adjust the pH value to 9.0, the silicon-coated wire was cooled to room temperature, placed in the above alkaline ethanol solution for cleaning, then rinsed with water, and dried with hot air to obtain the silicon-coated wire;

[0038] s2. Take heat-resistant protective glue, add 1.2wt% of curing agent, stir and mix at high speed at 600rpm for 8min, then vacuum degassing for 5min, immerse the silicon-coated wire in the degassing glue, take it out and level it naturally at room temperature for 15min, and after leveling, use a high-frequency heating furnace to quickly preheat it to 150℃, and then pass it through a tunnel heating furnace for three-stage baking and curing, wherein the first baking temperature is 180℃ and the baking time is 30min, the second baking temperature is 190℃ and the baking time is 18min, and the third baking temperature is 160℃ and the baking time is 15min, and then air-cool it to room temperature to obtain high-precision nickel-chromium-silicon-nickel-silicon-magnesium galvanic wire for automobiles.

[0039] Example 3

[0040] This embodiment prepares a high-precision nickel-chromium-silicon-nickel-silicon-magnesium galvanic wire for automotive use. The specific implementation process is as follows:

[0041] 1) Preparation of heat-resistant protective adhesive

[0042] a1. Add parachlorophenol, anhydrous ethanol and triethylamine to a reactor, introduce high-purity nitrogen until a stable airflow is discharged, so that the reactor is in a nitrogen protective atmosphere, preheat with electric heating, stir at 240 rpm until completely dissolved, then maintain a constant temperature at 50° C., set the stirring rate to 240 rpm, slowly add silane coupling agent KH550 within 1 hour, and continue to stir the reaction at a constant temperature. The overall addition reaction time is controlled to be 6 hours, and the reaction is subjected to vacuum rotary evaporation to remove the solvent and low-boiling substances mainly composed of anhydrous ethanol to obtain a phenol-modified coupling agent, wherein the amount ratio of parachlorophenol, silane coupling agent KH550, triethylamine and anhydrous ethanol is 0.1 mol:0.12 mol:3.2 mL:120 mL.

[0043] a2. Ultrafine diamond powder, phenol-modified coupling agent and 40% ethanol solution were added to a reactor, and potassium hydroxide was added to adjust the pH value to 9.5. Ultrasonic dispersion was performed at 40 kHz for 1.2 h, and the bottom precipitate was centrifuged and freeze-dried to obtain a modified coupling filler. The amount ratio of ultrafine diamond powder, phenol-modified coupling agent and ethanol solution was 10 g:18 g:230 mL.

[0044] a3. Add the modified coupling filler and a 37% formaldehyde solution into a reactor, apply 40 kHz ultrasonic dispersion for 10 minutes, introduce high-purity nitrogen protection again, raise the temperature to 48°C, add phenol and ammonia water, and apply mechanical stirring at 240 rpm for 30 minutes. Then continue to raise the temperature to 80°C for a primary reaction until the GT reaches 180s. Then switch to vacuum dehydration until the viscosity reaches 6 Pa·s. Add anhydrous ethanol (0.2 times the mass of the reaction substrate) and carry out a secondary reaction at 70°C until the GT reaches 140s. Adjust the viscosity to 4 Pa·s with anhydrous ethanol again to obtain a heat-resistant protective adhesive. The amount ratio of modified coupling filler, phenol, formaldehyde, and ammonia water is 16 g: 0.5 mol: 1.1 mol: 38 mL.

[0045] 2) Preparation of high-precision galvanic wire

[0046] s1. Place the alloy galvanic wire in a vacuum deposition machine and set the vacuum degree to no higher than 5*10 -5 Torr, the evaporation current was 220A, the evaporation current curve was set, the silicon film thickness was controlled to be 0.2μm, a 60% ethanol solution was used, sodium carbonate was added to adjust the pH value to 9.0, the silicon-coated wire was cooled to room temperature, placed in the above alkaline ethanol solution for cleaning, then rinsed with water, and dried with hot air to obtain the silicon-coated wire;

[0047] s2. Take the heat-resistant protective glue, add 1.5wt% of the curing agent, stir and mix at a high speed of 600rpm for 6min, and then vacuum degassing for 5min. Immerse the silicon-coated wire in the degassing glue, take it out and level it naturally at room temperature for 15min. After leveling, use a high-frequency heating furnace to quickly preheat it to 150℃, and then pass it through a tunnel heating furnace for three-stage baking and curing. Among them, the baking temperature of the first stage is 190℃ and the baking time is 22min, the baking temperature of the second stage is 220℃ and the baking time is 15min, and the baking temperature of the third stage is 160℃ and the baking time is 15min. Then air cool it to room temperature to obtain high-precision nickel-chromium-silicon-nickel-silicon-magnesium galvanic wire for automobiles.

[0048] Comparative Example

[0049] This comparative example is the Grade I nickel-chromium-silicon-nickel-silicon-magnesium galvanic wire sold by Jiangyin Chengxin Alloy Materials Co., Ltd.

[0050] The galvanic wires prepared in Examples 1 to 3 and the comparative example were subjected to accuracy tests in accordance with the GB / T 17615-2015 standard. The test temperature was set at 200° C. The test atmospheres were: air, 0.18% sulfur dioxide, 0.55% nitrogen oxides, and the remainder was air and unavoidable impurities, simulating exhaust gas and the complex application environment of the galvanic wires during automobile driving. Specific test data are shown in Table 1:

[0051] Table 1

[0052]

[0053] As can be seen from the data in Table 1, the galvanic wire prepared by the present invention has higher accuracy than the existing Class I nickel-chromium-silicon-nickel-silicon-magnesium galvanic wire. In particular, in complex application environments, the measurement accuracy of the galvanic wire of the present invention does not change significantly.

[0054] Throughout the specification, references to terms such as "one embodiment," "example," or "specific example" indicate that the specific features, structures, materials, or characteristics described in conjunction with that embodiment or example are included in at least one embodiment or example of the present invention. In this specification, schematic representations of these terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0055] The above contents are merely examples and explanations of the present invention. Those skilled in the art may make various modifications or additions to the described specific embodiments or replace them in similar ways. As long as they do not deviate from the invention or exceed the scope defined by the claims, they should all fall within the scope of protection of the present invention.

Claims

1. A high-precision nickel-chromium-silicon-nickel-silicon-magnesium galvanic wire for automobiles, comprising an alloy galvanic wire, characterized in that: The surface of the alloy galvanic wire is evaporated with a silicon film, and a heat-resistant protective layer is solidified on the outside of the silicon film; The heat-resistant protective layer is formed by compounding a heat-resistant protective adhesive and a curing agent and then baking and shaping them, wherein the heat-resistant protective adhesive is prepared by the following method: Step A1: dissolving p-chlorophenol, anhydrous ethanol, and triethylamine under nitrogen protection, maintaining a constant temperature of 45-52° C., setting a stirring rate of 180-240 rpm, and slowly adding silane coupling agent KH550. The total addition reaction time is 5-6 hours to obtain a phenol-modified coupling agent; Step A2: Mix ultrafine diamond powder, phenol-modified coupling agent, and ethanol solution, add potassium hydroxide to adjust the pH to 9.5, and ultrasonically disperse at 40 kHz for 1-1.5 hours. Then, centrifuge and freeze-dry the bottom precipitate to obtain a modified coupling filler; Step A3: Ultrasonic dispersion of the modified coupling filler and formaldehyde solution was performed. The temperature was raised to 45-50°C under nitrogen protection. Phenol and ammonia were then added and mixed. The temperature was then further raised to 80°C for a primary reaction until the GT reached 180s. The mixture was then vacuum dehydrated until the viscosity reached 6 Pa·s. Anhydrous ethanol (0.2 times the mass of the reaction substrate) was added, and a secondary reaction was performed at 70°C until the GT reached 140s. The viscosity was again adjusted to 4 Pa·s with anhydrous ethanol to obtain a heat-resistant protective adhesive.

2. The high-precision nickel-chromium-silicon-nickel-silicon-magnesium inductive couple wire for automobiles according to claim 1, characterized in that: The dosage ratio of p-chlorophenol, silane coupling agent KH550, triethylamine and anhydrous ethanol is 0.1 mol: 0.11-0.12 mol: 2.5-3.5 mL: 100-150 mL.

3. The high-precision nickel-chromium-silicon-nickel-silicon-magnesium electric couple wire for automobiles according to claim 2, characterized in that: The dosage ratio of the ultrafine diamond powder, the phenol-modified coupling agent and the ethanol solution is 10g:15-20g:180-250mL, and the concentration of the ethanol solution is 40%.

4. The high-precision nickel-chromium-silicon-nickel-silicon-magnesium electric couple wire for automobiles according to claim 3, characterized in that: The usage ratio of the modified coupling filler, phenol, formaldehyde and ammonia water is 10-20 g: 0.4-0.6 mol: 1-1.2 mol: 30-40 mL, the concentration of the formaldehyde solution is 37%, and the concentration of the ammonia water is 25%.

5. The high-precision nickel-chromium-silicon-nickel-silicon-magnesium electric couple wire for automobiles according to claim 4, characterized in that: The curing agent is an oligomer of resorcinol and formaldehyde.

6. The method for preparing a high-precision nickel-chromium-silicon-nickel-silicon-magnesium electric couple wire for automobiles according to claim 5, characterized in that: The steps include: Step S1: vacuum-evaporating a silicon film on the surface of an alloy galvanic wire, then washing it with an alkaline ethanol solution, and drying it with hot air to form a silicon-coated wire; Step S2: Mix the heat-resistant protective adhesive and the curing agent, vacuum-degassing, immerse the silicon-coated wire, level it, preheat, and then bake and cure it continuously to form a heat-resistant protective layer. Cool it to room temperature to make a high-precision nickel-chromium-silicon-nickel-silicon-magnesium galvanic wire for automobiles.

7. The method for preparing a high-precision nickel-chromium-silicon-nickel-silicon-magnesium electric couple wire for automobiles according to claim 6, characterized in that: The thickness of the silicon film is 0.2-0.3 μm.

8. The method for preparing a high-precision nickel-chromium-silicon-nickel-silicon-magnesium galvanic wire for automobiles according to claim 7, characterized in that: The usage of curing agent accounts for 1.2-1.6wt%, and the baking process is: the first stage baking temperature is 180-200℃, the baking time is 20-30min, the second stage baking temperature is 190-240℃, the baking time is 12-18min, and the third stage baking temperature is 160-180℃, and the baking time is 10-15min.

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