A high-precision platinum resistor slurry for environmental temperature measurement and preparation method thereof

Abstract

The present invention relates to a high-precision platinum resistor slurry for environmental temperature measurement and a preparation method thereof. The slurry is composed of a conductive functional phase, glass powder, an organic carrier and a diluent. The resistor slurry is sintered in an atmospheric environment. The sintered diaphragm is used to prepare a high-precision platinum resistor for temperature measurement. The diaphragm has the advantages of stable structure, high temperature measurement accuracy and good stability.

Description

Technical Field

[0001] The invention belongs to the technical field of electronic pastes, and in particular relates to a high-precision platinum resistor paste for environmental temperature measurement and a preparation method thereof. Background Art

[0002] Platinum resistors are important components in the field of temperature sensors. They have the advantages of high temperature measurement accuracy, good stability, wide temperature measurement range, and adaptability to harsh environments. They can be used in a variety of working environments. In addition to being widely used in environmental temperature measurement and control in industries such as petroleum, chemical, automobile, and food, they can also be used in military and national defense fields, such as aviation, aerospace, nuclear power, and military industry. For example, aerospace engine and combustion chamber monitoring, aircraft thermal management, battery and power management, material and structure monitoring, propulsion systems, aircraft surface and aerodynamic heating monitoring, and other fields. Under special working conditions, platinum resistors can ensure that key systems operate within a safe temperature range to prevent accidents and failures; provide and feedback accurate temperature measurement data, improve the reliability of equipment and systems, reduce maintenance and replacement frequency, and extend service life.

[0003] The platinum resistor is composed of a substrate layer, a conductive film layer, a packaging layer and lead wires. The core of the platinum resistor is the conductive film layer, which determines the temperature measurement accuracy and stability of the platinum resistor. The conductive film layer is made of platinum resistor slurry through screen printing and high-temperature firing. Compared with the platinum resistor with platinum wire wound on a skeleton, it has the advantages of high precision, small size, fast thermal response time, and good shock resistance. The resistance value of the platinum resistor will drift with the increase of use time, and the temperature measurement accuracy will decrease. The microstructure of the conductive platinum film layer of the conventional platinum resistor will change with the increase of working time, resulting in a large drift and a decrease in temperature measurement accuracy, which limits the use of the platinum resistor in high-precision and high-stability application environments. The present invention uses high-purity platinum powder, high-softening point glass powder, organic carrier and diluent to mix in a certain proportion, and after high-temperature sintering, the conductive platinum film structure reaches a stable state, thereby improving the temperature measurement accuracy and stability of the platinum resistor. Summary of the invention

[0004] The purpose of the present invention is to provide a high-precision platinum resistor slurry for environmental temperature measurement and a preparation method thereof. The components of the resistor slurry include a conductive functional phase, glass powder, an organic carrier and a diluent. The resistor slurry is sintered in an atmospheric environment. The sintered diaphragm is used to prepare a high-precision platinum resistor element for temperature measurement, which has the advantages of stable structure, high temperature measurement accuracy and good stability.

[0005] The technical solution of the present invention is:

[0006] The high-precision platinum resistor slurry for environmental temperature measurement has the following weight percentages of components: 5% to 10% glass powder, 20% to 35% organic carrier, 6% to 20% diluent, and the balance is a conductive functional phase; the conductive functional phase is high-purity platinum powder.

[0007] The platinum powder has a particle size of 500-800 nm, a purity of ≥99.99%, a spherical shape, and a specific surface area of ​​2.5-2.9 m 2 / g;

[0008] Preferably, the glass powder is lead-free, high softening point glass powder, with a particle size of 1 to 10 μm and a softening point of 950° C. to 1100° C.

[0009] The weight percentage of each component of the glass powder is: aluminum oxide Al 2 O 3 5%~10%, barium carbonate BaCO 3 15%~35%, Strontium carbonate SrCO 3 5%~15%, Boric acid H 2 BO 3 25%~40%, magnesium oxide MgO 1%~10%, and the balance is silicon oxide.

[0010] The organic carrier is composed of resin, organic additives and organic solvents, and the mass percentage of each component is: 5% to 15% of resin, 10% to 20% of organic solvent, and the balance is organic additives.

[0011] The resin is selected from any one or two of methyl cellulose and ethyl cellulose,

[0012] Preferably, the organic additive is selected from one or a combination of n-butanol, terpineol, and cyclohexanone;

[0013] Preferably, the organic solvent is selected from one or a combination of butyl acetate, dibutyl phthalate, ethylene glycol ethyl ether acetate, and toluene.

[0014] The diluent body consists of component A and component B, wherein component A accounts for 65% to 80% and component B accounts for 20% to 35%.

[0015] The component A is selected from one or a combination of n-butanol, terpineol, and castor oil, and the component B is selected from one or a combination of butyl acetate, dibutyl phthalate, and ethylene glycol ethyl ether acetate.

[0016] The method for preparing the slurry comprises the following steps:

[0017] 1) Preparation of organic carrier

[0018] The resin, organic additive and organic solvent are mixed, stirred at a speed of 40-60r / min for 3-5 minutes at room temperature, and then the resin is added, heated to 60-80°C for 8-12 hours, and cooled for use after being completely dissolved; wherein the molar ratio of the resin, organic additive and organic solvent is 1-2:6-9:1-3; the molar ratio of methyl cellulose and ethyl cellulose in the resin is 0-3:3-10, and the molar ratio of n-butanol, pineneol and cyclohexanone in the organic additive is 0-3:7-10:0-1;

[0019] 2) Preparation of diluent

[0020] Take components A and B of the diluent, mix them, stir them at a speed of 40-60 r / min for 5-10 minutes under normal temperature, and set aside; wherein the mass ratio of components A to B is 13-16:4-7, the molar ratio of n-butanol: pineneol: castor oil in component A is 0-3:6-10:0-2, and the molar ratio of butyl acetate: dibutyl phthalate: ethylene glycol ethyl ether acetate in component B of the diluent is 1-4:1-4:0-4;

[0021] 3) taking the conductive functional phase and the glass powder according to the above ratio, mixing them, and adding spheroidal graphite to obtain a mixed powder;

[0022] 4) Adding an organic carrier and a diluent to the mixed powder, wherein the molar ratio of the organic carrier to the diluent is 3-7:1-3, grinding for 20-30 minutes, and mixing evenly to obtain a platinum resistor slurry.

[0023] Step 3) The ball milling speed is 300-400 r / min, the time is 6-8 hours, and the ball milling is performed alternately in forward and reverse rotation, each for 30 minutes, with an interval of 15 seconds.

[0024] The beneficial effects of the present invention are as follows: the platinum resistor prepared by the present invention solves the problem of temperature measurement accuracy drift caused by changes in the microstructure of the conductive platinum film layer; the organic carrier and the diluent in the slurry can be chemically adsorbed and physically adsorbed, so that the solid and the liquid can be well infiltrated, the platinum powder and the glass powder are fully integrated, and firmly adhered to the substrate, thereby improving the uniformity and consistency of the film layer during the printing process of the slurry; the platinum powder and the glass powder in the slurry are diffusely bonded at high temperature to form a dense sintered body, the expansion coefficient of the substrate material is highly matched, and the microstructure of the platinum film layer is stable.

[0025] The invention adopts the atmospheric pressure sintering method to prepare the conductive platinum film layer, the preparation method is simple, easy to operate, and has strong practicality. The platinum resistor film prepared by the method of the invention has the advantages of high precision and good stability.

[0026] The applicant's experiments have verified that the platinum resistor made of the platinum slurry of the present invention has a stable microstructure and good electrical properties. The resistance value changes little before and after the test, the TCR remains unchanged, the environmental temperature measurement accuracy is high, and the stability is good. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 Schematic diagram of a platinum resistor sheet printed with platinum paste. DETAILED DESCRIPTION

[0028] Embodiment 1:

[0029] (1) Preparation of organic carrier:

[0030] Take 3g of methyl cellulose, 10g of ethyl cellulose, 8g of n-butanol, 40g of terpineol, 5g of cyclohexanone, 5g of butyl acetate, 4g of dibutyl phthalate, 4g of ethylene glycol ethyl ether acetate, and 2g of toluene, add them into a beaker, stir at a speed of 50r / min for 5 minutes, put it into a 70°C incubator for 10 hours, and then take it out to obtain an organic carrier;

[0031] (2) Preparation of diluent

[0032] Take 10g of n-butanol, 30g of terpineol, 10g of castor oil; 6g of butyl acetate, 6g of dibutyl phthalate, and 8g of ethylene glycol ethyl ether acetate, mix them, stir them at a speed of 60r / min for 6 minutes at room temperature, and put them into a reagent bottle to obtain a diluent;

[0033] (3) Preparation of glass powder

[0034] Weigh 35g SiO 2 , 6g Al 2 O 3 , 30g BaCO 3 , 10g SrCO 3 , 30g H 2 BO 3 , 4g MgO, after mixing all the raw materials evenly, sintering in a muffle furnace at 1400°C for 2h, quenching the obtained mixture with water to obtain glass slag, and grinding the glass slag into glass powder with a particle size of 1 to 10μm with a ball mill;

[0035] (4) Weigh 5 g of spherical platinum powder with a particle size of 400-600 nm, a purity of 99.99%, and a specific surface area of ​​2.5 m2 g-1, and 0.6 g of glass powder, place them in an agate jar, load them into a ball mill, and perform ball milling at a speed of 400 r / min for 6 hours, with the ball milling being performed alternately in forward and reverse rotation for 30 minutes each with an interval of 15 seconds to obtain a mixed powder;

[0036] (5) The mixed powder of step (4) is taken out and placed in an agate jar. 2.4 g of the organic carrier obtained in step (1) and 1.5 g of the diluent obtained in step (2) are added to the agate jar. The mixture is ground with an agate grinding rod for 20 minutes and mixed evenly to obtain a platinum resistor slurry for ambient temperature measurement.

[0037] Embodiment 2:

[0038] (1) Preparation of organic carrier

[0039] Take 6g of methyl cellulose, 9g of ethyl cellulose, 10g of n-butanol, 60g of terpineol, 4g of cyclohexanone, 7g of butyl acetate, 8g of dibutyl phthalate, and 5g of ethylene glycol ethyl ether acetate, add them into a beaker, stir at a speed of 50r / min for 5 minutes, put them into an 80°C incubator for 8 hours, and then take them out to obtain an organic carrier;

[0040] (2) Preparation of diluent

[0041] Take 6g of n-butanol, 35g of terpineol, 5g of butyl acetate, 5g of dibutyl phthalate, and 6g of ethylene glycol ethyl ether acetate, mix them, stir them at a speed of 50r / min for 8 minutes at room temperature, and put them into a reagent bottle to obtain a diluent;

[0042] (3) Preparation of glass powder

[0043] Weigh 20g SiO 2 , 5g Al 2 O 3 , 20g BaCO 3 , 9g SrCO 3 , 20g H 2 BO 3 , 2g MgO, after mixing all the raw materials evenly, place them in a muffle furnace for sintering at 1400℃, and keep them warm for 2h. After quenching the mixture with water, glass slag is obtained, and the glass slag is ground into glass powder with a particle size of 1 to 10μm by a ball mill.

[0044] (4) Weigh 6 g of particle size distribution 500-800 nm, purity 99.99%, specific surface area 2.8 m 2 g -1 0.55 g of spherical platinum powder and 0.55 g of glass powder were placed in an agate jar, loaded into a ball mill, and ball milled at a speed of 350 r / min for 7 hours. The ball mill was rotated forward and reversely alternately for 30 minutes each with an interval of 15 seconds to obtain a mixed powder;

[0045] (5) The mixed powder of step (4) is taken out and placed in an agate jar. 2.8 g of the organic carrier obtained in step (1) and 0.65 g of the diluent obtained in step (2) are added to the agate jar. The mixture is ground with an agate grinding rod for 20 minutes and mixed evenly to obtain a platinum resistor slurry for ambient temperature measurement.

[0046] Embodiment 3:

[0047] (1) Preparation of organic carrier

[0048] Take 10g of ethyl cellulose, 8g of n-butanol, 60g of terpineol, 4g of butyl acetate, 3g of dibutyl phthalate, 5g of ethylene glycol ethyl ether acetate, and 2g of toluene, add them into a beaker, stir at a speed of 60r / min for 5 minutes, put it into a 60℃ incubator for 12 hours, and then take it out to obtain an organic carrier;

[0049] (2) Preparation of diluent

[0050] 5g of n-butanol, 50g of terpineol; 10g of butyl acetate, 15g of dibutyl phthalate, mix the organic additive and the organic solvent, stir at a speed of 50r / min for 10 minutes at room temperature, and put into a reagent bottle to obtain a diluent;

[0051] (3) Preparation of glass powder

[0052] Weigh 18g SiO 2 , 6g Al 2 O 3 , 19g BaCO 3 , 7g SrCO 3 , 25g H 2 BO 3 , 3g MgO, after mixing all the raw materials evenly, place them in a muffle furnace for sintering at 1400℃, and keep them warm for 2h. After quenching the mixture with water, glass slag is obtained, and the glass slag is ground into glass powder with a particle size of 1 to 10μm by a ball mill.

[0053] (4) Weigh 6 g of particle size distribution 600-800 nm, purity 99.99%, specific surface area 2.6 m 2 g -1 0.7 g of spherical platinum powder and 0.7 g of glass powder were placed in an agate jar and loaded into a ball mill for ball milling at a speed of 320 r / min for 8 hours. The ball milling was performed alternately in forward and reverse directions for 30 minutes each with an interval of 15 seconds to obtain a mixed powder.

[0054] (5) The mixed powder of step (4) is taken out and placed in an agate jar. 1.5 g of the organic carrier obtained in step (1) and 1.2 g of the diluent obtained in step (2) are added to the agate jar. The mixture is ground with an agate grinding rod for 20 minutes and mixed evenly to obtain a platinum resistor slurry for ambient temperature measurement.

[0055] Performance Test:

[0056] The slurry is printed on a ceramic substrate, sintered at high temperature, and etched to obtain a platinum resistor sheet printed with platinum slurry (see Figure 1 ), test the platinum resistance temperature coefficient (TCR), the test is based on JJG 229-2010 "Industrial Platinum and Copper Thermal Resistors Verification Procedure"; after adjusting the resistance and making it into Pt100, test the resistance temperature coefficient of the platinum resistor, the results are shown in Table 1.

[0057] Table 1

[0058] Example <![CDATA[Post-printed TCR (10 -6 °C -1 )]]> <![CDATA[After making a platinum resistance thermometer (10 -6 °C -1 )]]> 1 3851 3851 2 3850 3850 3 3853 3853

[0059] According to GJB 9145-2017 "General Specifications for Platinum Thermal Resistors", the Pt100 platinum resistor is subjected to a temperature shock test. The test temperature is 150°C at high temperature and -55°C at low temperature. The test temperature is maintained for 30 minutes, the cycle is at least 10 times, and the test temperature conversion time is no more than 1 minute; the electrical aging test (electrical aging test is a method to accelerate component aging and assess the stability of the resistor film layer and component stability) has a current of 5 mA, a test temperature of 55°C, and a test time of 60 hours. The resistance value and resistance temperature coefficient of the platinum resistor before and after the test are tested. The test is based on JJG 229-2010 "Verification Procedure for Industrial Platinum and Copper Thermal Resistors".

[0060] Example 1 R0 R100 <![CDATA[TCR(10 -6 ℃ -1 )]]> Before the test 99.9698 138.4682 3851 After temperature shock test 99.9693 138.4675 3851 After electrical aging test 99.9690 138.4671 3851

[0061] Example 2 R0 R100 <![CDATA[TCR(10 -6 ℃ -1 )]]> Before the test 99.9634 138.4493 3850 After temperature shock test 99.9643 138.4506 3850 After electrical aging test 99.9608 138.4457 38500

[0062] Example 3 R0 R100 <![CDATA[TCR(10 -6 ℃ -1 )]]> Before the test 100.0010 138.5314 3853 After temperature shock test 100.0017 138.5324 3853 After electrical aging test 100.0016 138.5322 3853

[0063] It can be seen from the above test results that the platinum resistor made of the platinum slurry of the present invention has a stable microstructure and good electrical properties, the resistance value changes little before and after the test, the TCR remains unchanged, the environmental temperature measurement accuracy is high, and the stability is good.

Claims

1. A high-precision platinum resistor slurry for environmental temperature measurement, characterized in that: The weight percentage of each component of the slurry is 5% to 10% glass powder, 20% to 35% organic carrier, 6% to 20% diluent, and the balance is a conductive functional phase; the conductive functional phase is high-purity platinum powder; The platinum powder has a particle size of 500-800 nm, a purity of ≥99.99%, a spherical shape, and a specific surface area of ​​2.5-2.9 m 2 / g; The weight percentage of each component of the glass powder is: aluminum oxide Al2O3 5% to 10%, barium carbonate BaCO3 15% to 35%, strontium carbonate SrCO3 5% to 15%, boric acid H2BO3 25% to 40%, magnesium oxide MgO 1% to 10%, and the balance is silicon oxide; The diluent consists of component A and component B, wherein the component A is selected from one or a combination of n-butanol, terpineol, and castor oil, and the component B is selected from one or a combination of butyl acetate, dibutyl phthalate, and ethylene glycol ethyl ether acetate.

2. The slurry according to claim 1, characterized in that The glass powder is lead-free and high-softening-point glass powder, with a particle size of 1 to 10 μm and a softening point of 950° C. to 1100° C.

3. The slurry according to claim 1, characterized in that The organic carrier is composed of resin, organic additives and organic solvents, and the mass percentage of each component is: 5% to 15% of resin, 10% to 20% of organic solvent, and the balance is organic additives.

4. The slurry according to claim 3, characterized in that The organic additive is selected from one or a combination of n-butanol, terpineol and cyclohexanone.

5. The slurry according to claim 3, characterized in that The resin is selected from any one or two of methyl cellulose and ethyl cellulose; The organic solvent is selected from one or a combination of butyl acetate, dibutyl phthalate, ethylene glycol ethyl ether acetate and toluene.

6. The slurry according to claim 1, characterized in that The diluent contains 65% to 80% component A and 20% to 35% component B.

7. The method for preparing the slurry according to any one of claims 1 to 6, characterized in that: The following steps are involved: 1) Preparation of organic carrier The resin, organic additive and organic solvent are mixed, stirred at a speed of 40-60 r / min for 3-5 minutes under normal temperature, heated to 60-80°C for 8-12 hours, and cooled for use after being completely dissolved; wherein the molar ratio of the resin, the organic additive and the organic solvent is 1-2:6-9:1-3; the molar ratio of methyl cellulose and ethyl cellulose in the resin is 0-3:3-10, and the molar ratio of n-butanol, pineneol and cyclohexanone in the organic additive is 0-3:7-10:0-1; 2) Preparation of diluent Take components A and B of the diluent, mix them, stir them at a speed of 40-60 r / min for 5-10 minutes at room temperature, and set aside; wherein the molar ratio of components A to B is 6-10:2-4, the molar ratio of n-butanol, pineneol, and castor oil in component A is 0-3:6-10:0-2, and the molar ratio of butyl acetate, dibutyl phthalate, and ethylene glycol ethyl ether acetate in component B of the diluent is 1-4:1-4:0-4; 3) taking the conductive functional phase and the glass powder according to the ratio of claim 1, mixing and ball milling to obtain a mixed powder; 4) Add an organic carrier and a diluent to the mixed powder, with the molar ratio of the organic carrier to the diluent being 3-7:1-3, grind for 20-30 minutes, mix evenly, and obtain a platinum resistor slurry.

8. The method according to claim 7, characterized in that: Step 3) The ball milling speed is 300-400 r / min, the time is 6-8 hours, and the ball milling is performed alternately in forward and reverse rotation, each for 30 minutes, with an interval of 15 seconds.

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