Thermal shock resistant material and preparation method thereof

Abstract

The invention discloses a thermal shock resistant material and a preparation method thereof in the technical field of oxygen sensor materials. The thermal shock resistant material is prepared from the following raw materials in parts by weight: 5-10 parts of ethanol, 3-8 parts of fish oil, 5-10 parts of a dispersing agent, 10-25 parts of methylbenzene, 40-55 parts of oxidized metal mixed powder, 5-10 parts of a pore forming agent and 10-25 parts of an adhesive. Wherein the oxidized metal mixed powder is formed by mixing zirconium oxide, aluminum oxide and magnesium oxide, and the mass ratio of zirconium oxide to aluminum oxide to magnesium oxide in the oxidized metal mixed powder is 1: (1.5-2.5): (1.5-2.5). The oxygen sensor coated with the thermal shock resistant material provided by the invention can stably work for more than 6000 hours in an environment of 20 [mu] l / min, and the working time is more than 2000 hours than that of an uncoated oxygen sensor.

Description

Technical Field

[0001] The invention relates to the technical field of oxygen sensor materials, and in particular to a heat shock resistant material and a preparation method thereof. Background Art

[0002] With the advent of the era of integration of various electronic devices, electronic devices have put forward higher requirements for circuit miniaturization, high density, multifunctionality, high reliability, high speed and high power. Because co-fired multilayer ceramic substrates can meet many requirements of electronic devices for circuits, they have been widely used in recent years. Co-fired multilayer ceramic substrates can be divided into high-temperature co-fired multilayer ceramic (HTCC) substrates and low-temperature co-fired multilayer ceramic (LTCC) substrates. The typical application of high-temperature co-fired ceramics is oxygen sensors, which are the core components of automotive electronic fuel injection systems and make great contributions to environmental protection emissions.

[0003] Oxygen sensors made of high temperature co-fired ceramics (HTCC) are products based on zirconium oxide substrates. Oxygen sensors are used in high temperature exhaust gas environments, with harsh operating environments and severe vibrations. Therefore, a high-strength oxygen sensor is needed to cope with harsh environments. The strength of the oxygen sensor is determined by the strength of the zirconium oxide green ceramic. Zirconia green ceramics are prepared by hot pressing or tape casting. Zirconia oxygen sensors prepared by existing technologies have a short lifespan in high humidity environments and are prone to failure. Summary of the invention

[0004] The purpose of the present invention is to overcome the deficiencies in the prior art and provide a heat-shock resistant material and a preparation method thereof. An oxygen sensor coated with the heat-shock resistant material can stably work for more than 6000 hours in an environment of 20ul / min, which is more than 2000 hours longer than the working time of an uncoated material.

[0005] To achieve the above object, the present invention is implemented by adopting the following technical solutions:

[0006] In one aspect, the present invention provides a heat shock resistant material, which is made of the following raw materials in parts by weight: 5-10 parts of ethanol, 3-8 parts of fish oil, 5-10 parts of dispersant, 10-25 parts of toluene, 40-55 parts of metal oxide mixed powder, 5-10 parts of pore former and 10-25 parts of adhesive;

[0007] The metal oxide mixed powder is formed by mixing zirconium oxide, aluminum oxide and magnesium oxide, and the mass ratio of zirconium oxide, aluminum oxide and magnesium oxide in the metal oxide mixed powder is 1: (1.5-2.5): (1.5-2.5).

[0008] Further, the dispersant is selected from one or more of polyacrylamide and polyvinyl alcohol;

[0009] And / or, the pore-forming agent is selected from one or more of calcium carbonate, ammonium bicarbonate and carbon powder.

[0010] Furthermore, the adhesive includes one or more of gelatin and methyl cellulose.

[0011] In another aspect, the present invention provides a method for preparing the thermal shock resistant material, comprising the following steps:

[0012] Obtain raw materials of pore former, adhesive, dispersant, ethanol and toluene by weight, place them in a reaction kettle and stir them evenly; then pour the metal oxide mixed powder into the reaction kettle and stir them evenly to obtain slurry;

[0013] The slurry is poured out for vacuum degassing to obtain a slurry after vacuum degassing;

[0014] Apply the vacuum degassed slurry to the signal end of the oxygen sensor by end coating;

[0015] The oxygen sensor is placed in a sintering furnace for sintering to obtain an oxygen sensor coated with a thermal shock resistant material coating.

[0016] Furthermore, the metal oxide mixed powder is obtained by ball milling zirconium oxide, aluminum oxide and magnesium oxide obtained by weight, wherein the ball milling speed is 300-500r / min and the ball milling time is 10-16 hours.

[0017] Furthermore, the raw materials of pore former, adhesive, dispersant and organic solvent are obtained by weight, placed in a reaction kettle and stirred evenly, wherein the heating temperature of the reaction kettle is 50 degrees Celsius to 70 degrees Celsius, and the rotation speed is 15-20 rpm.

[0018] Furthermore, the ball-milled powder is poured into a reactor and stirred evenly to obtain a slurry, wherein the heating temperature of the reactor is 60 degrees Celsius to 70 degrees Celsius and the rotation speed is 30-35 rpm.

[0019] Furthermore, the vacuum degassing comprises rotating forward for 1500-1800 revolutions for 15-20 minutes, and then rotating reversely for 1500-1800 revolutions for 15-20 minutes.

[0020] Furthermore, the vacuum degassed slurry is coated on the signal end of the oxygen sensor by end coating, wherein the end coating height is 10-12 mm and the infiltration time is 10-20 s.

[0021] Furthermore, the oxygen sensor is placed in a sintering furnace for sintering, wherein the peak sintering temperature is 1200-1400 degrees Celsius and the sintering time is 30 minutes to 60 minutes.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] The present invention provides a heat shock resistant material and a preparation method thereof, wherein the heat shock resistant material is made of the following raw materials in parts by weight: 5-10 parts of ethanol, 3-8 parts of fish oil, 5-10 parts of dispersant, 10-25 parts of toluene, 40-55 parts of metal oxide mixed powder, 5-10 parts of pore former and 10-25 parts of adhesive; wherein the metal oxide mixed powder is a mixture of zirconium oxide, aluminum oxide and magnesium oxide, and the mass ratio of zirconium oxide, aluminum oxide and magnesium oxide in the metal oxide mixed powder is 1: (1.5-2.5): (1.5-2.5). The oxygen sensor coated with the heat shock resistant material provided by the present invention can stably work for more than 6000 hours in an environment of 20ul / min, which is more than 2000 hours longer than the working time of the uncoated one. DETAILED DESCRIPTION

[0024] The present invention is further described below. The following examples are only used to more clearly illustrate the technical solution of the present invention, and are not intended to limit the protection scope of the present invention.

[0025] The oxygen sensors used in the embodiments of the present invention are all HD6020 oxygen sensors produced by the 214th Institute of China North Industries Group Corporation.

[0026] Example 1

[0027] This embodiment provides a thermal shock resistant material and a preparation method thereof, the preparation method comprising:

[0028] (1) Obtaining raw materials 10 kg of zirconium oxide, 20 kg of aluminum oxide and 20 kg of magnesium oxide, and ball milling them at a ball milling speed of 400 r / min for 15 hours to obtain a ball-milled powder;

[0029] (2) Obtain raw materials: 5 kg carbon powder, 10 kg methyl cellulose, 5 kg polyacrylamide, 5 kg ethanol and 20 kg toluene, heat the reactor to 60 degrees Celsius, rotate at 18 rpm and stir evenly in the reactor;

[0030] (3) Pour the ball-milled powder into a reactor and stir evenly. The reactor is heated to 70 degrees Celsius and the speed is 30 rpm to obtain a slurry.

[0031] (4) Pour out the slurry for vacuum degassing, rotate forward 1600 times for 16 minutes, and then reverse 1600 times for 16 minutes to obtain the slurry after vacuum degassing;

[0032] (5) The vacuum degassed slurry is coated on the signal end of the oxygen sensor by end coating, with an end coating height of 11 mm and an immersion time of 15 s;

[0033] (6) The oxygen sensor is placed in a high-temperature sintering furnace for sintering at a temperature of 1250 degrees Celsius for 45 minutes to obtain an oxygen sensor coated with a heat shock resistant material coating.

[0034] Example 2

[0035] This embodiment provides a thermal shock resistant material and a preparation method thereof, the preparation method comprising:

[0036] (1) obtaining raw materials 12 kg of zirconium oxide, 19 kg of aluminum oxide and 19 kg of magnesium oxide and ball milling them at a ball milling speed of 400 r / min for 15 hours to obtain a ball-milled powder;

[0037] (2) Obtain raw materials: 7 kg carbon powder, 12 kg methyl cellulose, 6 kg polyacrylamide, 5 kg ethanol and 15 kg toluene, heat the reactor to 65 degrees Celsius, rotate at 20 rpm and stir evenly in the reactor;

[0038] (3) Pour the ball-milled powder into a reactor and stir evenly. The reactor is heated to 65 degrees Celsius and the speed is 32 rpm to obtain a slurry.

[0039] (4) Pour out the slurry for vacuum degassing, rotate forward 1800 times for 15 minutes, and then reverse 1800 times for 15 minutes to obtain the slurry after vacuum degassing;

[0040] (5) The vacuum degassed slurry is coated on the signal end of the oxygen sensor by end coating, with an end coating height of 11 mm and an immersion time of 17 s;

[0041] (6) The oxygen sensor is placed in a high-temperature sintering furnace for sintering at a temperature of 1300 degrees Celsius for 35 minutes to obtain an oxygen sensor coated with a heat-shock-resistant material coating.

[0042] Comparative Example

[0043] An oxygen sensor not coated with the heat shock resistant material coating provided by the present invention was used as a comparative example.

[0044] According to the relevant provisions of the technical requirements and test methods for automotive oxygen sensors, the humidity test of 5.4.2 was carried out on the oxygen sensors coated with the heat-resistant material coating provided in Examples 1 and 2 and the oxygen sensor not coated with the heat-resistant material coating provided in the comparative example in accordance with GB / T 2423.4-2008.

[0045] The test data are shown in Table 1, wherein No. 1#-4# are oxygen sensors provided in the comparative example that are not coated with the anti-heat shock material coating, No. 5#-6# are oxygen sensors provided in Example 1 that are coated with the anti-heat shock material coating, and No. 7#-8# are oxygen sensors provided in Example 2 that are coated with the anti-heat shock material coating.

[0046] Table 1

[0047] serial number Whether to apply thermal shock resistant coating 1000H failure condition 2000H failure condition 3000H failure condition 4000H failure condition 1# no Invalidation - - - 2# no Not expired Invalidation - - 3# no Not expired Invalidation - - 4# no Not expired Invalidation - - 5# yes Not expired Not expired Not expired Not expired 6# yes Not expired Not expired Not expired Not expired 7# yes Not expired Not expired Not expired Not expired 8# yes Not expired Not expired Not expired Not expired

[0048] As shown in Table 1, the oxygen sensors No. 1#-4# all failed after testing for 2000 hours, while the oxygen sensors No. 5#-8# still did not fail after testing for 4000 hours, which proves that the heat shock resistant material coating provided by the present invention can increase the average life of the oxygen sensor in a high humidity environment by more than 2000 hours.

[0049] The embodiments of the present invention are described above, but the present invention is not limited to the above-mentioned specific implementation modes. The above-mentioned specific implementation modes are merely illustrative and not restrictive. Under the guidance of the present invention, ordinary technicians in this field can also make many forms without departing from the scope of protection of the purpose of the present invention and the claims, which are all within the protection of the present invention.

Claims

1. A thermal shock resistant material, characterized in that: The invention is made of the following raw materials in parts by weight: 5-10 parts of ethanol, 3-8 parts of fish oil, 5-10 parts of dispersant, 10-25 parts of toluene, 40-55 parts of mixed powder of metal oxides, 5-10 parts of pore-forming agent and 10-25 parts of adhesive; The metal oxide mixed powder is formed by mixing zirconium oxide, aluminum oxide and magnesium oxide, and the mass ratio of zirconium oxide, aluminum oxide and magnesium oxide in the metal oxide mixed powder is 1: (1.5-2.5): (1.5-2.5).

2. The heat shock resistant material according to claim 1, characterized in that: The dispersant includes one or more of polyacrylamide and polyvinyl alcohol; And / or, the pore-forming agent is selected from one or more of calcium carbonate, ammonium bicarbonate and carbon powder.

3. The heat shock resistant material according to claim 1, characterized in that: The adhesive is selected from one or more of gelatin and methyl cellulose.

4. A method for preparing a thermal shock resistant material according to any one of claims 1 to 3, characterized in that: The following steps are involved: Obtain raw materials of pore former, adhesive, dispersant, ethanol and toluene by weight, place them in a reaction kettle and stir them evenly; then pour the metal oxide mixed powder into the reaction kettle and stir them evenly to obtain slurry; The slurry is poured out for vacuum degassing to obtain a slurry after vacuum degassing; Apply the vacuum degassed slurry to the signal end of the oxygen sensor by end coating; The oxygen sensor is placed in a sintering furnace for sintering to obtain an oxygen sensor coated with a thermal shock resistant material coating.

5. The method for preparing the thermal shock resistant material according to claim 4, characterized in that: The metal oxide mixed powder is obtained by ball milling zirconium oxide, aluminum oxide and magnesium oxide obtained by weight, wherein the ball milling speed is 300-500r / min and the ball milling time is 10-16 hours.

6. The method for preparing the heat shock resistant material according to claim 4, characterized in that: The raw materials of pore former, adhesive, dispersant and organic solvent are obtained by weight, placed in a reaction kettle and stirred evenly, wherein the heating temperature of the reaction kettle is 50 degrees Celsius to 70 degrees Celsius, and the rotation speed is 15-20rmp / min.

7. The method for preparing the heat shock resistant material according to claim 4, characterized in that: The ball-milled powder is poured into a reaction kettle and stirred evenly to obtain a slurry, wherein the heating temperature of the reaction kettle is 60 degrees Celsius to 70 degrees Celsius and the rotation speed is 30-35 rpm.

8. The method for preparing the heat shock resistant material according to claim 4, characterized in that: The vacuum degassing comprises rotating forward for 1500-1800 revolutions for 15-20 minutes, and then rotating reversely for 1500-1800 revolutions for 15-20 minutes.

9. The method for preparing the heat shock resistant material according to claim 4, characterized in that: The vacuum degassed slurry is coated on the signal end of the oxygen sensor by end coating, wherein the end coating height is 10-12 mm and the infiltration time is 10-20 s.

10. The method for preparing the heat shock resistant material according to claim 4, characterized in that: The oxygen sensor is placed in a sintering furnace for sintering, wherein the peak sintering temperature is 1200-1400 degrees Celsius and the sintering time is 30 minutes to 60 minutes.