Cooling liquid, preparation method thereof and application of cooling liquid in heat dissipation reliability test of electronic component

Abstract

The invention belongs to the field of reliability testing, and particularly relates to cooling liquid and application thereof in heat dissipation reliability testing of electronic components. The cooling liquid provided by the invention comprises 80-120 parts by weight of a cooling agent and 6-20 parts by weight of a drying agent, the cooling agent is perfluorohexanone or a fire extinguishing agent, and the drying agent is composed of one or more of activated aluminum oxide, a 3A molecular sieve, a 4A molecular sieve, a 5A molecular sieve, a 10X molecular sieve and a 13X molecular sieve. The cooling liquid provided by the invention has relatively good cooling performance, and when electronic components are soaked in the cooling liquid provided by the invention for operation, the working temperature can be as low as 35.2 DEG C. Meanwhile, the cooling liquid provided by the invention has no pollution to the environment and no corrosion to electronic components, and can ensure that the electrical properties of the electronic components are not influenced. The invention further provides application of the cooling liquid in the heat dissipation reliability test of the electronic component, and the problem that an existing method for testing the heat dissipation reliability of the electronic component is small in application range can be solved.

Description

Technical Field

[0001] The invention belongs to the field of reliability testing, and in particular relates to a coolant and a preparation method thereof, and an application of the coolant in a heat dissipation reliability test of electronic components. Background Art

[0002] Coolant is an indispensable part of the normal operation of electronic components. Existing coolants mainly include water-based coolants, synthetic coolants, environmentally friendly coolants and nano coolants. Among them, water-based coolants are water-based coolants with additives such as antifreeze, preservatives, and antioxidants. As an example, water-based coolants include water-based cutting fluids and water-based metal coolants. Water-based coolants are widely used due to their low cost, high thermal conductivity, and environmental friendliness. However, water-based coolants often have deficiencies in anti-boiling and anti-corrosion, and may cause overheating and damage to electronic components or corrosion of metal parts in the cooling system during use.

[0003] Synthetic coolants include organic acid salts, phosphates, silicates, and additives specifically designed to improve their performance, such as high-performance preservatives and anti-boiling agents. As examples, synthetic coolants include emulsions, synthetic cutting fluids, stearic acid cutting fluids, perfluoropolyethers, and silicone coolants. Because the components of synthetic coolants often contain high-performance anti-boiling agents and preservatives, they have better thermal stability, anti-boiling performance, and anti-corrosion capabilities. Although synthetic coolants have relatively excellent cooling performance, there will be more problems with the long-term use of synthetic coolants. For example, the organic acid components in some synthetic coolants may precipitate under long-term high-temperature use, causing blockage and corrosion of sealing equipment used in electronic components or related systems; at the same time, some synthetic coolants containing amine substances may further aggravate the metal corrosion of electronic components in high-temperature and high-pressure operating environments; in addition, due to the increase in water content, some synthetic coolants may cause scale and sediment to form on the surface of electronic components during use, which not only affects the cooling performance and heat dissipation efficiency, but may even cause the electronic components to fail to operate normally.

[0004] Environmentally friendly coolants are mixtures of water and ethylene glycol or mixtures of water and propylene glycol, as well as other easily biodegradable liquids. Environmentally friendly coolants are simple in composition, low in cost, and have high thermal conductivity and good material compatibility. Like most water-based coolants, environmentally friendly coolants have relatively little impact on the environment, and waste liquid disposal after use is also relatively convenient. Although environmentally friendly coolants generally have good biodegradability, some ingredients in environmentally friendly coolants will still have a negative impact on the environment under certain circumstances. For example, ethylene glycol, amines, nitrates, nitrites, phosphates, and borates will produce certain toxicity after degradation, causing environmentally friendly coolants to gradually lose their cooling performance after long-term use or under specific environmental conditions.

[0005] Nano coolant is a coolant prepared by nanotechnology. It improves the overall thermal conductivity and specific heat capacity of the coolant by using nanometer-sized particles, thereby improving the cooling efficiency. As an example, the nanoparticles in the nano coolant include carbon-based nanoparticles, oxide nanoparticles, magnetic nanoparticles, and mixed nanofluids. The composition of the nano coolant is mainly based on their thermophysical properties, chemical stability, and impact on equipment and the environment. However, during the use of the nano coolant, the nanoparticles themselves may be poorly dispersed, resulting in aggregation or deposition, which affects the heat dissipation performance of electronic components. Long-term aggregation or deposition will further cause blockage inside the electronic components, affecting the normal operation of the components. It can be seen that there are some problems with the existing coolants. These problems may cause the coolant to fail to achieve a cooling effect, or even damage the related electronic components that need to be cooled.

[0006] On the other hand, the heat dissipation reliability test of electronic components is an important means to ensure the stable and safe operation of equipment. Reasonable test schemes and analysis methods can effectively improve the heat dissipation reliability of components, while preventing component failures from causing equipment failures and personal safety hazards. Therefore, electronic components need to undergo heat dissipation reliability tests before leaving the factory to ensure that their performance meets the requirements and can operate normally under various conditions. Through heat dissipation reliability tests, potential heat dissipation defects of electronic components can be discovered and eliminated, which can prevent these defects from causing component failures in actual use.

[0007] On June 23, 2023, Chinese invention patent CN2023100881304 disclosed a reliability test method for integrated circuits under ultra-low temperature and current coupling conditions. The invention patent first sets different currents and extreme temperatures according to the interconnection structure of the integrated circuit and the application environment; secondly, the integrated circuit board is connected to the wire and placed in a controllable ultra-low temperature environment; then a large current is applied to the integrated circuit to form a physical field of temperature and current coupling; then the current and resistance changes during the test are monitored; finally, failure analysis is performed on abnormal circuits. However, this method can only perform reliability analysis on integrated circuits, and cannot perform reliability analysis on other electronic components outside integrated circuits. The types of electronic components used are relatively small, and cannot meet the heat dissipation reliability test requirements of electronic components.

[0008] Based on this, the field urgently needs a coolant with good cooling performance, no corrosion to electronic components and no pollution to the environment, and a test method that can test the heat dissipation reliability of various electronic components. Summary of the invention

[0009] In view of the above-mentioned deficiencies in the prior art, the present invention provides a coolant, the purpose of which is to improve the cooling performance while solving the problem of corrosion of electronic components and pollution of the environment caused by the existing coolant during use. In addition, a second purpose is to provide a method for preparing the coolant, and a third purpose is to provide an application of the coolant in the heat dissipation reliability test of electronic components.

[0010] To achieve the first invention objective, the present invention adopts the following technical solutions:

[0011] A cooling liquid comprising the following components by weight:

[0012] 80-120 parts of coolant;

[0013] 6 to 20 parts of desiccant.

[0014] Optionally, the coolant is perfluorohexanone or a fire extinguishing agent.

[0015] Optionally, the desiccant comprises activated alumina and / or molecular sieves.

[0016] Optionally, the particle size of the activated alumina is 2 to 10 mm.

[0017] Optionally, the particle size of the molecular sieve is 0.4 to 6 mm.

[0018] Optionally, the pore size of the molecular sieve is 0.3-1 nm.

[0019] Optionally, the molecular sieve includes one or more of 3A molecular sieve, 4A molecular sieve, 5A molecular sieve, 10X molecular sieve, and 13X molecular sieve.

[0020] Optionally, the desiccant needs to be dried at high temperature before use, and after drying, it is placed in a water-free environment for cooling.

[0021] Optionally, the drying temperature is 500-800°C.

[0022] Optionally, the drying time is 30 to 90 minutes.

[0023] Another object of the present invention is to provide a method for preparing the cooling liquid, comprising the following steps:

[0024] Weigh 80 to 120 parts of a coolant and 6 to 20 parts by weight of a desiccant, dry the weighed desiccant at 500 to 800° C. for 30 to 90 minutes, cool to room temperature in a nitrogen atmosphere after drying, and finally mix with the previously weighed coolant to obtain a coolant.

[0025] Another object of the present invention is to provide an application of the coolant in a heat dissipation reliability test of electronic components.

[0026] Optionally, the difference in electrical performance, external surface morphology, and internal structure of the electronic components before and after the test is used to comprehensively judge whether the electronic components meet the reliability test requirements. If any one of the three tests does not meet the test requirements, the electronic component is deemed to have failed the heat dissipation reliability test.

[0027] Optionally, the electronic components include integrated circuits, transistors, ball grid array packages, resistors, capacitors, inductors, connectors, frequency control elements, heat dissipation elements, circuit boards, electromagnetic compatibility components, radio frequency components, power supply components, optoelectronic components, sensors, relays, surface mount components, and through-hole components.

[0028] Beneficial effects of the present invention:

[0029] (1) The cooling performance of the coolant provided by the present invention can be further improved by compounding perfluorohexanone with a desiccant. When the diode is immersed in the coolant provided by the present invention and operated, the operating temperature can be as low as 35.2°C.

[0030] (2) The coolant provided by the present invention has an ozone depletion potential (ODP) of 0 and a global warming potential (GWP) of 1, and is environmentally friendly.

[0031] (3) The present invention uses perfluorohexanone as the main component of the coolant, which can avoid corrosion to electronic components while improving the cooling performance of the coolant, thereby ensuring that the electrical performance of the electronic components is not affected.

[0032] (4) Compared with the existing reliability test method that only performs reliability test on electronic components in one dimension, the present invention performs multi-dimensional comparative analysis on electronic components before and after the test to draw a conclusion on whether the electronic components meet the reliability test requirements, and the analysis result is more accurate. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 This is a graph showing the cooling performance test results of the coolant provided in Example 8 of the present invention and four existing coolants.

[0034] Figure 2 This is a photo of the alloy resistor after being immersed in the coolant provided in Example 8 of the present invention and undergoing an aging test.

[0035] Figure 3 This is a photo of the alloy resistor after being immersed in the water-based coolant used in Comparative Example 1 and undergoing an aging test.

[0036] Figure 4 This is the external surface morphology of the thermistor before the heat dissipation reliability test.

[0037] Figure 5This is the external surface morphology of the thermistor after the heat dissipation reliability test.

[0038] Figure 6 Ultrasonic imaging of the internal structure of a thermistor before thermal reliability testing.

[0039] Figure 7 Ultrasonic imaging of the internal structure of a thermistor after thermal reliability testing. DETAILED DESCRIPTION

[0040] In order to make the purpose, technical solution and effect of the present invention clearer and more specific, the present invention is further described in detail below. 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.

[0041] As used herein, the terms "comprises," "including," "having," "containing," or any other variation thereof, are intended to cover a non-exclusive inclusion. For example, a composition, process, method, article, or apparatus that comprises the listed elements is not necessarily limited to only those elements but may include other elements not expressly listed or inherent to such composition, process, method, article, or apparatus.

[0042] "Optional" or "any one" means that the subsequently described matter or event can or cannot occur, and that the description includes instances where the event occurs and instances where it does not.

[0043] The indefinite articles "a" and "an" before the elements or components of the present invention have no limitation on the quantity requirements (i.e. the number of occurrences) of the elements or components. Therefore, "a" or "an" should be interpreted as including one or at least one, and the elements or components in the singular form also include the plural form, unless the quantity obviously refers to the singular form only.

[0044] The terms "one embodiment", "some embodiments", "exemplarily", "specific examples" or "some examples" described in the present invention mean 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 document, the schematic representation of the above terms does not necessarily refer to the same embodiment or example.

[0045] The numerical range described in the present invention not only includes the point values ​​listed in the embodiments, but also includes any point values ​​not listed between the numerical ranges described in the present invention. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values ​​included in the range.

[0046] In the following examples, unless otherwise specified, all reagents and consumables were purchased from conventional reagent manufacturers in the field.

[0047] Existing coolants often have some problems during use:

[0048] For example, some coolants have a low boiling point and tend to boil under high-temperature operating conditions, resulting in reduced cooling effects.

[0049] Or some coolants may corrode metal equipment during use, especially traditional water-based coolants, which require regular addition of preservatives or replacement of coolants.

[0050] In addition, some coolants are harmful to the environment, mainly because they contain substances that are not easily biodegradable. These substances may contain heavy metals (such as lead, chromium, etc.), which will pollute groundwater and soil, thereby affecting the balance of the ecosystem.

[0051] In addition, the organic matter in some coolants will produce new organic matter during the recycling process at the end of use. If these organic matter are discharged into the atmosphere, they may form harmful substances such as ozone and fine particulate matter, causing secondary pollution and leading to a decline in air quality.

[0052] In addition to the above-mentioned influences caused by the type of coolant, there are some additional requirements for coolants, which will also affect the selection of coolants and bring some restrictions. For example, physical property restrictions require coolants to have high temperature stability and durability; chemical stability restrictions require coolants to be inert and not react with water, oxygen, etc. in the air. These restrictions have resulted in very few existing coolants that can meet the requirements, so further research and improvement are needed to improve the overall performance of coolants.

[0053] Based on this, this embodiment provides a cooling liquid, which includes the following components by weight:

[0054] 80-120 parts of coolant;

[0055] 6-20 parts of desiccant;

[0056] The desiccant includes activated alumina and / or molecular sieve.

[0057] In some specific embodiments, the coolant is perfluorohexanone or a fire extinguishing agent.

[0058] As shown in Formula I, in this embodiment, the coolant in the coolant is perfluorohexane, and the molecular formula of the perfluorohexane used is C6F 12 O, with 12 hydrogen atoms on its carbon chain replaced by fluorine atoms, is a colorless, odorless, non-toxic, non-flammable liquid with high stability.

[0059]

[0060] In this embodiment, the perfluorohexanone in the coolant is 80 to 120 parts. Perfluorohexanone is the main component in the coolant, which can ensure that the electronic components maintain a relatively stable temperature environment during operation. As an example, the weight percentage of perfluorohexanone can be 80, 85, 90, 95, 100, 105, 110, 115, 120, as long as the weight percentage of perfluorohexanone is within this range.

[0061] Because of the above properties brought by the structure of perfluorohexanone itself, it can be used in the field of firefighting. For example, it can be super-pressurized with nitrogen and stored in high-pressure gas cylinders as part of the fire extinguishing system. In addition, perfluorohexanone also has excellent environmental performance, with an ozone depletion potential (ODP) of 0 and a global warming potential (GWP) of 1.

[0062] Perfluorohexanone is mostly used in fluorine fine products, fire extinguishing agents and cleaning agents, widely used in the field of fire protection, and occasionally used in lithium-ion battery electrolytes, but there is no report on the application of perfluorohexanone in coolants. This example uses perfluorohexanone to prepare coolants to broaden the application field of perfluorohexanone.

[0063] In some specific embodiments, the coolant in the coolant is a fire extinguishing agent. In particular, the fire extinguishing agent used in this embodiment is FK511 fire extinguishing agent, which has excellent electrical insulation properties and will not damage electronic components during operation. FK5112 fire extinguishing agent is non-corrosive to metals commonly used in electronic components such as carbon steel, copper, aluminum, stainless steel and other materials, and is compatible with most materials in electronic components, will not cause secondary damage, and will not leave residues or pollute the environment after use. In addition, FK5112 fire extinguishing agent also has strong chemical and physical stability, which can ensure that it maintains cooling efficiency during long-term use and reduce the frequency of replacement and maintenance.

[0064] In this embodiment, the FK5112 fire extinguishing agent in the coolant is 80 to 120 parts. The main component of the FK5112 fire extinguishing agent is also perfluorohexanone, which can ensure that the electronic components maintain a relatively stable temperature environment during the heat dissipation reliability test. The mass fraction of perfluorohexanone in the FK5112 fire extinguishing agent used in this embodiment is 97%, which can fully meet the use requirements as a coolant for the heat dissipation reliability test of electronic components. As an example, the weight fraction of the FK5112 fire extinguishing agent can be 80, 85, 90, 95, 100, 105, 110, 115, 120, as long as the weight fraction of the FK5112 fire extinguishing agent is within this range.

[0065] In some specific embodiments, the desiccant can absorb moisture in the use environment, prevent moisture from corroding electronic components and affecting the conductivity, and ensure that the electronic components are not damaged during operation. As an example, the weight percentage of the desiccant can be 6, 8, 10, 12, 13, 15, 17, 18, 19, 20, as long as the weight percentage of the desiccant is within the range.

[0066] In some specific embodiments, the desiccant includes activated alumina and / or molecular sieve. Activated alumina is widely used in industrial drying due to its porous surface structure, and molecular sieve also has strong hydrophilic properties and can also absorb excess water. It should also be noted that the coolant provided in this embodiment does not contain water, and the need to add additional desiccant is because there may be moisture in the actual operating environment of the electronic components, including water vapor in the environment, which may also cause corrosion to the electronic components or related equipment during the operation of the electronic components.

[0067] In some specific embodiments, the particle size of the activated alumina is 2 to 10 mm, such as 2 mm, 3 mm, 4 mm, 5 mm, 6 mm, 7 mm, 8 mm, 9 mm, and 10 mm, as long as the particle size of the activated alumina is within the range.

[0068] In some specific embodiments, the molecular sieve includes one or more of 3A molecular sieve, 4A molecular sieve, 5A molecular sieve, 10X molecular sieve, and 13X molecular sieve.

[0069] In a specific embodiment, the pore size of the molecular sieve is 0.3-1 nm. For example, the pore size of the 3A molecular sieve is 0.3 nm, the pore size of the 4A molecular sieve is 0.4 nm, the pore size of the 5A molecular sieve is 0.5 nm, the pore size of the 10X molecular sieve is about 1 nm, and the pore size of the 13X molecular sieve is 1 nm.

[0070] In some specific embodiments, the particle size of the molecular sieve is 0.4 to 6 mm. As an example, the particle size of the molecular sieve can be 0.4 mm, 0.5 mm, 1 mm, 1.5 mm, 2 mm, 2.5 mm, 3 mm, 4 mm, 5 mm, 5.5 mm, 6 mm, as long as the particle size of the molecular sieve is within this range. Since molecular sieves of different particle sizes and pore sizes can cover a wider surface area and achieve a more efficient adsorption effect, this embodiment can more fully absorb the moisture that may exist in the operating environment of electronic components by compounding molecular sieves of different particle sizes and pore sizes and activated alumina as a desiccant and adding them to the coolant, ensuring the insulation performance of the coolant and ensuring that the heat conduction efficiency is not affected, thereby improving the heat dissipation performance of electronic components.

[0071] In some specific embodiments, the desiccant needs to be dried for 30 to 90 minutes in an anhydrous environment at 500 to 800°C before use. After drying, it needs to be cooled to room temperature in an anhydrous environment for standby use. Since the function of the desiccant itself is to absorb moisture that may exist in the test environment, it needs to be fully dried before use. As an example, the drying temperature can be 500°C, 550°C, 600°C, 650°C, 700°C, 750°C, 800°C, as long as the drying temperature is within this range. Correspondingly, the drying time can be 30min, 40min, 50min, 60min, 70min, 80min, 90min, as long as the drying time is within this range.

[0072] Another embodiment of the present invention provides a method for preparing the coolant, comprising the following steps:

[0073] Weigh 80 to 120 parts of a coolant and 6 to 20 parts by weight of a desiccant, dry the weighed desiccant at 500 to 800° C. for 30 to 90 minutes, cool to room temperature in a nitrogen atmosphere after drying, and finally mix with the previously weighed coolant to obtain a coolant.

[0074] In addition, another object of the present invention is to provide an application of the above-mentioned coolant in the heat dissipation reliability test of electronic components. The coolant provided by the present invention can be used to improve the heat dissipation performance of electronic components. By using a coolant with perfluorohexanone as the main component to cool down the electronic components in operation, the specific cooling method can be to immerse the electronic components in the coolant for operation or to circulate the coolant in the cooling pipe to take away the heat generated by the operation of the electronic components.

[0075] Specifically, the application is the application of coolant in the heat dissipation reliability test of electronic components, which is achieved through the following steps:

[0076] S1. Record the electrical properties, surface morphology, and internal structure of electronic components before testing;

[0077] S2. Place the electronic components into the aging tank, connect the corresponding positive and negative power lines, add coolant into the aging tank and seal it;

[0078] S3. Connect the positive and negative power lines to the programmable power supply to output the voltage and current required by the electronic components;

[0079] S4. Place the aging tank into the aging test chamber, set the temperature, pressure and running time of the aging test chamber, and start the test;

[0080] S5. After the test is completed, open the aging test box, wait until the aging test box returns to room temperature, take out the aging tank in the aging test box, open the aging tank, and take out the electronic components in the aging tank;

[0081] S6. Record the electrical performance data, surface morphology and internal structure of electronic components after testing;

[0082] S7. Comprehensively judge whether the electronic components to be tested meet the reliability test requirements based on the differences in electrical performance, external surface morphology, and internal structure of the electronic components before and after the test. If any of the three tests does not meet the test requirements, it is deemed that the electronic component has failed the heat dissipation reliability test.

[0083] In this embodiment, the electrical performance data, external surface morphology, and internal structure of the electronic components before and after the test are compared and analyzed to verify whether the electronic components meet the reliability test requirements. Through various detection methods such as resistance value change, power-on test, external surface observation, and ultrasonic scanning of the internal structure, the performance and structural changes of the electronic components can be evaluated in an all-round way. This comprehensive evaluation can more comprehensively cover various factors that may affect the reliability of components.

[0084] In some specific embodiments, the electronic components tested include integrated circuits, transistors, ball grid array packages, resistors, capacitors, inductors, connectors, frequency control components, heat dissipation components, circuit boards, electromagnetic compatibility components, radio frequency components, power supply components, optoelectronic components, sensors, relays, surface mount components, and through-hole components.

[0085] The integrated circuit includes a microprocessor, a microcontroller and a memory, the transistor includes a diode and a triode, the ball grid array package (GBA) includes a memory chip and a central processing unit, the connector includes a contact, an insulator, a pin and a jack, the frequency control element includes a crystal oscillator, the heat dissipation element includes a fan, the radio frequency element includes a radio frequency switch, a radio frequency attenuator, and a radio frequency coupler, the optoelectronic device includes a photodiode, a phototransistor, and a laser, and the relay includes a coil and an armature. The heat dissipation reliability test of these electronic components can adopt the method provided in this embodiment.

[0086] Compared with the prior art, this embodiment can perform reliability tests on electronic components other than integrated circuit boards, broadens the test scope, and improves the applicability of the test method.

[0087] In some specific embodiments, the temperature of the aging test box is 80-90°C. The aging test box is a test box that provides a test environment for electronic component reliability testing. Setting the temperature and pressure in the box can accelerate the aging of the electronic components in the aging tank, shortening the test time and process. As an example, the temperature of the aging test box can be 80°C, 82°C, 84°C, 86°C, 88°C, 90°C, as long as the temperature of the aging test box is within this range.

[0088] In some specific embodiments, the pressure of the aging test chamber is 200-400 kPa. As an example, the pressure of the aging test chamber can be 200 kPa, 220 kPa, 240 kPa, 250 kPa, 260 kPa, 280 kPa, 300 kPa, 320 kPa, 350 kPa, 375 kPa, 390 kPa, or 400 kPa, as long as the pressure of the aging test chamber is within the range.

[0089] In some specific embodiments, the operating time of the aging test chamber is 800 to 1200 hours. As an example, the operating time of the aging test chamber can be 800 hours, 850 hours, 900 hours, 950 hours, 1000 hours, 1050 hours, 1100 hours, 1150 hours, or 1200 hours, as long as the operating time of the aging test chamber is within the range.

[0090] In some specific implementations, the reliability evaluation criteria of electronic components include electrical performance testing, surface morphology analysis, and internal structure analysis.

[0091] In some specific implementations, the difference in electrical performance is evaluated by measuring the change in resistance value of the electronic component before and after the test. Resistance value is the most basic parameter of electronic components, which directly reflects the ability of electronic components to hinder current. In this embodiment, the measurement of resistance value before the start of the test can establish a reference point, and correspondingly, the resistance value of the electronic component is measured again after the test is completed to evaluate whether the performance of the electronic component changes during the test and to intuitively understand whether the component has withstood the test conditions and whether its electrical performance remains stable. This comparative analysis can discover potential reliability issues, evaluate the life characteristics of components, and predict their performance in practical applications.

[0092] In some specific implementations, the electrical performance test can also be evaluated by powering on the tested electronic components to check whether they can be used normally. Power-on detection is a relatively simple test method. The operator only needs to connect the electronic components to the corresponding circuit and observe their working status and output parameters to determine whether the components are working properly. This method does not require complex equipment and advanced skills and is easy to implement. At the same time, power-on detection is also a fast test method. Compared with other methods that require long-term measurement and analysis, power-on detection can test components in a short time and improve test efficiency.

[0093] In some specific embodiments, the difference in external surface morphology is evaluated by observing whether there are defects or melts on the surface of the electronic components after the test. The changes in the external surface can intuitively reflect whether the components have been subjected to thermal stress or other environmental pressures beyond their tolerance during the test, thereby helping to determine their reliability. The changes in the external surface of the electronic components can be recorded by taking photos, recording videos or describing them in detail, and by comparing them to determine whether the reliability test requirements are met.

[0094] In a specific embodiment, a digital microscope can be used to record the changes in the outer surface of the electronic components before and after the reliability test. The magnification of the digital microscope can be 50x to 200x, such as 50x, 75x, 100x, 125x, 150x, 175x, 200x, or other magnifications that are not within this range but are suitable for the actual size of the electronic components.

[0095] In some specific implementations, the internal structure difference of the reliability evaluation standard of the electronic components is evaluated by obtaining scanning images by ultrasonic scanning of the electronic components before and after the test. Ultrasonic scanning can provide high-resolution imaging to identify hidden internal defects, such as internal cracks and meltdowns, which will directly affect the heat dissipation performance and reliability of the components. Comparison of ultrasonic images before and after the test helps to accurately evaluate the impact of the heat dissipation test on the internal structure of the components.

[0096] The present invention will be further described below by means of specific embodiments:

[0097] Example 1

[0098] A coolant comprising the following components:

[0099] Components Weight (unit: kg) Particle size (unit: mm) Perfluorohexanone 100 —— Activated Alumina 10 3 .

[0100] The preparation method of the coolant is as follows:

[0101] Weigh 100 kg of perfluorohexanone and 10 kg of activated alumina (particle size is 3 mm), put the weighed activated alumina into an oven and dry it at 500°C for 90 minutes. After drying, cool it to room temperature under a nitrogen atmosphere, and finally mix it with the previously weighed perfluorohexanone to obtain a coolant.

[0102] Example 2

[0103] A coolant comprising the following components:

[0104] Components Weight (unit: kg) Particle size (unit: mm) FK5112 fire extinguishing agent 100 —— Activated Alumina 10 3 .

[0105] The preparation method of the coolant is as follows:

[0106] Weigh 100kg of FK5112 fire extinguishing agent and 10kg of activated alumina (particle size is 3mm), put the weighed activated alumina into an oven and dry it at 550°C for 80min. After drying, cool it to room temperature under a nitrogen atmosphere, and finally mix it with the previously weighed FK5112 fire extinguishing agent to obtain a coolant.

[0107] Example 3

[0108] A coolant comprising the following components:

[0109] Components Weight (unit: kg) Particle size (unit: mm) Perfluorohexanone 80 —— Activated Alumina 10 3 .

[0110] The preparation method of the coolant is as follows:

[0111] Weigh 80 kg of perfluorohexanone and 10 kg of activated alumina (particle size 3 mm), put the weighed activated alumina into an oven and dry it at 575°C for 85 minutes. After drying, cool it to room temperature under a nitrogen atmosphere, and finally mix it with the previously weighed perfluorohexanone to obtain a coolant.

[0112] Example 4

[0113] A coolant comprising the following components:

[0114] Components Weight (unit: kg) Particle size (unit: mm) Perfluorohexanone 100 —— 3A molecular sieve 10 3 .

[0115] The preparation method of the coolant is as follows:

[0116] Weigh 100 kg of perfluorohexanone and 10 kg of 3A molecular sieve (particle size is 3 mm), put the weighed 3A molecular sieve into an oven and dry it at 600°C for 50 minutes. After drying, cool it to room temperature under a nitrogen atmosphere, and finally mix it with the previously weighed perfluorohexanone to obtain a coolant.

[0117] Example 5

[0118] A coolant comprising the following components:

[0119] Components Weight (unit: kg) Particle size (unit: mm) Perfluorohexanone 100 —— Activated Alumina 10 2 .

[0120] The preparation method of the coolant is as follows:

[0121] Weigh 100 kg of perfluorohexanone and 10 kg of 3A activated alumina (particle size is 2 mm), put the weighed activated alumina into an oven and dry it at 700°C for 40 minutes. After drying, cool it to room temperature under a nitrogen atmosphere, and finally mix it with the previously weighed perfluorohexanone to obtain a coolant.

[0122] Example 6

[0123] A coolant comprising the following components:

[0124] Components Weight (unit: kg) Particle size (unit: mm) Perfluorohexanone 100 —— Activated Alumina 5 3 3A molecular sieve 5 3 .

[0125] The preparation method of the coolant is as follows:

[0126] Weigh 100 kg of perfluorohexanone, 5 kg of activated alumina (particle size 3 mm) and 5 kg of 3A molecular sieve (particle size 3 mm), put the weighed activated alumina and 3A molecular sieve into an oven and dry them at 700°C for 40 minutes. After drying, cool them to room temperature under a nitrogen atmosphere, and finally mix them with the previously weighed perfluorohexanone to obtain a coolant.

[0127] Example 7

[0128] A coolant comprising the following components:

[0129] Components Weight (unit: kg) Particle size (unit: mm) FK5112 fire extinguishing agent 100 —— Activated Alumina 20 3 .

[0130] The preparation method of the coolant is as follows:

[0131] Weigh 100 kg of FK5112 fire extinguishing agent and 20 kg of activated alumina (particle size is 3 mm), put the weighed activated alumina into an oven and dry it at 800°C for 30 minutes. After drying, cool it to room temperature under a nitrogen atmosphere, and finally mix it with the previously weighed FK5112 fire extinguishing agent to obtain a coolant.

[0132] Example 8

[0133] A coolant comprising the following components:

[0134] Components Weight (unit: kg) Particle size (unit: mm) FK5112 fire extinguishing agent 100 —— Activated Alumina 6 3 .

[0135] The preparation method of the coolant is as follows:

[0136] Weigh 100 kg of FK5112 fire extinguishing agent and 6 kg of activated alumina (particle size is 3 mm), put the weighed activated alumina into an oven and dry it at 800°C for 30 minutes. After drying, cool it to room temperature under a nitrogen atmosphere, and finally mix it with the previously weighed FK5112 fire extinguishing agent to obtain a coolant.

[0137] Example 9

[0138] A coolant comprising the following components:

[0139] Components Weight (unit: kg) Particle size (unit: mm) Perfluorohexanone 120 —— Activated Alumina 3 2 Activated Alumina 2 5 Activated Alumina 2 10 3A molecular sieve 2 6 4A molecular sieve 3 3 5A molecular sieve 3 2 10X molecular sieve 3 1 13X molecular sieve 2 0.4 .

[0140] The preparation method of the coolant is as follows:

[0141] Weigh 120kg of perfluorohexanone, 3kg of activated alumina (particle size: 2mm), 2kg of activated alumina (particle size: 5mm), 2kg of activated alumina (particle size: 10mm), 2kg of 3A molecular sieve (particle size: 6mm), 3kg of 4A molecular sieve (particle size: 3mm), 3kg of 5A molecular sieve (particle size: 2mm), 3kg of 10X molecular sieve (particle size: 1mm) and 2kg of 13X molecular sieve (particle size: 0.4mm), put the weighed activated alumina and molecular sieves into an oven and dry them at 700°C for 60min. After drying, cool them to room temperature under a nitrogen atmosphere, and finally mix them with the previously weighed perfluorohexanone to obtain a coolant.

[0142] Example 10

[0143] A coolant comprising the following components:

[0144] Components Weight (unit: kg) Particle size (unit: mm) Perfluorohexanone 100 —— Activated Alumina 10 10

[0145] .

[0146] The preparation method of the coolant is as follows:

[0147] Weigh 100 kg of perfluorohexanone and 10 kg of activated alumina (particle size of 10 mm), put the weighed activated alumina into an oven and dry it at 500°C for 90 minutes. After drying, cool it to room temperature under a nitrogen atmosphere, and finally mix it with the previously weighed perfluorohexanone to obtain a coolant.

[0148] Embodiment 11

[0149] This embodiment is carried out for the third invention purpose of the present invention (application of coolant in heat dissipation reliability test of electronic components), and specifically includes the following steps:

[0150] This embodiment tests the heat dissipation reliability of thermistors, and the specifications of thermistors are as follows:

[0151] 47000.0ohm-0mA-NTC-SMD-0805-B25 / 85=4000-4107K.

[0152] S1. Record the electrical properties, external surface morphology, and internal structure of the thermistor before testing;

[0153] S2. Place the thermistor in a high-temperature and high-pressure aging tank, connect the corresponding positive and negative power lines, add the coolant provided in Example 8 to the aging tank and seal it;

[0154] S3. Connect the positive and negative power lines to the programmable power supply, and output the required voltage of the thermistor, 0.5V, and current, 0.2mA;

[0155] S4. Place the aging tank in the aging test chamber, set the temperature of the aging test chamber to 85 ° C, the pressure to 300 kPa, and the running time to 1000h, and start the test;

[0156] S5. After the test is completed, open the aging test box, let it stand for 8 hours until the aging test box returns to room temperature, take out the high-temperature and high-pressure aging tank in the aging test box, open the high-temperature and high-pressure aging tank, and take out the thermistor in the high-temperature and high-pressure aging tank;

[0157] S6. Record the electrical performance data, external surface morphology, and internal structure of the thermistor after testing, as follows:

[0158] The resistance change of thermistor before and after the test, as well as the reliability judgment criteria and results are as follows:

[0159]

[0160] Electrical performance analysis:

[0161] Through the electrical performance test results, it can be found that the resistance difference before and after the thermistor test is only 0.028KΩ, which is far less than the 1KΩ deviation range required by the thermistor reliability test. It can be considered that the electrical performance of the thermistor is not affected after the test, so it can be judged that the thermistor can meet the electrical performance requirements of heat dissipation reliability.

[0162] External surface morphology analysis:

[0163] The surface morphology of the thermistor tested in this embodiment was recorded using a digital microscope at a magnification of 100x. Figure 4 As shown, after the test, the thermistor was recorded again at the same magnification. The external surface morphology after the reliability test is as follows Figure 5 After comparison, it can be seen that there are no cracks, corrosion, or scale on the outer surface of the thermistor after the test, so it can be judged that the thermistor can meet the outer surface morphology requirements of the heat dissipation reliability test.

[0164] Internal structure analysis:

[0165] The thermistor used in this embodiment is subjected to ultrasonic scanning analysis. The internal structure ultrasonic image of the thermistor used in this embodiment before the test is as follows: Figure 6 As shown, the ultrasound image of the internal structure after the test is as follows Figure 7 After comparison, it can be seen that the internal structure of the thermistor did not break or melt after the test, so it can be judged that the thermistor can meet the internal structure requirements of the heat dissipation reliability test.

[0166] By comparing and analyzing the electrical properties, external surface morphology and internal structure of the thermistor before and after the reliability test, it was found that all three tests of the thermistor met the requirements, so it can be determined that the thermistor meets the heat dissipation reliability test requirements.

[0167] Cooling performance test

[0168] The electronic components selected for the test are diodes. After connecting the diodes to a power source, they are immersed in the coolants obtained in Examples 1 to 10, respectively. The power source is turned on to allow the diodes to operate. After operating for 1 hour, the temperature of the diodes is measured. The details are shown in Table 2:

[0169] Table 2 Coolant performance test results of Examples 1 to 10

[0170]

[0171] Data Analysis:

[0172] 1. The coolants provided in all embodiments can maintain the operating temperature of electronic components in a relatively low range. It can be seen that the coolants provided in the present invention have good cooling performance.

[0173] 2. By comparing Example 1 and Example 2, it can be seen that the only difference between the coolant in Example 1 and the coolant in Example 2 is that FK5112 fire extinguishing agent is used instead of perfluorohexanone. However, the cooling performance of the coolant does not change significantly after the replacement. Therefore, it can be determined that FK5112 fire extinguishing agent also has a good cooling effect and can be used as a coolant.

[0174] 3. Examples 1 to 3 all use activated alumina as a desiccant component to prepare coolant. Activated alumina can effectively improve the purity of perfluorohexanone by absorbing trace moisture and other polar impurities in the perfluorohexanone. The perfluorohexanone with improved purity has more stable thermal conductivity and insulation, so it can keep the single sub-components immersed in the coolant at a lower operating temperature.

[0175] 4. Although the amount of perfluorohexanone used in Example 3 is less than that in Example 1, it is still within the range of 80 to 120 parts by weight specified in the present invention, and thus can also meet the cooling performance requirements.

[0176] 5. By comparing Example 1 and Example 4, it can be seen that in Example 4, the activated alumina in the desiccant is replaced with 3A molecular sieve of the same particle size, but the cooling performance is improved. The inventors analyzed that the reason may be that the adsorption capacity of the molecular sieve is stronger than that of the activated alumina, especially under low humidity requirements, and the cooling system can be fully dried to prevent moisture from corroding electronic components, and on this basis, the cooling performance of the coolant is improved.

[0177] 6. Comparing Example 1 with Examples 5 and 10, it can be seen that the small-particle activated alumina as a desiccant allows the coolant of Example 5 to exhibit a better cooling effect. This is because the small-particle activated alumina has a larger specific surface area than the large-particle activated alumina. The larger specific surface area provides more adsorption sites, so that the small-particle activated alumina can more effectively adsorb the moisture in perfluorohexanone, thereby improving the drying efficiency.

[0178] 7. Comparing Examples 1, 4, and 6, it can be seen that the coolant to which the desiccant composed of activated alumina and 3A molecular sieve is added has better cooling performance than the desiccant composed of single activated alumina and single 3A molecular sieve. The inventors analyzed that the reason may be that the pore structure distribution on the surface of activated alumina is relatively messy, with large pores being the majority, so it has better adsorption performance for impurities with larger particle sizes, but its adsorption capacity for impurities with smaller particle sizes is weaker. The pore size on the surface of the molecular sieve is smaller than that of activated alumina, and accordingly, it has better absorption effect on small molecular impurities, but is also not good at absorbing impurities with larger particle sizes. Example 6 can further improve the adsorption performance of impurities of different particle sizes by compounding activated alumina and 3A molecular sieve to form a mixed desiccant, thereby further reducing the content of other impurities in the coolant except perfluorohexanone, which can effectively improve the cooling performance of the coolant.

[0179] 8. Comparing Examples 2, 7, and 8, it can be seen that the difference between the desiccant in the three examples is only the amount of desiccant used, but the cooling performance of the coolant has not changed significantly, so it can be determined that the content of the desiccant has no significant effect on the cooling performance of the coolant. That is, as long as the content of the desiccant is within the specified range of the present invention, the drying requirements for the coolant can be met.

[0180] 9. By comparing Example 9 with other examples, it can be seen that Example 9 uses different types and different particle sizes of desiccants in combination, and the coolant obtained after mixing with perfluorohexanone has better cooling performance.

[0181] Comparative Example 1

[0182] To further demonstrate the cooling performance of the coolant provided by the present invention, water-based coolant, synthetic coolant, environmentally friendly coolant, and nano coolant are selected to perform temperature tests on the same electronic components (diodes) after working for 1 hour under the same test conditions as in Example 8. The components of the other coolants used are as follows in parts by weight:

[0183] ① Water-based coolant: 60% water, 30% ethylene glycol, 6% sodium chloride, 4% magnesium sulfate.

[0184] ②Synthetic coolant: 50% polyalphaolefin (molecular weight 200-650), 20% natural gas synthetic oil, 30% synthetic ester (dimethyl silicone oil).

[0185] ③Environmentally friendly coolant: 50% propylene glycol, 40% corrosion inhibitor (disodium hydrogen phosphate), 10% antioxidant (citric acid).

[0186] ④Nano coolant: 35% carbon nanotubes, 25% aluminum oxide, 25% ferroferric oxide, and 15% copper oxide.

[0187] The temperature test results of the above four coolants are as follows: Figure 1 As shown, through Figure 1 It can be seen that only the diode immersed in the coolant of Example 8 showed a lower stable operating temperature, while the stable operating temperatures in the other four coolants exceeded 80°C, and the operating temperature in the water-based coolant even reached 105.6°C. It can be seen that the coolant provided by the present invention has more outstanding coolant performance.

[0188] Comparative Example 2

[0189] In order to further prove that the coolant provided by the present invention does not cause corrosion to components, a comparative test is now conducted, as follows:

[0190] Name of electronic component to be tested: alloy resistor.

[0191] Specifications of electronic components to be tested: -1W -0.02ohm -+ / -1% -1206 -Diversified.

[0192] Specific test operation: two alloy resistors of the same specification are respectively placed in a high-temperature aging test equipment filled with the coolant of Example 8 of the present invention and the water-based coolant used in the test of Comparative Example 1, and the power is turned on and sealed to operate for 1000 hours in an environment of 300 kPa and 85°C. After the operation is completed, the two alloy resistors are taken out and observed. Figure 2 The alloy resistor placed in the coolant of Example 8 of the present invention after aging test. It can be seen that the alloy resistor placed in the coolant of Example 8 of the present invention does not show any corrosion on the surface after the aging test, and the integrity of the electronic components is good.

[0193] Figure 3 The alloy resistor after aging test in the water-based coolant of Comparative Example 1 is: Figure 3 The marked parts are where corrosion or rust occurs. It can be seen that the alloy resistor has obvious corrosion after the aging test in the water-based coolant used in Comparative Example 1. After comparison, it can be seen that the coolant provided by the present invention will not corrode electronic components when used, and can provide better protection for electronic components.

[0194] It should be understood that the application of the present invention is not limited to the above examples. For ordinary technicians in this field, improvements or changes can be made based on the above description. All these improvements and changes should fall within the scope of protection of the claims attached to the present invention.

Claims

1. A cooling liquid, characterized in that: The components include the following by weight: 80-120 parts of coolant; 6-20 parts of desiccant; The desiccant includes activated alumina and / or molecular sieves.

2. The coolant according to claim 1, characterized in that: The coolant is perfluorohexanone or a fire extinguishing agent.

3. The coolant according to claim 1, characterized in that: The particle size of the activated alumina is 2 to 10 mm; The particle size of the molecular sieve is 0.4-6 mm, and the pore size is 0.3-1 nm.

4. The coolant according to claim 3, characterized in that: The molecular sieve includes one or more of 3A molecular sieve, 4A molecular sieve, 5A molecular sieve, 10X molecular sieve and 13X molecular sieve.

5. The coolant according to claim 1, characterized in that: The desiccant needs to be dried at high temperature before use, and after drying, it is placed in a water-free environment to cool.

6. The coolant according to claim 5, characterized in that The high temperature drying treatment has a drying temperature of 500 to 800° C. and a drying time of 30 to 90 minutes.

7. A method for preparing the coolant according to any one of claims 1 to 6, comprising the following steps: Weigh 80 to 120 parts of a coolant and 6 to 20 parts by weight of a desiccant, dry the weighed desiccant at 500 to 800° C. for 30 to 90 minutes, cool to room temperature in a nitrogen atmosphere after drying, and finally mix with the previously weighed coolant to obtain a coolant.

8. Use of the coolant prepared by the coolant preparation method according to claim 7 in heat dissipation reliability testing of electronic components.

9. The use of the coolant according to claim 8 in the heat dissipation reliability test of electronic components, characterized in that: Whether the electronic components meet the reliability test requirements is comprehensively judged by the differences in electrical performance, external surface morphology, and internal structure of the electronic components before and after the test. If any one of the three tests does not meet the test requirements, it is considered that the electronic component has failed the heat dissipation reliability test.

10. The use of the coolant according to claim 8 in the heat dissipation reliability test of electronic components, characterized in that: The electronic components include integrated circuits, transistors, ball grid array packages, resistors, capacitors, inductors, connectors, frequency control components, heat dissipation components, circuit boards, electromagnetic compatibility components, radio frequency components, power supply components, optoelectronic components, sensors, relays, surface mount components, and through-hole components.

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