With the rapid development of science and technology, smart wearable devices have gradually integrated into our daily life, especially in the field of sports and health play an irreplaceable role. From tracking exercise to monitoring heart rate, these devices offer us unprecedented convenience and comfort. However, with the continuous evolution of artificial intelligence technology, the degree of intelligence of smart wearable devices is increasing, and the requirements for device shell materials are becoming increasingly stringent. The purpose of this paper is to discuss the advantages and disadvantages of existing smart wearable device shell materials, and look forward to the future innovation direction.

 

Introduction to ZrO2 Ceramic as a Potential Shell Material for Smart Wearables

At present, the watch bezel of smart wearable devices is mostly made of metal or plastic. The metal shell is favored for its good heat dissipation performance, but it also brings the problem of hot equipment caused by too fast heat conduction, affecting the user experience. In addition, after the metal shell is anodized and multi-color spray painting treatment, although the appearance is bright, once the physical collision occurs, it is easy to drop paint and oxidation, reducing gloss and affecting the appearance.

 

Advantages and Disadvantages of Current Smart Wearable Shell Materials

The plastic shell is slightly inferior because of its poor texture. Although manufacturers are constantly trying to add design elements such as patterns and imitation leather to enhance the feel, the plastic shell still looks dull compared to the premium feeling generated by metal and glass materials. At the same time, the heat dissipation effect of the plastic shell is general, and the heat cannot be dispersed in time, which may have a negative impact on the operation effect of the equipment.

 

The Limitations of Metal and Plastic Shell Materials

Given the limitations of existing materials, future innovations in the housing materials of smart wearable devices will be crucial. On the one hand, the need to develop new metal materials, both to maintain good heat dissipation performance, but also to avoid heat conduction too fast resulting in hot problems. At the same time, new metal materials should have stronger collision resistance to reduce the risk of paint loss and oxidation.

 

The Promise of ZrO2 Ceramic and Other Non-Metallic Materials

On the other hand, new non-metallic materials, such as ceramics and glass, should be actively explored. These materials not only have a better texture and enhance the overall beauty of the device, but may also have better heat dissipation and wear resistance. In addition, with the development of advanced manufacturing technologies such as 3D printing, the zirconia ceramic watch bezel will be more diversified in the future to meet the needs of users for personalized and customized.

 

Future Directions in Smart Wearable Shell Material Innovation

Smart wearable devices are indispensable supplies in future life, and the innovation of its shell materials will directly affect the user experience and the overall performance of the device. By constantly exploring new metallic and non-metallic materials, we are expected to see more beautiful, durable and intelligent smart wearable devices in the future. These devices will not only better serve our sports and health needs, but also bring us a more convenient and comfortable life experience. Therefore, the innovation of smart wearable device shell materials is not only the embodiment of scientific and technological progress, but also an important guarantee for the improvement of the quality of life in the future.

With the continuous progress of ceramic materials science and technology, silicon carbide (SiC), as a class of high-performance non-oxide ceramic materials, has shown great application potential in many industrial fields because of its unique physical and chemical properties. Especially in high temperature kilns, silicon carbide crucible , with its excellent high temperature resistance, corrosion resistance and high thermal conductivity characteristics, has become a key component for bearing and protecting the high temperature sintering process. The purpose of this paper is to investigate the material composition of sic crucible, analyze the characteristics of its core material, and examine how auxiliary materials work together to optimize the overall performance of the crucible.

 

 

Characteristics of silicon carbide core material

1. High hardness and wear resistance: the hardness of silicon carbide is second only to diamond, which gives the crucible excellent wear resistance and effectively extends the service life.

2. Excellent corrosion resistance: silicon carbide has good chemical stability for a variety of acid and alkali media, and is suitable for sintering operations in a variety of complex environments.

3. High thermal conductivity: Its high thermal conductivity contributes to rapid and uniform heating, improving sintering efficiency and reducing energy consumption.

 

Addition and performance optimization of auxiliary materials

1. The role of the binder: by adding an appropriate amount of the binder, such as silicate, alumina, etc., can improve the agglomeration of silicon carbide powder, enhance the plasticity of the material, and facilitate molding processing.

2. The introduction of plasticizers: Plasticizers (such as polyvinyl alcohol, paraffin, etc.) can effectively reduce the viscosity of the material, improve the compactness and uniformity of the billet, which is conducive to the subsequent sintering process.

3. The addition of reinforcing phase: by adding reinforcing phases such as carbon fiber, graphite or silicon nitride, the mechanical strength and thermal shock resistance of the crucible can be significantly improved, and its stability at extreme temperatures can be enhanced.

 

Effect of manufacturing process on performance

Process parameters such as mixing uniformity, forming pressure, sintering temperature and holding time have important effects on the final performance of sic crucible. Reasonable process design can give full play to the potential of materials and realize the optimization of performance.

 

In summary, the performance optimization of sic crucible is a comprehensive process involving material composition, auxiliary material selection and manufacturing process control. By precisely regulating the ratio of silicon carbide core material and auxiliary material, combined with scientific manufacturing process, the hardness, wear resistance , corrosion resistance and mechanical strength of the crucible can be significantly improved, while optimizing its thermal conductivity to meet the diverse needs of the field of high temperature sintering. In the future, with the in-depth development of material science and the continuous innovation of preparation technology, the performance of silicon carbide crucible will be further improved, and the application field will continue to expand, contributing to the technological progress and sustainable development of related industries.

For a long time, most of the substrate materials of high-power hybrid integrated circuits have been using Al2O3 and BeO ceramics, but the thermal conductivity of the Al2O3 substrate is low, and the thermal expansion coefficient is not well matched with Si. Although the comprehensive performance of BeO is excellent, its high production cost and highly toxic shortcomings limit its application and promotion. Therefore, from the performance, cost and environmental protection factors, the two can not meet the needs of modern electronic power devices and development.

 

 

Aluminum nitride ceramics have excellent comprehensive properties, is a new generation of advanced ceramics that has been widely concerned in recent years, and has a wide range of application prospects in many aspects, especially its advantages of high thermal conductivity, low dielectric constant, low dielectric loss, excellent electrical insulation, thermal expansion coefficient matching silicon and non-toxicity. Making it an ideal material for high-density, high-power and high-speed integrated circuit boards and packages.

 

High thermal conductivity is the most significant characteristic of aluminum nitride substrate. The main mechanism is: through lattice or lattice vibration, that is, through lattice wave or thermal wave heat transfer.

 

 

AlN ceramics are insulating ceramic materials, for insulating ceramic materials, heat energy is transferred by atomic vibration, which belongs to phonon heat conduction, phonons play an important role in its heat conduction process. The thermal conductivity of aluminum nitride can theoretically reach 320w/ (m·k), what causes this gap?

There are impurities and defects in aluminum nitride, resulting in the thermal conductivity of aluminum nitride substrate is far from the theoretical value. The impurity elements in the aluminum nitride powder are mainly oxygen and carbon, and there are also a small amount of metal ion impurities, which produce various defect forms in the lattice, and the scattering of these defects on the phonon will reduce the thermal conductivity.

 

So what are the factors that affect the mean free path of phonons?

1. In the heat transfer process, the defects, grain boundaries, holes, electrons and phonons themselves will produce phonon scattering, thereby reducing the mean free path of phonons and further affecting the thermal conductivity.

Impurity oxygen and Al2O3 play a major role in phonon-defect scattering.

1. Because AlN is easy to hydrolysis and oxidation, a layer of Al2O3 is formed on the surface, and Al2O3 is dissolved into the AlN lattice to produce aluminum vacancies. 2.AlN has a strong affinity with oxygen, which is easy to enter the aluminum nitride lattice, and the oxygen in the lattice has a high displacement solubility, which is easy to form oxygen defects.

The relationship between defects in the AlN lattice and oxygen concentration:

When [O] <0.75% O is uniformly distributed in the AlN lattice, it occupies the N position in AlN and is accompanied by Al vacancy.

When [O] ≥0.75% Al atom position changes, Al vacancy is eliminated at the same time, and an octahedral defect is formed.

At higher concentrations, extended defects will be formed, such as oxygen-containing layer faults, inversion domains, polybodies, etc.

The presence of oxygen impurities seriously affects the thermal conductivity of AlN. The presence of oxygen defects increases the scattering area cross section of phonons and decreases the thermal conductivity of AlN.

Therefore, the presence of oxygen impurities seriously affects the thermal conductivity of AlN, which is the main factor for the reduction of thermal conductivity.

 

In summary, aluminum nitride ceramics with its unique comprehensive properties, especially its high thermal conductivity, low dielectric constant, low dielectric loss, excellent electrical insulation and silicon matching thermal expansion coefficient and non-toxicity characteristics, become the ideal material for modern high-density, high-power and high-speed integrated circuit board and packaging. However, the actual thermal conductivity of aluminum nitride ceramics is often much lower than its theoretical value, which is mainly due to the presence of impurities and defects in the material, especially oxygen impurities, the scattering effect on the phonon heat transfer process.

Oxygen impurities not only easily enter the aluminum nitride lattice to form oxygen defects, but also cause more complex crystal structure changes at higher concentrations, such as octahedral defects, oxygen-containing layer faults, inversion domains, etc., which greatly reduce the thermal conductivity of aluminum nitride. Therefore, optimizing the preparation process of Al nitride ceramics, reducing the content of oxygen impurities and controlling the formation of crystal defects are the key to improve the thermal conductivity of Al nitride ceramics.

Looking forward to the future, with the continuous progress of material science and preparation technology, the performance of aluminum nitride ceramics will be further improved, and its application in high-power integrated circuit board and other high-tech fields will be more extensive and in-depth. At the same time, the in-depth study on the thermal conductivity mechanism and influencing factors of aluminum nitride ceramics will also provide important reference for the development of other advanced ceramic materials.

With the rapid development of electronic technology, the comprehensive performance of electronic chips is improving day by day, but the overall size is shrinking. This trend brings significant performance improvements, but it also comes with a serious challenge - a dramatic increase in heat flux. For electronic devices, even a small increase in temperature can have a significant impact on their performance and life. According to research, every 10℃ increase in device temperature, its effective life will be shortened by 30% to 50%. Therefore, how to effectively manage the heat and improve the heat dissipation capacity of the device has become the key technical bottleneck for the development of high-power devices. In this context, aluminum nitride substrate with its excellent performance, is gradually becoming the preferred material in the field of power device packaging.

 

 

Performance Advantages of Aluminum Nitride Substrate

High thermal conductivity

Aluminum nitride (AlN), as a high-performance ceramic material, stands out for its excellent thermal conductivity. Its thermal conductivity is not only comparable to some metals, but also more than traditional polymer substrates. This feature allows the aluminum nitride substrate to quickly export the heat generated by the chip, effectively reducing the operating temperature of the chip, which significantly improves the reliability and service life of the device. For extremely high power density devices such as high-power leds, aluminum nitride substrates are undoubtedly ideal for heat management.

 

Excellent heat resistance

under high temperature environment, aluminum nitride substrate can maintain stable performance and is not easy to thermal expansion or thermal deformation. This feature is particularly important for electronic devices that need to operate under high temperature conditions, ensuring the long-term stability and reliability of the package structure.

High insulation: The excellent insulation properties inherent in ceramic materials are fully reflected in the aluminum nitride substrate. High insulation not only prevents short circuits, but also protects the safety of electronic components, providing more flexibility and security for package design.

 

High strength and excellent thermal matching

Aluminum nitride substrate not only has high strength, can withstand the mechanical and thermal stress during the packaging process, but also has good thermal matching with a variety of chip materials (such as silicon, gallium nitride, etc.). This feature helps reduce thermal stress due to differences in the coefficient of thermal expansion, further improving the overall reliability of the package.

 

Application Field and Development Prospect

With its comprehensive advantages in thermal conductivity, heat resistance, insulation, strength and thermal matching, aluminum nitride substrate has been widely used in semiconductor lighting, laser and optical communication, aerospace, automotive electronics, deep sea drilling and other high-tech fields. These areas have extremely high performance requirements for packaging materials, and aluminum nitride substrates successfully meet these needs with their excellent performance, promoting the continuous development and progress of related technologies.

 

Conclusion

In summary, aluminum nitride substrate, as a high-performance packaging material, has shown great potential and value in solving the heat dissipation bottleneck of power devices. With the continuous progress of electronic technology and the continuous expansion of application fields, the market demand for aluminum nitride substrate will continue to grow. In the future, we have reason to believe that aluminum nitride substrate will play its unique advantages in more fields and contribute more to the development of the electronics industry.

In the field of advanced ceramic materials, silicon nitride (Si3N4) has attracted much attention for its excellent mechanical strength, chemical stability and high temperature properties. However, the thermal conductivity of silicon nitride ceramics, as one of the key factors affecting its wide application, has been an important subject in materials science research. This paper aims to investigate the heat transfer mechanism of silicon nitride ceramics, especially the lattice vibration and scattering phenomenon during phonon conduction, and focus on the unique role of carbon additives in the sintering process of silicon nitride and the mechanism of improving the thermal conductivity. Through the comprehensive analysis of experimental data and theoretical models, this paper aims to provide new ideas and strategies for the preparation of silicon nitride substrate with high thermal conductivity.

 

Reunderstanding of heat transfer mechanism

As a typical covalent bonded ceramic material, the heat transfer mechanism of silicon nitride mainly depends on lattice vibration and phonon conduction. The nonlinear propagation and collision between phonons in the lattice are not only restricted by the lattice structure itself, but also influenced by the microstructure characteristics such as internal defects, impurities and grain boundaries. In particular, lattice oxygen is the main scattering source, and its content is directly related to the mean free path of phonons, which affects the thermal conductivity of silicon nitride. Therefore, reducing the lattice oxygen content becomes one of the key ways to improve the thermal conductivity of silicon nitride.

 

Discussion on the introduction and mechanism of carbon additives

In recent years, the research of carbon as a sintering additive for non-oxide ceramics has attracted extensive attention. In the silicon nitride system, carbon is introduced not only to remove the oxide impurities on the surface of the oxide powder, but more importantly, it can play a significant reduction role in the nitriding and post-sintering process. Specifically, carbon can reduce the partial pressure of SiO and promote the reduction of oxygen-containing impurities such as SiO2, thus reducing the content of lattice oxygen. This process not only purified the lattice environment, but also promoted the growth of silicon nitride grains and the optimization of structure.

 

Effect of carbon additives on thermal conductivity of silicon nitride ceramics

The experimental results show that the thermal conductivity of silicon nitride ceramics can be significantly improved by adding proper amount of carbon. Specifically, the reduction of carbon increases the secondary N/O atomic ratio between silicon nitride grains, forming a bimodal microstructure conducive to heat conduction. This structural feature is characterized by the coexistence of large grains and elongated grains, which provide efficient heat conduction channels, while elongated grains help to reduce phonon scattering, and jointly improve the thermal conductivity of silicon nitride ceramics.

In addition, the use of carbon additives also reduces the strict requirements for the oxygen content of raw materials and the selection of sintering additives. Traditionally, in order to obtain high thermal conductivity silicon nitride ceramics, it is often necessary to choose raw material powder with low oxygen content and high performance sintering additives, which undoubtedly increases the preparation cost. The introduction of carbon additives alleviates this problem to a certain extent, so that silicon nitride ceramics with excellent thermal conductivity can be prepared in a wider range of raw materials and additives.

 

Industrial application prospect

With the continuous progress of technology and the continuous optimization of cost, the method of carbon additive-assisted sintering to prepare high thermal conductivity silicon nitride ceramics is expected to be widely used in industrial production. This method not only improves the thermal conductivity of silicon nitride ceramics, but also reduces the preparation cost, providing a more economical and efficient solution for high-performance electronic packaging, aerospace and energy conversion fields. In the future, we look forward to further promoting the innovative application and development of silicon nitride substrate materials in more fields through more in-depth research and process optimization.

 

In summary, carbon addition-assisted sintering, as an innovative preparation technology for silicon nitride ceramics, optimizes the microstructure of the material through its unique reduction effect and significantly improves the thermal conductivity of silicon nitride ceramics. This discovery not only opens up a new way for the preparation of high-performance silicon nitride ceramics, but also provides a more economical and efficient solution for the development of electronic packaging, aerospace and energy conversion. With the continuous deepening of research and continuous progress of technology, we have reason to believe that silicon nitride ceramics will show its unique charm and wide application prospects in more fields. At the same time, this will also encourage us to continue to explore new material preparation technology, and promote the progress and development of materials science.

As a new material with excellent optical properties, transparent ceramics have shown great application potential in optical Windows, laser devices, high temperature sensors and other fields. In the process of its preparation, molding technology is one of the key links, which directly affects the performance and quality of the final product. Among the many molding methods, dry pressing has become a popular molding method in the preparation of transparent ceramics because of its simple operation, low cost and high production efficiency. This paper aims to discuss the basic principle, operation process and application of dry pressing technology in the preparation of transparent ceramics, and analyze how to improve the quality of ceramic blank by optimizing the forming process.

 

 

The basic principle and process of dry pressing

By placing the powder (which can be adjusted by adding an appropriate amount of solvent) after ball milling granulation treatment in the mold, applying a certain pressure to form a ceramic green with a specific shape and strength.

The method is easy to operate, suitable for the production of small size and simple shape of transparent ceramic samples, and has significant cost benefit.

 

Type and density distribution of dry pressing

Dry pressing is divided into two kinds: one way pressing and two way pressing. One-way pressing applies pressure from one side only, while two-way pressing applies pressure from both sides.

In the process of dry pressing, the density of the material near the pressure side is higher, and the density away from the pressure side is lower, resulting in uneven distribution of the density inside the body. This phenomenon requires strict control of the molding speed to reduce the density difference and ensure the quality of the ceramic blank.

 

Strategies to optimize the dry pressing process

In order to obtain high quality transparent ceramic blank, it is necessary to optimize the molding parameters, such as adjusting the pressure, molding speed and mold design, so as to improve the density uniformity inside the blank.

The use of advanced mold materials and design, as well as the precise control of particle size distribution and water content in the powder treatment process, is also an effective way to improve the dry press molding effect.

 

To sum up, the dry pressing technology occupies an important position in the field of transparent ceramic preparation with its unique advantages. Through in-depth understanding of the basic principle of dry pressing, combined with the accumulation of experience and technical innovation in actual operation, the problem of uneven density distribution inside the blank body can be effectively solved, and the finished quality and performance of transparent ceramics can be further improved. In the future, with the continuous progress of material science and molding technology, dry press molding technology is expected to play a more critical role in the preparation of transparent ceramics and other advanced ceramic materials, and promote the sustainable development and innovation of related industries.

As a kind of high performance material, transparent ceramics show great application potential in optics, electronics, aerospace and other fields because of its excellent light transmission, high hardness, high temperature resistance and other characteristics. However, the preparation process of transparent ceramics is complicated, and the molding technology is one of the key factors to determine its final performance. Among the many molding methods, isostatic pressing has become one of the most commonly used molding techniques in the preparation of transparent ceramics because of its ability to apply uniform pressure and effectively avoid the formation of internal defects. This paper focuses on the application and advantages of cold isostatic pressing in the preparation of transparent ceramics.

 

 

First, the basic principle and characteristics of cold isostatic pressing

 

Cold isostatic pressing is the process of loading the powder material into a rubber bag and then placing it in a steel mold, and densifying and forming the powder by applying pressure from all directions. The core advantage of this method is that it can realize uniform pressure on the powder, and effectively overcome the disadvantage of uneven pressure distribution in the process of dry pressing, so as to improve the uniformity and density of the ceramic body.

 

Second, the classification and characteristics of cold isostatic pressing

 

Dry bag method: In this method, the pressurized die is fixed inside the cylinder. This way of operation is relatively simple, the production cycle is short, very suitable for large-scale production needs. Because the mold is fixed, the dimensional accuracy and shape stability in the molding process can be effectively controlled.

Wet bag method: Unlike the dry bag method, the mold in the wet bag method is separated from the pressure cylinder. This design makes the molding process more flexible, and can prepare more complex shapes of ceramic billets to meet the needs of diverse products.

Balanced pressing method: The method is similar to dry pressing in basic principle, but the uniform distribution of pressure is achieved through isostatic pressing, which further improves the quality of the ceramic body.

 

In summary, cold isostatic pressing technology plays an irreplaceable role in the preparation of transparent ceramics with its unique advantages. Through a variety of methods such as dry bag method, wet bag method and balanced pressing method, cold isostatic pressing not only realizes uniform pressure on the powder, but also meets the production needs of different shapes and sizes of products. With the continuous progress of material science and manufacturing technology, cold isostatic pressing technology will show a broader application prospect in the field of transparent ceramics, and contribute an important force to promote the development of related industries. In the future, further optimization of cold isostatic pressing process to improve production efficiency and product quality will be an important direction of research in this field.

With the continuous development of modern high-temperature industrial technology, the requirements for material properties are increasing. Silicon carbide crucible, with its unique material composition and a series of excellent properties, has become an indispensable material in the high-temperature industrial field. The purpose of this article is to discuss the seven excellent properties of sic crucible and its wide application in high temperature industry.

 

 

High Temperature Stability

 

Sic crucible has a very high melting point (about 2700°C), can remain stable at extremely high temperatures, and is not easily deformed or melted. This characteristic makes it ideal for use in processes requiring high temperature treatment, such as ceramic sintering, metal smelting, etc. In high temperature environment, silicon carbide crucible can maintain its structural integrity and stable performance, providing a reliable material guarantee for high temperature industry.

 

Excellent Thermal Conductivity

 

Silicon carbide is a good conductor of heat and can transfer heat quickly and evenly. This characteristic makes the sic crucible excellent in increasing heating efficiency and reducing energy consumption. At the same time, it can also effectively control the temperature gradient in the heat treatment process of the product to avoid thermal stress or cracking caused by uneven temperature, thus improving the quality and reliability of the product.

 

Good Wear Resistance

 

The silicon carbide material has high hardness and good wear resistance, which makes the silicon carbide crucible can resist the mechanical action such as particle erosion and wear during use. This feature extends the service life of the crucible, reduces the frequency and cost of replacement, and improves production efficiency.

 

Strong Corrosion Resistance

 

Silicon carbide has good resistance to a variety of acid, alkali and other corrosive media. When handling corrosive substances, sic crucible can remain stable and will not be damaged by corrosion. This characteristic makes sic crucible have a wide application prospect in corrosive environment such as chemical industry and metallurgy.

 

Good Thermal Shock Stability

 

Silicon carbide crucible can maintain good stability when it is subjected to sharp temperature changes (i.e., thermal shock) and is not easy to crack or damage. This performance is particularly important for processes that require frequent heating and cooling cycles, such as glass manufacturing, ceramic glaze firing, etc.

 

Light Weight and High Strength

 

Specially processed silicon carbide crucible is usually of higher strength and lighter weight. This feature makes the crucible easy to handle and operate, reduce labor intensity, and improve work efficiency.

 

Good Chemical Stability

 

Silicon carbide is not easy to chemically react with most substances at high temperatures. This feature enables the silicon carbide crucible to maintain its chemical stability during use without affecting the quality of the product. This performance is particularly important for processes that require product purity and chemical stability.

 

In summary, silicon carbide crucible shows a wide range of application prospects in the high-temperature industry because of its unique material composition and a series of excellent properties. Its high temperature stability, excellent thermal conductivity, good wear resistance, corrosion resistance, good thermal shock stability, light weight and high strength and good chemical stability, etc., make silicon carbide crucible become an indispensable important material in high temperature industry. With the continuous development of high temperature industry technology, the application field of silicon carbide crucible will be further expanded to provide strong support for the development of high temperature industry.

In modern power electronics systems, the IGBT (insulated gate bipolar transistor) module is the core component of energy conversion and control, and its long-term stability and reliability are very important. As the key component of IGBT module package structure, ceramic clad substrate not only carries the circuit components, but also bears the heavy task of heat conduction, which directly affects the heat dissipation efficiency and service life of the module. This paper aims to explore the influence of different ceramic substrate materials on the performance of ceramic copper clad plate, especially from the perspective of thermal conductivity and thermal expansion coefficient matching, analyze the advantages and disadvantages of alumina, silicon nitride and aluminum nitride ceramic substrate materials, in order to provide a theoretical basis for the selection of high power module packaging materials.

 

Application limitations of alumina substrates: Although alumina ceramic substrates are widely used due to their cost effectiveness and proven processes, their relatively low thermal conductivity and mismatch with the thermal expansion coefficient of silicon materials limit their application potential in high power density modules.

 

 

Prospects and challenges of silicon nitride substrates: Silicon nitride ceramics are known for their excellent overall performance, especially in high temperature environments. However, the actual thermal conductivity of silicon nitride ceramics is much lower than the theoretical value, and the research and development of high thermal conductivity silicon nitride ceramics is still in the laboratory stage, which becomes a key factor restricting its wide application.

 

 

Advantages of aluminum nitride substrate: With excellent thermal conductivity and thermal expansion coefficient similar to semiconductor materials (such as Si), aluminum nitride copper clad plate effectively solves the thermal management problem of IGBT module, reduces internal stress, significantly improves the reliability and service life of the module, and is regarded as the ideal substrate material for power electronic device packaging.

 

The main properties of the three ceramic substrate materials are compared in detail (as shown in Table 1). Although the alumina substrate has a high popularity, the problem of insufficient thermal conductivity and mismatch of thermal expansion coefficient has become increasingly prominent, especially in high-power modules, which may lead to increased thermal stress and affect the stability and life of the module. Although the overall performance of silicon nitride substrate is superior, but limited by the actual thermal conductivity, it is difficult to meet the demand for high thermal conductivity, and its commercialization process still needs time. In contrast, aluminum nitnitide copper clad plate with its high thermal conductivity and good thermal expansion coefficient matching, become the key to solve the IGBT module thermal management problem, not only accelerate the heat conduction, but also reduce the internal stress caused by the difference in thermal expansion, thereby improving the reliability and durability of the module.

 

In summary, the selection of ceramic substrate materials is crucial to the long-term performance of IGBT modules. Among the three materials of alumina, silicon nitride and aluminum nitride, aluminum nitride copper clad plates show great advantages in high-power module packages due to their excellent thermal properties and good matching with semiconductor materials. In the future, with the continuous progress of material science and the optimization of preparation technology, aluminum nitride ceramic substrates are expected to become the key materials to promote the development of higher power density and higher reliability in the power electronics industry. Therefore, for specific application scenarios, reasonable selection of ceramic substrate materials is of great significance for improving the overall performance and extending the service life of IGBT modules.

Boron nitride ceramic is a versatile material widely recognized for its remarkable thermal and electrical properties. Known as “white graphite” due to its hexagonal structure, boron nitride (BN) ceramic plays a pivotal role in advanced industrial applications. In this blog, we' ll explore the properties, applications, and benefits of boron nitride ceramic and compare it with other advanced ceramics to determine its suitability for various uses.

 

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What is Boron Nitride Ceramic?

 

Boron nitride ceramic is a synthetic material composed of boron and nitrogen atoms. Depending on its manufacturing process, it can exist in different crystalline forms, including hexagonal boron nitride (h-BN) and cubic boron nitride (c-BN). Hexagonal boron nitride is the most commonly used form due to its excellent thermal conductivity and electrical insulation properties.

 

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Key Properties of Boron Nitride Ceramic

High Thermal Conductivity Boron nitride ceramics efficiently dissipate heat, making them ideal for thermal management systems.

Electrical Insulation Despite their high thermal conductivity, BN ceramics are excellent electrical insulators, offering a rare combination of properties.

Thermal Stability BN ceramics can withstand temperatures up to 1,000°C in oxidizing atmospheres and even higher in inert conditions.

Lubrication and Low Friction BN ceramics have a naturally lubricious surface, reducing wear in mechanical systems.

Chemical Inertness BN is resistant to chemical reactions, even in harsh environments, making it suitable for applications involving corrosive substances.

 

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Applications of Boron Nitride Ceramic

1. Electronics and Semiconductors

BN ceramics are used as substrates and heat sinks for electronic devices, ensuring efficient thermal management.

2. Aerospace and Defense

Their high-temperature resistance and lightweight nature make them ideal for aerospace components and thermal shields.

3. Industrial Lubricants

BN's lubricious properties are utilized in high-performance lubricants, especially in extreme-temperature environments.

4. Metallurgical Applications

BN ceramics serve as crucibles, nozzles, and molds due to their thermal and chemical stability in metal processing.

5. Advanced Optics

Cubic boron nitride is used in optical components and as a material for high-durability cutting tools.

 

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Comparison: Boron Nitride vs. Other Advanced Ceramics

Thermal Conductivity: While BN ceramics excel in thermal conductivity, materials like aluminum nitride offer similar performance but lack the lubricious properties of BN.

Electrical Insulation: BN surpasses silicon carbide and alumina in combining thermal conductivity with electrical insulation, making it unique for electronics.

Durability: Cubic boron nitride rivals diamond in hardness, making it superior for cutting tools compared to other ceramics.

Chemical Resistance: While aluminum is resistant to many chemicals, BN's inertness in extreme environments provides an edge in certain applications.

 

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Advantages of Using Boron Nitride Ceramic

Versatility: Suitable for diverse applications, from electronics to aerospace.

Reliability: Maintains performance in extreme thermal and chemical environments.

Cost Efficiency: Long-lasting and reduces downtime in high-performance systems.

 

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FAQs

What are the disadvantages of boron nitride ceramic?

BN ceramics can be brittle and may require specialized handling. Additionally, their cost can be higher than traditional ceramics like alumina.

How strong is boron nitride ceramic?

Cubic boron nitride is among the hardest materials known, while hexagonal BN has moderate mechanical strength but excels in thermal and chemical applications.

Is boron nitride ceramic better than aluminum?

BN is superior for thermal and electrical applications, but aluminum is more cost-effective and durable in mechanical applications.

Which ceramic is the most thermally conductive?

BN ceramics are among the best for thermal conductivity, rivaled by materials like aluminum nitride.

 

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Is Boron Nitride Ceramic Right for Your Application?

Boron nitride ceramic is ideal for industries requiring high thermal conductivity, electrical insulation, and chemical resistance. Whether it's electronics, aerospace, or industrial lubrication, BN ceramics offer unmatched performance in challenging conditions.

 

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