With the rapid development of modern microwave communication technology, the design of microwave circuit components with high performance and high precision has become increasingly important. In microwave radio frequency (RF) modules, thin-film circuit technology has become a key design method with its unique advantages. In this paper, several thin film circuit components based on alumina substrate are introduced in detail, including thin film microstrip circuit, thin film filter, thin film load, thin film equalizer and thin film power divider. These components play an irreplaceable role in microwave circuits, and their design accuracy and performance directly affect the performance of the whole microwave system.

 

 

Applications of alumina substrate in circuit

 

1 Thin film microstrip circuit

Aluminum oxide ceramic substrate is used to design thin film microstrip circuit, the thickness of the gold layer can be up to 3.5um, and the metal wire bonding can be used to connect with the external circuit. The common plate thickness is 0.127mm, 0.254mm, 0.381mm, 0.508mm, and the transmission frequency can reach more than 40GHz. It meets the frequency band requirements of most microwave RF module modules, and the thin film circuit line accuracy of the thin film process is ±5um. The microwave RF field often uses ceramic substrates for microstrip transmission lines or circuit design with high precision.

 

2 Thin film filter

The frequency of the thin film filter made of alumina ceramic substrate can be as high as 40GHz, which is often used as a functional unit of frequency selection in various microwave module modules and systems. Thin film filter is processed by thin film technology, through sputtering, lithography, wet or dry etching, cleaning, slicing to obtain thin film filter substrate, common interfinger type, hairpin type, comb type, parallel coupling type, C-type and other structural filters can be designed based on alumina ceramic substrate processing, can be designed low pass high pass band pass band resistance and other different types of filters. Because the dielectric constant of the alumina ceramic sheet is greater than that of the general PCB substrate, the volume of the film filter made by the alumina ceramic sheet is smaller than that of the general microstrip filter, and the electrical parameters of the film filter made by the alumina ceramic sheet are good. It is usually fixed with conductive adhesive or gold tin eutectic.

 

3 Film load

The aluminum oxide ceramic substrate is used to design the thin film load, which is often used to match the terminal of the module assembly of the microwave circuit to absorb the excess reflected power. For the load, the machining accuracy of the resistance value is very important, and the greater the deviation, the worse the final load performance. Due to the controllable square resistance of the tantalum nitride film layer in the film process, the film load with high precision can be produced, and the film load volume is very small, which is a good choice for the miniaturization of component modules. It is usually fixed to the end of the circuit using conductive adhesive or gold tin eutectic.

 

4 Film equalizer

The thin-film equalizer is designed with alumina ceramic substrate, which is often used to adjust the broadband power flatness of microwave circuits. The output waveform of the device is adjusted by changing the square resistance of the integrated tantalum nitride film layer and the different resistance values of the graphic design, so as to balance the power signal at the front end to achieve the power flatness adjustment effect.

 

5 Film power divider

The thin-film power divider designed with alumina ceramic substrate is often used in the multi-channel communication network system. It has the function of power distribution according to a certain proportion, with one input and multiple output. Since the isolation resistor can be integrated into the thin film circuit using the tantalum nitride film layer to design a suitable resistance value, this can avoid the deterioration of the circuit performance due to the welding of the patch resistance of the microstrip power divider and the instability of the resistance value of the patch resistor, and the thin film power divider is easier to achieve the multi-stage ultra-wideband design, and the designed object is small in size, easy to integrate and good in performance.

 

In summary, alumina ceramic substrate plays a crucial role in the design of thin-film circuit components. From thin film microstrip circuit to thin film power distributor, these components not only meet the requirements of high precision and high frequency of microwave RF modules, but also realize the miniaturization and high performance of the components. Through the precise control of thin film technology, we can obtain thin film circuit components with excellent electrical parameters, which further improves the overall performance of microwave systems. In the future, with the continuous progress of microwave communication technology, thin film circuit components based on alumina ceramic substrates will continue to play a greater role in the microwave field, contributing to the development of wireless communication, radar detection and other fields.

In exploring silicon nitride (Si3N4) substrate materials as core to a high-performance thermal management solution, our understanding of their heat transfer mechanisms is critical. The main heat transfer mechanism of silicon nitride is known to rely on lattice vibration, a process that transfers heat through quantized hot charge carriers called phonons.

 

The propagation of phonons in the lattice is not a simple linear motion, but is affected by the complex coupling between the lattice, resulting in frequent collisions between phonons, which significantly reduces the mean free path of phonons, that is, the mean distance that phonons can travel freely between two collisions. This mechanism directly affects the thermal conductivity of silicon nitride materials.

 

Furthermore, various defects, impurities and grain interfaces in Si3N4 crystals become the main sources of phonon scattering. These scattering events also lead to a decrease in the mean free path of phonons, which in turn reduces the overall thermal conductivity of the material. In particular, lattice oxygen, as one of the main defects affecting the thermal conductivity of silicon nitride ceramics, significantly hinders the smooth propagation of phonons and reduces the thermal conductivity efficiency of the material.

 

To overcome this challenge and improve the thermal conductivity of the silicon nitride substrate, we started at the source and focused on reducing the oxygen content in the lattice. Specific strategies include:

 

 

Optimize raw material powder

Choosing Si powder with low oxygen content as starting material is the key. The oxygen impurity content in the initial raw material is reduced through a rigorous raw material screening and pretreatment process. Subsequently, a two-step nitrided sintering process is used, in which Si powder is first heated in a nitrogen atmosphere to close to its melting point (1414℃), so that it reacts with nitrogen to form porous Si3N4 sintered body. This process ensures adequate nitriding of Si while controlling the oxygen content in the newly generated silicon nitride. Then, porous Si3N4 was further sintered at high temperature to promote grain growth and pore closure, and finally the Si3N4 ceramic substrate with high density, low oxygen content and high thermal conductivity was formed.

 

 

Direct sintering of high purity α-Si3N4 powder

Another way is to use high purity α-Si3N4 powder with very low oxygen content for sintering. This method avoids the conversion process from Si to Si3N4 and directly uses α-Si3N4 powders with high purity and specific crystal structure for sintering, reducing the possibility of oxygen impurity introduction. By precisely controlling sintering parameters such as temperature, atmosphere and pressure, silicon nitride substrates with high density, few defects and excellent thermal conductivity can be obtained.

 

 

Sintering application of β-Si3N4

Although β-Si3N4 may differ from α-Si3N4 in some physical properties, its low oxygen content and high purity are also suitable for the preparation of high-performance silicon nitride substrates. The use of β-Si3N4 powder for sintering can also prepare high thermal conductivity silicon nitride materials, especially in specific application scenarios, some characteristics of β-Si3N4 may be more advantageous.

 

In summary, the Silicon nitride (Si3N4) substrate material is a key component of a high-performance thermal management solution, and the optimization of its thermal conductivity is crucial to improve the overall thermal management efficiency. By deeply understanding the heat transfer mechanism of silicon nitride, namely lattice vibration and phonon conduction process, we realize that phonon scattering is one of the key factors affecting the thermal conductivity. In particular, oxygen defects in the lattice, acting as the main scattering source, significantly reduce the mean free path of phonons, thereby hindering the effective conduction of heat.

To overcome this challenge, we propose a variety of strategies to reduce the oxygen content in the silicon nitride substrate, thereby improving its thermal conductivity. From the optimal selection of raw material powder, to the direct sintering of high-purity α-Si3N4 powder, to the sintering application of β-Si3N4, each method aims to reduce the introduction of oxygen impurities at the source and achieve high density and low defect status of the material through fine process control.

Future research will further focus on exploring more efficient silicon nitride preparation processes and further understanding the mechanism by which different crystal structures and microstructure affect the thermal conductivity of silicon nitride. Through these efforts, we are expected to develop silicon nitride substrate materials with higher thermal conductivity and lower thermal resistance, providing strong support for high-performance thermal management in electronic packaging, aerospace, energy conversion and other fields.

In practical applications, in addition to high thermal conductivity and high electrical insulation properties, aluminum nitride substrates are also required to have high bending strength in many fields. At present, the three-point bending strength of aluminum nitride in circulation on the market is usually 400~500MPa, which seriously limits the promotion and application of aluminum nitride ceramic substrates, especially in the field of IGBT power devices with high reliability requirements. Due to the complex production process and high production cost of AlN materials, most of the domestic AlN materials are still unable to meet the application requirements of high thermal conductivity and high strength.

 

In the preparation of aluminum nitride ceramic substrate, the selection of sintering methods and sintering additives is often twice the result with half the effort, and the introduction of sintering additives is a common method for sintering aluminum nitride ceramics at present. On the one hand, the formation of low temperature eutectic phase, the realization of liquid phase sintering, promote the compact body; On the other hand, the oxygen impurity in aluminum nitride is removed, the lattice is improved, and the thermal conductivity is increased. At present, the sintering additives used in sintering AlN ceramics mainly include Y2O3, CaO, Yb2O3, Sm2O3, Li2O3, B2O3, CaF2, YF3, CaC2, etc., or their mixtures.

  

In the sintered aluminum nitride ceramic formula system, when Y2O3 is higher than 3.5wt%, the content of Y-Al-O increases significantly and aggregates in the sintering process. Due to the low thermal conductivity of Y3Al5O12 (about 9 W/ (m·K)), the thermal conductivity of aluminum nitride ceramic products after sintering is seriously affected. When the content of CaF2 and Li2O is higher than 1.33wt%, due to the volatilization of fluoride and Li-containing compounds, the porosity of the sintered aluminum nitride ceramic body is increased during the sintering process, and the density of the ceramic is reduced, resulting in a sharp decline in the bending strength of aluminum nitride ceramic products after sintering. When each additive is less than the minimum value, the effect of enhancing mechanical properties cannot be played or the effect is very small.

 

In summary, aluminum nitride ceramic substrate in practical applications face the comprehensive requirements of high thermal conductivity, high electrical insulation properties and high bending strength, but the flexural strength of the products in circulation on the market is generally low, limiting its wide application in the field of high reliability such as IGBT power devices. At the same time, the domestic AlN material is difficult to meet the application needs of high thermal conductivity and high strength due to the complex production process and high production cost. Therefore, in the preparation of aluminum nitride ceramic substrate, it is very important to select the appropriate sintering method and sintering additives, not only to form a low temperature eutectic phase to promote the compact body, but also to remove oxygen impurities to improve the thermal conductivity. However, the selection and dosage of sintering additives need to be strictly controlled to avoid negative effects on thermal conductivity and bending strength. In the future, in order to improve the performance of aluminum nitride ceramic substrates, it is still necessary to further optimize the sintering process and formulation system to meet the needs of higher levels of application.

In the field of high-tech materials, aluminum nitride (AlN) ceramics, with its excellent thermal conductivity, excellent electrical insulation properties and excellent mechanical strength, have become the core material in key fields such as electronic packaging, power electronics and microwave communication equipment. However, the preparation of aluminum nitride substrate is a complex process, in which the sintering process and the selection of sintering additives have important effects on the properties of the final product. In this paper, starting from the preparation process of aln ceramic substrate, the selection of sintering additives and their influence on the performance of the substrate will be discussed in detail, and combined with frontier research, how to improve the comprehensive performance of aluminum nitride substrate by optimizing the sintering additives and sintering process will be analyzed.

 

Preparation Technology of Aluminum Nitride Substrate

The preparation of aluminum nitride substrate mainly includes raw material preparation, mixing, molding, sintering and other key steps.

 

1. Raw material preparation

Raw material preparation is the first step in the preparation of aluminum nitride ceramic substrate, which mainly includes the selection and ratio of aluminum nitride powder, alumina powder and additives. As the main material, aluminum nitride powder is required to have the characteristics of high purity, small particle size, large specific surface area, low carbon content and low oxygen content. Alumina powder is usually used as part of the sintering aid to form a low melting point composite oxide during the sintering process to promote the densification of aluminum nitride ceramics. Additives are used to regulate the molding properties, sintering properties and mechanical properties of the material.

 

2. Mix and form

In the mixing process, it is necessary to mix aluminum nitride powder, alumina powder and additives according to a certain ratio to ensure the uniformity and stability of subsequent molding. Mixing can be done by dry or wet method. Molding is usually by pressing molding, injection molding or die molding, etc., the mixed raw materials are made into billets with a certain shape and size.

 

3. Sintering

Sintering is the last process and the most critical step in the preparation of aluminum nitride ceramic substrate. Under the condition of high temperature, the particles in the billet are combined by sintering to form a dense ceramic substrate. In the sintering process, temperature, atmosphere and time need to be controlled to ensure the forming quality and performance of the ceramic substrate. The commonly used sintering processes include hot pressing sintering, non-pressing sintering, microwave sintering, discharge plasma sintering and self-propagating sintering.

 

The Selection of Sintering Additives and Its Influence on The Properties of Substrate

Sintering additives play an important role in the preparation of aluminum nitride ceramic substrates. They react with the alumina composition on the surface of the aluminum nitride particle to form a composite oxide with a low melting point, resulting in a liquid phase in the sintered body. These liquid phases surround the aluminum nitride particles, and the particle rearrangement and internal pore discharge occur under the action of capillary force, and finally the compact sintering of aluminum nitride ceramics is realized.

 

1. Commonly used sintering additives

The commonly used sintering auxiliaries for aluminum nitride ceramic substrates include CaO, Li2O, B2O3, Y2O3, CaF2, CaC2 and CeO2. These materials play a dual role in the sintering process: first, they combine with aluminum oxide on the surface of aluminum nitride particles to form liquid aluminate, accelerating mass transfer and promoting sintering; Secondly, they can react with oxygen to reduce the lattice oxygen content and increase the thermal conductivity of aluminum nitride ceramics.

 

2. Principle of selection of sintering additives

When selecting sintering additives, it is necessary to consider their influence on the properties of aluminum nitride ceramic substrate. On the one hand, the sintering additives should promote the densification of aluminum nitride ceramics, improve the thermal conductivity and mechanical strength; On the other hand, sintering additives should avoid the introduction of excessive impurities, so as not to affect the electrical insulation properties and chemical stability of aluminum nitride ceramics. Therefore, when selecting sintering additives, a lot of experiments and optimization are needed to determine the best sintering additives formula.

 

3. Influence of sintering additives on substrate performance

The selection and content of sintering additives have significant influence on the performance of aluminum nitride ceramic substrate. For example, Y2O3, as one of the commonly used sintering additives, can significantly improve the thermal conductivity and bending strength of aluminum nitride ceramics when the content is moderate. However, when the content of Y2O3 is too high, Y-Al-O phase will be formed, resulting in a significant decrease in thermal conductivity. Therefore, when preparing aluminum nitride ceramic substrate, it is necessary to precisely control the content of sintering additives to obtain the best performance.

 

Improved Performance of AlN Substrate

In order to meet the high requirements for the performance of aluminum nitride ceramic substrates in different application fields, researchers are constantly exploring new sintering additives, optimizing sintering processes and developing new preparation technologies.

 

1. Development of new sintering additives

In order to further improve the performance of aluminum nitride ceramic substrates, researchers are actively developing new sintering additives. For example, by introducing rare earth elements or transition metal elements, the lattice structure of aluminum nitride ceramics can be optimized to improve thermal conductivity and mechanical properties. In addition, a variety of properties can be achieved through the use of composite sintering additives.

 

2. Optimization of sintering process

The optimization of sintering process is the key to improve the performance of aluminum nitride ceramic substrate. By adjusting sintering temperature, holding time and atmosphere, the microstructure of aluminum nitride ceramics can be accurately controlled. For example, rapid sintering methods such as microwave sintering or discharge plasma sintering can significantly shorten the sintering time and improve the production efficiency. At the same time, the microstructure and properties of Al nitride ceramics can be further optimized by precisely controlling the oxygen content and temperature gradient in the sintering atmosphere.

 

3. Innovation of preparation technology

With the continuous development of preparation technology, researchers are constantly exploring new preparation methods to improve the performance of aluminum nitride ceramic substrates. For example, the precise preparation of aluminum nitride ceramic substrate can be achieved by using advanced molding technologies such as casting molding and injection molding. In addition, the welding performance, stability and corrosion resistance of aluminum nitride ceramic substrate can be further improved by electroless copper plating, ceramic substrate encapsulation and other post-treatment processes.

 

Conclusion

In summary, the preparation of aluminum nitride ceramic substrate and the selection of sintering additives have important effects on its properties. The comprehensive properties of aluminum nitride ceramic substrate can be significantly improved by optimizing the sintering auxiliary formula, improving the sintering process and developing new preparation technology. In the future, with the continuous development of material science and preparation technology, the application field of aluminum nitride ceramic substrate will be further expanded, providing strong support for the development of electronic packaging, power electronic devices and microwave communication equipment. At the same time, we also need to pay close attention to the development trend of new technologies and new materials, constantly expand the research horizon, and promote the continuous progress and innovation of aluminum nitride ceramic substrate technology.

In the field of semiconductor materials, silicon carbide (SiC) with its excellent thermal conductivity, wide band gap characteristics, high breakdown electric field strength and high electron mobility, is gradually becoming a research and development hotspot, leading the innovation of a new generation of electronic devices. As a substrate material for key components, the broad application prospects of silicon carbide are self-evident, from high-efficiency power electronics to high-frequency communication chips, its figure is everywhere. However, the extremely high hardness of silicon carbide materials (Mohs hardness of about 9.5) is like a double-edged sword, both giving it excellent physical properties, but also set up numerous obstacles for its processing.

 

 

Faced with the difficult problem of polishing and grinding silicon carbide substrate, traditional processing methods are often inadequate, inefficient and costly. It is in this context that the metal friction induced reaction grinding technology came into being, and opened up a new path for the efficient processing of silicon carbide. This technology cleverly uses the chemical reaction produced by metal and silicon carbide friction at high temperature, through the continuous formation and removal of the reaction metamorphic layer, to achieve high speed and low damage removal of silicon carbide materials. This innovation not only overcomes the processing problems caused by the high hardness of silicon carbide, but also significantly improves the processing efficiency and surface quality.

 

It is worth noting that the metal friction-induced reaction grinding technology needs to be applied under precisely controlled conditions to avoid the decomposition of silicon carbide at high temperatures and the formation of unstable compounds with the metal, thus exacerbating tool wear. The experimental data show that the selection of suitable metals (such as iron, pure nickel) as friction media can achieve differentiated and efficient removal of different surfaces of silicon carbide substrate (carbon and silicon). Due to its structural stability, the surface quality of carbon surface is almost free of damage. Although there are crystal defects in the silicon surface, the material removal rate can reach 534µm/h under the friction of pure nickel, showing the great potential of this technology under certain conditions.

 

Looking forward to the future, metal friction induced reaction grinding technology is expected to achieve a wider application in the field of silicon carbide substrate processing. With the deepening of the research and the maturity of the technology, the technology is expected to expand to the processing of large-size silicon carbide wafers, and further improve the manufacturing efficiency and yield of silicon carbide devices. At the same time, combined with other advanced processing technologies, such as ultra-precision polishing and laser-assisted processing, it is expected to achieve comprehensive optimization of silicon carbide material processing and promote the silicon carbide semiconductor industry to a new height.

 

In short, silicon carbide substrate processing challenges and opportunities coexist, and the emergence of metal friction induced reaction grinding technology provides an innovative solution to this problem. With the continuous progress of technology and the continuous expansion of application fields, silicon carbide semiconductor materials will certainly play a more important role in the future development of electronic science and technology.

Silicon nitride (Si3N4) balls show great potential in the field of high-speed, high-precision, long-life bearings due to their excellent properties, such as lightweight, self-lubricating, high insulation, non-magnetic, high elastic modulus and excellent corrosion resistance. This paper aims to discuss the optimization of the spray granulation process of Si3N4 powder, especially the pressure spray granulation method, in order to improve the density, mechanical properties and microstructure of Si3N4 balls, so as to meet the urgent demand for high-performance bearing materials in aerospace, automotive and wind power generation fields.

 

With the rapid development of industrial technology, the requirements for material properties are increasingly stringent. As a new type of high performance bearing material, Si3N4 ceramic ball has become a research hotspot to further improve its performance. Among them, the blank density, as a key factor affecting the final performance of ceramic balls, is directly related to the number of micro-pores and fatigue life of ceramic balls after sintering. Therefore, optimizing the spray granulation process of Si3N4 powder to achieve regular powder morphology, uniform particle size distribution and increased bulk density is an effective way to improve the performance of ceramic balls.

 

Performance Advantages and Application Fields of Si3N4 Balls

With its unique physical and chemical properties, Si3N4 ceramic balls show significant advantages in many fields: low mass reduces the overall load of the bearing system and improves the operating efficiency; Self-lubricating features reduce lubrication requirements and reduce maintenance costs; High insulation and non-magnetic suitable for special environments; High elastic modulus and corrosion resistance ensure long-term stable operation under extreme conditions. These advantages make Si3N4 ceramic balls widely used in high-speed, high-precision and long-life bearing systems such as machine tool spindles, electric spindles, automotive engines, aerospace engines and wind turbines.

 

Effect of Spray Granulation Process on Properties of Si3N4 Ball

 

The Importance of Blank Density

The density of blank is a key parameter in the preparation of ceramic ball, which directly affects the density and properties of ceramic ball after sintering. Increasing the density of the blank is helpful to reduce the formation of pores in the sintering process, so as to improve the mechanical properties and fatigue life of ceramic balls.

 

The Relationship Between the Morphology of Spray-pelleted Powder and the Bulk Density

Spray granulation is one of the important processes for preparing high quality ceramic powders. Through pressure spray granulation, Si3N4 slurry is sprayed into the granulation tower under high pressure, and the droplets are quickly dried into spherical powder in the hot air flow. In this process, controlling the evaporation rate of the solvent on the particle surface is the key to obtain the powder with regular morphology and uniform particle size distribution. The regular spherical powder is beneficial to increase the loose density of the powder, and then improve the density and uniformity of the blank.

 

Optimization Strategy

1. Optimize the slurry formula: adjust the proportion of each component in the slurry and the use of dispersant to reduce agglomeration and settling stratification and improve the uniformity and stability of the slurry.

 

2. Precise control of spray parameters, such as spray pressure, nozzle design, hot air flow temperature, etc., to optimize the particle size distribution and drying rate of droplets, to ensure the regularity of powder morphology and the improvement of loose density.

Post-treatment optimization: The powder after spray granulation is screened and graded, and unqualified particles are removed to further improve the overall quality of the powder.

 

3. Experiment and result analysis

Through a series of experiments, we found that the raw density of Si3N4 ceramic balls prepared by optimized pressure spray granulation technology was significantly increased, and the sintered ceramic balls showed lower microporosity, higher hardness and better fatigue resistance. The microstructure analysis shows that the grain structure of the ceramic ball is more dense and the interface bonding strength is enhanced.

 

 

Conclusion and Prospect

In this paper, through the optimization of Si3N4 spray granulation process, especially the in-depth study of pressure spray granulation method, the density, mechanical properties and microstructure of Si3N4 ceramic balls have been successfully improved, which provides theoretical basis and technical support for the preparation of high-performance ceramic balls. In the future, with the continuous progress of material science and preparation technology, Si3N4 ceramic balls will show their unique advantages in more high-end fields and promote the sustainable development of related industries. At the same time, further exploration of new spray granulation technology and process parameter optimization will be an important direction to improve the performance of ceramic balls. Optimizing the Si3N4 spray granulation process to improve the performance of ceramic balls: Performance advantages, application areas and process exploration

 

With the rapid development of high-tech industry, the requirements for fineness, purity and consistency of powder materials are increasing. As a key component in the powder preparation process, the performance of grinding medium directly determines the quality of the final product. Traditionally, zirconia ceramic balls are widely used in the field of ultra-fine grinding because of their high bending strength, wear resistance and certain high toughness. However, its timeliness failure and performance instability at high temperatures limit its application in high-end powder manufacturing. This paper aims to explore the unique advantages of silicon nitride balls as a new generation of grinding media, and explain how they can replace zirconia balls and significantly improve the quality of high-tech powder products.

 

Powder industry as an important branch of materials science, the performance of its products is directly related to the development of semiconductor, biomedicine, aerospace and other high-tech fields. As the core tool of powder preparation, the selection of grinding medium directly affects the grinding efficiency, particle size distribution and impurity content. Silicon nitride (Si₃N₄) ceramics, a high performance engineering ceramic material, have shown great potential in materials science and engineering in recent years, especially as an alternative to traditional grinding media.

 

Performance Advantages of Silicon Nitride Balls

Excellent high-temperature stability

Silicon nitride ceramics have extremely high thermal stability and thermal conductivity, and can maintain structural stability and physical properties at high temperatures, and will not lose metastable phase at high temperatures like zirconia, resulting in performance degradation. This feature enables the silicon nitride ceramic ball to work stably in the high temperature grinding process, meeting the needs of high-tech powder materials for high temperature treatment.

Excellent wear resistance and durability

Silicon nitride ceramics have extremely high hardness and good wear resistance, far exceeding zirconia ceramics. In the long, high-intensity grinding process, the silicon nitride ceramic ball can effectively resist wear and maintain the geometry and dimensional accuracy of the ball, thus ensuring the grinding efficiency and the uniformity of the product particle size.

Excellent chemical stability

Silicon nitride ceramics show good chemical inertia to most acids, bases and organic solvents, which means that it is not easy to chemically react with the material during the grinding process, thus avoiding the introduction of impurities and product pollution, which is particularly important for the preparation of high-purity powders.

No timeliness problem

Compared with zirconia ceramic balls, silicon nitride ceramic balls do not have the performance degradation problem caused by long placement time. Its stable physical and chemical properties ensure the long-term stability and reliability of the grinding medium, which provides the possibility for large-scale and long-term continuous production.

 

Application Prospect of Si3N4 Ball in the Preparation of High-tech Powder Products

Based on the above performance advantages, silicon nitride ceramic ball as a grinding medium in the preparation of high-tech powder products shows broad application prospects. Especially in the fields of semiconductor materials, precision ceramic powders, high-performance metal powders and biomedical materials, silicon nitride ceramic balls can effectively improve the purity, particle size distribution uniformity and processing efficiency of the powder, so as to meet the strict requirements of the high-end market for product quality.

 

 

Conclusion

In summary, silicon nitride ceramic balls with its excellent high temperature stability, wear resistance, chemical stability and timeless advantages, successfully make up for the shortcomings of zirconia ceramic beads in the application of grinding media, become an important choice to improve the quality of high-tech powder products. With the continuous progress of material science and the continuous optimization of manufacturing processes, silicon nitride ceramic balls are expected to replace traditional grinding media in a wider range of fields, and promote the development of the powder industry to a higher level. In the future, further optimized design and cost control for silicon nitride ceramic balls will be the key to promote their wide application.

Silicon carbide, the emerging star of the semiconductor material industry, is gradually leading the innovation trend of microelectronics technology with its excellent performance indicators. Its unique thermal conductivity, far superior to traditional semiconductor materials, provides the possibility for efficient heat dissipation, especially in high-power electronic devices show unparalleled advantages. Coupled with its wide band gap characteristics, the silicon carbide substrate can maintain stable electrical performance in extreme environments and is not affected by temperature fluctuations, which greatly broadens its scope of application in high-end applications such as aerospace and new energy vehicles. In addition, the two key parameters of high breakdown electric field and high electron mobility have laid a solid foundation for the application of silicon carbide in high-frequency and high-voltage electronic devices, such as power electronic converters, RF communication devices, etc., and have achieved a leap in performance because of it.

The wide application of silicon carbide is not only limited to the above high-end fields, it also goes deep into many core links of the semiconductor industry chain, including as a substrate material for high-performance chips, supporting more complex circuit structures; In the epitaxial growth process, its stable substrate properties promote the growth of high-quality films, which provides a possibility for the optimization of device performance. In the device design stage, the characteristics of silicon carbide inspire designers to unlimited creativity, giving birth to more innovative, high-performance semiconductor products; At the wafer manufacturing stage, the introduction of silicon carbide has put forward higher requirements for the manufacturing process, and promoted the technological progress of the entire semiconductor manufacturing industry.

However, it is precisely such a near-perfect material, its extremely high hardness - Mohs hardness close to diamond, has become a major problem restricting its wide application. In the precision machining process, the hardness of silicon carbide makes the traditional polishing and grinding technology difficult to display, not only the processing efficiency is low, but also easily lead to the surface quality is not up to standard, increasing the production cost. Therefore, how to overcome the problem of silicon carbide processing has become one of the key technologies to be solved urgently in the field of semiconductor materials. Researchers are constantly exploring new processing methods, such as the use of advanced chemical mechanical polishing technology, laser processing technology, etc., in order to ensure the processing accuracy at the same time, improve processing efficiency, and promote the application and development of silicon carbide materials in a wider range of fields.

 

Sol-gel polishing technology is a green and efficient polishing method, through the use of semi-consolidated abrasives and flexible substrates, by virtue of the flexible characteristics of the soft matrix, the "tolerance" effect of the abrasive particles is achieved to achieve ultra-smooth and low defect density surface on the extremely hard semiconductor substrate. This method combines chemical and mechanical action to effectively polish extremely hard semiconductor substrates without causing severe surface or subsurface damage. Compared with traditional CMP, sol-gel polishing technology can significantly reduce the surface roughness in a short time and achieve a higher material removal rate. Due to its good flexibility, the soft matrix can work under lower polishing pressure, reduce the pressure demand on the workpiece and equipment, reduce the wear and fall off of the wear particle, and extend the service life of the wear particle. The precursor material (usually a metal-organic compound) is converted to sol, which forms a gel through hydrolysis and condensation reactions. In the sol-gel polishing pad, the wear particles are partially fixed in the gel matrix, which can provide a certain mechanical strength while maintaining the movement of the wear particles. Domestic scholars used this technology to process HTHP single crystal diamond (111) surface, polishing 22h, the surface roughness from 230nm to 1.3nm. By the way, the capacitance effect refers to that in the polishing process, when the abrasive touches the machined surface, due to the presence of soft matrix, the more prominent abrasive can produce rebound, thus ensuring that the surface abrasive can process the workpiece approximately in the same horizontal plane, avoiding the damage of the larger size abrasive to the machined surface, and obtaining uniform material removal. A better polishing effect is achieved.

 

In summary, silicon carbide, as a new star in the semiconductor material industry, is leading the innovation of microelectronics technology with its unique performance advantages. Its wide application not only promotes the technological progress in the high-end field, but also profoundly affects every link of the semiconductor industry chain. However, the high hardness properties of silicon carbide also pose challenges for its processing. In the face of this problem, researchers are actively exploring innovative solutions, such as sol-gel polishing technology, these emerging technologies not only improve processing efficiency and surface quality, but also open up new ways for the application and development of silicon carbide materials in a wider range of fields. With the continuous progress of technology, silicon carbide materials will certainly play a more important role in the future field of science and technology.

With the rapid development of modern mechanical engineering technology, the requirements for material properties are increasingly stringent, especially under extreme conditions such as high temperature, high speed, strong corrosion, etc., traditional metal materials and polymer materials have been difficult to meet the needs. Silicon nitride (Si ₄) As an advanced ceramic material with excellent overall properties, the silicon nitride balls made of it show their unique characteristics and wide application prospects in the field of mechanical engineering. In this paper, the properties and characteristics of silicon nitride balls are reviewed, their specific applications in mechanical engineering are discussed, and their future development trends are prospected.

 

Silicon nitride ceramics are known as "the pearl in the crown of advanced ceramics" for their high strength, high hardness, good thermal stability, corrosion resistance, oxidation resistance and self-lubrication. As an important form of silicon nitride ceramics, silicon nitride ball not only inherits the excellent properties of silicon nitride ceramics, but also has unique mechanical properties and wide application potential because of its spherical structure. In the field of mechanical engineering, the application of silicon nitride balls is gradually becoming one of the key technologies to improve equipment performance, extend service life and reduce maintenance costs.

 

Performance Characteristics of Silicon Nitride Ball

1. High temperature stability

Silicon nitride balls are known for their excellent high temperature stability and are able to maintain their excellent mechanical properties in extremely high temperature environments. This material will neither soften nor melt at high temperatures, making it ideal for bearings, seals and transmission components in high temperature environments. Their excellent thermal stability makes silicon nitride balls excellent in industrial applications that require high temperature loads, such as aerospace and nuclear industries.

2. Excellent wear resistance

The high hardness and self-lubricating properties of the silicon nitride ball give it excellent wear resistance. In friction pairs, silicon nitride balls can significantly reduce wear, thereby extending the service life of the equipment. This characteristic makes the silicon nitride ball particularly suitable for applications under high speed, heavy load and dry friction conditions, such as high-speed bearings and sliding guides. In these applications, silicon nitride balls can effectively reduce the coefficient of friction and improve the operational efficiency and reliability of the equipment.

3. Corrosion and oxidation resistance

Silicon nitride ball has excellent resistance to a variety of acids, bases and oxidizing media. This material can maintain stable performance in harsh chemical environments and is not easy to be corroded or oxidized. Therefore, silicon nitride balls have a wide range of application prospects in chemical, petroleum and other industries, and can be used to make corrosion-resistant pipes, valves, pumps and other key components.

4. Insulation and non-magnetism

Silicon nitride balls are a good electrical insulator and are not magnetic. This characteristic makes the silicon nitride ball have unique application value in the fields of electronics, medical and precision instruments. In the electronics industry, silicon nitride balls can be used to make high-performance electronic components; In the medical field, its biocompatibility and corrosion resistance make it an ideal material for high-end medical products such as artificial joints and dental implants; In the field of precision instruments, the high-precision machinability and non-magnetic characteristics of silicon nitride balls make them an important part of calibration and measurement tools.

5. High precision processing

With the continuous progress of ceramic processing technology, silicon nitride balls have been able to achieve high precision processing. This high-precision processability enables silicon nitride balls to meet the high requirements of precision machinery for dimensional accuracy and surface quality of parts. In the field of precision manufacturing, the high-precision processability of silicon nitride balls has brought a wide range of application opportunities, such as for the manufacture of high-precision bearings, guides, gears and other key components.

 

Use of Silicon Nitride Ball in Mechanical Engineering Field

1. Bearings and sliding parts

Silicon nitride balls are widely used in high-speed bearings and sliding rails because of their excellent wear resistance and high temperature stability. These components generate a lot of friction and heat at high speeds, and silicon nitride balls can effectively reduce wear and heat accumulation, thereby improving the operating efficiency and reliability of the equipment.

2. Sealing element

In the environment of high pressure, high temperature and corrosive media, traditional sealing materials are often difficult to meet. The silicon nitride ball seal can perform well, effectively prevent media leakage and ensure the safe and stable operation of the equipment. This kind of sealing element has a wide application prospect in chemical industry, petroleum industry, etc.

3. Precision measurement and calibration

The high-precision workability and non-magnetic properties of the silicon nitride ball make it an ideal standard ball or calibration element in precision measuring instruments. During the measurement and calibration process, the silicon nitride ball provides an accurate reference and ensures the accuracy and reliability of the measurement results. This is of great significance for improving product quality and reducing production cost.

4. Medical devices

In the field of medical devices, the biocompatibility and corrosion resistance of silicon nitride balls make them an ideal material for high-end medical products such as artificial joints and dental implants. These medical products need to be implanted into the human body for a long time and in direct contact with human tissues, so the biocompatibility and corrosion resistance of the material is extremely high. Silicon nitride balls are able to meet these requirements and provide safe and reliable medical services to patients.

5. Aerospace and Nuclear industry

In extreme conditions such as the aerospace and nuclear industries, the application of silicon nitride balls shows great potential. Devices in these areas need to withstand extreme conditions such as high temperatures and high radiation, and silicon nitride balls are able to maintain their excellent performance and meet these requirements. Therefore, silicon nitride ball has a wide range of application prospects in key fields such as aircraft engine bearings and nuclear reactor components.

 

As an important representative of advanced ceramic materials, silicon nitride balls show excellent performance characteristics and wide application prospects in the field of mechanical engineering. With the continuous progress of material science and processing technology, the preparation cost of silicon nitride balls will be further reduced, the processing accuracy and performance will continue to improve, and its application fields will continue to expand. In the future, silicon nitride balls are expected to play a key role in more high-end equipment manufacturing and promote the innovation and development of mechanical engineering technology. At the same time, further study on the relationship between microstructure and properties of silicon nitride spheres and exploration of new composite silicon nitride materials will be an important direction of future research.

With the rapid development of modern electronic technology, the design of microwave RF components and high-frequency circuits is becoming more and more complex, and the performance requirements of components are becoming higher and higher. In order to meet these needs, thin film technology, as an advanced microelectronic technology, plays an increasingly important role in the design of microwave components and high-frequency circuits. This article introduces several thin film components based on alumina substrate design, including thin film attenuators, thin film couplers, thin film Bridges, thin film resistors, and thin film capacitors. These components play an indispensable role in microwave RF components and high-frequency circuits with their unique properties and wide application fields.

 

 

1 Film attenuator

The design of thin film attenuator using alumina ceramic substrate is often used for large signal attenuation in microwave RF module, or for multi-stage adjustment of attenuation value in programmed attenuation circuit. It is also based on the reasonable design of the square resistance of tantalum nitride film layer and the film process design of alumina ceramic circuit. Thin film attenuators can achieve high flatness of attenuation value in ultra-wide band with stable performance.

 

2 Thin film coupler

Aluminum oxide ceramic substrate design film coupler, often used in microwave component system power detection or signal separation, can be designed into any weak coupling degree coupler, and can use tantalum nitride design integrated isolation load, the port can be designed into the form of surface paste package, directly welded in the circuit for work. It can be designed into a multi-stage form when it needs to be applied to a wide band.

 

3 Film bridge

The use of alumina ceramic substrate design film bridge, also called 3dB bridge, often used to separate the signal and make it have a 90° or 180° phase difference, lange bridge is a form of its application more, through the gold wire bonding to achieve the signal connection between the lines.

 

4 Thin film resistance

The use of alumina ceramic substrate design film resistor, often used in high-precision, low noise and high stability of the circuit, often integrated in the microstrip film circuit design and processing, can also be designed separately into a variety of resistance types of film resistor used, or designed into a resistance network, through the gold wire bonding to select the required resistance value.

 

5 Thin film capacitance

The thin-film capacitor is designed with alumina ceramic substrate, which is often used in high-frequency filtering. The thin-film capacitor with arbitrary capacitance can be designed for power supply. The performance is more stable than that of ordinary chip capacitor, and it is suitable for high-frequency circuit.

 

In summary, thin-film components designed on alumina ceramic substrates, such as thin film attenuators, thin film couplers, thin film Bridges, thin film resistors and thin film capacitors, have shown excellent performance and wide application prospects in microwave RF components and high-frequency circuits. These components not only have the advantages of high precision, low noise and high stability, but also can achieve high performance indicators in the ultra-wide band, which provides a strong support for the development of modern electronic technology. With the advancement of science and technology and the improvement of demand, thin film technology will continue to play a more important role in the design of microwave RF components and high-frequency circuits, and promote the continuous development and innovation of electronic technology.