What are the requirements for alumina powder in high value-added applications?
Alumina high-density particles for sapphire crystal growth
In fact, sapphire is an alumina single crystal. Its growth uses high-purity alumina powder with a purity of >99.995% (commonly called 5N alumina) as a raw material. However, due to the small packing density of micronized alumina particles, it is generally Less than 1g/cm3, the charging amount of a single furnace is small, which affects the production efficiency. Generally, the alumina is densified into high-density particles through appropriate treatment before charging to grow crystals.
Nano-alumina abrasives for CMP polishing abrasives
Currently, the commonly used CMP polishing fluids include silica sol polishing fluid, cerium oxide polishing fluid and alumina polishing fluid. The first two have small abrasive grain hardness and cannot be used for polishing high-hardness materials. Therefore, the oxide polishing fluid with Mohs hardness of 9 Aluminum is widely used in the precision polishing of sapphire fairings and flat windows, crystallized glass substrates, YAG polycrystalline ceramics, optical lenses, high-end chips and other components.
The size, shape, and particle size distribution of abrasive particles all affect the polishing effect. Therefore, alumina particles used as chemical mechanical polishing abrasives should meet the following requirements:
1. In order to achieve angstrom-level flatness, the alumina particle size must be at least 100nm and the distribution must be narrow;
2. In order to ensure hardness, complete α-phase crystallization is required. However, to take into account the above particle size requirements, sintering needs to be completed at a lower temperature to avoid complete α-phase transformation while the grains grow.
3. Since the polishing of wafers has extremely high purity requirements, Na, Ca, and magnetic ions need to be strictly controlled, up to ppm level, while radioactive elements U and Th need to be controlled at ppb level.
4. Polishing fluids containing Al2O3 have low selectivity, poor dispersion stability, and easy agglomeration, which can easily cause serious scratches on the polishing surface. Generally, modifications are required to improve its dispersion in the polishing fluid to obtain good polished surface
Low-alpha emissive spherical alumina for semiconductor packaging
In order to ensure the reliability of semiconductor devices and enhance the core competitiveness of products, it is often required to use Low-α ray spherical alumina as packaging material. On the one hand, it can prevent the operation failure of memory devices caused by α rays, and on the other hand, it can utilize its high heat The conductivity provides good heat dissipation performance for the device.
Alumina transparent ceramic
First of all, in order to prevent impurities in Al2O3 powder from easily forming different phases and increasing the scattering center of light, resulting in a reduction in the intensity of the projected light in the incident direction, thereby reducing the transparency of the product, the purity of Al2O3 powder is required to be no less than 99.9%, and It should be α-Al2O3 with a stable structure. Secondly, in order to weaken its own birefringence effect, its grain size should also be reduced as much as possible. Therefore, the particle size of the powder used to prepare alumina transparent ceramics should also be less than 0.3 μm and have high sintering activity. In addition, in order to avoid agglomeration into large particles and losing the advantages of the original small particles, the powder should also meet the requirements of high dispersion.
High frequency communication alumina ceramic substrate
High-purity alumina ceramics are currently the most ideal and most widely used packaging substrate material due to their good dielectric properties, rigid load-bearing capacity, and resistance to environmental erosion. However, the main performance of alumina substrates increases with the increase in alumina content. In order to meet the needs of high-frequency communications, the purity of alumina ceramic substrates is required to reach 99.5% or even 99.9%.
Sintered NdFeB manufacturing process-jet mill
Jet mill (JM) powder making is a new type of powder making method that uses high-pressure airflow (usually high-purity nitrogen) to accelerate powder particles to supersonic speed in the airflow grinding chamber, causing the powder particles to collide with each other and break.
The specific process is: mix the crushed hydrogen flakes (SC) with a certain proportion of antioxidant, then add it to the airflow mill feeding bin, add it to the airflow grinding chamber according to the quantitative amount, and high-pressure nitrogen (7kg) is sprayed from the four nozzles of the grinding chamber. , accelerate the material to supersonic speed to form a fluidized bed, and the particles collide with each other and break. The diameter of the broken particles is distributed between 1-8 μm.
Depending on the performance and distribution of the materials, the average airflow milling powder size SMD is between 2.5-4μm. The powder produced by airflow milling is uneven and requires three-dimensional mixing. Before mixing, a certain proportion of lubricant and antioxidants are added to the material tank according to the process to control the oxygen content and improve the molding orientation performance.
The “core strength” of semiconductor equipment—silicon carbide components
Silicon carbide (SiC) is a structural ceramic material with excellent properties. Silicon carbide parts, that is, equipment parts made of silicon carbide and its composite materials as the main materials, have the characteristics of high density, high thermal conductivity, high bending strength, large elastic modulus, etc., and can be adapted to wafer epitaxy, etching, etc. Due to the highly corrosive and ultra-high temperature harsh reaction environment in the manufacturing process, it is widely used in major semiconductor equipment such as epitaxial growth equipment, etching equipment, and oxidation/diffusion/annealing equipment.
According to the crystal structure, there are many crystal forms of silicon carbide. Currently, the common SiC are mainly 3C, 4H and 6H types. Different crystal forms of SiC have different uses. Among them, 3C-SiC is also often called β-SiC. An important use of β-SiC is as a film and coating material. Therefore, β-SiC is currently the main material for graphite base coating.
According to the preparation process, silicon carbide parts can be divided into chemical vapor deposition silicon carbide (CVD SiC), reaction sintered silicon carbide, recrystallization sintered silicon carbide, atmospheric pressure sintered silicon carbide, hot pressing sintered silicon carbide, hot isostatic pressing sintering and carbonization Silicon etc.
Silicon carbide parts
1. CVD silicon carbide parts
CVD silicon carbide components are widely used in etching equipment, MOCVD equipment, SiC epitaxial equipment, rapid heat treatment equipment and other fields.
Etching equipment: The largest market segment for CVD silicon carbide components is etching equipment. CVD silicon carbide components in etching equipment include focusing rings, gas shower heads, trays, edge rings, etc. Due to the low reactivity and conductivity of CVD silicon carbide to chlorine- and fluorine-containing etching gases, it becomes a plasma Ideal material for components such as focus rings in etching equipment.
Graphite base coating: Low-pressure chemical vapor deposition (CVD) is currently the most effective process for preparing dense SiC coatings. The thickness of CVD-SiC coatings is controllable and has the advantages of uniformity. SiC-coated graphite bases are commonly used in metal-organic chemical vapor deposition (MOCVD) equipment to support and heat single crystal substrates. They are the core and key components of MOCVD equipment.
2. Reaction sintered silicon carbide parts
For reaction-sintered (reactive infiltration or reaction bonding) SiC materials, the sintering line shrinkage can be controlled below 1%, and the sintering temperature is relatively low, which greatly reduces the requirements for deformation control and sintering equipment. Therefore, this technology has the advantage of easily achieving large-scale components and has been widely used in the fields of optical and precision structure manufacturing.
12 Modification Methods of Bentonite
The modification of bentonite usually uses physical, chemical, mechanical and other methods to treat the surface and purposefully change the physical and chemical properties of the mineral surface according to application needs.
1. Sodium modification
Since montmorillonite has a stronger adsorption capacity for Ca2+ than Na+, the bentonite found in nature is generally calcium-based soil. However, in practical applications, it is found that the exchange capacity of Ca2+ in calcium-based soil is much lower than that of Na+. Therefore, calcium-based soil is often sodiumified before being put into the market.
2. Lithium modification
Lithium bentonite has excellent swelling, thickening and suspending properties in water, lower alcohols and lower ketones, so it is widely used in architectural coatings, latex paints, casting coatings and other products to replace various organic cellulose suspending agents. There are very few natural lithium bentonite resources. Therefore, artificial lithiation is one of the main methods for preparing lithium bentonite.
3. Acid leaching modification
The acid modification method mainly uses acids of different types and concentrations to soak bentonite. On the one hand, the acid solution can dissolve the interlayer metal cations and replace them with H+ with smaller volume and lower valence, thereby reducing the interlayer van der Waals force. The interlayer spacing increases; on the other hand, impurities in the channel can be removed, thereby expanding the specific surface area.
4. Roasting activation modification
The bentonite roasting modification method is to calcine bentonite at different temperatures. When bentonite is calcined at high temperature, it will successively lose surface water, bound water in the skeleton structure, and organic pollutants in the pores, causing the porosity to increase and the structure to become more complex.
5. Organic modification
The basic principle of the organic modification method is to organicize bentonite, using organic functional groups or organic matter to replace the bentonite layers to exchange cations or structural water, thereby forming an organic composite bonded by covalent bonds, ionic bonds, coupling bonds or van der Waals forces. Bentonite.
6. Inorganic pillar modification
Inorganic modification is to expand the interlayer spacing by forming an inorganic columnar structure between the bentonite layers, increase the specific surface area, and form a two-dimensional hole network structure between the layers. It also prevents the bentonite from collapsing in high temperature environments and improves its thermal stability.
7. Inorganic/organic composite modification
The inorganic/organic composite modification method takes advantage of the large interlayer gaps and cation exchangeability of bentonite. It mainly uses inorganic polymers to open up the interlayer domains, and then uses activators to change the surface properties of bentonite. method.
8. Microwave modification
The principle of microwave modification is to use microwaves with a frequency range between 300Hz and 300GHz to process bentonite and activate it. Microwave treatment has the advantages of strong penetration, uniform heating, safe and simple operation, low energy consumption, and high efficiency. It has better results when combined with traditional acidification and roasting methods.
9. Ultrasonic modification
Ultrasonic modified bentonite can improve its adsorption performance. Short-term ultrasound can increase the interlayer spacing and loosen the structure, making it easier for metal ions to enter; long-term ultrasound can change the Si-O-Si bonds on the surface of the crystal lamellae in bentonite, adding some metal ions to the bentonite.
10. Inorganic salt modification
Inorganic salt modification is to immerse bentonite in salt solution (NaCl, MgCl2, AlCl3, CaCl2, Cu(NO3)2, Zn(NO3)2, etc.). The adsorption capacity of bentonite modified by salt solution is even better than that of the original soil. has seen an increase.
11. Rare earth metal doping modification
Commonly used rare earth modifiers are lanthanum salts and their oxides. After doping bentonite with the rare earth metal lanthanum, a certain amount of metal oxides and hydroxides are introduced on its surface or between layers, thus weakening the montmorillonite in the bentonite. of interlayer bond energy.
12. Metal-loaded modification
Metal-loaded modified bentonite uses bentonite as a carrier and uses sol-gel method, direct precipitation method, impregnation method and other processes to highly disperse the metal active components on the carrier, using the carrier to have good pore size structure and other characteristics The active components can exert a better catalytic effect in the catalytic reaction.
What methods can help surface modification of ultrafine powders?
Ultrafine powder, also known as nanopowder, refers to a type of powder whose particle size is in the nanometer range (1~100nm). Ultrafine powder can usually be prepared by ball milling, mechanical crushing, spraying, explosion, chemical deposition and other methods.
Nanopowders have attracted people's attention due to their special properties in terms of magnetism, catalysis, light absorption, thermal resistance and melting point due to their volume effect and surface effect. However, due to their small size and high surface energy, nanoparticles have a tendency to spontaneously agglomerate. The existence of agglomeration will affect the performance of nanopowder materials. In order to improve the dispersion and stability of the powder and make the application range of the material wider, it is necessary to modify the surface of the powder.
There are many methods of surface modification, which can generally be divided into: surface coating modification, surface chemical modification, mechanochemical modification, capsule modification, high-energy modification, and precipitation reaction modification.
Surface coating modification
Surface coating modification means that there is no chemical reaction between the surface modifier and the particle surface. The coating and the particles are connected by physical methods or van der Waals forces. This method is suitable for the surface modification of almost all types of inorganic particles. This method mainly uses inorganic compounds or organic compounds to coat the surface of the particles to weaken the agglomeration of the particles. Moreover, the steric repulsion generated by the coating makes it very difficult for the particles to reunite. Modifiers used for coating modification include surfactants, hyperdispersants, inorganic substances, etc.
Applicable powders: kaolin, graphite, mica, hydrotalcite, vermiculite, rectorite, metal oxides and layered silicates, etc.
Surface chemical modification
Surface chemical modification uses the adsorption or chemical reaction of functional groups in organic molecules on the surface of inorganic powder to modify the particle surface. In addition to surface functional group modification, this method also includes surface modification using free radical reaction, chelation reaction, sol adsorption, etc.
Applicable powders: quartz sand, silica powder, calcium carbonate, kaolin, talc, bentonite, barite, wollastonite, mica, diatomaceous earth, brucite, barium sulfate, dolomite, titanium dioxide, aluminum hydroxide, Various powders such as magnesium hydroxide and aluminum oxide.
Mechanochemical modification
Mechanochemical modification refers to the change of mineral lattice structure, crystal form, etc. through mechanical methods such as crushing, grinding, and friction. The energy in the system increases and the temperature rises, which promotes particle dissolution, thermal decomposition, and free generation. A modification method that uses radicals or ions to enhance the surface activity of minerals and promote the reaction or attachment of minerals and other substances to achieve the purpose of surface modification.
Applicable powders: kaolin, talc, mica, wollastonite, titanium dioxide and other types of powders.
Capsule modification
Capsule modification is a surface modification method that covers the surface of powder particles with a uniform and certain thickness film.
High energy modification method
High-energy modification method is a method that uses plasma or radiation treatment to initiate polymerization reaction to achieve modification.
Precipitation reaction modification
The precipitation reaction method is to add a precipitant to a solution containing powder particles, or add a substance that can trigger the generation of the precipitant in the reaction system, so that the modified ions undergo a precipitation reaction and precipitate on the surface of the particles, thereby coating the particles. Precipitation methods can be mainly divided into direct precipitation methods, uniform precipitation methods, non-uniform nucleation methods, co-precipitation methods, hydrolysis methods, etc.
Applicable powders: titanium dioxide, pearlescent mica, alumina and other inorganic pigments.
Application of jet mill in anticorrosive coatings
Fly ash, also called fly ash, is a powdery waste formed by calcining in boilers.
Fly ash is typically captured from the flue gas by an electrostatic precipitator or other particle filtering device before the flue gas reaches the chimney.
Fly ash is composed of crystals, glass bodies, and residual carbon. It is gray or gray-black and irregular in shape. Most of the particles are microspherical, with a particle size of 0.1 to 300.0 μm, a density of about 2 g/cm3, and a bulk density of 1.0 to 300.0 μm. 1.8 g/cm3, it has a large specific surface area and strong adsorption activity.
Anti-corrosion performance mechanism of fly ash enhanced coatings
Fly ash contains a large number of microbeads and sponge vitreous structures. Moreover, after the microbeads are crushed, that is, after the surface is destroyed, more pore structures and sponge vitreous structures will be exposed, which can increase the specific surface area of the powder. Utilizing these characteristics, it can be used as a filler in other products, thereby making it a better functional filler for coatings. Research shows that ultrafine fly ash, as a paint filler, can combine covering, leveling and wear resistance.
The corrosion resistance of the coating is closely related to the porosity of the coating. Fly ash is added as a filler in the coating. Due to the pozzolanic effect of fly ash, it can fill the pores of the coating to prevent corrosive media from penetrating into the interior of the coating through the anti-corrosion coating.
Fly ash has good mechanical properties. The fly ash/resin composite coating can increase the durability of the coating, prevent local pores due to wear and loss of protection, and greatly extend the service life of the coating.
The addition of conductive polymer not only improves the water-blocking performance of the coating, but also reduces the oxidation rate of the metal. By adding zinc powder or aluminum powder to the anti-corrosion coating, the active material becomes the anode of the corrosion reaction and protects the metal matrix as the cathode.
Application of jet mill in anticorrosive coatings
Different from the traditional mechanical crushing principle, under the action of high-speed airflow, the material is crushed through the impact between its own particles, the impact and shearing effect of the airflow on the material, and the impact, friction and shearing of the material and other parts. In addition to impact force, the crushing force also includes friction and shearing forces. Friction is caused by the friction and grinding motion between the material particles and the inner wall. Of course, this friction and grinding process also occurs between particles. Because the two crushing methods of impact and grinding are mainly suitable for fine crushing of brittle materials, they are especially suitable.
Jet crushing has some special characteristics because it is different from ordinary crushers in terms of crushing methods and principles:
The fineness of the product is uniform. For the airflow crusher, during the crushing process, due to the centrifugal force of the airflow rotation, the coarse and fine particles can be automatically classified.
The average particle size of the crushed materials is fine and can be crushed to sub-micron level;
The production process is continuous, the production capacity is large, and the degree of self-control and automation is high.
Calcite ultrafine powder preparation process flow
Calcite ultrafine powder, as a commonly used non-metallic mineral material, has a wide range of applications in industry and technology. Its preparation process and quality directly affect the performance and market competitiveness of the product. In this article, we will introduce you to the preparation process of calcite ultrafine powder and its price, hoping to provide you with valuable information.
Calcite ultrafine powder preparation process flow
The preparation of calcite ultrafine powder mainly involves the grinding process. The following is the general process flow:
1. Raw material selection
Selecting high-quality calcite ore as raw material is the first step in preparing ultra-fine powder. The quality of raw materials is directly related to the purity and performance of the final product.
2. smash
The selected calcite ore is crushed, usually using jaw crusher, cone crusher and other equipment to crush the original ore into smaller particles.
3. Grinding
After crushing, the particles are further ground using ultra-fine grinding equipment to obtain the required ultra-fine powder. The selection of ultrafine grinding equipment and the adjustment of process parameters have an important impact on the fineness and particle distribution of the product.
4. Grading
The ground calcite powder may have certain particle inhomogeneity. The ultra-fine powder is screened and classified through classification equipment to obtain the required fineness.
5. Packaging
The finally obtained calcite ultrafine powder is packaged through packaging equipment to ensure product quality and facilitate storage, transportation and sales.
Calcite ultrafine powder is an important non-metallic mineral material, and its preparation process and price are crucial to related industries and application fields.
Whether the surface modification effect of silica powder is good or not depends on these points!
Silica powder itself is a polar and hydrophilic substance. It has different interface properties with the polymer matrix and has poor compatibility. It is often difficult to disperse in the base material. Therefore, surface modification of silica powder is usually required. Purposefully change the physical and chemical properties of the surface of silica powder according to the needs of the application, thereby improving its compatibility with organic polymer materials and meeting its dispersion and fluidity requirements in polymer materials.
Factors such as the raw material quality of silica powder, modification process, surface modification method and modifier, modifier dosage, modification process conditions (modification temperature, time, pH and stirring speed) all affect the surface modification effect of silica powder. Among them, surface modification methods and modifiers are the main factors affecting the modification effect.
1. Quality of silica powder raw materials
The type, particle size, specific surface area, surface functional groups and other properties of silica powder directly affect its combination with surface modifiers. The modification effects of different types of silica powder are also different. Among them, spherical silica powder has good fluidity, is easy to combine with the modifier during the modification process, and can be better dispersed in the organic polymer system. And the density, hardness, dielectric constant and other properties are significantly better than the angular silica powder.
2. Surface modification methods and modifiers
At present, the surface modification methods of silica powder are mainly organic modification, inorganic modification and mechanochemical modification, among which the most commonly used modification method is organic modification. When the single modification effect is not good, you can consider combining organic modification with other modification methods for composite modification.
(1) Organic modification
Organic modification is a method that uses functional groups in organic matter to carry out physical adsorption, chemical adsorption and chemical reactions on the surface of silica powder to change the surface properties of silica powder.
(2) Inorganic modification
Inorganic modification refers to coating or compounding metals, inorganic oxides, hydroxides, etc. on the surface of silica powder to give the material new functions. For example, Oyama et al. used a precipitation method to cover the SiO2 surface with Al(OH)3, and then wrapped the modified SiO2 with polydivinylbenzene, which can meet certain special application requirements.
(3) Mechanochemical modification
Mechanochemical modification refers to first using ultra-fine grinding and other strong mechanical forces to activate the surface of powder particles to increase active points or active groups on the surface of silica powder, and then combining modifiers to achieve composite modification of silica powder.
3. Modifier dosage
The amount of modifier is usually related to the number of active points (such as Si-OH) on the surface of silica powder and the monomolecular layer and bimolecular thickness of the modifier covering the surface.
When the amount of modifier is too small, the degree of activation of the surface of the modified silica powder will not be high; when the amount of modifier is too large, it will not only increase the cost of modification, but also form a multi-layer physical layer on the surface of the modified silica powder. Adsorption causes the interface between silica powder and organic polymer to form a weak layer, resulting in the inability to function as a single molecule bridge.
4. Modification process and condition optimization
Commonly used modification processes for silica powder mainly include dry modification, wet modification, and composite modification.
Dry modification is a modification in which silica powder is dispersed in a modification equipment in a relatively dry state and combined with a certain amount of surface modifier at a certain temperature. Dry modification process is simple and has low production cost. It is currently the main method of surface modification of domestic silica powder and is suitable for micron-level silica powder.
In addition, in order to achieve good modification effect of silica powder, the temperature, pH, time, stirring speed and other process conditions during the modification process should be controlled.
Modification temperature is an important condition for the condensation, dehydration and formation of strong covalent bonds between the modifier and silica powder. The modification temperature should not be too high or too low. Too high a temperature will cause the modifier to decompose or volatilize, and too low a temperature will cause the modifier to decompose or volatilize. This will reduce the reaction rate between the modifier and the silica powder, affecting the modification effect.
Learn about black silicon and its applications
The origin of the name black silicon is that as seen by the human eye, the color is black. Because of the microstructure on the surface, black silicon can absorb nearly 100% of the incident light, and very little light is reflected, so it appears black to the human eye.
The unique optical and semiconductor properties of black silicon materials have brought a wide range of applications to photoelectric sensors (photodetectors, thermal imaging cameras, etc.), such as low-light cameras that work in the visible and near-infrared dual-bands, bringing great benefits to civilian and military applications. Come to many conveniences.
One of the most attractive properties of black silicon is its fairly low reflectivity and wide-angle absorption capabilities over a wide spectral range. The reflectivity of black silicon can usually reach less than 10%, which is very useful for nanocones or nanowires. The special structure of diameter ratio can further reduce the average reflectivity to less than 3% by optimizing process parameters.
With the development of silicon fine processing technology, the microstructure of black silicon has developed from the earliest nanocone structure processed by femtosecond laser to pyramid, hole, nanowire and composite structures.
After years of exploration, various processing systems have been established for black silicon processing methods. Commonly used methods include femtosecond laser method, electrochemical etching method, reactive ion etching method, acid method, alkali method, metal-assisted etching method, etc. method. Each processing method has different microstructure morphology and available optical properties.
At the same time, the definition of black silicon has gradually expanded. It is no longer limited to microstructured silicon processed by femtosecond laser, and the color is not limited to black. As long as it has obvious light trapping ability, it can be called microstructured silicon. It is black silicon material.
By controlling the characteristic structural size of multilayer porous silicon, researchers artificially control changes in its refractive index. The silicon surface has different absorption effects for different light, and ultimately different colors appear under human eyes. This technical solution can be applied to a four-quadrant detector, so that each quadrant exhibits different spectral response characteristics.
As a new material, black silicon has many excellent properties and has been used in many fields, such as extremely high light absorption rate and light sensitivity, which can be used as the absorbing layer of photodetectors; using black silicon's anti-reflection properties and wide angle Characteristics such as absorption can improve device performance such as photoelectric response rate and response spectral range; black silicon's pyramidal structure has excellent field emission characteristics, so it can be used as a field emission material. Black silicon also has excellent photoemission properties. Due to its luminescent properties, it can be used as a photoluminescent material; using the ultra-high specific surface area of black silicon, it can be used as a solid adhesive or heat dissipation structure between silicon materials.
In many applications, black silicon materials have shown their great value in improving the photovoltaic efficiency of industrial crystalline silicon solar cells. With the explosive development of diamond wire cutting silicon wafer technology, the damage layer during silicon wafer cutting has been greatly reduced, and thinner monocrystalline or polycrystalline silicon wafers can also be provided, which has greatly promoted the vigorous development of the photovoltaic industry and improved the performance of devices. Photoelectric conversion efficiency, photovoltaic cells are in urgent need of front surface technology with low reflectivity and wide-angle absorption and structural design with enhanced absorption. Black silicon technology shows natural coupling in the photovoltaic field.
What are the applications of graphene in the field of thermal conductivity?
At present, with the continuous deepening of research, the application of graphene in the field of thermal conductivity has achieved remarkable results, including the formation of graphene films through chemical bonds between sheets, as a filler in thermally conductive composite materials and thermally conductive coatings, and the preparation of graphene. Polyethylene fiber new functional textile materials, etc.
1. Graphene thermal film
Artificial graphite film has been the most ideal choice for thermal conductive films for a long time in the past. It can usually be used as a heat sink in electronic components and is attached to the surface of electronic components that easily generate heat to evenly disperse the heat generated by the heat source. However, since high thermal conductivity graphite films are mainly prepared using the technical route of PI film carbonization-graphitization method, which requires high-quality polyimide films as raw materials, and its research and development and production have high technical barriers, so the industry has always hoped Other alternatives can be found to solve the problem of raw materials being blocked by technology, and graphene thermal conductive film is an ideal alternative.
2. Thermal conductive filler
As a two-dimensional thermally conductive filler, graphene is easier to form a thermally conductive network than granular fillers, and has good application prospects in thermal interface materials and thermally conductive coatings.
a. As a thermal interface material thermally conductive filler
Compared with traditional granular thermally conductive fillers, thermally conductive fillers using graphene as a thermal interface material can not only utilize its ultra-high in-plane thermal conductivity, but its large diameter-to-thickness ratio is also more conducive to the construction of a three-dimensional thermal conductivity network. It has strong advantages in compounding with fillers of other dimensions to improve the thermal conductivity of thermal interface materials.
b. As a filler for heat dissipation coatings
Heat dissipation problem is a big bottleneck restricting the development of lightweight high-performance devices. As a special industrial coating, heat dissipation coating can increase the heat dissipation speed and efficiency of the surface of the object by enhancing the infrared radiation rate of the heat source surface, and reduce the surface temperature of the material. Meet the need for efficient heat dissipation of devices despite space and size constraints.
3. High thermal conductivity graphene fiber functional textiles
High thermal conductivity graphene fiber is a new type of carbon fiber material composed of graphene units assembled and arranged in an orderly manner. It is assembled in an orderly manner using graphene oxide dispersion or functionalized graphene dispersion through wet spinning. . Its main advantage is that it has good mechanical, electrical and thermal properties at the same time, and can be combined with textile technology to produce functional textiles in large quantities through wet spinning.
Currently, the ultra-high thermal conductivity of graphene can be used to produce electric heating clothing that can keep warm and keep out the cold, as well as thermally conductive and cool-feeling textiles. Graphene electric heating clothing mainly uses graphene to convert the energy of the power supply into heat, and then combines the ultra-high thermal conductivity of graphene to evenly transfer heat to the entire body. It can keep the fabric light and soft while providing excellent thermal insulation performance. The thermally conductive and cool-feeling textiles utilize the high thermal conductivity of graphene, which causes rapid heat loss from the skin surface after skin contact with textiles, significantly lowering body temperature and providing people with a more comfortable wearing experience.