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High Thermal Conductivity Insulating Composite Powder
1. Introduction
The main components are boron nitride, aluminum nitride, silicon carbide, and other high-heat-conducting materials. The appearance is gray fluffy powder. The product has high purity, small particle size, uniform distribution and large specific surface area. Easy to disperse, high surface activity, low bulk density, insulating thermal conductive nanopowder has high thermal conductivity, thermal conductivity up to 420W/MK, close to copper thermal conductivity, and good insulation, resistivity is 10 to the 16th power Above, it can withstand 2000 degree high temperature, and it has special surface treatment of insulated and thermally conductive nano-powder. The surface oxygen content is extremely low, and the purity can reach about 99.9. Because its thermal conductivity is extremely strong, the general addition ratio is about 1-5%. The resin can reach a thermal conductivity of about 3 watts, which can completely replace the high-added nano-alumina powder, boron nitride, aluminum nitride, silicon carbide, graphite, carbon powder and the like which are currently used.
2. Chemical Index
| Technological Specification | CS01 | CS02 |
|---|---|---|
| Appearance | Gray fluffy powder | Gray fluffy powder |
| Purity | >99.9% | >99.9% |
| Specific surface area | 78m²/g | 65m²/g |
| Bulk density | 0.08g/cm³ | 0.12g/cm³ |
| Tap density | 1.34g/cm³ | 1.34g/cm³ |
| Average particle size | 40nm | 100nm |
3. Common thermal insulation filler thermal conductivity and introduction
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| Filler | Molecular formula | Thermal conductivity (W/m•K, 20℃) | Density(g/cm3) |
|---|---|---|---|
| Hexagonal Aluminum Nitride | AlN(hexagonal) | 320 | 3.3 |
| Beryllium Oxide (poisonous) | BeO | 219 | 3.02 |
| Hexagonal Boron Nitride | BN(hexagonal) | 110(a-axis) | 2.29 |
| Magnesium Oxide | MgO | 36 | 3.58 |
| α-Aluminum Oxide | α-Al2O3 | 30 | 3.9 |
| Silicon Oxide | SiO2 | 10 | 10 |
- 3.1 Aluminum Nitride, the thermal conductivity is very high, but expensive; the aluminum nitride has a large specific surface area and a high oil absorption value. As the filling rate of aluminum nitride in the resin increases, the viscosity of the system rises sharply, and the actual thermal conductive film is formed. The filling rate of aluminum nitride is very low, which seriously affects the thermal conductivity of the thermal conductive film. In addition, aluminum nitride will hydrolyze with water after moisture absorption, and Al(OH)3 produced by hydrolysis will interrupt the heat conduction path, thereby affecting the transmission of phonons. Therefore, the thermal conductivity of the product will be continuously reduced, that is, used. The surface treatment of the silane coupling agent does not guarantee that the 100% filler surface is coated.
- 3.2 Beryllium Oxide, although its thermal conductivity is very high, due to its high toxicity, it is greatly limited in practical applications.
- 3.3 Boron Nitride, has very high thermal conductivity and stable properties. According to the purity and granularity of products, the price difference is relatively large, ranging from several hundred yuan to 1000 yuan per kilogram. Although high thermal conductivity can be achieved by using boron nitride alone, it is similar to aluminium nitride. With the increase of boron nitride filling rate in resin, the viscosity of the system will rise sharply after adding more than 40% of boron nitride in the system, which has a great impact on the dispersion of mixtures and fillers. The filling rate of boron nitride in the thermal conductive film is very low. The thermal conductivity is low. Some foreign manufacturers produce spherical boron nitride, which has large particle size, small specific surface area, high filling rate and is not easy to increase viscosity, but the high price limits its application.
- 3.4 Magnesium Oxide, cheap, but easy to absorb moisture in the air, easy to absorb moisture and carbon dioxide and gradually become basic magnesium carbonate, strong viscosity, can not be filled in large quantities, thermal conductivity is extremely unstable. In addition, because of its poor acid resistance, its application in acidic environment is limited.
- 3.5 Silicon Oxide, crystalline silicon micropowder is less expensive and suitable for a large amount of filling to reduce costs. However, due to its low thermal conductivity, it is not suitable for the production of high thermal conductivity products.
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4. Introduction to thermal conductivity
- 4.1 Thermal conduction mechanism of organic polymer materials: The heat transfer does not travel from one end of the object to the other along a straight line, but instead uses a diffusion situation. The main heat conduction carrier of organic materials is phonons, but the organic polymer materials have poor structural regularity and poor phonon conductivity, so the thermal conductivity is poor.
- 4.2 Thermal conduction mechanism of filled polymer composites:The thermal conductivity of filled polymer composites mainly depends on the thermal conductivity of fillers, the distribution of fillers in the matrix and the interaction with the matrix. When the filler dosage is small, although the filler is evenly dispersed in the resin, it fails to form contact and interaction with each other, and the thermal conductivity is not improved greatly. When the filler dosage is increased to a certain critical value, the contact and interaction between fillers forms, and a similar network or chain structure is formed in the system, i.e., a heat conduction network chain is formed. When the orientation of the heat conduction network chain is consistent with the direction of heat flow, the thermal conductivity of the material improves rapidly. When the heat conduction network chain is not formed in the direction of heat flow, the thermal resistance in the direction of heat flow will be very large, resulting in the poor thermal conductivity of the material.High purity materials service for Optic glass, Electronic, Storage Battery, Pharmaceutical.
- 4.3 The necessity of modifying the surface of the filler The thermal conductivity of the system depends not only on the thermal conductivity of the filler itself, but also on the degree of easy wetting of the ionic surface. This is because the degree of wetting of the surface of the filler affects the degree of adhesion of the filler to the substrate, the thermal barrier of the substrate and the surface of the filler, the dispersibility of the filler, the amount of filler added, and other factors that directly affect the thermal conductivity of the system. In particular, the nanofiller cannot be dispersed in the resin in a nanometer size if it cannot be effectively surface modified. When a special process is used to form a "isolated distribution" of the thermally conductive filler in the matrix, even a small amount will impart a higher thermal conductivity to the composite.
5. Application
- 5.1 Used in Thermally conductive silicone and thermal epoxy
- 5.2 Used for thermally conductive plastic, high thermal conductivity silicone rubber
- 5.3 Used in crucible for melting gallium arsenide and semiconductor materials, evaporation boat, protective tube of thermocouple, high temperature resistant insulator, microwave dielectric material, high temperature and corrosion resistant structural ceramics and transparent microwave ceramics
- 5.4 Used in polyimide resin, thermal insulation mica tape, thermal grease, insulating paint and heat transfer oil
6. Package
Packing in 25kg plastic bag.
7.Storage Mode
- 5.1 Store at a dry, cool environment
- 5.2 It is not suitable for long-term exposure to the air to prevent agglomeration due to moisture, affecting dispersion performance and use effect.
- 5.3 Avoid heavy pressure, do not contact with oxidizing agents, and transport them as normal cargo.
High purity materials service for Optic glass, Electronic, Storage Battery, Pharmaceutical.
