Mica powder is a non-metallic mineral that contains multiple components, mainly SiO2, with a content generally around 49% and Al2O3 content around 30%. Mica powder has good elasticity and toughness. It is an excellent additive with characteristics such as insulation, high temperature resistance, acid and alkali resistance, corrosion resistance, and strong adhesion. It is widely used in industries such as electrical appliances, welding electrodes, rubber, plastics, paper making, paint, coatings, pigments, ceramics, cosmetics, new building materials, etc., with extremely wide applications. With the continuous development of science and technology, people have opened up more new application fields. Mica powder is a layered silicate structure consisting of two layers of silica tetrahedra sandwiched with one layer of aluminum oxide octahedra, forming a composite silica layer. Completely cleaved, capable of splitting into extremely thin sheets, with a thickness of up to 1 μ Below m (theoretically, it can be cut to 0.001) μ m) , with a larger diameter to thickness ratio; The chemical formula of mica powder crystal is: K0.5-1 (Al, Fe, Mg) 2 (SiAl) 4O10 (OH) 2 ▪ NH2O, general chemical composition: SiO2: 43.13-49.04%, Al2O3: 27.93-37.44%, K2O+Na2O: 9-11%, H2O: 4.13-6.12%.

Mica powder belongs to monoclinic crystals, which are in the form of scales and have a silky luster (muscovite has a glass luster). The pure blocks are gray, purple rose, white, etc., with a diameter to thickness ratio of>80, a specific gravity of 2.6-2.7, a hardness of 2-3, high elasticity, flexibility, good wear resistance and wear resistance; Heat-resistant insulation, difficult to dissolve in acid-base solutions, and chemically stable. Test data: elastic modulus 1505-2134MPa, heat resistance 500-600 ℃, thermal conductivity 0.419-0.670W. (m.K), electrical insulation 200kv/mm, radiation resistance 5 × 1014 thermal neutron/cm irradiance.

In addition, the chemical composition, structure, and structure of mica powder are similar to those of kaolin, and it also has certain characteristics of clay minerals, such as good dispersion and suspension in aqueous media and organic solvents, white color, fine particles, and stickiness. Therefore, mica powder has multiple characteristics of both mica and clay minerals.

The identification of mica powder is very simple. Based on experience, there are generally the following methods for your reference only:

1、 The whiteness of mica powder is not high, about 75. I often receive inquiries from customers, stating that the whiteness of mica powder is around 90. Under normal circumstances, the whiteness of mica powder is generally not high, only around 75. If doped with other fillers such as calcium carbonate, talc powder, etc., the whiteness will be significantly improved.

2、 Mica powder has a flaky structure. Take a beaker, add 100ml of pure water, and stir with a glass rod to see that the suspension of mica powder is very good; Other fillers include transparent powder, talc powder, calcium carbonate and other products, but their suspension performance is not as excellent as mica powder.

3、 Apply a small amount of it to your wrist, which has a slight pearlescent effect. Mica powder, especially sericite powder, has a certain pearlescent effect and is widely used in industries such as cosmetics, coatings, plastics, rubber, etc. If the purchased mica powder has poor or no pearlescent effect, attention should be paid at this time.

The main applications of mica powder in coatings.

The application of mica powder in coatings is mainly reflected in the following aspects:

1. Barrier effect: The sheet-like fillers form a basic parallel oriented arrangement within the paint film, and the penetration of water and other corrosive substances into the paint film is strongly blocked. When high-quality sericite powder is used (the diameter to thickness ratio of the chip is at least 50 times, preferably more than 70 times), the penetration time of water and other corrosive substances through the paint film is generally extended by three times. Due to the fact that sericite powder fillers are much cheaper than special resins, they have very high technical and economic value. The use of high-quality sericite powder is an important means to improve the quality and performance of anti-corrosion coatings and exterior wall coatings. During the coating process, sericite chips are subjected to surface tension before the paint film solidifies, automatically forming a structure that is parallel to each other and also to the surface of the paint film. This layer by layer arrangement, with its orientation exactly perpendicular to the direction in which corrosive substances penetrate the paint film, has the most effective barrier effect.
2. Improving the physical and mechanical properties of the paint film: The use of sericite powder can improve a series of physical and mechanical properties of the paint film. The key is the morphological characteristics of the filler, namely the diameter to thickness ratio of the sheet-like filler and the length to diameter ratio of the fibrous filler. The granular filler, like sand and stone in concrete, plays a reinforcing role in reinforcing steel bars.
3. Improving the wear resistance of the paint film: The hardness of the resin itself is limited, and the strength of many fillers is also not high (such as talc powder). On the contrary, sericite is one of the components of granite, with high hardness and mechanical strength. Therefore, adding sericite powder as a filler in the coating can significantly improve its wear resistance. Most car coatings, road coatings, mechanical anti-corrosion coatings, and wall coatings use sericite powder.
4. Insulation performance: Sericite has extremely high resistance and is itself the most excellent insulation material. It forms a complex with organic silicon resin or organic silicon boron resin and converts it into a ceramic material with good mechanical strength and insulation performance when encountering high temperatures. Therefore, wires and cables made of this type of insulation material still maintain their original insulation state even after being burned down in a fire. It is very important for mines, tunnels, special buildings, special facilities, etc.
5. Flame retardant: Sericite powder is a valuable flame retardant filler. If combined with organic halogen flame retardants, flame retardant and fireproof coatings can be prepared.
6. UV and infrared resistance: Sericite has excellent performance in shielding against ultraviolet and infrared radiation. So adding wet sericite powder to outdoor coatings can significantly improve the UV resistance of the paint film and delay its aging. Its infrared shielding performance is used to prepare insulation and insulation materials (such as coatings).
7. Thermal radiation and high-temperature coatings: Sericite has good infrared radiation ability, such as in combination with iron oxide, which can create excellent thermal radiation effects.
8. Sound insulation and shock absorption effect: Sericite can significantly change a series of physical moduli of materials, forming or changing their viscoelasticity. This type of material efficiently absorbs vibration energy, weakens vibration waves and sound waves. In addition, the repeated reflection of vibration waves and sound waves between mica chips also weakens their energy. Sericite powder is also used to prepare soundproofing, soundproofing, and shock absorbing coatings.