Expandable Graphite
Size
0.50mm or 0.106mm, etc
Package
25 kg small bags into ton bags
Origin
China
Features
Preservative/Electrical and thermal conductivity, etc.
Application
Fireproof sealing element, flame retardant, refractory brick, etc.
Expandable graphite crystal is a typical layered carbon material. Other heterogeneous particles such as atoms, molecules, ions, and even atomic clusters are inserted into the interlayer of crystalline graphite by physical or chemical methods to form a new layered compound, which is called graphite interlayer compound, namely expandable graphite.
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Expanded graphite is a kind of loose and porous vermicompost prepared by graphite flakes through the process of intercalation, washing, drying and high temperature expansion. Insect-like substance. Expanded graphite can instantly expand its volume by 150-300 times when exposed to high temperature, changing from flake to worm, so that the structure is loose, dispersed, porous and curved. The surface area is enlarged, the surface energy is improved, the adsorption force of flake graphite is enhanced, and the worm-like graphite can be self-sufficient and fitting, which increases its softness, resilience and plasticity.
Expanded graphite is also called flexible graphite. It removes impurities from natural flake graphite. After being treated with a strong oxidizing mixed acid, it becomes graphite oxide. Graphite oxide is decomposed by heat to release carbon dioxide, and the volume expands rapidly, becoming loose, soft and tough expanded graphite. Flexible graphite can be made into plates and then molded into sealing packings.
Magical characteristics of expanded graphite
Expanded graphite is characterized by the following good features.
1. Excellent heat resistance and cold resistance
Expanded graphite has almost no physical properties from the ultra-low temperature of -270 degrees to the high temperature of 3650 degrees (in non-oxidizing gas). It can also be used up to about 600 degrees in the air.
2. Good self-lubrication
It is the same as natural graphite, under the action of external force, it is easy to slip between layers, so it has lubricity, good friction reduction and small friction coefficient.
3. Excellent chemical corrosion resistance
Expanded graphite has almost no corrosion in other acids, alkalis and solvents except in strong oxidizing media such as nitric acid and concentrated sulfuric acid.
4. High rebound rate
When the shaft or sleeve has radial circular runout due to eccentricity in manufacturing and installation, it has sufficient floating performance. Even if the graphite cracks, it can still fit well, so as to ensure tight fit and prevent leakage.
(2) Expansion volume: Franli factory found that the expansion volume of sample A was larger than that of sample B before 500 °C, and the expansion volume of sample B was larger than that of sample A after 500 °C. As the temperature increased, the volume difference increasingly obvious.
Development trend of different types of expanded graphite
According the expansion temperature, we can divide it into different types of graphite.
1. High-temperature expanded graphite: the initial expansion temperature is 290-300°C, and the expansion volume is ≥230ml/g. This type of expanded graphite is mainly as flame retardant for engineering plastics and rubber.
2. Low initial expansion temperature, low temperature expanded graphite: The temperature at which this type of expanded graphite begins to expand is 80-150°C, and the expansion volume reaches 250ml/g at 600°C.
3. Particle expanded graphite: small particle expanded graphite mainly refers to 300 mesh expandable graphite, and its expansion volume is 100ml/g, this product is mainly used in flame retardant coatings, and its demand is very high.
Expanded graphite not only retains the excellent and magical properties of graphite such as high temperature resistance, corrosion resistance, radiation resistance, electrical conductivity, and high thermal conductivity etc.. And it also has many unique properties, such as softness, resilience, self-adhesiveness, impermeability, adsorption and low density and other features. The price of expanded graphite produced by Franli is stable, and it have a very wide range of applications which is widely used in petroleum, chemical industry, atomic energy, electric power, and other aspects.
