The special properties and USES of Expandable Graphite
The Expandable Graphite has the following special properties due to its special structure:
1, high temperature resistance, Expandable Graphite melting point is 3850 + 50 ℃, boiling point is 4250 ℃, even by the ultra high temperature arc ignition, weight loss is small, thermal expansion coefficient is small. Expandable Graphite with temperature increase and strengthen the intensity, at 2000 ℃, Expandable Graphite double strength.
2. Conduction and thermal conductivity: the conductivity of the Expandable Graphite is a hundred times higher than the normal non-metallic ore. Thermal conductivity exceeds steel, iron, lead and other metal materials. The thermal conductivity decreases with the increase of temperature, even at extremely high temperature, can expand the graphite to adiabatic.
3. Lubricity: the lubricating property of Expandable Graphite depends on the size of the Expandable Graphite scales. The larger the scale, the smaller the friction coefficient and the better lubrication performance.
4. Chemical stability: the Expandable Graphite has good chemical stability under normal temperature, which can resist acid, alkali and organic solvent.
5. Plasticity: the malleable graphite has a good toughness, but it can be very thin.
6, thermal shock resistance: can be expanded graphite at room temperature when using the drastic change to withstand without damage, temperature mutations, Expandable Graphite volume change is not big, won't produce crack.
Expandable Graphite is the carbon element crystalline mineral, its crystal lattice is hexagon layer structure, electrical conductivity, and the diamond, carbon, carbon nanotubes are 60 elemental carbon, they are allotropes.
Expandable Graphite is widely used in industrial applications for the production of high-temperature crucibles in smelting, lubricant for mechanical industry, electrode and pencil lead. High-grade refractory material and coating is widely used in metallurgical industry, military industry, fire engineering pencil lead on material stabilizer, light industry, electrical industry of carbon brush catalyst, electrode of battery industry, fertilizer industry, etc.
Expansible graphite flake after deep processing, but also produce the Expandable Graphite and Expandable Graphite sealing material and composite material, Expandable Graphite products, Expandable Graphite mould, Expandable Graphite antifriction additives such as high-tech products, has become an important nonmetallic mineral raw material of each industrial sector.
Expandable Graphite electrolytic oxidation method, and the anode oxidation method, is a mixture of sulfuric acid or sulfate with a small amount of additives as electrolyte, put in the electrolyte, expansible graphite by the two electrodes method of anodic oxidation, which rely on expansible graphite anode oxidation and potential can be overcome in the electric field of Expandable Graphite layer between fann binding energy, an interpolation between ions into the layer, cambium between compounds.
The working principle of Expandable Graphite electrolytic oxidation process is mainly under the action of electric field, gathered a large number of ions around Expandable Graphite, both inside and outside the Expandable Graphite layer formed great concentration, with the aid of the role of the external force in the Expandable Graphite layer is formed between the oxidation reaction, generate sulfuric acid, the law is not strict with the concentration of oxidant, low concentration oxidant soaking solution are available, and produce less harmful gas, electrolyte and aqueous solution can be recycled, reduce the pollution of the environment.