Fields of application
- Construction industry
- Thermal conductivity and insulation
- Antistatic effect
- Fire resistance
- Powder metallurgy
- Lubricants, Carbon brushes
- Refractory applications, Crucibles
- Fuel cells, LI-Ion, Polymer and Alkaline battery systems
Main users in Hungary: Forging plants, Catalyst manufacture, Fire-protective paint manufacture, Carbon profile manufacture, Rubber factories
The carbon occurs in the Sun and the most of the planet's atmosphere in large quantities. On the Earth, carbon is basis of organic compounds and the life itself, even if it occurs in less than 0.1%. This feature arises from the fact that carbon willing to create compounds with itself and with other elements, such as oxygen, hydrogen or nitrogen. The carbon crystal has four known types of occurrence:
The graphite has a great thermal and electrical conductivity; this is due to the free electrons.This property is highly depends on the size and location of crystals.
Outstanding lubrication qualities
The excellent lubricating properties of graphite can be, because of the crystal-lattice layers can easily displaced against each other. Under high temperature and pressure conditions, the graphite can retains advantageous properties.
Protection against oxidation and thermal-shock
Because of the crystal-structure, graphite is an excellent resistance of oxidation and to most chemicals, which is preferred and used very often for fire-resistant (Refractory) materials.
Component of host-compounds
Because of the bonding-strength between carbon layers, the graphite is suitable for storing certain molecules in own lattice-structure. This capability what makes it suitable for as a lubricant or making rechargeable batteries.
Due to the layered structure if graphite, atoms os small molecules can be introduced between the carbon layers (intercalation). During this process a so-called expandable graphite salt or GIC (Graphite Intercalation Compound) is produced. Outstanding expandable graphite grades have a high proportion of intercalated layers. Usually sulphur or nitrogen compounds are used as intercalation agent.
Under the influence of heat the layers separate like an accordion, and the graphite flakes expand. Depending upon the grade of material expansion can commence at as low as 180oC and can occur suddenly and rapidly. In the case of free expansion the final volume can be several hundred times greater than the initial volume.
The properties of expandable graphite, i.e. initial expansion temperature and degree of expansion, are primarily defined by the quality of intercalation (proportion of intercalated layers) and by the intercalation agent.
Expandable graphite as a flame retardant
One of the principal applications of expandable graphite is as a flame retardant. As a result of the heat of a fire the graphite expands and creates an intumescent layer ont he surface of the material. This retards the spread of fire and minimises one of the most harmful effects of combustion, the creation of toxic gases and fumes.
List of standard grades
With huge know-how from long-time experience, Graphit Kropfmühl AG composed a well-balanced and versatile scope of graphite grades. This scope meets the extensive requirements resulting from the vast variety of applications of graphite. On customer's demand we can also provide graphite grades for special specifications.
Different types of packaging are available. The typical forms of packaging are paper bags, shrink wrapped on Euro-pallets and Big Bags. Other types of packaging and transport can be arranged on request.