What is graphite? What is carbon (as a chemical element)? What is carbon (as an industrial component)? What is carbon-graphite? Can graphite and carbon-graphite be machined? Is graphite and carbon-graphite brittle? What is carbon fiber? What is the difference between carbon rod and carbon-fiber rod?
What is graphite?
There are two types of graphite: natural and synthetic.
Natural graphite is mined primarily in China, Mexico, Canada, Ukraine and Brazil, and it is used as a lubricant, carbon additive, filler for flexible graphite, and pencil lead.
Synthetic graphite is a petroleum-based composite material used in a variety of applications requiring superior to natural graphite properties. Synthetic graphite is also called artificial graphite, and is classified by method of manufacturing and/or by production stage.
There are four methods of manufacturing synthetic graphite: extrusion, vibration molding, compression molding and isostatic molding. There are also four production stages: baking, graphitization, purification and impregnation. The combination of methods of manufacturing and production stages determines the future properties of graphite. Manufacturing graphite is a lengthy and expensive process. However, the result of this process is a material offering a combination of some very unique properties: - Excellent electrical conductivity
- Good thermal shock resistance
- High mechanical strength
- Low coefficient of thermal expansion
- Low coefficient of friction
- Superb chemical resistance
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What is carbon (as a chemical element)?
Carbon has four electrons in its valence shell (outer shell). Since this energy shell can hold eight electrons, each carbon atom can share electrons with up to four different atoms. Carbon can combine with other elements as well as with itself. This allows carbon to form many different compounds of varying size and shape.
Carbon alone forms the familiar substances of graphite and diamond. Both are made only of carbon atoms. Graphite is very soft and slippery, yet diamond is the hardest substance known to man. If both are made of the same element, carbon, what gives them different properties? The answer lies in the way the carbon atoms form bonds with each other.
There are strong covalent bonds between carbon atoms in each layer. But, only weak forces exist between layers. This allows layers of carbon to slide over each other in graphite.
On the other hand, in a diamond each carbon atom is the same distance to each of its neighboring carbon atoms. In this rigid network atoms cannot move. This explains why diamonds are so hard and have such a high melting point.
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What is carbon (as an industrial component)?
There are many different products called carbon. People often refer to graphite as carbon. As a matter of fact, carbon is a precursor to graphite. When mixed petroleum coke and pitch formed into a shape and baked, the resulting product is called carbon. It would take a process of re-crystallization, also known as graphitization, to convert carbon into graphite.
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What is carbon-graphite?
Carbon-graphite is a specially formulated, formed and baked mix of petroleum coke, pitch and graphite. Due to the presence of graphite, carbon-graphite extruded and molded grades do not have to be graphitized, thus making the finished product harder and stronger than graphite, and more suitable for mechanical applications. However, these grades will also lack the electrical conductivity and the thermal resistance of graphite.
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Can graphite and carbon-graphite be machined?
All grades of graphite and carbon-graphite sold through the GraphiteStore.com can be machined into various shapes using conventional machining techniques and tools. It is, however, recommended that carbide tools be used for better performance. For a large volume machining an efficient dust collection system is required. Please read the material safety data sheet for more details.
GraphiteStore.com provides custom machining services. We also offer the same day quotation and the fastest turn-around time in the industry.
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Is graphite and carbon-graphite brittle?
Yes.
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What is carbon fiber?
As with graphite, the phrase "carbon fiber" has different meanings with respect to different applications. First of all, carbon fiber is a synthetic material derived from either PITCH or PAN.
Pitch–based carbon fiber is a light weight, strong, self-lubricating material with excellent thermal and corrosion resistant properties, making it a good candidate for low friction, sealing and insulating applications.
Pan-based fibers offer higher strength properties, making it a better fit as a structural component for automotive and aerospace applications.
There is also a multitude of carbon fiber based products that bear the name “carbon-fiber”. These are: carbon-fiber rods, bars, tubes, plates; carbon-fiber textiles; carbon-fiber insulation boards; etc.
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What is the difference between carbon rod and carbon-fiber rod?
Carbon rods or carbon-graphite rods are hard, strong and brittle materials suitable for mechanical bushings, bearings and other high-temp related applications.
Carbon-fiber rods are light weight, strong materials commonly used as reinforcement elements.
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