Melting Point Of Graphite

Graphite’s melting point is important for the steel, battery and semiconductor industries. Dose graphite melt? This question is often used in trips to explore graphite. The high temperature resistance characteristics endowed by the melting point of graphite lay a solid foundation for technological breakthroughs and process innovations in many fields.

The specific value of graphite melting point

The melting point of graphite is a high value on the Fahrenheit temperature scale. Normally, the melting point of graphite is about 6332°F.

The accepted value of graphite melting point

In scientific research, the accepted melting point of graphite is about 3652-3697 °C at standard atmospheric pressure (different experimental conditions and measurement methods may lead to slight differences in values). This temperature range shows that graphite can withstand extremely high heat characteristics. And it also shows that it is a high temperature resistant material.

Compare the melting points of other carbon allotropes

Compared with graphite, the melting point of diamond (diamond) is also very high. The melting point of diamond is about 4000 °C. This is because the crystal structure of diamond and graphite is different, diamond is a typical atomic crystal, each carbon atom and four adjacent carbon atoms are covalent bond, this tight structure makes it need more energy to melt. Graphite is a mixed crystal, which has both covalent bonds and intermolecular forces, but the overall melting heat is still very high.

Factors affecting the melting point of graphite

Crystal structure is dominant

The high melting point of graphite is mainly related to its structure. The graphite crystal is a hexagonal planar network structure composed of covalent bonds between carbon atoms, with weak van der Waals forces between layers. During heating, these covalent bonds need to be overcome in order for the graphite to melt. And these covalent bonds are strong, so they need very high temperatures to achieve. At the same time, external pressure and other factors will also have a certain impact on the melting point, but at standard atmospheric pressure, this effect is relatively small.

Interference by impurity elements

If the graphite contains impurity elements, such as boron, nitrogen, etc., it will change the lattice integrity and chemical bond energy of the graphite crystal, and then affect the melting point. Impurities may destroy the homogeneity of the covalent bond to a certain extent, making the melting point lower or higher, depending on the type and content of impurities.

External environment correlation

Although the effect of pressure is relatively small at standard atmospheric pressure. But the extremely high pressure environment will compress the graphite crystal structure, enhance the interatomic interaction. Thereby increasing the melting point. In a specific atmosphere, if the atmosphere reacts with graphite, the surface structure and composition of graphite may be changed. This will affects its thermal stability and melting point.

The importance of graphite’s melting point in practical applications

The graphite crucible

The graphite crucible takes advantage of the high melting point of graphite. In the metallurgical industry, it is necessary to melt various metals, such as copper, iron, etc., graphite crucible can withstand the high temperature when the metal is melted, and will not react with the metal to ensure the purity of the metal. In high-temperature chemical experiments, graphite’s high melting point also makes it an ideal material for reaction vessels. For the electronics industry, graphite is also used for heat dissipation of electronic components in high temperature environments. Because of its high temperature resistance, it can resist the damage of high temperature to its own structure and performance to a certain extent. Effectively conduct heat out, and ensure the normal operation of electronic components.

In the field of aerospace

In aerospace engineering, rocket nozzles face extreme high temperature and high velocity airflow. With its high melting point, graphite can withstand the high temperature of thousands of degrees Celsius at the nozzle, ensure the stability of the structure. Meanwhile, it prevent the damage of the nozzle due to the melting of the material, and ensure the smooth propulsion of the rocket.

Graphite blocks in metallurgical and resistance furnaces

Graphite blocks in metallurgical furnaces and resistance furnaces make full use of the high melting point characteristics of graphite. In the smelting of copper, iron and other metals, the graphite block can withstand high temperature for a long time, maintain the high temperature environment in the furnace. Moreover, it does not react with the metal to ensure the quality and purity of metal smelting.

Graphite cathode carbon block in aluminum electrolysis

The graphite cathode carbon block plays a key role in the process of aluminum electrolysis. Its high melting point makes it stable in high temperature electrolytic environment, provides a suitable electrode interface for aluminum ion reduction. In addition, it resists electrolyte erosion and high temperature impact to ensure efficient and stable operation of aluminum electrolytic production.

Conclusion

Graphite has a high melting point. Its melting point characteristics are closely related to its internal structure, and are also unique in comparison with the melting points of other carbon allotropes, such as diamond. The research and utilization of the melting point of graphite will help us to better play the advantages of graphite. And then expand its application in more high-temperature environment related fields.