What is the Difference Between Graphitization and Carbonization

What is Graphitization?

Graphitization is an industrial process in which carbon is converted into graphite. This microstructural change occurs in carbon or low-alloy steels exposed to temperatures between 425 and 550 degrees Celsius for extended periods, sometimes up to a thousand hours. This process can lead to embrittlement.

For instance, the microstructure of carbon-molybdenum steels typically contains pearlite, which is a mixture of ferrite and cementite. When subjected to graphitization, this material decomposes into ferrite and randomly dispersed graphite particles. This transformation weakens the steel because the presence of graphite reduces its strength due to the random distribution of particles within the matrix.

To prevent graphitization, we can use more resistant materials that are less sensitive to this process. Additionally, modifying the environment—such as increasing the pH or reducing chloride content—can also help mitigate the risk of graphitization. Another effective method for prevention is the application of coatings, including cathodic protection for cast iron.

What is Carbonization?

Carbonization is an industrial process that converts organic matter into carbon. The organic materials involved typically include plants and animal carcasses. This process occurs through destructive distillation and is classified as a pyrolysis reaction, which involves multiple chemical reactions happening simultaneously. Examples of these reactions include dehydrogenation, condensation, hydrogen transfer, and isomerization.

Carbonization differs from char production because it occurs at a much faster rate; its reaction speed is many orders of magnitude quicker. The temperature applied during the process can influence the extent of carbonization and the remaining content of foreign elements in the final product. For instance, at a temperature of 1200 K, the carbon content of the residue is approximately 90% by weight, whereas at around 1600 K, the carbon content increases to about 99% by weight.

In general, carbonization is an exothermic reaction, which means it releases heat. It can be made self-sustaining and utilized as an energy source without generating any carbon dioxide gas. However, if organic material is subjected to a sudden temperature change, such as in a nuclear explosion, the biological matter will carbonize almost instantly, transforming into solid carbon.

In conclusion, both graphitization and carbonization are industrial processes that involve carbon either as a reactant or a product. Carbonization refers to the process of converting organic matter into carbon, while graphitization involves transforming carbon into graphite. Therefore, carbonization is classified as a chemical change, whereas graphitization is recognized as a microstructural change.

Semicorex offers high-quality graphite solutions for semiconductor processes. If you have any inquiries or need additional details, please don't hesitate to get in touch with us.

Contact phone # +86-13567891907

Email: sales@semicorex.com