Sousan Rasouli - Associate professor in Institute for Color Science and Technology N۰ ۵۵, Hossein-Abad Sq. Vafamanesh St. Tehran-Iran

Graphite is used in a diverse number of applications from pencils to lubricants and batteries to other more extreme applications, such as nuclear fusion and steel manufacturing, Due to its high temperatures withstanding, graphite is a common refractory material. However, for high temperature application like steelmaking graphite undergo oxidation in reacting with oxygen. This causes some economic, environmental and manufacturing issues. To overcome this problem a protective coating based on colloidal silica is proposed in this work. Two series of graphite pieces were prepared with and without the protective coating. The samples were transferred into a tube furnace and heated to ۱۰۰۰ C for ۱, ۲, ۳ and ۴ hours. The burn-off of the samples was considered as oxidation rate. Results demonstrated that under high temperature, graphite samples coated with as-prepared coating showed high resistance to oxidation in comparison to the samples without the coating. Beside the protective coating reduces the contact between graphite surface and oxygen the SiO۲ nanoparticles could penetrate into the graphite surface pores and locally reaction between SiO۲ and carbon led to creation of a thin protective layer of SiC

Graphite, oxidation, nanoparticle, coating