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Title

Synthesis of reduced graphene oxide and study of its tribological behavior as an additive in engine oil

Alternative Title

Σύνθεση του ανηγμένου οξειδίου του γραφενίου και μελέτη της τριβολογικής του συμπεριφοράς ως πρόσθετο σε λάδι μηχανής

Author

Μιχαήλ, Στέλλα

Thesis advisor

Κουτσολέλος, Αθανάσιος

Abstract

Since it was first isolated, graphene has attracted enormous interest by the scientists due to its unique optical, electrical and mechanical properties. It is considered the hardest material in nature, due to its special mechanical properties, while at the same time it is very light, weighing only 0.77 mg per square meter. Also, the thermal conductivity of graphene is one of its very important properties, on which this diploma thesis was based and in combination with its excellent tribological properties make it ideal to be used as a lubricant and as an additive in engine oil. It is commonly used in scientific fields, such as super capacitors, biosensors, photovoltaics, and touch panels. In the present diploma thesis, rGO was used as additive in a commercialized synthetic engine oil (Shell 5W-40). As engine oil, it is an important type of lubricants and coolants, it serves to eliminate friction in moving parts of an engine as well as to cool them. More specifically, samples of different concentration (0.01%w/w, 0.02%w/w, 0.04%w/w, 0.06%w/w, 0.08%w/w, 0.1%w/w and 0.2%w/w) of rGO, SWCNTs, rGO+SWCNTs and MWCNTs dispersions in engine oil (5W-40) were studied. The twenty-five samples were established by turbidimetry method and the tribological behavior of the most favourable ones, was determined through a reciprocating tribometer, using steel ball (100 CR6 or 52100) on special cut steel blocks (Sverker 21-AISI D2) to investigate their wear and friction behavior. The best results obtained, concerned the dispersions of rGO in engine oil with concentrations 0.02%w/w and 0.04%w/w, where the friction data was decreasing. Further experiments were performed for examining the viscosity of rGO, in engine oil, since it gave out the best results during the study of the tribological behavior, under various temperatures and concentrations. The experiments were carried out initially at the temperature 20 oC and then at 80 oC for the concentrations 0%w/w, 0.01%w/w, 0.02%w/w, 0.04%w/w and 0.06%w/w. The results revealed that the viscosity decreases by increasing the temperature and increases by increasing the concentration. The best additive in engine oil which gives out the best results is 0.06% w/w rGO, since viscosity is more similar to the plain oil.

Language

English

Issue date

2021-11-24

Collection

School/Department--School of Sciences and Engineering--Department of Chemistry--Graduate theses

Type of Work--Graduate theses

Permanent Link

https://elocus.lib.uoc.gr//dlib/3/c/3/metadata-dlib-user1632053804-8449.tkl

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