Banca de DEFESA: FRANCISCO ALVES MAIA DE ALMEIDA JUNIOR

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
STUDENT : FRANCISCO ALVES MAIA DE ALMEIDA JUNIOR
DATE: 29/01/2021
TIME: 09:00
LOCAL: https://meet.google.com/qvo-tiht-jje
TITLE:

INSTRUMENTATION OF A RAMAN SPECTROSCOPY TRIBOMETER FOR IN SITU EVALUTION OF LUBRIFICANT FILM FORMATION

KEY WORDS:

Tribology, Raman spectroscopy, Boundary lubrification

PAGES: 115
BIG AREA: Engenharias
AREA: Engenharia Mecânica
SUMMARY:

With the modernization of the industry, the demand for more sustainable lubricants has grown exponentially worldwide, due to its renewable and biodegradable aspects. The properties of lubricants are conferred through their additives, however, most of these additives are compounds based on sulfur and other compounds that are toxic to the environment. In this context, the use of nanoparticles as an alternative additive has gained space and proved to be very efficient, however, wear reduction in nanoadditivated biolubricants occurs through mechanisms that need to be explained, which leads to the need for adequate characterization techniques for this. Raman spectroscopy is a technique that stands out in the characterization of tribomechanical systems, due to the ease of obtaining data without preliminary sample preparation. This work aims to instrument a pin-to-disk tribometer with a Raman spectrometer and a high-speed camera, in order to characterize the formation of lubricating film in lubricated systems that act under relative motion. The borderline lubrication regime was adopted, with low speed and with a variation of three loads, 100 N, 150N and 200 N. The Raman analysis was performed on top of the wear track, the tribopar used was SAE 1045 steel (Disc) and SAE 52100 steel (sphere), the lubricant used was pure epoxidized soybean oil and additive with DLC nanoparticles in concentrations of 0.05%, 0.1% and 0.2%. After tribological tests, the wear track on the disc was evaluated by scanning electron microscopy, Raman spectroscopy and profilometry. The results show that the developed Raman spectrometer is functional. For low additive concentrations, the surface rolling and surface mending mechanisms were identified, which improve lubrication and decrease wear; for higher concentrations, nanoparticles intensify the abrasive effect due to agglomeration with secondary nanoparticles and the formation of a third body

BANKING MEMBERS:
Presidente - 1481705 - SALETE MARTINS ALVES
Externo à Instituição - DANTE FERREIRA FRANCESCHINI FILHO - UFF
Externa à Instituição - VALDICLEIDE SILVA E MELLO - UFES