Banca de DEFESA: RONALDO RODRIGUES RAMOS DA SILVA

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
STUDENT : RONALDO RODRIGUES RAMOS DA SILVA
DATE: 11/08/2025
TIME: 09:00
LOCAL: google meets
TITLE:

Electrochemical Wear in Electric Vehicles: An Experimental Investigation on the Effectiveness of Ionic Liquids and Diamond-Like Carbon Coatings

KEY WORDS:

electric vehicles, reduction gearboxes, wear, electrolytic erosion, electrolysis, DLC, ionic liquid, lubricant, bearings.

PAGES: 83
BIG AREA: Engenharias
AREA: Engenharia Mecânica
SUMMARY:

The growing demand for electric vehicles (EVs) has driven the need to improve the durability and efficiency of their components, especially gearboxes. Due to the high speed of electric motors, these gearboxes use lubricants to reduce friction and wear. However, the presence of electrical currents in these systems can generate electrochemical phenomena, such as electrolytic erosion, accelerating component wear, especially in the case of electric vehicle gearboxes. This study experimentally investigated electrochemical wear in lubricated contacts, simulating conditions in electric vehicle gearboxes. For this purpose, a pin-on-disc tribometer was adapted to apply electric currents (0 A, 2.9 A, and 5.6 A) under a voltage of 10 V to the tribological pair, composed of SAE 52100 steel balls and discs. The effectiveness of two mitigation strategies was evaluated: the application of a Diamond-Like Carbon (DLC) coating on the discs and the addition of a polyalphaolefin base oil (PAO 8) with an ionic liquid (IL) at concentrations of 0%, 0.5%, and 1%. The tests were performed under a load of 20 N and a speed of 0.19 m/s, over a distance of 1026 m. The results indicated that the passage of electric current significantly increased both the coefficient of friction and the volumetric wear rate for the uncoated substrates, confirming the deleterious effect of the electrochemical phenomenon. The addition of the ionic liquid proved effective in reducing wear, with the 1% concentration presenting the best protective performance, attributed to the formation of a tribofilm on the contact surface, as suggested by Raman and EDS analyses. The DLC coating proved to be the most robust strategy, not compromising wear under all conditions, even under the highest electrical current. Analysis of the surfaces by SEM, Raman, and 3D profilometry, and of the oil by FTIR and XRF, allowed the identification of the wear mechanisms, which ranged from abrasive to corrosive-oxidative. The synergistic combination of the DLC coating with the lubricant additive with 1% IL resulted in the best overall performance, presenting the lowest wear and friction, which points to a promising solution for extending the service life of components in electrified systems.

COMMITTEE MEMBERS:
Presidente - 1481705 - SALETE MARTINS ALVES
Interno - 3138731 - RAPHAEL ARAUJO CARDOSO
Externa à Instituição - HENARA LILLIAN COSTA MURRAY - FURG