Banca de DEFESA: RAFAEL CALLEGARI

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
STUDENT : RAFAEL CALLEGARI
DATE: 17/12/2025
TIME: 18:30
LOCAL: Campus Farroupilha - plataforma Google Meet
TITLE:

Analysis of the effect of lubricant surface energy on chromium and AlCrN-based coatings on VH-SUPER® steel.

KEY WORDS:

surface energy; wettability; metallic coatings; hard chromium; PVD AlCrN; industrial lubricants; thermal degradation.

PAGES: 103
BIG AREA: Engenharias
AREA: Engenharia de Materiais e Metalúrgica
SUBÁREA: Metalurgia de Transformação
SPECIALTY: Tratamentos Térmicos, Mecânicos e Químicos
SUMMARY:

This dissertation investigated the tribological behavior and physicochemical properties of different metallic coatings applied on steel, with emphasis on hard chromium electrodeposited layers and PVD coatings Alcrona® (AlCrN) and Formera® (high-performance AlCrN). Initially, the substrates and coatings were characterized regarding microstructure, surface morphology, and contact angles with standard liquids (distilled water and glycerol), enabling the determination of the solid surface energy through the Owens–Wendt–Rabel–Kaelble (OWRK) method. The results showed that coatings with higher contact angles exhibited lower surface energy, while those with greater polar affinity presented higher values, indicating significant differences in wettability. In the next stage, the interaction of three industrial lubricants with distinct chemical compositions (A, B e C) with the coatings was evaluated, considering both initial wettability and the effects of thermal degradation. For this purpose, thermogravimetric analysis (TGA) and Fourier-transform infrared spectroscopy (FTIR) were performed, allowing the identification of major functional groups and the thermal stability of the lubricants. It was observed that the presence of microcracks in the electrodeposited hard chromium intensified lubricant degradation, whereas the PVD coatings showed greater stability and more controlled surface interaction. Overall, the results demonstrate that coating surface energy plays a decisive role in lubricant adhesion and spreading, directly influencing tribological performance. Furthermore, the combined analysis of wettability, thermal degradation, and spectroscopic characterization enabled the correlation between coating and lubricant properties, providing technical insights for the selection of more efficient coating–lubricant systems in forming and machining processes.

COMMITTEE MEMBERS:
Presidente - DANIELA LUPINACCI VILLANOVA
Interno - EDSON LUIZ FRANCISQUETTI
Externa ao Programa - LISIANE TREVISAN
Externo à Instituição - VINÍCIUS MARTINS - IFSUL