Banca de QUALIFICAÇÃO: ELLA RAQUEL DO VALE SOUZA DE LIMA

Uma banca de QUALIFICAÇÃO de DOUTORADO foi cadastrada pelo programa.
STUDENT : ELLA RAQUEL DO VALE SOUZA DE LIMA
DATE: 03/03/2023
TIME: 08:30
LOCAL: Auditório do Laboratório de Cimentos da UFRN
TITLE:

Selflubricating Ni-composites sintered using DC plasma

KEY WORDS:

Nickel. Solid lubrication. DC Plasma Sintering. Powder metallurgy.

PAGES: 80
BIG AREA: Engenharias
AREA: Engenharia de Materiais e Metalúrgica
SUBÁREA: Metalurgia de Transformação
SPECIALTY: Metalurgia de Pó
SUMMARY:

The present work aimed to evaluate the respective effects of different solid lubricants dispersed throughout the volume in the nickel matrix, produced via powder metallurgy. The work was divided into two stages regarding the type of solid lubricant incorporated in the matrix. In the first step, graphite was used as a solid lubricant, which was introduced into the matrix by the conventional route in the simple mixing step, and the lubricant generated “in situ” by the dissociation of silicon carbide (SiC) during sintering. In the mixtures, the graphite and SiC content was fixed at 10 vol.%, the conformation of the samples was carried out by uniaxial compaction at a pressure of 600MPa, the sintering took place in a hybrid plasma DC reactor and conventional oven, different sintering temperatures were applied (800, 900 and 1000ºC). he study of the microstructure and mechanical behavior of these materials was carried out using the analysis of green and sintered densities, XRD, Raman spectroscopy, MO, SEM/FEG-EDS and Vickers microhardness, which showed the influence of different solid lubricants, temperature and sintering medium on the formation of composites, on the continuity of the nickel matrix and on the dissociation kinetics of SiC. The silicon resulting from the dissociation of silicon carbide enriches the nickel matrix, in which the solubility of carbon varies with temperature, however the retained carbon precipitates and remains in the form of graphite. The addition of solid lubricant in the matrix promoted a reduction in the density of the sinter. Increasing the sintering temperature reduced the percentage of pores and graphite deposits, therefore, sintering at 1000ºC promoted higher hardness values. Based on this information, the tribological behavior of the composites will be evaluated. In the second stage, different types of graphene will be evaluated as solid lubricants and the analyzes will be replicated.

COMMITTEE MEMBERS:
Presidente - 1298936 - ANTONIO EDUARDO MARTINELLI
Interno - 2414250 - MEYSAM MASHHADIKARIMI
Externo à Instituição - ARMANDO MONTE MENDES - UFRN