Banca de QUALIFICAÇÃO: MARIA GERLÂNIA DE OLIVEIRA QUEIROZ

Uma banca de QUALIFICAÇÃO de MESTRADO foi cadastrada pelo programa.
STUDENT : MARIA GERLÂNIA DE OLIVEIRA QUEIROZ
DATE: 22/04/2025
TIME: 17:00
LOCAL: Google meet
TITLE:

Synthesis and characterization of high-entropy AlCuCrMnZn alloy produced by CCyPD for anti-corrosion applications

KEY WORDS:

 

High entropy alloys, CCyPD, AlCuCrMnZn, Corrosion, Civil construction.

PAGES: 85
BIG AREA: Engenharias
AREA: Engenharia Mecânica
SUMMARY:

This work investigates the development and characterization of a high entropy alloy (HAA) with equiatomic composition AlCuCrMnZn, synthesized by plasma deposition using the cathodic cylinder cage plasma deposition (CCyPD) technique. The results correspond to the first documented use of the CCyPD technique in the production of HAAs, contributing to the advancement of the knowledge frontier in the area of low-cost functional coatings with chemical composition greater than 4 elements. The main objective of this study was to evaluate the feasibility of synthesizing the AlCuCrMnZn alloy by means of the technique in question, as well as to analyze its phase formation, microstructure, chemical composition and vibrational properties as a function of the deposition temperature. The HAAs were produced on CA-60 steel substrates, widely used in civil construction, under temperatures of 350°C to 500°C and controlled atmosphere of Ar and H2. The coatings were characterized by X-ray diffraction (XRD) in conjunction with Rietveld refinement, scanning electron microscopy (SEM), Raman spectroscopy, electron scattering spectroscopy (EDS) and Vickers hardness. The diffractograms revealed the formation of crystalline structures composed of body-centered cubic (BCC) and face-centered cubic (FCC) phases, with predominance of the CFC phase as the temperature increased. Raman spectroscopy demonstrated that temperature directly influences the formation of complex oxides on the alloy surface. The sample treated at 350°C presented vibrational bands characteristic of ZnO, CuO and Mn3O4, while in the samples treated at 450°C and 500°C, bands attributed to Cr2O3, Al2O3 and possible high-entropy spinel phases containing multiple metal cations were identified. It was observed that increasing the deposition temperature intensifies the formation of more stable and dense oxides. Morphological analysis showed uniform deposition, with columnar growth and low roughness, aspects favorable to adhesion and film integrity in applications that require thermal stability and corrosion resistance. The presence of multiple oxides on the surface, especially Cr and Al oxides, indicates the potential of the alloy for application as a protective barrier in oxidizing environments, such as reinforced concrete systems subject to severe pH variations. It is concluded that the deposition of the AlCuCrMnZn alloy by CCyPD is technically feasible and promotes the formation of coatings with promising microstructural and chemical properties, contributing to the advancement of the use of LAEs in industrial applications.

COMMITTEE MEMBERS:
Interno - ***.133.814-** - IGOR OLIVEIRA NASCIMENTO - UFRN
Presidente - 2614274 - MICHELLE CEQUEIRA FEITOR
Interno - 2550377 - THERCIO HENRIQUE DE CARVALHO COSTA