resumo
The corrosion behaviour over time in 0.5 M NaCl of TiCN spark plasma sintered at low temperature (1400 degrees C) with 5 vol% Si aids and its reference pure TiCN spark plasma sintered at high temperature (2100 degrees C) were investigated by electrochemical techniques (i.e., open circuit potential, current-potential curves, and electrochemical impedance spectroscopy) and microstructural characterisation (i.e., optical microscopy, scanning electron microscopy, and energy-dispersive X-ray spectroscopy), and compared. It is shown that both TiCN materials are very resistant to corrosion in 0.5 M NaCl. After two months of immersion the surfaces remained pristine, without any signs of attack. Their impedance responses revealed capacitive behaviour and very high impedance at low frequencies. The protective passive films strengthened during anodic polarisation and the samples withstood considerable overpotentials before film rupture. The TiCN material fabricated with Si aids is preferable due to its slightly higher corrosion resistance and much lower sintering temperature.
palavras-chave
CERMETS; MECHANISM; COATINGS; POWDERS; TOOLS; TIN
categoria
Materials Science
autores
Ojalvo, C; Senos, AMR; Ortiz, AL; Bastos, AC
nossos autores
Ana Maria de Oliveira e Rocha Senos
Colaborador
António Alexandre Cunha Bastos
Investigador AuxiliarGrupos
G2 - Materiais Fotónicos, Eletrónicos e Magnéticos
G3 - Materiais Eletroquímicos, Interfaces e Revestimentos
Projectos
CICECO - Aveiro Institute of Materials (UIDB/50011/2020)
CICECO - Aveiro Institute of Materials (UIDP/50011/2020)
Associated Laboratory CICECO-Aveiro Institute of Materials (LA/P/0006/2020)
agradecimentos
The authors acknowledge the financial support provided by the Ministerio de Ciencia e Innovation (Gobierno de Espana) under Grant no. PID2022 -137393NB-I00, co-financed with FEDER funds. This work was developed within the scope of the project CICECO-Aveiro Institute of Materials, UIDB/50011/2020, UIDP/50011/2020 & LA/P/0006/2020, financed by national funds through the FCT/MCTES (PIDDAC). Cristina Ojalvo acknowledges support from the Spanish Ministry of Universities through the program " Margarita Salas para la formacion de jovenes doctores ", co-funded by the European Union. A.C. Bastos is funded by Portuguese national funds (OE), through FCT-Fundacao para a Ciencia e a Tecnologia, I.P., in the scope of the framework contract foreseen in the numbers 4, 5 and 6 of the article 23, of the Decree-Law 57/2016, of August 29, changed by Law 57/2017, of July 19.