Among thermal spraying methods, an attractive technical possibility lies in the fabrication of protective coatings or free-standing components by means of reactive plasma spraying (RPS) techniques. Using reactive gases, such as nitrogen or methane, it is possible to synthesize hard nitride or carbide phases in reactive metals like Ti, Cr or Al. In this investigation composite titanium-nitrides/titanium coatings produced by RPS through a controlled atmosphere plasma spray system (CAPS), were electrochemically tested to evaluate their corrosion behaviour. Two environments were selected: a neutral (0.5 M NaCl) and an acid aqueous solution (0.5 h 5 NaCl + 1 M HCl). The influence of porosity and nitrogen content on the corrosion resistance has been investigated. Polarization curves of coated samples, detached coatings, AISI304 substrate and commercially pure titanium (grade 2) are also reported and discussed. The corrosion resistance of coated samples was found to be mainly dependent on porosity values, thus optimization of plasma spraying parameters assumes a fundamental role to obtain wear and corrosion resistant deposits. (C) 2000 Elsevier Science S.A. All rights reserved.
Corrosion resistance properties of reactive plasma-sprayed titanium composite coatings / Valente, Teodoro; F. p., Galliano. - In: SURFACE & COATINGS TECHNOLOGY. - ISSN 0257-8972. - 127:1(2000), pp. 86-92. [10.1016/s0257-8972(00)00549-1]
Corrosion resistance properties of reactive plasma-sprayed titanium composite coatings
VALENTE, Teodoro;
2000
Abstract
Among thermal spraying methods, an attractive technical possibility lies in the fabrication of protective coatings or free-standing components by means of reactive plasma spraying (RPS) techniques. Using reactive gases, such as nitrogen or methane, it is possible to synthesize hard nitride or carbide phases in reactive metals like Ti, Cr or Al. In this investigation composite titanium-nitrides/titanium coatings produced by RPS through a controlled atmosphere plasma spray system (CAPS), were electrochemically tested to evaluate their corrosion behaviour. Two environments were selected: a neutral (0.5 M NaCl) and an acid aqueous solution (0.5 h 5 NaCl + 1 M HCl). The influence of porosity and nitrogen content on the corrosion resistance has been investigated. Polarization curves of coated samples, detached coatings, AISI304 substrate and commercially pure titanium (grade 2) are also reported and discussed. The corrosion resistance of coated samples was found to be mainly dependent on porosity values, thus optimization of plasma spraying parameters assumes a fundamental role to obtain wear and corrosion resistant deposits. (C) 2000 Elsevier Science S.A. All rights reserved.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
