Comportement à la corrosion des alliages TiNi et TA6V4 dans la salive artificielle et performance d’usure

Ce travail porte sur l’etude du comportement tribologique sans lubrification et electrochimique dans la salive artificielle des alliages TiNi (50/50) et TA6V4 pour les applications en orthodontie (implants dentaires). L'alliage TiNi (50/50) a ete prepare dans un four a induction sous vide alors que l'alliage commercial TA6V4 sera utilise comme materiau de reference. L’analyse microstructurale et la composition chimique des deux alliages TiNi et TA6V4 a ete realisee par microscopie electronique a balayage (MEB) couplee a l’EDS. Les resultats montrent que l'alliage TiNi presente une meilleure resistance a l'usure par glissement a sec (1,327x10 -4 mm 3 /Nm) par comparaison avec l'alliage TA6V4 (9,506x10 -4 mm 3 /Nm). Les mecanismes d’usure ont ete clairement identifies pour les deux alliages et sont principalement bases sur une usure abrasive et adhesive pour l'alliage TiNi, et une usure abrasive associee a une oxydation, pour l’alliage TA6V4. L'etude electrochimique a revele que les deux alliages presentent un caractere passif avec une resistance elevee a la corrosion. Mots cles: Alliages de titane- Microstructure- Comportement a l'usure- Resistance a la corrosion- Impedance. Corrosion Behavior of TiNi and TA6V4 Alloys in Artificial Saliva and Wear Performance This work aims to study the tribological performance in dry conditions and electrochemical behavior, in the artificial saliva of TiNi (50/50) alloys in comparison with TA6V4 alloys in the focus to use them for dental applications. The TiNi alloy was prepared in a vacuum induction melting furnace whileTA6V4 commercial alloy should be used as a reference material. The TiNi alloy (50/50) was prepared in a vacuum induction melting furnace while the TA6V4 commercial alloy will be used as a reference material. The microstructural analysis and chemical composition of the two TiNi and TA6V4 alloys was determined by scanning electron microscopy (SEM) coupled to EDS. Results showed that TiNi alloy exhibits a better wear resistance in dry sliding mode (1.327x10 -4 mm 3 / Nm) when compared to the alloy TA6V4 (9,506x10 -4 mm 3 / Nm). The wear mechanisms of both alloys have been clearly established. It can be retained that NiTi alloy degradation is governed by an adhesive and abrasive wear mechanism, but for the TA6V4 alloy, abrasive and oxidative wear mechanisms are determined. Electrochemical studies reveal a passive behavior character and higher resistance against corrosion. Key words : Titanium alloys- Microstructure- Wear behavior- Corrosion resistance- Impedance.