Effect of Cu and Co Additions on Corrosion Behavior of NiTi Alloys for Orthodontic Applications

Abstract

The aim of this study is to investigate effect of Cu and Co additions on corrosion behavior of NiTi shape memory alloys for orthodontic application. Ni50.6Ti49.4, Ti49Ni46Cu5 and Ti50Ni47Co3 (at%) alloys were prepared. The specimens were melted by arc-melting furnace and homogenized at 800oC for 3.6 ks. Transformation temperatures were analyzed by differential scanning calorimeter (DSC). The corrosion behavior was assessed electrochemically in artificial saliva (pH 5.35) at 37oC. Open circuit potential (OCP) was monitored 3.6 ks followed by potentiodynamic techniques. The results show that all of specimens revealed transformation temperature close to oral temperature which may be utilized as orthodontic wire. Surface roughness was measured in order to ensure that there is no significant difference which might affect corrosion resistance. It is seen that by adding Co and Cu into NiTi alloys, the corrosion potential (Ecorr) and pitting corrosion potential (Ebreak) increase resulting in lower corrosion rate. Conceivably, Co and Cu additions considerable affect the corrosion behavior of NiTi alloys by improving corrosion resistance in artificial saliva.

Effect of cobalt addition on the corrosion behavior of near equiatomic NiTi shape memory alloy in normal saline solution: electrochemical and XPS studies

“…30 Recently, we have investigated the electrochemical and corrosion behavior of Co-based magnetic shape memory alloys (MSMAs) in 0.5 M NaCl to reveal signicant corrosion resistance of the studied MSMAs, evidenced through electrochemical and XPS studies, together with SEM/EDX examinations. 31 However, the number of papers published so far is insufficient to adequately cover the bio-corrosion behavior of NiTi SMAs, particularly ternary NiTi-based SMAs, 32,33 and is not commensurate with the medical importance of these materials. In addition, literature revealed limited number of articles concerning the effect of Co addition on the corrosion behavior of NiTi SMAs.…”

The Influence of Microstructure on the Passive Layer Chemistry and Corrosion Resistance for Some Titanium-Based Alloys

“…%) for each investigated alloy is displayed in Table 4 and Table 5. It was evident that the Ti, Al, Sn and Zr elements tended to more segregate to α phase than to β phase [27]. However, V, Nb, Cr and Mo were β forming elements [28], meaning that higher ratios of these elements werefound in β phase rather than in α phase.The detailed EDS linescan/map analyses are discussed in the Supplementary Materials (Figures S1–S3).…”

Assessment of Corrosion Behavior in Artificial Saliva of Wires for Orthodontic Applications

“…Localized corrosion resistance can be improved in a 3.5% NaCl solution in the case of TiNiCu alloys in which Cu is substituted for Ni. Base on potentiodynamic polarization test, it is proven that Cu additions can be better than that of TiNi alloys [6][7]. The biocompatibility of these alloys relies on the tendency of their surface to be covered by TiO 2 based oxides in natural conditions.…”