Corrosion Behaviour of Titanium β Type Ti-12Cr in 3% NaCl Solution

Abstract

Titanium alloy, especially titanium type Ti-12Cr for biomedical application has been a concern of many researchers recently. This titanium has excellent biocompatibility and controllable mechanical properties. Generally, titanium β type contains many alloying elements that lead to a high price. Therefore, it is interesting to develop β type with only one cheap alloying element such as Ti-12Cr that is designed as a low-cost implant material. Initially, Ti-12Cr has been developed, in particular for spinal fixation. Nowadays, the research of Ti-12Cr emphasizes only on mechanical properties. The corrosion behavior of this alloy has not been understood well yet. Therefore, corrosion characteristics of this alloy in any circumstances are necessary to investigate. This paper reports the corrosion behavior of Ti-12Cr in a salted environment using the weight loss method. Ti-12Cr samples were immersed in a 3% NaCl solution for 2, 4, and 6 weeks. Samples consist of Ti-12Cr (as-received), Ti-12Cr (ST) and Ti-12Cr (AT 30 ks). Weight of samples was measured before and after the immersing process using the digital balance. Microstructure and composition of the sample surfaces were examined by using SEM and EDX, respectively. The lowest corrosion rate after exposure for 6 weeks while the highest one is Ti-12Cr (as-received) is Ti-12Cr (AT 30 ks) that is 0,003 mmpy. The microstructure all of the samples shows black spots in the surfaces indicating corrosion has been started to occur on the samples. It was found that the corrosion is due to destruction of the chrome-oxide layer in some weak point as a result of a chemical reaction between the metal (Cr) with Cl-ions. Some oxides are formed on the surface of titanium, as indicated by a significant increment of oxygen content is the corrosive sample surface. This study indicates the corrosion resistance of Ti-12Cr (AT 30 ks) is much better than other materials in this research.

Improvement of the Corrosion Resistance and Potential for Metal Ion Release of Titanium Alloy Ti-6Al-4V ELI in Hanks Balanced Salt Solution (HBSS) after Thermomechanical

“…Fig.6Corrosion Rate of Ti-6Al-4V ELI in Hank's Solution Pre and Post Thermomechanical Treatment Figure6shows that the average corrosion rate of Ti-6Al-4V ELI after thermomechanical treatment with increasing immersion time has a slightly increasing trend but not linear with the immersion time. This finding confirms those of other studies[32],[31],[35]. The corrosion rate was found to increase in the thermomechanical treatment with 10% deformation, namely by 3.1% (from 2 to 4 weeks) and 18.7% (from 4 to 6 weeks).…”

“…Prior to corrosion test, each specimen was weighed to determine its initial weight, then immersed in the corrosive solution HBSS for 2, 4, and 6 weeks using an immersion test [31]. The container for the immersion was in the form of measuring cups (ASTM G31-72).…”

“…After observing the corrosion behavior of the material, the researchers focused on the solution after the immersion. Three variations of immersion time were set, namely 2 weeks, 4 weeks, and 6 weeks (four specimens were prepared for each treatment) using the immersion test method [31]. The immersion container was in the form of measuring cups (ASTM G31-72).…”