Effect of (Zn & Mg) on Corrosion Behavior of Shape Memory Alloys


Nickel-Titanium shape memory alloy (Nitinol or NiTi) is a fascinatingmaterial for dental applications. In this work the alloy has been produced by powdermetallurgy approach. The effect of Mg and Zn additives studied on the; hardness,porosity percentage, and corrosion rate has been studied. Master Samples (withoutadditives) were prepared using powder mixture of 55 wt% Ni and 45 wt% Ti bymixing them in a ball mill for two hours, then compacted at 300, 400, 500, 600, 700,and 800 Mpa, then sintered at 950 oC for 9 hours under controlled atmosphere(argon). The same approach was used for the prepared samples with Mg and Znadditions compacted at 800 Mpa. XRD examination shows that the sintered samplesare consisting of two phases martensite and austenite at room temperatures, this meanthermal NiTi shape memory alloy. From the results, it was found that Mg additivesincrease hardness and decrease the corrosion rate while Zn additives increase thecorrosion rate.