Corrosion behavior of hot rolled Mg-1.6Gd alloys as degradable materials implant

Abstract

The small addition of rare earth elements (REE) in magnesium have been investigated which can improve the corrosion properties. Gadolinium (Gd) element has a large solubility in Mg (23.49 wt % at 548 °C) so that could lead to multi-functionality of the designated alloys. The aim of this study is to determine corrosion rate on the hot rolled og Mg-1.6 Gd alloys with the different immersion time. Unidirectional rolling (UR) and Crossing rolling (CR) of the binary Mg-1.6Gd alloy ingots were prepared as a degradable materials implant. Hot rollied materials were observed in the temperature range of recrystallization (400-550 °C) with a speed of 10 mm min−1 and a total reduction of 95 % at 23.75 % per-stage. Corrosion experiments were investigated after 3, 7 and 14 days of immersion in Ringer solutions. Corrosion morphology was observed using optical, SEM and EDAX. The results show that the corrosion rate decrease with the increase immersion time and the higher temperature of hot rolled Mg-Gd alloys. It was found the amounts of Gd in Mg matrix. The highest corrosion rate significantly occurred for the short time immersion by pitting corrosion as the main damage which was not formed oxide layer yet as covering the Mg-Gd alloys. Detailed explanation of the corrosion rate on Mg-Gd alloys for different immersion time is discussion in this paper.