疑似体液中で腐食させたMgの力学的評価

抄録

Magnesium (Mg) would be promised as biodegradable material for producing a stent applied in blood vessels. Though Mg had the advantage properties of biocompatibility and adjustment in body, it had the disadvantage properties of low corrosion resistance and so strength. We had tried to conduct two kinds of immersion tests for corrosion behavior with 99.9wt% Mg ribbon. One is that an immersion test was conducted under physiologic saline (0.9%NaCl) and the other is that under simulated body fluid (SBF) at 37℃ for 0, 48, 120 hours. The corrosion behavior was evaluated to focus on any corrosion products, tensile strength and surface morphology. It resulted that specimens immersed in 0.9%NaCl produced Mg(OH)₂ as corrosion products and showed general corrosion. The tensile strength decreased with the surface roughness increased. The specimens immersed in SBF produced Ca₃(PO₄)₂ and showed pitting corrosion, and the tensile strength decreased with the increase of surface roughness. As a result, a corrosion behavior can have an effect on the relationship between surface roughness and tensile strength. Both solutions relationship between surface roughness and tensile strength was different and corrosion state affected mechanical property. Next, the immersion test was conducted that the specimens were applied some loads with the equipment designed by ourselves. Then, the test solution was 0.9%NaCl and temperature was at 37℃. Consequently, the specimen was fractured for shorter time because of accelerating anodic reaction at specimen surfaces concentrated on impurities and then cracking.