| The corrosion behavior of Mg-Y-Nd-(La+Ce)-Zr alloy as the bio-absorbable magnesium stent material was investigated in present study. To investigate the effects of rare earth element on the corrosion property of magnesium alloy, we designed different relative content of yttrium(Y),neodymium (Nd) and Lanthanum(La)+Cerium(Ce), and prepared different component and heat treating magnesium alloy. The corrosion behavior of magnesium alloy were investigated by immersion test and electrochemical testing technique.The immersion test included the pH of simulate body solution and the average corrosion rate which evaluated corrosion resistance of magnesium alloy at every time point. The corrosive morphology of magnesium alloys were investigated by scanning electron microscopy(SEM) and energy dispersive X-ray analyses(EDAX), and corrosive procedure of magnesium alloys were analyzed. Making use of measuring and testing technique of electrochemistry analyzed the corrosive mechanics of magnesium alloy at earlier, intermediate and final corrosion stage.In this paper, we compared different of corrosive property firstly. The different was caused by the diversity of component and texture of magnesium alloys which are as cast and heat treating. Then corrosive properties of as cast alloys and heat treating alloys were studied individually at every component. To analyzed corrosive morphology and reaction mechanics of magnesium during corrosion processing better, the immersion test of pure magnesium was carried on, the solution circumstance include sodium chloride, sodium hydrogen phosphate, and PBS. Finding the difference of corrosive morphology between pure magnesium and alloys is to get the result of the test. On this basis, the paper had analyzed corrosive property of different magnesium alloys through research on data results of electrochemistry testing. We had studied influence of pitting corrosion to the result. The results are consistent by comparing the results between immersion test and electrochemical testThe result indicated that as cast alloy have bad corrosion resistance compared with heat treating states in the same component. The corrosion resistance of alloys were greatly improved after heat treating processing. The corrosion rate with immersion time is a regularity curve which is related to the extent of alloying component uniformity. The corrosion resistance of different magnesium alloy at same stage related to alloying chemical property and level of organization. Experienced with solution and artificial aging treatment, the fifth alloy had more lower corrosion rate earlier, and its average corrosion rate was 0.292mm/a at the tenth day. The alloy 5 as cast condition had better property of pitting resistance. The average corrosive rate of the alloy 2 after heat treating is 0.3 mm/a～0.6 mm/a. The current density of the alloy 2 didn't sudden change by electrochemical test. It had a feature about controllable degradation rate. |
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