Ce对Mg-9Gd-4Y-1Nd-0.6Zr合金微观组织和耐蚀性的影响

为获得高强耐蚀的镁稀土合金，采用扫描电镜、X射线衍射分析、腐蚀失重法、电化学阻抗和动电位极化等研究了元素Ce对Mg-9Gd-4Y-1Nd-0.6Zr合金微观组织和耐蚀性的影响。结果表明添加0.5% Ce后合金耐腐蚀性能较好，合金的腐蚀电流密度为不含铈合金的55.6%，腐蚀电位正移约141 mV。适量Ce元素的加入导致其他稀土元素在晶界处富集并呈网状分布，使第二相粒子尺寸变小，体积分数变大。

EFFECTS OF Ce ON MICROSTRUCTURE AND CORROSION RESISTANCE OF Mg-9Gd-4Y-1Nd-0.6Zr ALLOY

To obtain high strength and good corrosion resistance of Mg-9Gd-4Y-1Nd-0.6Zr alloy,effects of Ce on microstructure and corrosion resistance of Mg-9Gd-4Y-1Nd-0.6Zr magnesium alloy was investigated by means of scanning electron microscopy,X-ray diffraction,corrosion mass loss test,electrochemical impedance spectroscopy and potentio-dynamic polarization test.The Mg alloy with 5%Ce shows better corrosion resistance. Its corrosion current density decreased about 55.6%.Its corrosion potential moved positive about 141 mV than that of Mg-9Gd-4Y-1Nd-0.6Zr alloy.Rare earth elements in the Mg alloy enriched along grain boundary as network distribution were caused by proper content of Ce.Corrosion resistance of the Mg alloy was enhanced by change of second phase particles.Their volume fraction in the Mg alloy surface increased higher and their sizes decreased than those of Mg-9Gd-4Y-1Nd-0.6Zr alloy.