摘要
采用光学显微镜(OM)、扫描电镜(SEM)、能谱仪(EDS)、X射线衍射仪(XRD)及动电位极化测试等手段研究了稀土镧添加量对AZ91D镁合金组织和耐蚀性的影响。结果表明:镧的添加使AZ91D镁合金组织细化,β-Mg_(17)Al_(12)相的体积分数减小,并且由连续网状分布变为断续、弥散分布,同时生成新的稀土相Al_(11)La_3,其腐蚀速率明显降低,自腐蚀电位和耐蚀性得到提高。当镧的质量分数为1.0%时,镁合金的腐蚀速率为0.157mg·cm^(-2)·h^(-1),约为AZ91D镁合金的58%;腐蚀电流密度为8.8×10^(-4) A·cm^(-2),相对于AZ91D镁合金的显著降低;自腐蚀电位为-1 429mV(SCE),相比于AZ91D镁合金的自腐蚀电位提高了95.4mV。
The microstructure and corrosion resisitance of AZ91 Dalloy with different additions of lanthanum were investigated by OM,SEM,EDS,XRD and electrochemical polarization testing.Results show that the addition of La refined the microstructure of AZ91 D Mg alloy,and decreased the volume fraction ofβ-Mg17Al12 phase,made their distribution change from continuously netlike to discontinuously disperse.At the same time,a new phase Al11La3 formed.Certain amount of La decreased the corrosion rate and the corrosion current density obviously.Also,they had more positive corrosion potential and improved the corrosion property.Especially when the addition of La was1.0mass%,the corrosion rate decreased to 0.157mg·cm-2·h-1 about 58% of the AZ91 Dalloy.And it had more positive corrosion potential,-1 429mV（SCE）,which was 95.4mV higher than that of AZ91 Dalloy.Besides the corrosion current density（8.8×10-4 A·cm-2）decreased significantly compared with the AZ91 Dalloy.
出处
《腐蚀与防护》
CAS
北大核心
2016年第4期313-316,共4页
Corrosion & Protection
基金
江西省科技落地计划项目(KJLD13078)
