Self-catalytic degradation of iron-bearing chemical conversion coating on magnesium alloys — Influence of Fe content  

作　　者：Zheng-Zheng Yin Wei Huang Xiang Song Qiang Zhang Rong-Chang Zeng 

机构地区：[1]Corrosion Laboratory for Light Metals,College of Materials Science and Engineering,Shandong University of Science and Technology,Qingdao,266590,China [2]School of Materials Science and Engineering,Zhengzhou University,Zhengzhou,450002,China

出　　处：《Frontiers of Materials Science》2020年第3期296-313,共18页材料学前沿（英文版）

基　　金：This work was supported by the National Natural Science Foundation of China(Grant No.51571134);the Scientific Research Foundation of Shandong University of Science and Technology Research Fund(2014TDJH104).

摘　　要：A number of industrial and biomedical fields,such as hydraulic fracturing balls for gas and petroleum exploitation and implant materials,require Mg alloys with rapid dissolution.An iron-bearing phosphate chemical conversion(PCC)coating with self-catalytic degradation function was fabricated on the Mg alloy AZ31.Surface morphologies,chemical compositions and degradation behaviors of the PCC coating were investigated through FE-SEM,XPS,XRD,FTIR,electrochemical and hydrogen evolution tests.Results indicated that the PCC coating was characterized by iron,its phosphates and hydroxides,amorphous Mg(OH)2 and Mg3-n(HnPO4)2.The self-catalytic degradation effects were predominately concerned with the Fe concentration,chemical composition and microstructure of the PCC coating,which were ascribed to the galvanic corrosion between Fe in the PCC coating and the Mg substrate.The coating with higher Fe content and porous microstructure exhibited a higher degradation rate than that of the AZ31 substrate,while the coating with a trace of Fe and compact surface disclosed a slightly enhanced corrosion resistance for the AZ31 substrate.

关 键 词：magnesium alloy iron-bearing chemical conversion coating self-catalytic degradation galvanic corrosion 

分 类 号：TG146.22[一般工业技术—材料科学与工程]