ZUO Yang,WEI Han,ZUO Yu,ZHANG Han-lu,TANG Yu-ming,ZHAO Xu-hui.Corrosion Protection of Graphene Particles Modified Mg-rich Coating on AZ91D Magnesium Alloy[J],50(1):395-404
Corrosion Protection of Graphene Particles Modified Mg-rich Coating on AZ91D Magnesium Alloy
Received:June 07, 2020  Revised:August 03, 2020
View Full Text  View/Add Comment  Download reader
DOI:10.16490/j.cnki.issn.1001-3660.2021.01.036
KeyWord:graphene  Mg-rich coating  AZ91D magnesium alloy  EIS  cathode protection
                 
AuthorInstitution
ZUO Yang Key Laboratory of Carbon Fiber and Functional Polymer, Ministry of Education, Beijing University of Chemical Technology, Beijing , China
WEI Han Key Laboratory of Carbon Fiber and Functional Polymer, Ministry of Education, Beijing University of Chemical Technology, Beijing , China
ZUO Yu Key Laboratory of Carbon Fiber and Functional Polymer, Ministry of Education, Beijing University of Chemical Technology, Beijing , China
ZHANG Han-lu No.92228 PLA, Beijing , China
TANG Yu-ming Key Laboratory of Carbon Fiber and Functional Polymer, Ministry of Education, Beijing University of Chemical Technology, Beijing , China
ZHAO Xu-hui Key Laboratory of Carbon Fiber and Functional Polymer, Ministry of Education, Beijing University of Chemical Technology, Beijing , China
Hits:
Download times:
Abstract:
      The work aims to further improve the protection performance of Mg-rich coating on magnesium alloy on the condition of ensuring the cathodic protection and decreasing content of the magnesium powder. Firstly, graphene modified Mg-rich coating were prepared by adding different mass fractions of graphene (1wt%, 2wt% and 4wt%) to Mg-rich coating to replace part of the magnesium powders. Then, the protection performance of different graphene modified Mg-rich coatings was studied by Machu test, electrochemical impedance measurement (EIS), open circuit potential (OCP) and scanning electron microscopy (SEM). The results show that the addition of excessive graphene (4wt%) to the Mg-rich coating results in a significant deterioration of the protective effect of the coating. However, addition of a small amount of graphene (1wt% and 2wt%) to the epoxy magnesium-based coatings can significantly improve the compactness of the coating and the adhesion force between coating and Mg alloy. Among them, the protective performance of the coating with the 2wt% graphene and 48wt% Mg powder is the best and the OCP result shows that the cathode protection period of the graphene modified Mg-rich coating is extended to 145 h. Thus, the protective effect of the Mg-rich coating on AZ91D magnesium alloy is significantly improved. The addition of graphene to the Mg-rich coating can effectively enhance the electrical contact between the metals, which is beneficial to improve the effective utilization of the pure Mg particles and reduce the corrosion rate of AZ91D substrate, and meanwhile does not change the protection mechanisms of the Mg-rich coating on AZ91D magnesium alloy. In addition, because of the unique two-dimensional (2D) structure and small size, graphene could prolong the penetration path of the aggressive solution and block the defect pores of the Mg-rich coating firmly, which improves the barrier property of the coating.
Close