Open AccessCorrosion behavior of lithium silicate-based Zn-5.5Al-4.5Mg-0.3Ce coating
Author(s) -
Shaoguang Han,
Chengjin Shen,
Shuzheng Zhou
Publication year - 2020
Publication title -
materials research express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.383
H-Index - 35
ISSN - 2053-1591
DOI - 10.1088/2053-1591/ab80a8
Subject(s) - materials science , alloy , corrosion , microstructure , coating , metallurgy , eutectic system , chemical engineering , lithium (medication) , composite material , medicine , engineering , endocrinology
The effects of Ce on the microstructure of Zn-5.5Al-4.5Mg alloy and the corrosion mechanism of Zn-5.5Al-4.5Mg-0.3Ce alloy and its coatings were investigated in this research. The results show that the structure of Zn-5.5Al-4.5Mg-0.3Ce alloy is composed of hcp-Zn, fcc-Al and ternary eutectic structure (Zn/Al/MgZn 2 /Mg 2 Zn 11 ), without dendritic tissue and MgZn 2 . The salt spray corrosion performance of Zn-5.5Al-4.5Mg-0.5CMC-2C coating was significantly better than that of Zn-5.5Al-4.5Mg-0.3Ce coating and Zn-5.5Al-4.5Mg-0.5CMC coating. The corrosion current density of Zn-5.5Al-4.5Mg-0.5CMC-2C coating was 3.217 μ A cm −2 , which was significantly lower than 3.96 μ A cm −2 of Zn-5.5Al-4.5Mg-0.3Ce alloy and 5.879 μ A cm −2 of Zn-5.5Al-4.5Mg alloy. Sodium carboxymethylcellulose and graphene improve the film formation and electrical conductivity of water-based lithium silicate resin. During corrosion of Zn-5.5Al-4.5Mg-0.3 Ce series alloy and coatings, Zn and Mg 2 Zn 11 dissolved preferentially to form corrosion products of Zn 5 (OH) 6 (CO 3 ) 2 and Zn 5 (OH) 8 Cl 2 ·H 2 O. Mg 6 Al 2 (OH) 16 CO 3 ·4H 2 O and Zn 4 Al 2 (OH) 12 CO 3 ·3H 2 O bimetallic hydroxide colloidal membranes were formed, which attached and wrapped on the surface of early corrosion products. Mg 6 Al 2 (OH) 16 CO 3 ·4H 2 O and Zn 4 Al 2 (OH) 12 CO 3 ·3H 2 O, preventing the dissolution of soluble corrosion products, improved the corrosion resistance of Zn-5.5Al-4.5Mg-0.3Ce alloy.