Effect of montmorillonite modified with different intercalator on the protection property of sol-gel coating on AZ31B magnesium alloy

Abstract

Composite coating was prepared on magnesium alloy AZ31B through different hyamine intercalated montmorillonite (MMT) doping in glycidoxypropyltrimethoxysilane (GPTMS) and tetraethoxysilane (TEOS) hydrolyzed hybrid sol-gel system. Corrosion behaviors of different coated samples were investigated using potentiodynamic polarization. The results indicated an improvement of protective performance when modified MMT doped in, and the CC-MMT doped sol-gel coating showed better corrosion resistance than the CTA-MMT doped one. Combining the MMT characterization and structure of the coating, it could be concluded that this difference came from the tough bonding between CC-MMT and sol-gel system, while that did not exist in CTA-MMT/sol-gel coating. Due to this tough bonding, CC-MMT could guide the assembly of hydrolyzed silane molecules and silica sol particles, thus a denser structure and better protection performance.