Corrosion protection of AZ91D magnesium alloy with sol–gel coating containing 2-methyl piperidine
By Shi, Hongwei; Liu, Fuchun & hou Han, En
Published in Progress in Organic Coatings
2009
Abstract
Sol–gel coatings were prepared using 3-glycidoxypropyltrimethoxysilane (GPTMS) and tetraethoxysilane (TMOS) as precursors, diethylentriamine as curing agent. Inhibition effect of 2-methyl piperidine on AZ91D in 0.005%, 0.05% and 0.5% (wt.%) NaCl solution is investigated. Potentiodynamic polarization tests revealed that 2-methyl piperidine significantly decreased the anodic activity of AZ91D especially at high concentration. Corrosion behaviors of sol–gel coatings incorporated with 2-methyl piperidine on AZ91D in the Harrison's solution were analyzed using electrochemical impedance spectroscopy (EIS). EIS results showed the corrosion resistance of sol–gel coatings and sol–gel sealed phosphate conversion coating on AZ91D were significantly improved through addition of 2-methyl piperidine. Fourier transform infrared spectra (FT-IR) confirmed that the 2-methyl piperidine was compatible with sol–gel matrix.