Carbon-Dot-Assisted Mg-Al-Layered Double Hydroxide Dispersion in Waterborne Epoxy Coating with Enhanced Corrosion...

Area of Science:

• Materials Science
• Corrosion Science
• Nanotechnology

Background:

• Two-dimensional layered nanomaterials like graphene and MXene are vital reinforcing fillers in organic coatings for corrosion prevention.
• The dispersion state of these nanomaterials within the polymer matrix critically impacts coating performance.

Purpose of the Study:

• To develop a simple, cost-effective method for synthesizing functionalized layered double hydroxide-carbon dot (LDH-Cdot) nanohybrids.
• To evaluate the anticorrosion performance of coatings incorporating these novel nanohybrids.

Main Methods:

• Carboxyl-rich carbon dots (Cdots) were synthesized via pyrolysis and introduced into LDH galleries to form LDH-Cdot nanohybrids.
• LDH-Cdot nanocomposites were incorporated into a waterborne epoxy matrix to create corrosion-resistant coatings.
• Electrochemical impedance spectroscopy (EIS) and localized electrochemical impedance spectroscopy (LEIS) were used to assess corrosion resistance.

Main Results:

• LDH-Cdot nanohybrids exhibited significantly improved water dispersion compared to pure LDH.
• The LDH-Cdot epoxy coating demonstrated superior corrosion resistance, with an impedance modulus at 0.01 Hz decreasing in the sequence LDH-Cdot epoxy > LDH epoxy > pure epoxy.
• The LDH-Cdot epoxy coating maintained a high impedance modulus (|Z|0.01 Hz) of 4.05 × 10^8 Ω·cm^2 after 90 days of immersion.

Conclusions:

• The synthesized LDH-Cdot nanohybrids offer enhanced dispersion and superior anticorrosion properties for coatings.
• Carbon dots anchored onto LDH facilitate passivation layer formation by coordinating with metal ions, effectively slowing corrosion kinetics.