Effect of polymeric structure on the corrosion protection of epoxy coatings
2002; Elsevier BV; Volume: 44; Issue: 4 Linguagem: Inglês
10.1016/s0010-938x(01)00091-9
ISSN1879-0496
AutoresShuyong Zhang, Yifu Ding, Shanjun Li, Xiao-Xiao Luo, Wei‐Fang Zhou,
Tópico(s)Copper Interconnects and Reliability
ResumoTwo epoxy resins, EP and EPA, with similar backbone structure but different water affinity, was obtained by curing o-cresol novolac epoxy resin with phenol novolac resin and phenol novolac acetate resin, respectively. By using these two resins, the effect of the polymeric structure on the corrosion protection of the coatings was studied. The free volume in EPA is larger than that in EP as demonstrated by room-temperature density measurement and positron annihilation, while water sorption of EPA is only half of that of EP. Therefore, water affinity of the resin is more important in determining water sorption of the resin than free volume. The cross-sectional area of water passage at coating/metal interface (Aw) was estimated using the electrochemical impedance spectroscopy and compared with that in the resin matrix (Acs). It was found that, for EPA, Aw is much less than Acs, which suggests a significant narrowing of water passage at the coating/metal interface. This narrowing of water passage at coating/metal interface due to the formation of a hydrophobic layer can greatly improve the corrosion protection of the coating.
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