| 研究実績の概要 |
1) Galvanic corrosion mechanism and the accelerating/inhibiting factors
The anisotropic electrochemical behavior of carbon fiber (CF) was studied. Test results proved that the cross-sectional surface of a CF is electrochemically much more active than the cylindrical surface. The way of CF contact to steel was considered as an inducing factor for galvanic corrosion occurrence. Moreover, the increased temperature and water film can evidently accelerate the galvanic corrosion rate, which was calculating from Arrhenius equation. Nevertheless, the residual rust layer was considered an inhibited factor in galvanic corrosion between CFRP and corroded steel parts, because of (i) rust contains moisture which can increase the electrical contact resistance; (ii) surface roughness leads to incomplete surface contact. In future study, corrosion surface treatment and rust transformation will be investigated.
2) Enhancement on bond strength and environmental durability of CFRP-steel composite joint
An investigation on the bond behavior of a CFRP-strengthened steel system using a wet layup carbon fiber fabric, with emphasis on the improvement in the surface treatments of the steel substrate, thermal properties of the epoxy resin, and curing process of the composite. It has been proved that the surface roughness is important for adhesion and durability of composite joint. Besides, raising the initial curing temperature is advantageous for the mechanical properties of epoxy matrix, while post-curing can improve the thermal properties of composite.
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