リン酸-酸化鉄-PVB系さび安定化処理法のさび非晶質化に及ぼすP, Cuの影響 [in Japanese] Effect of P and Cu on Rust Amorphization in Phosphoric Acid-Iron Oxide -PVB Surface Treatment for Rust Stabilization [in Japanese]
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Long-term atmospheric exposure of weathering steel coated with a phosphoric acid-iron oxide-PVB surface treatment for rust stabilization produces a dense, stable oxide layer. This layer is itself made up of an outer layer of rust, which includes a deteriorated treatment film, and an inner layer of rust, which is mainly amorphous rust.<br>Artificial (magnetite) rust testing performed to investigate the effect of PO<sub>4</sub><sup>3-</sup> and Cu<sup>2+</sup> on rust morphology showed that PO<sub>4</sub><sup>3-</sup> has a strong amorphization effect on rust and is especially effective in oxygen-deficient environments. Cu<sup>2+</sup> also has a rust refinement effect in oxygen-deficient environments, although this effect is weaker than that of PO<sub>4</sub><sup>3-</sup>.<br>From these results, it can be inferred that the amorphous rust underneath the treatment film is formed by an reaction between Fe<sup>2+</sup> produced by an iron matrix corrosion and PO<sub>4</sub><sup>3-</sup> and Cu<sup>2+</sup> that flow out from the treatment film in an oxygen-deficient environment. Furthermore, by acting to encourage the oxidation of Fe<sup>2+</sup> to Fe<sup>3+</sup>, Cu<sup>2+</sup> and PO<sub>4</sub><sup>3-</sup> have an effect of suppressing"rust outflow"
- Jitsumu Hyomen Gijutsu
Jitsumu Hyomen Gijutsu 47(4), 360-365, 1996-04
The Surface Finishing Society of Japan