PE及PVC金屬塗層耐蝕性之研究

Anti-Corrosion Behavior of PE and PVC Coatings on Galvanized Steel

金屬鍍層（metallic coating）器材，例如熱浸鍍鋅鋼材（galvanized steel）常作為防蝕材料，用在電信金屬器材防蝕方面則有鍍鋅鋼絞線及鍍鋅繞線夾等。上述材料若使用於濱海鹽害區、風砂沖蝕較嚴重之地區或硫害地區，則在短時間內（1.5～3.5年）即會有腐蝕甚至產生斷裂之情形發生。本研究即在熱浸鍍鋅鋼材上塗覆兩種不同之外被塗裝，包括聚乙烯（polyethylene，PE）及聚氯乙烯（polyvinyl chloride，PVC）。除了採用傳統的鹽水噴霧加速腐蝕試驗評估鍍層之而蝕性外，對其他特性包括：耐候試驗、耐鹽水性試驗、熱劣化特性測試。並利用交流阻抗測試技術探討兩種不同塗裝在鹽水中之耐蝕特性，由Nyquist圖形中可以發現塗層孔洞阻抗之臨界值。

Metallic coatings have been used for centuries for corrosion protection. Galvanized steel wire strand has been widely used to support aerial cable and telecommunication anti-corrosion materials. In coastal area the existing zinc-coated steel wire strand corroded and even fractured in short time. Two polymer coatings formed on the galvanized steel plate were prepared to evaluate the anti-corrosion behavior in corrosive environments. The testing techniques include salt spray test, weather-ometer test, salt water resistance test ,thermal deterioration test and ac impedance measurement. Results from the Nyquist plot have shown the critical pore resistance of polymer-coated galvanized steel .