熱處理對磷酸錳皮膜微結構之影響

Effect of Heat Treatment on the Microstructure of Manganese Phosphate Conversion Coating

本研究主要探討熱處理對鉻鉬釩合金鋼表面磷酸錳皮膜微結構之影響。實驗結果顯示：在鉻鉬釩鋼上形成的磷酸鹽主要為磷酸錳（Mn5H2（PO4）4·4H2O，Mn-Hureaulite）、磷酸鐵錳（（Fe,Mn）5H2（PO4）4·4H2O，Mn, Fe-Hureaulite）以及FePO4·2H2O（Strengite）。在300℃以下經30分鐘熱處理後，結構及結晶性質未有較明顯的變化。若熱處理溫度提高到400℃以上時，磷酸錳（Mn5H2（PO4）4·4H2O，Mn-Hureaulite）及磷酸鐵錳（（Fe, Mn）5H2（PO4）4·4H2O，Mn, Fe-Hureaulite）將失去其結晶性。在3.5 wt%的水溶液中，結晶性較弱的磷酸鹽皮膜有較高的開路電位。

The effect of heat treatment on the microstructure of manganese phosphate conversion coating formed on the surface of Cr-Mo-V alloyed steel was investigated. The results showed that the composition of the phosphate coatings consisted of Mn5H2(PO4)4·4H2O (Mn-Hureaulite), (Fe,Mn)5H2(PO4)4·4H2O (Mn,Fe-Hureaulite) and FePO4·2H2O (Strengite). Heat treatment below 300 ℃ for 30 min. resulted in the loss of crystallinity of Mn5H2(PO4)4·4H2O and (Fe,Mn)5H2(PO4)4·4H2O. In 3.5 wt% NaCl solution, the phosphate coatings with poor crystallinity exhibited the higher open circuit potentials.