华光礁出水铁器腐蚀产物及脱盐研究

Research on corrosion products and removal of salts in iron ware from Huaguang ReefⅠ

首次研究了"华光礁Ⅰ号"出水铁器腐蚀产物及有害盐脱除,其中HTQ6#铁器锈蚀产物表面电阻率为(3×103)～(1×108)Ω,已完全矿化且具有磁性,腐蚀产物主要为Fe3O4、α-FeOOH、γ-FeOOH、FeOCl。为避免有害锈γ-FeOOH、FeOCl进一步转化并破坏文物原貌,探索采用2.5%NaOH溶液,电流密度为-0.5mA.cm-2的恒电流法对完全矿化铁器文物的脱盐过程进行研究,得出终点脱氯时间为264h,此时氯离子迁出率为53.31%,略高于脉冲电流法脱除的氯离子比例,脱氯溶液中氯离子浓度为6.1mg.L-1,电效率为1.95%,文物基体内氯离子含量从2.03%下降到0.95%。所施加电位为-2.25～-1.61V,最后稳定在-1.61V。

Corrosion products on iron ware from ＂Huaguang Reef Ⅰ＂ and the removal of harmful salts were investigated.The surface resistivity of the rust on one iron ware named HTQ6# was（3×103）—（1×108） Ω,and the rust was completely mineralized.The rust including Fe3O4,α-FeOOH,γ-FeOOH and FeOCl was magnetic.In order to avoid the damage of the harmful rust including γ-FeOOH and FeOCl on the original appearance of the cultural relics,desalination process using constant current density of-0.5 mA·cm-2 in 2.5% NaOH solution was studied.The results were shown as follows.The proportion of chloride ion removed was 53.31%,which was higher than that by using impulsive current,at the final time of desalination for 264 h.Meanwhile,the concentration of chloride ion in the solution was 6.1 mg·L^-1 and electrical efficiency was 1.95%.In this process,the amount of chloride ion in the iron matrix decreased from 2.03% to 0.95% at applied potential of-2.25—-1.61 V with the potential stabilized at-1.61 V.