采用手工脱氧、打磨脱氧、浸渍脱氧三种不同的前处理工艺对新型 2198 铝锂合金进行前处理,之后手工刷涂 Alodine1200 s 化学处理液进行化学转化处理。 通过极化曲线和交流阻抗谱,研究了所得试样在 3 . 5%NaCl 溶液中的腐蚀行为,并结合微观形貌分析,研究了前处理方式对试样耐蚀性的影响。 结果表明:打磨脱氧前处理的试样击穿电位最正,自腐蚀电流密度最低,容抗弧半径最大,阻抗模值最大,低频段阻抗相位角最接近于-90 ^o ,耐蚀性最好。

Three pretreatments including manual brushing deoxidizing, sanding deoxidizing and dipping deoxidizing were respectively applied on Al-Li alloy 2198 . Subsequently, Alodine1200 s chromate conversion solution was manually brushed on the samples. The corrosion resistances of the chromate conversion coated samples in 3 . 5 % NaCl solution were studied by polarization curve and electrochemical impedance spectroscopy ( EIS) , and the influence of the pretreatment on corrosion resistances of the samples was analyzed by scanning electron microscopy ( SEM) . The results show that Eb of the sanding deoxidizing sample is the most positive and J_corrof this sample is the lowest . The radius of capacitive arc in Nyquist plot and the modulus of corrosion resistance in Bode plot arrive at the maximum because of the sanding deoxidizing pretreatment . Under the same condition, the phase angle of corrosion resistance in the low frequency range is most close to-90 ^o . Therefore, the corrosion resistance of the sanding deoxidizing sample is the best .