固体颗粒沉积对7B04 铝合金初期大气腐蚀行为的影响

目的研究Na Cl,C,Si O2三种固体颗粒对7B04铝合金初期大气腐蚀行为的影响。方法通过对三种固体颗粒沉积试样进行户内暴露试验,结合质量增量测试、腐蚀形貌观察、微区电化学测试等手段研究7B04铝合金在不同固体颗粒沉积下的初期腐蚀行为。结果经过不同周期暴露试验后,Na Cl与Si O2颗粒沉积7B04铝合金在腐蚀初期即有点蚀萌生,且腐蚀质量增量随暴露时间呈上升趋势;C颗粒沉积7B04铝合金在暴露后期出现少量点蚀,无明显腐蚀质量增量。三种颗粒沉积后7B04铝合金表面电位呈不均匀分布,并随暴露时间的增加,电位分布发生了变化。结论在25℃,RH为95%条件下,Na Cl与Si O2颗粒沉积均可诱发7B04铝合金的大气腐蚀,而C颗粒沉积则无诱发作用。

The Influence of Deposition of Solid Particles on the Initial Atmospheric Corrosion of7B04 Aluminum Alloy

Objective To study the effect of deposition of NaCl, C and SiO2 on the initial atmospheric corrosion of 7B04 aluminum alloy. Methods Indoor accelerated testing of 7B04 with the deposition of three particles was carried out. Weighting of corrosion products, corrosion morphology observation and electrochemistry testing were combined to study the initial corrosion behavior on 7B04 aluminum alloy.Results After different exposure time, pitting was formed on 7B04 aluminum alloy with the deposition of NaCl and SiO2, which resulted in the increase of weight gain; a small amount of pitting were found on 7B04 with deposition of C during the late exposure, without much obvious weight gain; the potential distribution of 7B04 aluminum alloy with deposition of three different particles was asymmetrical, and changed with exposure time.Conclusion At 25℃ with rela-tive humidity of 95%, the deposition of NaCl and SiO2 may accelerate atmospheric corrosion of 7B04 aluminum alloy, but C has contrary results.