微量元素Sr对Al-Mg-Si-Cu基合金车身板腐蚀性能的影响

Effect of microelement Sr on corrosion properties of Al-Mg-Si-Cu based alloy auto sheets

采用全浸腐蚀实验、盐雾实验和电化学实验研究了微量元素Sr对AlMgSiCu合金车身板腐蚀性能的影响。全浸腐蚀实验结果表明合金加入Sr后,其质量损失速度由2.76mg/(h·cm2)降为1.39mg/(h·cm2),盐雾实验结果表明合金加入Sr后,其质量损失速度由8.56×10-3mg/(h·cm2)降为5.90×10-3mg/(h·cm2),Sr可以明显减缓合金的腐蚀速度。电化学实验结果表明合金加入Sr后,合金稳定电位较负,稳定时间长,合金钝化区较短,腐蚀电位φcorr更负,且腐蚀电流密度较小。

The effect of microelement Sr on the corrosion properties of Al-Mg-Si-Cu based alloy auto sheets was studied by means of immersion corrosion, salt spray corrosion and electrochemistry test. The results of immersion tests show that the rate of mass loss is depressed from 2.76 to 1.39mg/(h·cm2) when Sr is added into the alloy and the rate of mass loss is depressed from 8.56×10~3 to 5.90×10~3 mg/(h·cm2) in salt spray tests. Sr can minish the corrosion rate of the alloy obviously. The results of electrochemistry tests show that when Sr is added into alloy, the steady voltage of alloy is more negative, the steady time is prolonged, the passivation area of alloy becomes shorter, φ_~corr is negative and the density of corrosion current becomes smaller.