摘要
测试了TC1和TC4钛合金在氢氟酸-硝酸溶液中腐蚀加工的E-t曲线和极化曲线,分析了腐蚀加工过程的速率变化,观察了腐蚀加工形貌。在氢氟酸-硝酸腐蚀加工液中,极化曲线呈现活化-钝化特征,氢氟酸浓度较高时,硝酸浓度增大到一定值后,极化曲线呈现自钝化倾向。钝化膜的生成速率和厚度由氢氟酸和硝酸体积比决定,氢氟酸和硝酸体积比为1∶2时,腐蚀加工速率最大。腐蚀加工初期钛合金表面氧化膜被破坏,自腐蚀电位迅速变负,加工速率较大,继续加工,硝酸使钛合金表面发生钝化,导致速率降低,钝化膜的生成和破坏同时进行,当钝化膜的生成与基体溶解达到动态平衡时,自腐蚀电位和加工速率趋于稳定。TC1和TC4钛合金中的Ti和Al优先溶解,随着硝酸浓度的增加,钛合金表面微观凹坑变浅。
E-t and polarization curves of corrosion processing for TC1 and TC4 titanium alloy were measured in hydrofluoric acid-nitric acid solution,and the rate variation of corrosion processing was discussed,meanwhile morphology of corrosion processing was observed.Active-passive transition characteristics were found in the polarization curve in hydrofluoric acid-nitric acid corrosion processing solution.In the case of hydrofluoric acid with high concentration,the polarization curve show the self-passivation trend when the concentration of nitric acid reaches the threshold value.The growth rate and the thickness of passive film were determined by volume ratio between hydrofluoric acid and nitric acid.In the condition of 1∶ 2 volume ratio between hydrofluoric acid and nitric acid,corrosion processing rate was the greatest.At the initial period of corrosion processing,oxide film on the surface of titanium alloy was dissolved.Corrosion potential sharply became negative and faster corrosion processing rate was found.With the extension of time,nitric acid promotes the surface passivation,which results in the decrease of corrosion processing rate.The growth and destruction of passive film simultaneously occurred.Corrosion potential and corrosion processing rate tended to be stable when the growth of passive film and dissolution of the matrix achieved dynamic balance.Ti and Al of TC1 and TC4 titanium alloy were preferentially dissolved,and micro pits became shallow with the increasing concentration of nitric acid.
出处
《航空材料学报》
EI
CAS
CSCD
北大核心
2010年第6期43-50,共8页
Journal of Aeronautical Materials
基金
航空科学基金(2009ZE56010)
江西省教育厅青年科学基金(GJJ09495)
关键词
TC1钛合金
TC4钛合金
腐蚀加工
电化学行为
TC1 titanium alloy
TC4 titanium alloy
corrosion processing
electrochemical behavior
