钛的腐蚀与钝化机理电子理论研究  

Electronic theoretical study on the corrosion and passivation mechanism of Ti metal

作　　者：刘贵立[1] 

机构地区：[1]沈阳工业大学建筑工程学院,沈阳110023

出　　处：《物理学报》2008年第7期4441-4445,共5页Acta Physica Sinica

基　　金：国家自然科学基金(批准号:50671069);辽宁省教育厅科学研究计划(批准号:20060807;05L297);沈阳市科技发展计划(批准号:1072026100)资助的课题~~

摘　　要：建立了位错塞集引发的裂纹原子集团模型,采用递归法计算了钛的电子结构参量,并研究了氧、氯、钯等元素对钛电子结构的影响.发现氧能降低费米能级附近的态密度,使钛的物理化学活性降低.氧降低钛的原子结合能,与钛原子之间有较大的亲和力,易与钛反应形成氧化膜.Cl在钛中的稳定性及与钛的亲和力均不及氧,很难取代钛表层中的氧,使得钛的氧化膜非常稳定,不会出现过钝化现象.Pd在钛中裂纹处的环境敏感镶嵌能较低,易扩散到裂纹处,且Pd元素使H在裂纹处的环境敏感镶嵌能明显升高,有效减小H向裂纹处的扩散,提高钛的应力腐蚀抵抗力.The atomic cluster models of the crack in αTi formed by dislocation accumulation were set up. The electronic structure of Ti was calculated by using recursion method, and the influence of O, Cl, and Pd on the electronic structure of Ti was studied. The calculated results show that, the total density of states near Fermi level is lowerd due to the existence of O, which leads to the decrease of the chemical activity of Ti. The binding energy of Ti is reduced by oxygen. The affinity between O and Ti is large, so O is easy to react with Ti to form the oxide film. The stability of Cl in Ti and the affinity with Ti are not as good as O. Cl is difficult to substitute the O atom on the surface of Ti, so the oxide film of Ti is very stable, the phenomenon of over passivation can not occur. The environment-sensitive embedding energy of Pd in the crack is smaller than in αTi grain, so Pd is easy to diffuse to the crack and makes the environment sensitive embedding energy of H rise obviously, which leads to the weakening of H diffusion to the crack and the improvement of the stress-corrosion resistance of Ti.

关 键 词：钛 腐蚀 钝化 电子结构 

分 类 号：TG171[金属学及工艺—金属表面处理]