Nitinol fatigue resistance using electropolishing, magnetoelectropolishing, anodizing and magnetoanodizing or combinations thereof under oxygen evolution regime

摘要

The method for improvement of Nitinol fatigue fracture resistance may be accomplished by electropolishing or magnetoelectropolishing under oxygen evolution regime, and by anodizing or magnetoanodizing the intermetallic compound. All four processes are performed under an oxygen evolution regime and by these processes the outermost and subsequent underlying oxide layers are enriched with oxygen which saturates, fills oxygen vacancies and bridges surface oxide lattice defects making the passive oxide layer more stoichiometric and homogenous, elastic and, as a result of the oxygen enrichment, more fatigue fracture resistant.