Exploring the crick-tip mechanisms driving environmental degradation of alloys through controlled oxidation study of alloyed nanoparticles
EMSL Project ID
39399
Abstract
Nanoparticles offer a unique way to observe the formation of small voids produced by vacancy injection during early stages of oxidation without sample cutting or polishing. Recent work at PNNL on pure Fe nanoparticle has demonstrated that nanoparticles are ideal for exploring the mass flow during corrosion and oxidation. The formation of voids has been investigated at the core shell interface during the oxidation of Fe nanoparticles [2]. Initial observations were for particles <10 nm in diameter with subsequent exams finding voids nucleating at the oxide-metal interface in larger nanoparticles (30-50 nm). The accumulation of vacancies into voids is usually found only after more extensive amounts of oxidation. They can be observed in nanoparticles for two reasons. First, the geometry of the particles effectively concentrates vacancy migration to the oxide-metal interface during the oxidation into a smaller volume where they are easier to observe. Second because of the small size of the particles, TEM measurements can be performed without polishing or otherwise processing the samples in a way that masks, destroys or confounds observation of the voids. This not only makes observation easier but it allows repeated observation without damaging sample preparation. Therefore, the objective this research is to probing into the oxidation behavior of pure Ni and Ni doped with different amount of Cr and Fe. The microstructure and chemical composition of the nanoparticle will be analyzed using a combination of suite of capabilities housed in EMSL, typically HRTEM, EDS in TEM and SEM, XRD, and XPS.
Project Details
Project type
Exploratory Research
Start Date
2010-05-26
End Date
2011-05-29
Status
Closed
Released Data Link
Team
Principal Investigator
Team Members