Corrosion of Tungsten and Iridium by Field Desorption of Nitrogen and Carbon Monoxide

Abstract

By using an ultra‐high‐vacuum processed field ion microscope, two atomic adsorption sites of nitrogen and carbon monoxide were observed on tungsten and iridium surfaces. Field desorption of a nitrogen atom from a single site also removes the underlying tungsten or iridium atom. Field desorption of an adsorbed nitrogen molecule does not corrode the iridium substrate. Corrosion of both metals by field desorbing carbon monoxide is attributed to oxygen dissociated from the molecule by electron impact.