“Molecular Clusters” on the Surface of an Oxidizing Metal
FIELD ion microscopy, which holds the possibility of resolving the individual atoms in a metallic surface, should in principle be a powerful tool for the study of reactions on surfaces. As part of an extensive study of the mechanism of oxidation of several metals, we have recently observed the formation of characteristic, reproducible, small clusters of atoms of regular shape when a perfect iridium surface is exposed to oxygen.
The oxidation of Ni3Zr investigated by atom-probe field-ion microscopy and x-ray photoelectron spectroscopy
Abstract The oxidation of Ni3Zr at room temperature and 200°C in ≤50 Pa O2 was investigated by atom-probe field-ion microscopy (APFIM) and X-ray photoelectron spectroscopy (XPS). XPS analysis revealed the preferential oxidation of Zr under the treatment conditions used in this study. The APFIM results indicate a broad, diffuse oxide-metal interface, an O/Zr ratio of ≤;1.5 and extensive diffusion of O into the alloy. Zr surface enrichment upon oxidation was detected by both techniques.
Determining the Jaw Relationship
Contacts between the upper and lower posterior teeth of complete dentures take place during the opening and closing strokes of mastication (Brudvik and Howell 1990). These contacts are fast, gliding impacts of the mandibular teeth which contact close to the position of maximal intercuspation of the teeth, called the “intercuspal occlusion”. The intercuspal position is the position adopted by the mandible when the teeth are in intercuspal occlusion.