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The initial oxidation of Co86Cr14 and its constituent metals is investigated using an in situ dynamic secondary ion mass spectrometry (SIMS) technique. Simultaneous analysis and controlled formation of oxidation products, rather than just analysis, allows the oxidation to be studied at the very early stages of the process, i.e. when the oxidation product is of submonolayer extent. The technique, initiated by Hultquist(5-7) for the study of pure metals in various in situ environments, involves exposing a sputter-cleaned sample to various partial pressures of oxygen in the SIMS chamber and achieving an equilibrium between the formation and removal of the reaction products under the normal dynamic SIMS conditions. Here, the study is extended to give some insight into the interpretation of the SIMS data obtained by this method, and to determine a model for the oxidation of materials. An empirical model is derived for the oxidation of cobalt. A theoretical model is also derived based on the Langmuir model, but allowing for the more energetic nature of ion bombardment and oxide removal. The theoretical and empirical models are indistinguishable at low oxygen pressures. The cobalt component in the alloy Co86Cr14 behaves in a similar way to that of the pure metal, which suggests that the cobalt oxidizes independently of the chromium in the alloy., QC 20100525

The study of the abrasive wear of polymers is important both in the preparation of polymers prior to joining and in the techniques used to expose surfaces and interfaces for examination by a variety of analytical methods. In this investigation by X-ray photoelectron spectroscopy, the influence of the atmosphere on the chemical damage to polypropylene during the process of abrasion was examined, looking in particular for evidence of surface oxidation. The extent to which particles of abrasive, alumina in the present case, are introduced into the polymer was also examined. In this case a comparison of dry and lubricated polishing was made. The latter was found to be the more damaging, with damage increasing in relation to the solubility parameter of the solvent (lubricant). The work has shown that the simple cutting of the surface by an uncontaminated knife is the cleanest method for the exposure of the internal surfaces of the polymer. No advantage is gained by shaving the surface in argon or vacuum over that produced by shaving in air. Dry abrasion using alumina is effective in removing pre-existing contamination, but significant quantities of alumina are introduced into the surface. One effect of this is to produce a large oxygen signal that would make subsequent analytical interpretation difficult. As indicated above, lubricated abrasion seems quite unacceptable. © 1995 Chapman & Hall.