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Aluminium (Al) is an important structural engineering material, its usage ranking only behind ferrous alloys (Birbilis, Muster et al. 2011). The growth in usage and production of Al continues to increase (Davis 1999). The extensive use of Al lies in its strength:density ratio, toughness, and to some degree, its corrosion resistance. From a corrosion perspec‐ tive, which is most relevant to this chapter, Al has been a successful metal used in a num‐ ber of applications from commodity roles, to structural components of aircraft. A number of Al alloys can be satisfactorily deployed in environmental/atmospheric conditions in their conventional form, leaving the corrosion protection industry to focus on market needs in more demanding applications (such as those which require coating systems, for example, the aerospace industry).

The binding energy of the Ar2p 3 2 level of Ar implanted into insulating oxides has been determined via Au calibration. The Ar2p 3 2 binding energy has been demonstrated to be constant at a binding energy of 242.3 ± 0.1 eV for a range of oxides including γ-Al2O3, ZrO2, SiO2 and Y2O3.

The heat exchange method (HEM) process has been used to produce ingots up to 80 kg in weight. The minority carrier diffusion length of ingots has been measured principally by the time-resolved microwave reflectance technique to determine the factors limiting the diffusion length. Feedstock selection is important, but boron doping plays only a minor role. Intra-grain crystallographic defects appear to limit diffusion length strongly. Under optimized conditions a minority carrier diffusion length of 230 mu m at 1 Omega -cm resistivity has been achieved. Solar cell efficiencies of up to 12.7% have been achieved in production. >

Platinum-tin catalysts prepared by different methods, and supported on γ-Al2O3 have been studied with X-ray Photoelectron Spectroscopy (XPS), temperature-programmed reduction, and reaction measurements. Two major conclusions are drawn from the results. First, tin is present primarily in the oxidized form (Sn(II)) after high-temperature reduction (500 °C) of Pt-Sn γ- Al 2 O 3 catalysts, whereas alloy formation can occur on silica under the same conditions. No evidence for substantial amounts of Sn(0) is found on reduced γ-Al2O3-based catalysts. The spectroscopic reduction results are in agreement with TPR measurements in the present (and previous) work which show an average Sn reduction of 50%. Even PtSn complexes, which are readily reducible to Sn(0), are not reduced below Sn(II) on γ-Al2O3. Second, quantitative XPS measurements of surface tin concentration versus bulk loading reveal an inhomogeneous distribution of tin in the impregnated γ-Al2O3 samples, with a large excess of tin on the external surface of Al2O3 at loadings below 1 wt% Sn. The results show that impregnation of tin followed by platinum can result in separation of the two components due to the strong adsorption of tin ions in the outer surface of the γ-Al2O3 particles. The best distribution of tin is found in the coprecipitated Sn-γ-Al2O3 (Patent) preparations where the tin is uniformly distributed throughout the matrix. The reaction measurements of catalysts prepared via the different methods are compared and it was concluded that the activities and selectivities in methylcyclopentane and cyclohexane conversion are sensitive to the method of tin introduction. A catalyst prepared via the coprecipitation of Sn with γ-Al2O3 followed by impregnation of platinum gave the highest sensitivities to activity and selectivity changes in the latter reactions. Whereas it is important to have platinum and Sn(II) in the vicinity of each other on the support, the mechanism of interaction is not well understood at this stage.

In a recent paper, Kojima, Sugihara, Miyazaki and Yasumori concluded that methanol and formaldehyde adsorb molecularly (non-dissociatively) on polycrystalline copper at 300 K. Methanol and methyl formate were also found to produce adsorbed formaldehyde. We demonstrate that the “formaldehyde” UPS spectrum in their study was incorrectly assigned, and is identical to that of adsorbed formate generated during dissociative exposure of formaldehyde to a Cu(110) surface. We have measured the He II spectra of formaldehyde (120 K) and formate (300 K) on clean Cu(110) and show that they are distinctly different. No evidence is found in the present work for stabilization of molecular formaldehyde, methanol or methyl formate on the Cu(110) surface at 300 K.

Reduction of unpromoted Co- and promoted Co-ThO2-MgO-Kieselguhr catalysts has been studied with X-ray photoelectron spectroscopy and temperature-programmed reduction techniques. A mechanism of reduction is proposed based on spectroscopic measurements of the surface phases before and after H2 treatment at 400 °C. Cobalt oxide Co3O4 is present on all air-calcined catalysts, and is reduced rapidly to CoO at temperatures >300 °C in hydrogen. CoO is then more slowly reduced to Co metal on the unpromoted catalysts at 400 °C. If the promoters MgO and ThO2 are present, a reaction between CoO and promoter can occur resulting in new phases which are more resistant to reduction than CoO alone. XPS results suggest one phase as a CoO-MgO solid solution, but the CoO-ThO2 phase could not be identified. The cobalt in magnesia-promoted CoO phases is reduced completely to the metal at much higher temperatures (500–700°C) but at 400°C the surface reduction is limited to 55% ± 5 after 1 h. Variability in the degree of reduction of various promoted cobalt catalysts is therefore dependent on the nature and loading of the promoter and the reduction temperature. Promotion of a Co-Kieselguhr catalyst with ThO2 or MgO does allow a higher degree of control over the CoO reduction kinetics than is found with unpromoted catalysts.

The effect of magnesium impurities on the thermal stability of an irradiation-induced colour centre in LiF is described. Measurements of the splitting of a zero-phonon line at 8328 A under uniaxial stress show that the centre has trigonal symmetry. These results and evidence for the production of these defects by conversion from R centres support the identification as an R' centre.

The rate ofoxidation of metalsat high temperatures is usually controlled by the transport of metal ions or oxygen through the growing film of oxide on the surface. Since many technologically useful alloys (eg steels, nickelbased alloys) are based on the 3d transition metals, the transport properties of the oxides of these elements are of particular interest. In the temperature range 500–1000°C, where these alloys are used, the important transport paths in the oxide are not those that involve diffusion in the bulk crystal lattice, but other “short-circuit” paths. Basic experiments on the oxidation of nickel and direct tracer measurements of diffusion coefficients show that rain boundaries are the most important short-circuit paths under protective oxidation conditions. Similar conclusions can be drawn for other metals including chromium. The methods used in this work have been extended to study the way in which a surface treatment withCeO2reduces the oxidation rate of nickel, apparently by inhibiting the outward transport of metal ions along grain boundaries. Segregation of cerium ions to grain boundaries increases the diffusion coefficient of nickel; the inhibition is caused instead by particulates of CeO2in the middle region of the scale.

The interpretation placed by Murti and Sucheta [1] on their results of F ⇄ C conversion in irradiated NaCl is shown to be misleading. Their experiments are consistent with the accepted assignment of the C band to colloidal sodium centres.