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AbstractHigher efficiency processes are strongly dependent on the ability to process materials/components that can sustain more aggressive service conditions. β-NiAl intermetallic alloys are known for exhibiting superior high temperature properties, but are difficult to process. This study evaluated Ni–Al coatings processed in situby plasma transferred arc (PTA) welding. Coatings processed with mixtures of Ni and Al powders, Al content within the range 15–50 wt-%, were analysed. In situdevelopment of Ni aluminides was confirmed by X-ray diffraction analysis. Increasing aluminium (Al) content in the deposited mixture increased the penetration depth. The microstructure of coatings depended on the amount of Al in the deposited powder mixture associated with the exothermal synthesis of the β-NiAl intermetallic compound. The present study presents an important step towards the protection of components for equipment of higher efficiency processes, as results validated the potential of PTA hardfacing as a processing technique for surface tailoring.

Higher efficiency processes are strongly dependent on the ability to process materials/components that can sustain more aggressive service conditions. ß-NiAl intermetallic alloys are known for exhibiting superior high temperature properties, but are difficult to process. This study evaluated Ni–Al coatings processed in situby plasma transferred arc (PTA) welding. Coatings processed with mixtures of Ni and Al powders, Al content within the range 15–50 wt-%, were analysed. In situdevelopment of Ni aluminides was confirmed by X-ray diffraction analysis. Increasing aluminium (Al) content in the deposited mixture increased the penetration depth. The microstructure of coatings depended on the amount of Al in the deposited powder mixture associated with the exothermal synthesis of the ß-NiAl intermetallic compound. The present study presents an important step towards the protection of components for equipment of higher efficiency processes, as results validated the potential of PTA hardfacing as a processing technique for surface tailoring.

The angular distribution of photons scattered by healthy (adipose and glandular) and cancerous human breast tissue and by tissue-equivalent materials were measured for photon energies of 17.44 keV (Kα radiation of Mo) and 6.93 keV (Kα radiation of Co) using an x-ray tube equipped with a graphite monochromator and a goniometer system. The measurements of 17.44 keV were performed in transmission geometry with an acceptance of ±0.3° and an uncertainty of ~7%. The measurements at 6.93 keV were performed in reflection geometry with solid samples in order to detect crystal structures in the samples. All samples show scattering signatures similar to those of amorphous material, but some of them also present sharp peaks corresponding to crystalline structure. Strong differences between breast-equivalent material and breast tissue occur at low and medium scattering angles. Healthy and cancerous breast tissue show considerable differences. The results demonstrate that x-ray scattering signatures (coherent and incoherent) are good parameters for characterizing breast tissue. Copyright © 2002 John Wiley & Sons, Ltd.

The structural characterization of superlattices was carried out by X-ray diffraction, reflectivity measurements and TEM. Our results indicate that the superlattices are very different from the structural point of view, whereas the magnetoresistance values are rather similar with respect to the magnitude and field dependence at room temperature, independently of the Cu and Fe 50 Å seed layers grown on Si(111) or Si(111)/CaF2(111).