The Al h , s and Kp emission bands of noble and several transition metal aluminides have been investigated. I n the spectra of the alloys long-wavelength intensity peaks are observed which are not present in the spectrum of pure aluminium. The appearance of these peaks is Bseociated with the energy ban& originating from the d-states of the noble and transition metal atoms. For the Al ban& in CuAl,, Cu,Al, and PdAI, the position of the long-wavelength peaks relative to short-wavelength edges is found to correspond approximately to the position of the copper and palladium Lz,s-band peaks with respect to the absorption edges. It is aseumed that the energy region of the d-like bands in the vioinity of aluminium atoms contains an appreciable amount of states arising from the s and p aluminium atom states. This is suggested to be the reaaon for the long-wavelength intensity peaks to appear in the Al Lz,3-and Kp-bands of the alloys.Es wurden die Al-Lz,s-und Kp-Emissionsbanden der Edelmetall-und einiger ffbergangsmetallaluminide untersucht. I n den Legierungsspektren wurden einige langwellige Intensitiitsmaxima beobachtet, die in reinen Aluminium-Spektren nicht vorhanden sind.
Daa Auftreten dieser Maxima ist verbunden mit Energiebiindern, die von den d-Zuetiindender Edel-und Ubergangsmetallatome stammen. Fiir die Al-Banden von 014, Cu,Al und PdAl, wird gefunden, daB die Lage der langwelligen Maxima beziiglich der kurzwelligen Kante niiherungsweise mit der Lage der Kupfer-und Palladium-Lz,s-Bandmaxima beziiglich der Absorptionskanten korrespondieren. Es wird die Annahme gemacht, daD der Energiebereich der d-ahnlichen Biinder in der Niihe der Aluminiumatome betriichtliche Beitrage von Zustiinden enthiilt, die aus s-und p-Aluminiumatomzustiinden stammen.Es wird angenommen, daB dies der Grund fiir das Auftreten der langwelligen Intensitiitsmaxima in den Al-h,s-und Kp-Banden der Legierungen auftreten.
Parts manufactured by pressing from iron-base powders possess a certain porosity. The pores form a system of communicating capillaries inside the part which absorb the ambient products (gases from the atmosphere, dissolved substances from solutions) under the action of the capillary forces and diffusion. This causes surface and internal corrosion of the material. In order to prevent oxidation of parts produced from powder materials in their transportation, storage, and operation their surface should be coated by a thin oxide film (as in blueing) in which the pores are closed by the oxides. The results of a study of the composition of oxide phases in sintered porous steels after a steam oxide treatment by two regimes are presented.In accordance with the existing concepts of the kinetics of iron oxidation the composition of the oxide phases depends on the oxidation temperature and the nature of the oxidizing agent. For example, at room temperature iron oxidizes to Fe_~O 3, which causes corrosion (Fe203 9 H20 ) in the presence of moisture. When iron is heated above 200~ it is coated by an oxide film of the F%O 4 type (magnetite). Oxides of this type exist up to t < 570~ At t > 570~ the FeO oxide (wiistite) becomes more stable. Both magnetite and wiistite form very fine films on the iron surface, which protect the part from further oxidation at conventional temperatures [1 ].
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