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[en] The short-duration intense mixed metallic and gaseous ion beams, such as Ti⁺ and N⁺, produced by the multiplate chamber with central hole have been used for implantation. The compositions of titanium and nitrogen as a function of depth was determined using Auger electron spectroscopy PHI-550. It is proved that phase transitions of thin layer of steel bombarded by ion beams take place owing to the ion mixing and rapid cooling down of implanted area after melting by the pulsed beams with power density more than 10⁷W/cm⁷. The effective hardness increase is concluded from microhardness measurements. It is expected that the implantation with pulsed ion beam could open a new way for the significant industrial application

[en] The short-duration intense mixed metallic and gaseous ion beams, such as Ti⁺ and N⁺, produced by the multiplate chamber with central hole, have been used for implantation. The compositions of titanium and nitrogen as a function of depth was determined using Auger electron spectroscopy PHI-550. It is proved that phase transitions of thin layer of steel bombarded by ion beams take place owing to the ion mixing and rapid cooling down of implanted area after melting by the pulsed beams with power density more than 10⁷W/cm². The effective hardness increase is concluded from microhardness measurements. It is expected that the implantation with pulsed ion beam could open a new way for the significant industrial application.¹

[en] Transparent and colourless TiO₂ thin films were fabricated on microscope glass slides by d.c. magnetron reactive sputtering method using Ar and O₂ as working gases. Then Fe ions were implanted into the TiO₂ thin film to observe its effects on the photocatalytic activity. X-ray diffraction, X-ray photoelectron spectroscopy and UV-Vis-NIR spectrophotometer technologies were used to characterize the films. The photocatalytic activities of the samples were evaluated by the degradation of Rhodamine B dye. The effects of Fe ion implantation on the decrease in the photocatalytic activity of the TiO₂ thin film were discussed

[en] The recovery behavior of quenched-in defects in TiAl alloys was studied by positron annihilation lifetime measurements. The results indicate that there is a certain number of grain boundaries in fully annealed TiAl samples, and after being quenched, the samples contain quite a lot of secondary defects such as vacancy clusters besides a large amount of mono-vacancies. The vacancy clusters aggregate further in the temperature range from 300 to 600 C due to the impurity atoms. (orig.)

[en] Mn-TiO₂ sandwich composite films were grown on glass and silicon substrates by alternately using radio frequency and direct current magnetron sputtering. X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy were used to characterize the surface structure of the Mn-TiO₂ films. XPS analysis confirmed the presence of Mn and TiO₂. Transmission spectra show that the absorption edge has a red shift with increase in the thickness of an Mn thin film between two TiO₂ films, which originated from quantum confinement effect. The hysteresis loop shows that Mn-TiO₂ sandwich film has ferromagnetic behavior, which has the saturation magnetization of 4.2 emu/g, remanent magnetic induction of 0.47 emu/g and coercivity of 377.6 Oe for the Mn thin film with the thickness of 33.6 nm between the two TiO₂ films

[en] The isomer shift of La_1-xCa_xFeO_3-y decreases gradually with increasing x, indicating the gradually increasing average intermediate valence state of iron, which is interpreted as being due to electron delocalization among iron ions on identical octahedral sites. The Moessbauer spectra of La_0.50Ca_0.50FeO_3-y and their theoretical treatment show that electron delocalization slows down with dropping temperature. Two magnetic hyperfine patterns in the spectrum of this compound at 80 K may be assigned to Fe³⁺ and Fe⁵⁺ by assuming a charge disproportionation according to the scheme 2Fe⁴⁺→Fe³⁺+Fe⁵⁺. La_1-xBa_xFeO_3-y shows a six-line and/or a single-line at room temperature for various x. The six-line subspectrum with IS=0.41 mm/s and H=52 T results from an orthorhombic perovskite containing only Fe³⁺. The single-line subspectrum at 0.17 mm/s from a cubic perovskite can be assigned to neither Fe³⁺ nor Fe⁴⁺ but an intermediate valence state, which may be due to electron delocalization. The temperature dependence of electron delocalization in the compound La_0.40Ba_0.60FeO_3-y is presented

[en] Published in summary form only

[en] Single-crystal tantalum sheets were implanted by 110 keV nitrogen ions to a dose of 5 x 10¹⁷ ions/cm² at a temperature less than 100 C. The structural changes and the concentration depth profiles of the implanted layers were characterized by glancing-angle X-ray diffraction (GXRD), selected area diffraction (SAD) and Auger electron spectroscopy (AES), respectively. The microhardness, the friction coefficient and the wear rate of the specimens against hardened GCr15 steel balls were also determined before and after the implantation. Scanning electron microscopy (SEM) and electron probe micro-analyzer (EPMA) were used to analyze the wear tracks. The results showed that there exist deviations between the characterization results of AES and GXRD or SAD. The AES measurement suggests the formation of the tantalum nitrides with a maximum N/Ta ratio of 1/2, while the GXRD and SAD reveal the formation of bcc Ta(N), fcc TaN and a trace amount of hcp Ta₂N. This can be explained by considering the inhomogeneous distribution of nitrogen atoms in micro-regions: the enrichment of nitrogen atoms in local micro-regions leads to the formation of fcc TaN; however, the unfavorable structural compatibility between bcc Ta and hcp Ta₂N hinders the formation of hcp Ta₂N in the regions where the N/Ta ratio reaches 1/2. The detected trace amount of the hcp Ta₂N phase in the implanted layers can be considered as an after effect of nitrogen loss from the originally formed nitrides. The results also showed that the tribological properties of the Ta surfaces were improved due to the implantation. It is believed that the implantation-induced Ta(N), fcc TaN, and hcp Ta₂N phases are responsible for this improvement. (orig.)

[en] The annealing effect of the positron annihilation parameters of austenitic FeCrNi alloy samples are investigated after quenching from a high temperature, plastic deformation, and hydrogen charge. The configurations and recovery behavior of defects are discussed. (orig.)