Titanium dioxide (TiO2) presents particular importance, due to its general properties in a wide range of fields, such as catalysis, photocatalysis and antibacterial agents and as nano-paint (self-cleaning). Physical and chemical characteristics of TiO2, particle size and shape, phases of crystalline TiO2 with band gaps that rutile TiO2 of 3.0 eV and anatase TiO2 of 3.2 eV, determine the photocatalytic performance of TiO2. This review presents the theoretical concepts of the structure properties of this oxide and the elaboration methods that make TiO2 the ideal candidate for catalytic applications.

This paper presents structural evolution in iron oxide tablets at vibration testing for catalytic converters. The raw tablets composed from a mixture of cordierite powder with nanostructured iron oxide powders (pure and K-doped) and PVP binder. The analysis of the structural integrity of the raw tablets before vibration testing is evidenced by metallographic microscopic highlight the incidence of cracks. The raw tablets were mechanical vibration tested under normal operating conditions within the vibration damper to determine the structural integrity of the tablets. The mechanical vibration behavior of the tablets is essential in the development of new catalyst based on iron oxide nanoparticles for the reduction of gaseous pollutants from internal combustion engines.

A range of nanostructured oxides with excellent properties is used in technology and science for applications in several fields: catalysis, gas detection, biomedical applications. The most studied forms of oxides are hematite, maghemite and magnetite. In this study, microwave-assisted hydrolytic synthesis and microwave-assisted coprecipitation synthesis are described for the preparation of undoped and doped iron oxide powders using iron (III) chloride (FeCl3), potassium chloride (KCl) as precursors and sodium hydroxide (NaOH) solution as a hydrolysis agent. Microwave-assisted hydrolysis was performed at different concentrations of FeCl3 precursor: 0.1 M, 0.4 M, 0.7 M to which a constant concentration of hydrolysis agent was added, and the synthesis to obtain potassium-doped powders consisted of co-precipitation of 0.1M FeCl3 and 0.025M KCl precursor solutions in the presence of 2M NaOH hydrolysis agent. The developed powders were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and Fourier transform infrared spectroscopy (FTIR). The novelty is the use of potassium as a doping element for iron oxide, for potential application as catalyst. Hematite doped with 5% K was obtained by microwave-assisted coprecipitation synthesis. The presence of K was evidenced by EDS, while XRD spectra indicate successful doping of iron oxide with potassium, either interstitially or by substitution. By microwave synthesis, an increase in particle size was observed with increasing calcination temperature. The formation of the crystalline hematite phase was not obtained in the microwave heating process but following calcination of the powder

Our research focuses on the microstructure and mechanical properties of S6-5-2 speed steel. Studying austenite transformation in martensite and chemical composition changes of high speed steel, under heating conditions for austenitisation and cooling in oil bath, both performed under sub-atmospheric pressure (in rarefied atmospheres) is experimentally determined. The fields were these alloys can be preferred are: the electrical machines for avionics, the magnetic circuits of ultra-rapid relays and of other devices working in DC fields, the measure transformers and other transformers supplied on industrial frequency. To analyze microstructure�s modifications a combination of optical, scanning and electron microscopy was used. The mechanical properties were measured by hardness tests.

Nano-oxides attracted the attention of the reserchers due to their numerous applications. From this point of view, the development of new synthesis methods has become equally important for industry. The use of solar energy can become one of the ecological methods of obtaining nano-powders. Our paper presents the comparison of the morphology of nanopowders of Al-doped zinc oxide and Mn-doped copper oxide, obtained by physical vapour deposition using solar energy (SPVD), at different pressure and solar flux. The morphological characterization of doped oxide nanopowders synthesized by SPVD was performed by scanning electron microscopy.