The evolution of the nanocrystalline structure by ball milling in single component Ni and Nb powders was studied by a combination of XRD and TEM methods. Intensive plastic deformation during ball milling progressively creates arrays of dislocations which split the original Ni and Nb grains into sub-grains, eventually leading to a nanocrystalline structure. The rate of reduction in grain size was observed to be faster in Nb than in Ni. However, the difference between Ni and Nb grain size decreases with an increase in milling time so that after 20 h of milling time, both Ni and Nb exhibited similar grain size of ~15 nm.      

Modern vehicle bodies make intensive use of high strength steel grades to meet the contradicting demand of lighter weight and simultaneously better mechanical performance. For many steel grades microalloying by niobium is the key to achieve their characteristic property peroperty profile. In HSLA steels niobium serves as a stabilizing element some modern multiphase steels rely on niobium to achieve additional strength via grain refinement and precipitation hardening. Microstructure control constitutes a powerful means to further optimize properties relevant to automotive processing such as cutting and forming. The role of niobium microalloying in that respect will be outlined.

To find a suitable treatment in the preparation of Nb surface for platinum electrodeposition, different methods such as thermal oxidation, anodic oxidation, mechanical roughening, and mechanical roughening with subsequent anodic etching were examined. X-ray photoelectron spectroscopy was used to study the chemical composition of depth analysis of the surface. Moreover, in order to examine the morphology and surface roughness, the samples were analyzed by Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM). The results showed that the most appropriate method for niobium surface preparation is mechanical roughening by shot blasting or abrading with emery and then anodic etching at the current density of 200A/m2 for 40 min. in a solution containing 95% methanol, 2.5% hydrofluoric acid, and 2.5% hydrochloric acid at the temperature of 35oC.

A variety of aldehydes undergoes smooth nucleophilic addition with allylbromide in the presence of niobium penta chloride in acetonitrile. The reaction conditions were very mild and the corresponding products of homoallylic alcohols were obtained in excellent yields.

In this research, the Ti-48Al/Ti2AlC and Ti-48Al (8Nb)/Ti2AlC composites were synthesized by means of mechanical alloying and hot pressing. Firstly, the mixture of elemental powders were subjected to mechanical alloying for 75 h and then to produce bulk samples, the milled powders were hot pressed for 1 h at 1000oC. Oxidation tests were carried out in air at 1000oC to compare the oxidation behavior of samples. Synthesized and oxidized samples were studied by scanning electron microscopy, energy dispersive spectroscopy (EDS) and X-ray diffractometry (XRD). According to X-ray diffraction patterns, the presence of g-TiAl and Ti2AlC phases were detected for produced samples and no phases on the base of Nb were formed. The results showed that the oxidation resistance of alloy was improved by niobium addition. The growth of rutile was suppressed by substitution Nb for Ti in TiO2 lattice. Furthermore, scale composition changed with addition of niobium that was related to the stabilization of nitride layer.

In this research, the effects of partially replacing of vanadium and molybdenum with niobium on the mechanical properties of AISIH 13 hot-work tool steel have been studied. Cast samples made of the modified new steel were homogenized and austenitized at different conditions, followed by tempering at the specified temperature ranges. Hardness, red hardness, three point bending test and Charpy impact test were carried out to evaluate the mechanical properties together with characterizing the microstructure of the modified steel using scanning electron microscope. The results show that niobium addition modifies the cast structure of Nb–alloyed steel, and increases its maximum hardness. It was found that bending strength; bending strain, impact strength, and red hardness of the modified cast steel are also higher than those of the cast H13 steel, and lower than those of the wrought H13 steel.

Abstract: A common and routine method for producing nitrogen-13 is 16O (p, α) 13N reaction, wherenitrogen-13 is produced with the bombardment of O-16 through the induced proton, and is accompanied byemission of α-particles. Target material for N-13 production is pure water. The first experiment is carriedout with a gold target. Because of the gold reaction with nitrogen-13, labeled ammonia (Au++n13NH3=Au(13NH3)+n), a new liquid target made of niobium, was designed to overcom this drawback. Oneof the advantages of niobium element is its high chemical resistivity. The 13N radioisotope was produced atthe Agricultural, Medical and Industrial Research School (AMIRS), where the target was irradiated withproton particles of 17.5 MeV energy and the current of 12 μA for 20 min. The yield of the radioisotope wasabout 84.5 mCi/μA h.