The current investigation demonstrates that it is possible to molecularly design supported niobium oxide catalysts with the assistance of molecular characterization methods such as Raman spectroscopy. The formation and location of the surface niobium oxide species are controlled by the surface hydroxyl chemistry, and the surface niobium oxide species are located in the outermost layer of the ca...

The proposed linear electron-positron collider TESLA is based on 1.3 GHz superconducting niobium cavities for particle acceleration. For a center-of-mass energy of 500 GeV an accelerating field of 23.4 MV/m is required which is reliably achieved with a niobium surface preparation by chemical etching. An upgrade of the collider to 800 GeV requires an improved cavity preparation technique. In thi...

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 m...

The accelerating gradient performance of superconducting niobium cavities is rapidly progressing as a result of reduced field emission due to improvement in surface preparation techniques. Beyond the field emission limitation, there exists a fundamental limit imposed by the critical magnetic field of niobium. One way to tackle this limit is to reduce the ratio of the peak magnetic field to the ...

A study was made of the preparation of a uranium 10 w/o niobium alloy by the bomb reduction of a suitable form of niobium and uranium tetrafluoride with calcium. A compound with a probable formula of Na2NbOF5 proved to be most satisfactory as the source of niobium. High yields and good metal-slag separations were obtained. Chemical analysis and density determinations showed the composition to b...

The influence of various preparation methods on the performance of V-Nb-0 catalysts has been investigated. It was found that the activity and selectivity of a vanadium site depend on the nature of the neighbouring atoms. Vanadium neighbours provide activity, while niobium neighbours provide selectivity. Careful preparation of these catalysts ensures a homogeneous distribution and good mixing of...

At CERN a compact Quadrupole Resonator has been developed for the RF characterization of superconducting samples at different frequencies. In this contribution measurements on bulk niobium and niobium film on copper samples are presented. Surface resistance results are being correlated to surface analyses measurements carried out on the same samples.

The DESY R&D program on cavities fabricated from large-grain niobium explores the potential of this material for the production of approximately 1000 nine-cell cavities for the European XFEL. The program investigates both basic material properties, comparing large grain material to standard sheet niobium, and material availability, production, and preparation aspects. Several single-cell caviti...

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 profile. in hsla steels niobium enhances the strength primarily by grain refinement. in interstitial free high strength steels...

In the present research, to form niobium carbide coating on the surface of AISI L2 steel Thermo-Reactive Deposition method (TRD) in a molten bath was used. Niobium carbide coating treatment was carried out at 1173 K, 1273 K, and 1373 K for 2, 4, and 8 hours. The molten bath contained 20wt.% borax (Na2B4O7), 5 wt.% boric acid (B2O3), and 75 wt.% ferro-niobium. The presence and properties of...