RESUMEN
The effects of exposure to overheating (temperature above 1000 °C) on the degradation (modification) of layers of coatings (coatings based on aluminum) of uncooled polycrystalline rotor blades of aircraft turbine jet engines were investigated under laboratory conditions. In order to determine the nature of the changes as well as the structural changes in the various zones, a multi-factor analysis of the layers of the coating, including the observation of the surface of the blades, using, among others, electron microscopy, structural tests, surface morphology, and chemical composition testing, was carried out. As a result of the possibility of strengthening the physical foundations of the non-destructive testing of blades, the undertaken research mainly focused on the characteristics of the changes occurring in the outermost layers of the coatings. The obtained results indicate the structural degradation of the coatings, particularly the unfavorable changes, become visible after heating to 1050 °C. The main, strongly interacting, negative phenomena include pore formation, external diffusion of Fe and Cr to the surface, and the formation and subsequent thickening of Fe-Cr particles on the surface of the alumina layer.
RESUMEN
The authors are sorry to report that the yield of the hydrosilylation reaction in [P44414][NTf2] (1) IL with [RhCl(PPh3)3] was replaced with the yield reported for [P44414][NTf2] (1) IL with K2PtCl4 in their published paper [1]. [...].
RESUMEN
A group of imidazolium and pyridinium based ionic liquids has been synthetized, and their ability to dissolve and activate the catalysts used in hydrosilylation reaction of 1-octane and 1,1,1,3,5,5,5-heptamethyltrisiloxane was investigated. An organometallic catalyst as well as inorganic complexes of platinum and rhodium dissolved in ionic liquids were used, forming liquid solutions not miscible with the substrates or with the products of the reaction. The results show that application of such a simple biphasic catalytic system enables reuse of ionic liquid phase with catalysts in multiple reaction cycles reducing the costs and decreasing the amount of catalyst needed per mole of product.
Asunto(s)
Líquidos Iónicos/química , Octanos/química , Platino (Metal)/química , Rodio/química , Siloxanos/química , CatálisisRESUMEN
Crossing the line: A pH-induced "crossover" in 3D shapes of supramolecular constructs derived from trans(NH3)2Pt(II), [Pd(II)(en)], and the purine model nucleobase 9-methylhypoxanthine (see figure) is reported in which [Pd(en)(H2O)](2+) and [Pd(en)(OH)](+) are the decisive players (en = ethylenediamine).