Indian Institute of Technology Ropar

About: Indian Institute of Technology Ropar is a education organization based out in Ropar, India. It is known for research contribution in the topics: Catalysis & Computer science. The organization has 1014 authors who have published 2878 publications receiving 35715 citations.

Characterization and High-Temperature Oxidation Behavior of Cold-Sprayed Ni-20Cr and Ni-50Cr Coatings on Boiler Steels

Abstract: Microstructure and mechanical properties of cold-spray coatings are usually required in order to explore the potential industrial application of the latter. This article demonstrates the successful formulation of Ni-20Cr and Ni-50Cr coatings on two boiler steels, namely, SAE 213-T22 and SA 516 steel by cold-spray process. The microstructure, coating thickness, phase formation, and microhardness properties of the coatings were evaluated. The coatings were subjected to cyclic heating and cooling cycles at an elevated temperature of 1173.15 K (900 °C) to ascertain their high-temperature oxidation behavior. Moreover, these cyclic exposures can give useful information regarding the adhesion of the coatings with the substrate steels. Of all the coatings, the Ni-50Cr coating on SA 516 steel had a maximum average hardness value of 469 Hv. As observed from the surface field emission–scanning electron microscopy (FE-SEM) analysis, the coatings were found to have nearly dense microstructure with the sprayed particles in interlocked positions. It was concluded that the cold-spray process is suitable for spraying the preceding powders onto the given boiler steels to produce nearly dense and low oxide coatings. The coatings, in general, were found to follow the parabolic rate of oxidation and were successful in maintaining their surface contact with their respective substrate steels.

New tripodal and dipodal colorimetric sensors for anions based on tris/bis-urea/thiourea moieties

Abstract: Seven neutral tripodal and dipodal receptors having mesitylene/triethylbenzene as core moiety, urea/thiourea as binding groups and p-nitrobenzene as signalling unit have been reported. The receptors act as selective colorimetric, naked eye sensors for small and spherical F− ion with some interference from tetrahedral ions. Thiourea derivatives form stable 1:1 H-bonded complexes with F− anion and to some extent with anions, whereas for urea derivatives, the recognition is simply based on acid–base reaction between ureidic protons and basic F− ions and is a completely reversible phenomenon. The pre-organisation of thiourea derivatives coupled with their high-intrinsic acidity is supposed to help them in the formation of strong H-bonded complexes with F− anion. The urea-based receptors do not respond at lower concentrations of the anion, but at higher concentrations, they undergo completely reversible deprotonation concomitant with a colorimetric change, with the production of stable [HF2]− anion.

Flower-Shaped Self-Assembled Ni0.5Cu0.5Co2O4 Porous Architecture: A Ternary Metal Oxide as a High-Performance Charge Storage Electrode Material

Abstract: In this work, a wet-chemical followed by thermal annealing strategy is employed to prepare Ni0.5Cu0.5Co2O4 without using any template. The material with flower-like architecture is composed of several nanorods that exhibit good textural properties (surface area: 120 m2/g, pore volume: 0.35 cc/g) and exposed facets and thus offers numerous electroactive sites for ion diffusion at the vicinity of electrode–electrolyte. The fabricated electrode with Ni0.5Cu0.5Co2O4 exhibits a higher specific capacitance of 367.4 F/g compared to fabricated electrodes using NiCo2O4 (280.3 F/g) and CuCo2O4(133.5 F/g) at the current density of 1 A/g. The material also exhibits high electronic conductivity (low Rct) and impressive cycling stability (89% retention after 5000th cycle). The combination of the synergistic effect of the variable oxidation state of three metal ions, large electroactive surface area, and fast ion diffusion through the porous structure are responsible for this high performance supercapacitive property of...