National Aerospace Laboratories

About: National Aerospace Laboratories is a facility organization based out in Bengaluru, India. It is known for research contribution in the topics: Coating & Corrosion. The organization has 1838 authors who have published 2349 publications receiving 36888 citations.

Formation of a protective nitride layer by electrochemical nitridation on 316L SS bipolar plates for a proton exchange membrane fuel cell (PEMFC)

Abstract: In the present study, an attempt has been made to increase the corrosion resistance of 316L stainless steel (SS) bipolar plates (Bp) through electrochemical nitridation using a nitrate bearing electrolyte solution of 0.1 M HNO3 and 0.5 M KNO3. The X-ray photoelectron spectroscopy (XPS) studies revealed that the modified SS was covered with ammonium ions and mixed nitrides, namely CrN and Cr2N, on the surface. The average contact angle value with water for nitrided SS favored a PEMFC operating environment. The electrochemical corrosion behaviour was studied in a simulated PEMFC environment (0.5 M H2SO4 and 2 ppm of HF) to ensure that the modified SS exhibits enhanced corrosion resistance. Surface resistance values for both untreated and nitrided SS showed low values and increased conductivity after the polarization studies.

Silver as a dopant and as a constituent in AsAgTe glasses: electrical conductivity

Abstract: Electrical conductivity data (from 200 to 360 K) on fifteen glass compositions of the AsAgTe system are reported and discussed. The glasses were prepared using a two-stage melt-quenching method. For the (As2Te3)1−xAgx glasses, features are seen in the electronic properties, corresponding to a change in the role of Ag from a dopant (for Ag ≤ 1 at.%), to a constituent (for Ag > 1 at.%.). At this composition, step-like changes occur, in the activation energy for electrical conductivity and in the pre-exponential factor. Examination of the data indicate that, as a dopant, Ag acts as neutral scattering centres for charge carriers. As a constituent, Ag enhances the hopping channel for conductivity near the valence band edge.

Control of Incident Shock-Induced Separation Using Vane-Type Vortex-Generating Devices

Abstract: An experimental investigation was conducted to control an incident shock-induced boundary-layer separation associated with a 14 deg shock generator in a Mach 2.05 flow. Two vane-type configurations...