Papers by Author: R.K. Singh Raman

Abstract: Nanocrystalline and microcrystalline Fe-10Cr alloys were prepared by high energy ball milling followed by compaction and sintering, and then oxidized in air for 52 hours at 400°C. The oxidation resistance of nanocrystalline Fe-10Cr alloy as determined by measuring the weight gain after regular time intervals was compared with that of the microcrystalline alloy of same chemical composition (also prepared by the same processing route and oxidized under identical conditions). Oxidation resistance of nanocrystalline Fe10Cr alloy was found to be in excess of an order of magnitude superior than that of microcrystalline Fe10Cr alloy. The paper also presents results of secondary ion mass spectrometry of oxidized samples of nanocrystalline and microcrystalline Fe-Cr alloys, evidencing the formation of a more protective oxide scale in the nanocrystalline alloy.

Abstract: In this study, an attempt was made to enhance the degradation resistance of magnesium alloys for potential biodegradable implant applications through surface treatment. AZ91 magnesium alloy was taken as the test sample and was alkali-treated for two different periods of time and then the in vitro degradation behaviour of the alloy was studied using electrochemical impedance spectroscopy and polarization techniques in simulated body fluid. The study suggests that alkali-treatment reduces the degradation rate in AZ91 magnesium alloy.