Gas corrosion damage in Ti-stabilized interstitial free steel

The selective oxidation damage in the Ti-stabilized interstitial free steel during 60 s of recrystallization annealing at 820 °C under the different compositions of protective H2-N2 atmosphere at low dew point (–40 °C) was investigated using various experimental techniques. It was found that Mn, Al and Si oxide particles are the main products of external and internal oxidation. Increase of the H2 content in gas atmosphere favors external oxidation and leads to appearance of greater nonwetted surface areas.Physical chemistry 2006 : 8th international conference on fundamental and applied aspects of physical chemistry; Belgrade (Serbia); 26-29 September 200

The Effects of Microbial Polysaccharides on the Copper Accumulation in Daphnia magna

Copper is one of the leading metal pollutants in the water, which can cause adverse effects when present in high concentrations. The Daphnia magna is a model organism usually used for the determination of ecotoxicological effects of various compounds since it is highly sensitive to toxic compounds [1]. The aim of this work was to investigate the potential application of microbial extracellular polysaccharides (EPS), levan and pullulan, as agents for reducing the copper toxicity to D. magna. The protective effects of EPS were estimated based on the accumulation of copper in the D. magna cells. Levan is a branched fructane EPS [2] and the one used in this study was produced by Bacillus licheniformis NS032. Pullulan, a linear glucan EPS [3], was produced by Aureobasidium pullulans CH-1. The D. magna were exposed to 50 µg/dm3 of Cu (II) or a combination with 50 mg/dm3 and 100 mg/dm3 of levan or pullulan for 48h in the acute test. Additionally, the prolonged test was performed, where the daphnia were exposed to a 10 µg/dm3 of Cu (II) with or without 50 mg/ dm3 of levan or pullulan for 5 days. After the exposure period, the samples were digested and the accumulation of copper in D. magna was analysed using the iCAP Qc ICP-MS (Thermo Scientific, United Kingdom). The results showed that animals exposed to Cu (II) only, accumulated Cu (II) in a greater amount after the prolonged test compared to the acute one, despite the lower concentration. The treatment with EPS during the acute test increased the copper accumulation for both EPS concentrations tested, whereas during the prolonged exposure test, the Cu (II) accumulation was inhibited. Considering that protective effects of levan and pullulan were observed only with lower copper concentrations and 5 days of exposure, additional experiments are necessary to determine the mechanism of EPS action in order to confirm their possible use as protective agents

Ispitivanje bioremedijacionog potencijala bakterijskih konzorcijuma sedimenata čukaričkog kanala (Beograd)

Poster presented at: Prvi naučnog skupa:“Zaštita životne sredine“, (26. maj 2011., Sremska Kamenica)Abstract: [https://cer.ihtm.bg.ac.rs/handle/123456789/5063

Ispitivanje bioremedijacionog potencijala bakterijskih konzorcijuma sedimenata čukaričkog kanala (Beograd)

Poster presented at: Prvi naučnog skupa:“Zaštita životne sredine“, (26. maj 2011., Sremska Kamenica)Abstract: [https://cherry.chem.bg.ac.rs/handle/123456789/5421

Interactions between wear and corrosion on cast and sintered Ti-12Nb alloy in comparison with the commercial Ti-6Al-4V alloy

This work investigates the corrosion and tribocorrosion behavior of alpha + beta Ti-12Nb alloy processed by casting and sintering, in 9 g/l NaCl solution at body temperature, and compares the results with the commercial Ti-6Al-4 V alloy. Different electrochemical techniques were used to access the corrosion behavior. Tribocorrosion behavior was studied at open circuit potential under continuous and intermittent sliding, and at anodic potentiostatic condition under continuous sliding. Results revealed that Ti-12Nb alloys presented similar tribocorrosion behavior although the sintered one exhibited a better corrosion behavior. Nevertheless, Ti-6Al-4 V presented better overall degradation resistance than both Ti-12Nb alloys.- This work was supported by FCT national funds, under the national support to R&D units grant, through the reference project UIDB/04436/2020 and UIDP/04436/2020, together with M-ERA-NET/0001/2015, and co-supported by Brazilian agencies CNPq [grants #308.204/2017-4 and #125.954/2018-2] and FAPESP M-ERA-NET [grant #2015/50.280-5], also by MINECO (Spain) through the program PCIN-2016-123 and the Ramon y Cajal project RYC-2014-15014. I. Caha is grateful for a PhD grant under the NORTE-08-5369-FSE-000012 project

Influence of H-2-N-2 atmosphere composition and annealing duration on the selective surface oxidation of low-carbon steels

The selective surface oxidation of the Ti-stabilized interstitial free (Ti-IF) and dual phase (DP) steel during recrystallization annealing at 820 degrees C under the variety of exposure time and composition of protective H-2-N-2 atmosphere at low dew point (-40 degrees C) was examined. It was found that Mn, Al, Si and Cr oxides are formed in all cases, but higher Mn and Si concentration in DP steel leads to an increase in a density of coarse nonwettable MnSiO3 particles. An increase in annealing time enhances surface coverage with oxides, while increased H, content in gas atmosphere results in less coverage with external oxides improving the wettability. The influence of the stronger reducing atmosphere is more exhibit on Ti-IF steel where after 120 s of annealing in 15vol.%H-2-85vol.%N-2 atmosphere the wetting angle theta stabilized to a value of the order of 6 degrees. The presence of surface BN and the TiN particles also affects the full surface coverage by external oxides. (C) 2005 Elsevier Ltd. All rights reserved

The effect of dual phase steel surface roughness on selective oxidation and surface wettability

Surface roughness effect on the morphological characteristics of the dual phase (DP) steel surfaces selectively oxidized during recrystallization annealing at 820 degrees C under 5vol.%H-2-95vol.%N-2 gas atmosphere was investigated in this study. Oxidation behaviour of DP steel was examined using X-ray photoelectron spectrometer (XPS) and scanning electron microscope (SEM) equipped with energy-dispersive spectrometer (EDS). It was found that on the unpolished steel sheets the thicker and more uniformly distributed surface layer of Mn, Al, Si and Cr oxides is formed. As a result, wettability of unpolished steel surface was considerably decreased. According to the results of this paper the presence of BN surface particles at the polished steel surface affects the full surface coverage by external oxides and in that way improves surface wettability

Damage of Ti-stabilized interstitial free steel by gas corrosion

Degradation of Ti-stabilized interstitial free steel and damage of this steel caused by selective oxidation during 60 s of recrystallization annealing at 820 degrees C under the different compositions of protective H(2)-N(2) atmosphere at low dew point (-40 degrees C) was investigated using X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and energy dispersive spectrometry (EDS). During the high-temperature annealing the reduction of the native Fe-oxide layer occurred. Results of the analyses also showed that Mn, Al and Si oxide particles are the main products of selective external and internal oxidation. Moreover, appearance of greater nonwetted surface areas was caused by the increase of the H(2) content in gas atmosphere, which favours external oxidation