MICROSTRUCTURE AND OXIDATION BEHAVIOR OF THE OXIDE DISPERSION STRENGTHENED STAINLESS STEEL 316L WITH ZIRCONIA DISPERSION

Synthesis of the oxide dispersion sODS steels was performed by dispersing 0.5 wt % zirconia to the stainless steel SS 316L by the powder metallurgy method. The ball milling process was carried out for pre-alloying the elements continued with the consolidation performed by the compaction and sintering process using the APS (Arc Plasma Sintering). Analysis of microstructure was performed by observing the morphology, identify the phase and evaluate the oxide distribution. An oxidation test was carried out at 700oC for 8 hours using the MSB (Magnetic Suspension Balanced) apparatus to evaluate the primary oxidation curve. The same grain fineness consists of 2 dominant phases, so the presence of an austenitic phase and a ferritic phase has been analyzed from the X-Ray Diffraction pattern. The homogeneous distribution of zirconia was observed, followed by improvements in mechanical properties, which could be identified by hardness testing. The parabolic phenomenon oxidation curve was explained by the excellent high-temperature oxidation behaviour of the ODS steel, followed by the formation of ZrO2 oxide protective thin layer.

Functionalized Carbon Nanotubes for Chemical Sensing: Electrochemical Detection of Hydrogen Isotopes

In this study, we propose a palladium-functionalized CNT composite working as a sensitive material to evaluate the deuterium concentration in aqueous samples. The sensitive material was prepared by the deposition of Pd nanoparticles onto MWCNT–OH by the micellization process. A modified electrode was prepared by drop casting 60 μL of Pd-decorated MWCNT suspension on a clean glassy carbon electrode surface. The sensing behavior was investigated in a series of deuterium-enriched solutions ranging from 25 to 10.000 ppm. We performed cyclic voltammetry and impedance spectroscopy studies on the samples. The process is quasi-reversible with the reduction curve more pronounced than the oxidation curve, which indicates a low tendency to desorption for the hydrogen atoms.

DEVELOPMENT AND OXIDATION RESISTANCE OF PLASMA SPRAYED Mo(Si,Al)2 COATING ON Nbss/Nb5Si3 IN SITU COMPOSITES

A Mo ( Si , Al )2 coating is developed to protect Nb ss/ Nb 5 Si 3 in situ composite by plasma spraying. The binary layers of this coating consist of an inner interdiffusion layer surrounded by Mo ( Si , Al )2 layer with C40 crystal structure. After oxidation at 1250°C for 100h, Mo ( Si , Al )2 coating exhibited an excellent protection against oxidation and good adherence to substrate. The oxidation curve followed parabolic law and even after oxidation at high temperature for 100h, the weight gain per unit area of Mo ( Si , Al )2 coating is 8.24mg/cm2. No evident spalling of coating to substrate was observed but a continuous and compact layer of Al 2 O 3 was formed on coating surface to prevent oxidation below coating and substrate.

Graphical evaluation of the kinetic parameters for bacterial growth

Kinetic rate parameters governing the rates of growth and substrate use by bacteria may be estimated by a graphical method which makes use of the bacterial substrate oxidation curve. The method is simple and rapid and may be used to estimate rate parameters in situations in which more precise computer estimates cannot be performed.

The Influence of Vulcanization on the Oxidizability of Rubber. Vulcanizing Agents Other Than Sulfur

In a previous publication the influence of vulcanization by sulfur and sulfur compounds on the oxidizability of rubber was shown. The most important conclusion was that, in principle, the higher the proportion of combined sulfur, the greater is the oxidizability. However, with very high proportions, the activity of the sulfur changes, i.e., above a certain upper limiting range, the oxidizability tends towards a plateau, whereas below a lower limiting range the oxidation curve passes through a minimum. After having obtained these results, it seemed to be of interest to complete the investigation by studying the effects of vulcanization by agents other than sulfur on oxidizability. In the present work we have examined vulcanization by nitro compounds and peroxides, taking as examples m-dinitrobenzene, trinitrobenzene and benzoyl peroxide. This domain of rubber chemistry has been relatively little explored and certain points either have not received final confirmation or have even led to contrary conclusions. Accordingly it seemed useful to review from a purely objective point of view what has been done on this subject.

The Ultra-Rapid Testing of Rubber. The Testing of its Oxidizability in One Quarter of an Hour

It is hardly necessary to go into further detail to demonstrate the great advantages of such a test when used in a practical way. In the control laboratory, it will supplement and confirm the various other routine tests and, most important, immediately detect an error which the other tests will not do, particularly the omission, insufficiency or incomplete distribution of antioxygen. It will also reveal the presence of harmful impurities. For specifications and in manufacture, it will enable the article itself to be tested, either by removing a small piece or by providing a cavity for this purpose in the mould. Of course it is not necessary to limit the testing time to a quarter of an hour. If greater differences in the manometric levels are desired, the oxidation curve may be continued for a longer period, one hour, for example. Finally this oxidizability test at 120° C. would appear to fulfill the requirements of rapidity and precision of control testing, at least in the present state of stability of rubber products. Only in case of greatly increased resistance to oxidation would it be necessary to prolong the test for more than one quarter of an hour.