Binding of Water & Organic Liquid Components (Ethyl Alcohol, Methyl Alcohol, Propyl Alcohol, Formic Acid, Acetone, Pyridine & Glycerol) at Interface & the Gibbs Surface Excess

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Electrical, Magnetic and Electrochemical Behaviour of Nanocrystalline Fe70.5Nb4.5Cu1Si16B8 Alloy

The electrical, magnetic and electrochemical behaviour of Fe70.5Nb..5CuiSi,638 has been studied in the as-received and heat treated conditions. The as-received material was amorphous which crystallized in two different stages at 780K and 940K when heated continuously. At the primary crystallization stage, nanometre sized grain of ordered FesoSi20 phase was formed. The superior soft magnetic properties were achieved after primary crystall-ization which were attributed to the averaging out of magnetocrystalline anisotropy due to the nanocrystalline structure and the reduction of magnetoelastic anisotropy energy due to the negative magnetosirictive nature of Fe8oSi20 phase and positive magnetosirictive value of the rest amorphous phase. After primary crystallization spon-taneous passivating nature of the alloy is also observed in electrochemical study

Influence of Quench Rates on the Properties of Rapidly Solidified FeNbCuSiB Alloy

FeNbCuSiB based materials were produced in the form of ribbons by rapid solidification techniques. The crystallization, magnetic, mechanical and corrosion behaviour were studied for the prepared materials as a function of quenching rate from liquid to the solid state. Higher quench rates produced a more amorphous structure exhibiting superior soft magnetic properties with improved corrosion resistance

An Approach to Beneficiation of Apatite Ore of Purulia

West Bengal Mineral Development and Trading Corporation operates the apatite mine in Purulia District of West Bengal. The produce three grades of samples, i.e. (i) High grade above 30% P2O5 (ii) Average grade of about 20% P2O5 and (iii)Low grade of 12% P2O5. The average is directly marketed as fertiliser for application in tea garden etc. The medium or average grade sample is mined from areas around the main ore body and contains substantial amount of ferruginous material besides other gangue minerals. The low grade ore is dumped separately and occasionally blended with high grade of ore to prepare the average grade for direct marketing. Thus every bit of apatite from the mines is used except for the top soil. But with reduc-ed demand, the manufacturer is faced with a selling problem and reduced production. Value addition by way of making high grade product is one option to pursue with. The typical problem is of iron removal as presence of high iron hinders value addition in terms of phosphate during down stream operation. Studies on the average grade sample indicated that using suitable processing steps the phos-phate content could be increased to +38% P205 with very low content of iron & silica. The present paper deals approach adopted in beneficiating the average grade apatite ore of Purulia. Key Words: apatite, Purulia, iron, magnetic separation, flotation

Pitting Stochastic Study in Airframe Aluminium Alloy using Non-linear Ultrasonic

Pitting corrosion is considered to be one of the principal degradation mechanisms for high-strength aluminum alloys. The aircraft airframe has been the most demanding application for aluminum alloys. The combined effects of corrosion and cyclic loading have been shown to produce cracks from corrosion pits and pits have frequently been the source of cracks on aircraft components operating in fleets. Once the pit or group of pits form, the rate of pit growth is dependent mainly on the material, environmental conditions and type and state of stress. Therefore, to estimate the total corrosion fatigue life of a component, it is of great importance to develop realistic models to establish the component life in these situations and to formulate methods by which designers and operators know likely sources of pitting early in the design and fleet operation. There are certain gaps in knowledge with regards to life prediction for pitting initiated fatigue. The need is to gauge the extent of pitting damage of a component or material non-destructively and predict the remaining life through superimposition of the pertinent operational, environmental and material parameters. However, a foolproof non-destructive means to characterize and three-dimensionally map pits is not available. The pitting phenomenon has to be analyzed statistically and the kinetics of pitting assessed through a change in the statistical distribution parameter of pits rather than deterministic equations relating pit dimensions to time. In this work we have applied high frequency ultrasonic and non-linear ultrasonic to assess the damage due to pitting and attempt has been made to establish correlations between this non-destructive tools and pit stochastic

Fatigue crack growth retardation in an HSLA steel in benign environments

The crack growth and closure were examined for fatigue loading of an HSLA steel in non-corroding media. R and ΔK dependent significant crack growth retardation was observed in NaOH. Presence of a passive film at high R and self repair of the film and formation of an additional oxide layer at low R could explain the retardation

Salvaging the values from the rejects of a by-product recovery plant

Two samples of table tailings (-147 pm and -74 pm in size) from refrac¬tory linings of the precious metal recovery (PMR) plant of Indian Copper Complex (ICC), Ghatshila were received to study the possbility to re¬cover residual values of precious metals from them. Analyses, as reported by ICC, were 0.021% Au and 0.39% Ag for the -147 pm sample and 0.023% Au and 0.47%Ag for the -74 pm sample. Multi-Gravity Separator (MGS) studies, with varying design and operating variables, showed three fold upgradation - assay of Au improved from 0.023% to 0.076% and assay of Ag improved from 0.47% to 1.53%. The -74 pm sample yielded better results with MGS than the -147 pm sample

Gravity separation at variable 'g' for management of mineral wastes and pollution

The treatment of mineral wastes in the form of slimes and its utilisation, for management of pollution and conservation of mineral wealth, have become very important now-a-days. Multi Gravity Separator (MGS) is the latest inclusion to various gravity separation machines developed far the treatment offines and ultrafines. In this paper, results of recent studies carried out at NML with MGS using slimes of chromite ore, iron ore, phosphatic soil etc. are discussed to evaluate the effectiveness of the equipment for the treatment of slimes. In most of the cases, three to four fold upgradations have been achieved even at very fine sizes