Now showing items 1-5 of 5
| Abstract: | Optimum conditions and experimental details for the formation of v-Fe203 from goethite have been worked out. In another method, a cheap complexing medium of starch was employed for precipitating acicular ferrous oxalate, which on decomposition in nitrogen and subsequent oxidation yielded acicular y-Fe203. On the basis of thermal decomposition in dry and moist nitrogen, DTA, XRD, GC and thermodynamic arguments, the mechanism of decomposition was elucidated. New materials obtained by doping ~'-Fe203 with 1-16 atomic percent magnesium, cobalt, nickel and copper, were synthesised and characterized |
| Description: | Bull. Mater. Sci., Vol. 6, No. 1, February 1984, pp. 59--64. |
| URI: | http://dyuthi.cusat.ac.in/purl/4410 |
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| Development of ... ped gamma ferric oxide.pdf | (378.9Kb) |
| Abstract: | Preparatiun or aci cular maghemi te containing dopan ls li ke Mg. i and Gd and their characleris,llion us ing different analytica l techniques have been reported. These in vestigat ions reveal that the addition of dopants li ke Mg. Ni and Gd modifies the magnetic properties without cfrecting any structural changes. The opt ical bandgaps of these doped compositions have ,li S() hecn determ ined. Evidence is ,li so av,li lab le from spectroscopic investi gations suggest ing thalmaghcllli te prepared vi,l the ()xa l,ltc precursor route does nm exhi bit a hydrogen fe rrite structure |
| Description: | Ind ian Joum,ll of Pure & Applied Phys ics Vol. 37. November 1999. pr. 842-847 |
| URI: | http://dyuthi.cusat.ac.in/purl/4435 |
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| Influence of do ... roperties of maghemite.pdf | (1.171Mb) |
| Abstract: | Magnetic materials meant for audio/video recording applications necessitate that polycrystalline materials be in acicular shape. So preparation of acicular precursors for magnetic storage materials assumes significance. The employment of aqueous solutions do not produce needle shape crystallites. Glycerol is one of the complexing media used for the precipitation of ferrous oxalate dihydrate. An inexpensive method using starch for preparation of acicular particles is described. The influence of an additive namely Gd on acicularity is also investigated |
| Description: | Bull. Mater. Sci., Vol. 20, No. 7, October 1997, pp. 975 980 |
| URI: | http://dyuthi.cusat.ac.in/purl/4398 |
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| A new inexpensi ... gnetic recording media.pdf | (1.271Mb) |
| Abstract: | Optimum conditions for the preparation of tape recording quality Y-Fe20 s by the thermal decomposition of ferrous oxalate dihydrate have been established. Formation of the intermediate F%O~ which is most important in forming Y-FezO 3 takes place only in the presence of water vapour. Various stages of decomposition have been characterised by DTA, TG, DTG, and x-ray powder diffraction. The method for the preparation of acicular "Y-Fe208 that matches very well with the commercial tape recording material has been developed |
| Description: | Bull. Mater. Sei., Vol. 3, Number 2, July 1981, pp. 201-208 |
| URI: | http://dyuthi.cusat.ac.in/purl/4396 |
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| Preparation and ... ape recording material.pdf | (374.1Kb) |
| Abstract: | Acicular FeC~O4-2H20 was precipitated from glycerol and starch media. Thermal decomposition of this oxalate in dry and moist nitrogen yielded primarily FeO and Fe 3Oa respectively. Characterization was attempted through DTA, TG, x-ray diffraction, TEM and magnetization studies. It was found that the oxalate can be completely decomposed to FeaO~ in moist nitrogen (PH~o ,"-" 35 torr) at 775 K and then oxidised by dry air to acicular "/-Fe~Oa at 575 K. The resulting material has saturation magnetization (,-,., 70 emu/g), coercive field (N300 Oe) and squareness ratio ( ,~, 0-60-0-65), which values art comparable with those of the commercial samples |
| Description: | Bull. Mater. Sci,, Vol, 3, Number 3, November 1981, pp. 275-280. |
| URI: | http://dyuthi.cusat.ac.in/purl/4419 |
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| Synthesis and c ... magnetic tape material.pdf | (317.5Kb) |
Now showing items 1-5 of 5
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