Taïna, indienne des Caraïbes, a été instruite dès son enfance pour devenir chamane, mais Christophe Colomb et les Espagnols arrivent...
The present work is aimed to develop metal toughened alumina composite which will be used as a cutting tool material, primarily by addition of silver, then microstructural characterization and property measurement of the developed composite. In the work a chemical synthesis using the sol-gel method was carried-out to prepare alumina powder from aluminium nitrate Al (NO3)3,9H2O. Then AgNO3 was well mixed with the prepared -Al2O3 powder in aqueous solution followed by evaporation and heating, to get 5 and 12 volume percent of Ag in the Al2O3-Ag mixture. A conventional powder metallurgical route was followed to prepare Al2O3-Ag composite pellets. First PVA was added as binder with the mixture, and then the powder was compacted in a circular shaped hole die-punch assembly at certain uni-axial pressure for the samples in a hand press to prepare disc pellets of size 16 mm diameter and thickness of ~6mm and ~3mm . The pellets were first dried at 500°C for 2 hours to burn off the PVA, then pre- sintered at 950°C for 2 hours and finally sintered at 1600°C for 2 hours as soaking time in a furnace.
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Taïna, indienne des Caraïbes, a été instruite dès son enfance pour devenir chamane, mais Christophe Colomb et les Espagnols arrivent...
Une belle adaptation, réalisée par un duo espagnol, d'un des romans fondateurs de la science-fiction, accessible dès 12 ans.
Merci à toutes et à tous pour cette aventure collective
Lara entame un stage en psychiatrie d’addictologie, en vue d’ouvrir ensuite une structure d’accueil pour jeunes en situation d’addiction au numérique...