Papers by Keyword: Elaboration

Abstract: The calcium phosphate nanostructured bioceramics and nanocomposites with calcium phosphate matrix are subjects of research and have raised scientific, political, industrial and commercial interest because these biomaterials present differentiated properties from microporosity, bioactivity and cell adhesion on the surface of grain and micropores compared to conventional biomaterials. This work aimed at the wet synthesis of a nanostructured hydroxyapatite bone matrix for subsequent preparation of nanocomposite hydroxyapatite/α-Al₂O₃ sol-gel powders, at concentrations 1, 2, 3 and 5% in volume of nanocrystalline α-Al₂O₃ dispersed in inter-intragranular position in the hydroxyapatite matrix. The method used for the preparation of HA/α-Al₂O₃ nanocomposite powders was high-energy attrition milling. This method allows obtaining nanocomposite powders formed by fine particles with sizes smaller than 100nm. The technique of scanning electron microscopy served for observation of morphology, microstructure and nanostructure. The X-ray diffractometry, laser particle analysis method and differential thermal analysis technique were used to identify the phases, particle sizes and thermal behavior for nanostructured powders retrieved from the attrition milling.

Abstract: The present paper refers to the remelting of light waste. The research aims to provide a substantial decrease of the oxidation losses and a decrease of the noxious expulsion resulting from the production of aluminium alloys. The fundamental solution found consists in achieving a stable flux layer. For this the wastes are introduced directly in the metallic bath, without a previous preparation. Data about oxidation losses, the content of gases and the correlation between the casting properties and the quality of remelting secondary alloys are presented. Several samples are analysed in order to point out the quality of the alloy and the relationship between the chemical composition, the content of gases and the free linear contraction of the alloy.