Combustion synthesis of mechanically-activated Nb-Al mixtures
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2003
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INTERNATIONAL LATIN-AMERICAN CONFERENCE ON POWDER TECHNOLOGY, 4th
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Resumo
In this work shake milling were used to mechanically activate Nb — Al powder mixtures
at different relative proportions (Nb80A1, Nb65A1, Nb54A1 e Nb42A1). All milling process
parameters were unchanged, e.g., powders mass, ball/powder mass ratio, balls diameter, quantity
and kind of process control agent. Uniaxially compacted cylindrical pellets of milled powders were
vacuum reacted. After a two-step degassing treatment (290°C for 0.5 h and 400°C for 4 h), samples
were heated at 30°C/min. Ignition and combustion temperatures were measured by a thermocouple
inserted in a hole drilled into the pellets. The microstructure of milled powders and reacted pellets
were characterized by X -ray diffraction and SEM analysis. Bulk density of the pellets was
measured by water iimnersion (Archimedes). The results showed a decrease of both ignition and
combustion temperature with mechanical activation as seen by comparison with reacted pellets of
the same composition not mechanically activated (simple mixtures). By increasing the heating hate
the completeness of the reactions were improved. The lower the aluminum contents the lower the
ignition and combustion temperatures and also the densification. The decrease on ignition
temperature was caused by a more effective dispersion (and so more activation) attained by samples
with lower aluminum content.
Como referenciar
BURACOVAS, F.; GONCALVES, V.S.; ROCHA, C.J.; LEAL NETO, R.M. Combustion synthesis of mechanically-activated Nb-Al mixtures. In: INTERNATIONAL LATIN-AMERICAN CONFERENCE ON POWDER TECHNOLOGY, 4th, Nov. 19-21, 2003, Guaruja, SP. Proceedings... Disponível em: http://repositorio.ipen.br/handle/123456789/15550. Acesso em: 19 Feb 2025.
Esta referência é gerada automaticamente de acordo com as normas do estilo IPEN/SP (ABNT NBR 6023) e recomenda-se uma verificação final e ajustes caso necessário.