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Artigo Científico | Transformação de Fases | Inglês | 10/04/2006
Autores: Antônio Sérgio Bezerra Sombra, C.M.R. Remédios, Cléber Costa Silva, J.M. Sasaki, M.A.R. Miranda
Palavras-chave: mechanical alloying, powder diffraction, sulfate, x ray
Resumo: Nanocrystalline powder of tripotassium sodium sulfate (K3Na(SO4)2 - KNS) was successfully obtained by mechanical alloying a mixture of potassium sulfate (K2SO4) and sodium sulfate (Na2SO4) with a proportion of 3:1 in a planetary mill. X ray powder diffraction (XRPD) was used to characterize this material. Powders produced with high milling times: 15, 30, 45 and 60 hours, have shown a single phase. For 60 hours of milling time, the powder was formed with very small grains (60 nm in average). We also prepared several samples with low milling times: 30, 60, 120, 150 and 180 minutes. The results for this series show that 120 minutes of milling is enough to produce a single crystalline phase of KNS. Therefore, we showed that a nanocrystalline powder of tripotassium sodium sulfate is easily obtained by mechanical alloying and that the grain size can be controlled by the amount of milling time.
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