Effect of spray drying treatment on the optical properties of Mg–Al spinel ceramics
Résumé
In recent years, Mg–Al spinel ceramic has been in the spotlight due to its large transparency range and goodmechanical properties. The aim here, was to control the state of agglomeration of powder to improve densifi-cation behaviour and consequently optical and mechanical properties of the ceramics. Commercial powder with asmall particle size was used and exhibits poorflowability, which was found to be detrimental to shaping and ledto a translucent ceramic with an opaque crown. The powder was granulated by spray drying and the influence ofthe molecular mass of added polyethylene glycol on the granulate size, compaction andfinally sinteringbehaviour was investigated. Special attention was paid to the differences in rheological behaviour of powders,which was thoroughly characterized with a FT4 powder rheometer. Agglomeration of powder improved in-linetransmission at 650 nm up to 71% compared to 3% for ceramic from as-received powder
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