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Effect of the Consolidation Technique on the Sintering Ability and Thermal Properties of AlN Processed from Aqueous Suspensions

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Abstract:

In this work, two different consolidation techniques were used to obtain AlN samples: slip casting and dry pressing of granules obtained from aqueous suspensions by freeze granulation. The green samples were sintered at a temperature (1750°C) lower than those usually used (>1800°C), using CaF2 and YF3 as sintering aids. The microstructural features were analysed by scanning electron microscopy (SEM) and the crystalline phases formed were identified by X-ray (XRD). Full dense AlN-based ceramics were obtained from both consolidation techniques; however the thermal conductivity values were quite different. The presence of carbon in the samples derived from the freeze granulated powder containing organic processing additives de-waxed in an inert atmosphere revealed to be helpful in the cleaning of oxygen present at the grain boundaries and consequently, for enhancing the thermal conductivity.

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Periodical:

Materials Science Forum (Volumes 514-516)

Pages:

1531-1535

DOI:

https://doi.org/10.4028/www.scientific.net/MSF.514-516.1531

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Online since:

May 2006

Authors:

Susana M.H. Olhero, José Maria F. Ferreira

Keywords:

Aluminum Nitride (AlN), Aqueous Processing, Freeze granulation, Sintering, Slip Casting

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© 2006 Trans Tech Publications Ltd. All Rights Reserved

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References

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