Relaxation effects in large injection moulded ceramic bodies
β Scribed by T. Zhang; J.R.G. Evans
- Publisher
- Elsevier Science
- Year
- 1993
- Tongue
- English
- Weight
- 1001 KB
- Volume
- 12
- Category
- Article
- ISSN
- 0955-2219
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β¦ Synopsis
Small cubic samples were cut from various positions within large unfired injection moulded ceramic bodies and thermal expansion in different directions was measured by dilatometrv. Dramatic heterogeneities and anisotropies in apparent thermal expansion were observed. Negative apparent expansions were noted in some cases. The results have implications for the way in which local deformation occurs during reheating such mouldings to remove the organic' vehicle. Small organised displacements o[particles resulting .from the relaxation o[ the organic phase during binder removal may contribute to the defects which appear at that stage. Kleine, kubus/6rmige Proben wurden aus verschiedenen Bereichen groJ3er, ungebrannter SpritzguJ3keramike n herauspriipariert und die thermische Ausdehnung in verschiedene Richtungen mit Hilfe der Dilatometrie untersucht. Dabei wurden dramatische Heterogenitiiten und Anisotropien in der scheinbaren thermischen Ausdehnung beobachtet. In einigen Fdllen konnte eine negative, scheinbare Ausdehnung gemessen werden. A us den Ergebnissen ldflt sich folgern, in welcher Weise lokale Deformationen wdhrend des Erw6rmens der Formen zur Entfernung des organischen L6sungsmittels auftreten. Kleine, koordinierte Verriickungen yon Partikeln, resultierend aus der Relaxation der organischen Phase wdhrend des Entfernens des Binders, tragen m6glicherweise zu den in diesem Stadium auftretenden DΒ’/'ekten bei. De petits bchantillons cubiques ont btk dbcoupbs h divers endroits d'un objet mould par injection et non cuit. La dilatation thermique de ces kchantillons a btb suivie par dilatomdtrie. Des hbtbrogbnditbs impor-
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