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Impact of additives on the quality of oxide/oxide tow-pregs obtained by continuous fibre impregnation
Ist Teil von
Composites. Part A, Applied science and manufacturing, 2024-09, Vol.184, Article 108238
Ort / Verlag
Elsevier Ltd
Erscheinungsjahr
2024
Link zum Volltext
Quelle
Elsevier ScienceDirect Journals Complete
Beschreibungen/Notizen
[Display omitted]
•Aqueous alumina slurries with varying additives nature and content were assessed for continuous tow impregnation.•Using a hygroscopic plasticizer enables moisture conditioning of impregnated tows, enhancing composite formation from them.•Glycerol both stabilizes the slurry and reduces plasticizer content while facilitating its thermal degradation.•Boehmite presence enhances the surface of impregnated tows.•The most promising slurry compositions for composite manufacturing contain boehmite and 20 wt% glycerol.
This paper focuses on the formulation of aqueous alumina slurries compatible with manufacturing alumina/alumina ceramic matrix composite (CMC) by a continuous tow impregnation process. Two hygroscopic organic plasticizers, sorbitol and glycerol, along with a gelling powder, boehmite, are evaluated for their impact on both slurry behaviour and the quality of impregnated tows. The interest of using glycerol instead of sorbitol is demonstrated, as glycerol exhibits smaller impact on slurry viscosity and stability, while being more hygroscopic and plasticizing, enabling a reduction in organic content. Combining glycerol with boehmite powder improves the surface and the tack of impregnated tows, although boehmite increases slurry viscosity and shear-thinning behaviour. Furthermore, thermal degradations of sorbitol and glycerol are studied through thermogravimetric analysis, to define an autoclave curing cycle for each plasticizer removing, to achieve optimal compaction of tow-pregs and hence reduce the porosity of the resulting CMCs.