Hi everybody,
I've come across some discussions and I would be grateful if someone could clarify whether we can prepare a well-dispersed aqueous-based slurry consisting of ceramic particles which are hydrophobic? Say, for instance, with PVA as a binder and PEG as the plasticizer.
Any contribution of ideas would be helpful.
Thank you.
Kind Regards.
You can prepare any ceramic suspension you want, with powders of ZrO2, Al2O3, cordierite, silica, Si3N4, SiC, for porcelain, gres, and everyone has different surface characteristics, etc... And the suspension will be stable (not sedimenting). At least it will be tixotropic but it could be a gift for certain applications. You should chech the Z potential of your powder (in aqueous or other suspension medium) and find a suitable dispersant: it is not relevant the nature of the powder: the right dispersant in the right amount is able to conditionate the surface charachteristics and interactions both with the solven and the other dispersed particles. Generally, dispersants are polycarboxylic salts- acrylic homopolymer solutions (e.g. series of Duramax, Dolapix, Reotan , etc.) organics, that together with binders and plasticizers can yield a stable slurry, suitable for gel-casting and porous materials, able to be shaped in moulds or poured in tapes without cracks and inhomogeneities after drying and successive sintering. I think you could find a lot of publications about. Good work!
Dear Mauro,
Thanks a lot for the above clarification and encouragement. In that case, it means somehow that whether the ceramic is hydrophobic in nature, I could still prepare a slurry with the right amount of binder/plasticizer/dispersant.
Best Wishes!
you can use some surfactant agents (such as IgePAL), which contains a hydrophobic tip at one end and a hydrophilic tip at another, to transfer the hydrophobic ceramics particles into hydrophilic phase. After this surface modification, the mixture can be homogeneous. Such method is called reverse emulsion, which you can find a lot of publications.
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