bubbles in the slurry

[treeying]

I'm quite new in the field of ceramic engineering. Here my question is how to remove the bubbles from the ceramic slurry. The vacumm vessel is used and the pressure is set up at -29inHg. There are still a lot of bubbles in the slurry. I'm wondering how long it will be needed for the bubble removal? Is there any good methods or tips to prevent bubbles? And it is noted that -29inHg is very close to the solvent vapor pressure. Do you think these bubbles might come from the solvent evaporation? How could I know if the bubble is air bubble or solvent bubble?

 

[Compositepro]

Once the solvent (not water?) starts to boil air buubles are almost instantly and completly removed. Boiling is completely different from "bubble removal". Boiling is the generation of solvent bubbles and it will turn-on or turn-off at a very specific pressure or temperature. Air bubbles will expand a limited amount under vacuum and will slowly rise to the surface where they will hopefully pop. Air bubbles will not disappear completely as pressure is increased but will only shrink - leaving a froth on the surface of the liquid. Solvent bubbles completely disappear when the pressure increases because the solvent condenses.