I tried several configurations with no success (B4C, SiC @1100 °C at 0.5mbar vacuum hoven)
Are you trying to investigate the composite of Al with SiC/B4C for thermal storage option? I have tried this as well. So I 'd like to share with you some of my experience.
Actually, Al will melt at round 700 C and its viscosity will decrease as temperature goes higher, this can lead to leaking, oxidisation, or even evaporation of Al depending on its physical and chemical properties at 1100 C.
So I suggest you sinter the carbide preforms first at 1100C, and then infiltrate Al into it? If not possible, then you could sinter them both at lower temperature at 700-850C. This would give enough strength to hold the Al components in the ceramic preforms.
Hope my suggestion help you in this issue.
I'd love to know more about your research on this topic in the future.
Cheers,
Cheng (Wallace) Zhou
You can use potassium hexafluorotitanate as a flux. It can dissolve the alumina layer and will make the molten aluminium less viscous. You did not say which carbides you want to infiltrate though. If they are carbides of low thermodynamic stability like SiC or B4C (they react with aluminium) you need to watch out as the removal of the alumina layer will make reaction with the carbide easier.
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