Advantages
- Manufactured from partially stabilized zirconia ceramic
- Rated to temperatures up to 1700˚C
- Excellent thermal shock resistance
- Excellent resistance to chemical (slag) attack
- Excellent filtration efficiency
- Excellent flow modification
It should be pointed out that foam filters have some shortcomings.
- The filters are fairly difficult to prime, and the metal may need to be poured at a higher temperature to prevent it from freezing off during the initial phases of pouring.
- The filters have an irregular and inconsistent structure. This may result in variable flow rates and capacities from filter to filter.
- Foam filters tend to be friable, and small strands can break off. It is possible that these strands could end up in the casting.
Despite these shortcomings, foam filters have been used successfully by multiple foundries for many years.
