Table 1.
Properties of purple-sand female mold calcinated at different temperatures (with calcinating time of 3 hours)
| Temperature (°C) | 920 | 940 | 960 | 980 | 1000 | 1020 | 1040 |
|---|---|---|---|---|---|---|---|
| Colora | + | + | ++ | ++ | ++ | +++ | +++ |
| Breathabilityb | +++ | +++ | ++ | ++ | + | + | + |
| Siphonagec | +++ | +++ | ++ | ++ | ++ | + | + |
| Shrinkage-1 (%) | 89.6 | 86.9 | 84.8 | 83.6 | 81.7 | 79.8 | 79.5 |
Notes:
a
+, yellow; +++, black.
b
+++, polymer solution can be pulled into microholes within 1 minute; ++, ≤5 minutes; +, >5 minutes.
c
+++, hydrophilic and diffused; ++, hydrophilic; +, hydrophobic.