Jan 6 2004
This form of leachable ceramic is used in the precision foundry industry. The tubes and rods are incorporated into moulds in the lost wax process.
Using this technique, very fine tolerances on diameter can be obtained. The ceramic is leached away by the using sodium hydroxide solution once the metal has solidified.
This leachable ceramic has a high porosity, does not have an organic binder, but does absorb water.
Key Properties
The key properties of leachable ceramic are tabulated below.
Table 1. Key properties
| Chemical Resistance |
| Acids - concentrated |
Fair |
| Acids - dilute |
Fair |
| Alkalis |
Poor |
| Halogens |
Fair |
| Metals |
Good |
| Physical Properties |
| Apparent porosity ( % ) |
25 |
| Density ( g.cm-3 ) |
2.1 |
| Water absorption - saturation ( % ) |
14 |
| Thermal Properties |
| Coefficient of thermal expansion ( x10-6 K-1 ) |
1.98 @ 20-1000 °C |
| Upper continuous use temperature (°C ) |
1050 |
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