Improving hydration resistance of Al powder for carbon containing castables using inorganic–organic hybrid coatings

Abstract

The hydration behaviour of uncoated and inorganic–organic hybrid coated Al powders has been investigated after 36 h in water at 60 and 100°C by examining phase and microstructural changes. While significant hydration is detected in uncoated Al powder, no obvious hydration is detected in coated Al powder, indicating that its hydration resistance has been greatly improved. Oxidation resistance of graphite coexisting with uncoated or coated Al powder was also investigated after 1.5 h in air at 1250°C. The oxidation ratio of graphite coexisting with coated Al powder was similar to that of graphite coexisting with uncoated Al powder, indicating that both powders showed similar antioxidising behaviour. This lack of change in antioxidising behaviour, along with the much improved hydration resistance, makes the coated Al powder a potential antioxidant in carbon containing castable systems.

Keywords:

• ALUMINIUM
• ANTIOXIDANT
• CARBON CASTABLES
• HYDRATION
• HYBRID COATING