Functional Requirements for Molds and Cores

In foundry practice, these requirements are tried to be fulfilled with suitable combinations of sand and binder. The variables at hand of the foundry engineer are sand type (quartz, aluminum oxide, olivine, chromium, zirconium dioxide, artificial sands, like hollow sphere made from mullite), sand grain size and distribution, binder type, binder amount, hardener (amines, carbon dioxide), and curing temperature. 

Typical problems occurring with conventional sand-binder systems will not be reviewed here but discussed within the context of the aerogel binders and aerogel-based nanoadditives. 

Polymeric aerogels were developed as binders for foundry sands in the last decade to solve certain problems, which are typical for classical organic binders. In the last few years, organic and inorganic aerogels were developed in granular form as additive to foundry sands to improve certain properties such as metal penetration, fineness, and collapsibility. 

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