Aerogel-Cores: Using foundry technology to produce complex shaped parts from aerogel granulates and binder

Abstract

High-temperature stable aerogels are often brittle and prone to fractures. It is not easy to produce defined shapes or large complex shaped forms. Looking at the casting industry, they make defined, very complex moldings out of sand and binder by shooting sandcores with a so called core shooting machine. A wide range of binders (inorganic or organic, hot-box or cold-box, etc.) are used. Binder contents of 0.5 – 4 weight-% are common. In our study we used a sandcore-shooting-machine to produce simple and complex parts of aerogels. Different types of aerogels, grain sizes and binder systems were examined. Amount of binder, curing time and shooting pressure also play an important role. Superplasticizer and / or release agents were used to facilitate the shooting process and the core / part removal. Not all recipes appeared to produce aerogel parts successfully. Only through the adjustments of the experimental conditions stable cores and parts of aerogel could be produced. More binder content and a longer curing time at lower temperatures are needed. Thermal conductivity measurements and mechanical properties are presented.