Fused silica is an amorphous siliceous glass produced by high temperature fusion of high quality crystalline silica (quartz). This fusion produces a substance characterised by very low thermal expansion and a high resistance to temperature and thermal shock.
Fused silica is employed in a variety of industrial applications including foundry (investment casting slurry and stucco, and mould release agent), refractory and ceramic (crucibles, saggars, rollers, pouring cups, ceramic cores, gas fire radiants and items for steel, nonferrous metal and glass industries), and filler (electronic and adhesives). Dupré Minerals realised early on that the secret of manufacturing investment powder lay in the quality of the raw materials available.
The company has carried out an extensive global sourcing project and has located what it considers to be some of the highest quality refractories so far made available to investment foundries. These include Fused Silica produced from quartz of exceptional purity with an SiO2 content of 99.9%. The source also has particularly low iron, potassium and sodium oxides and such a low trace element content to fall well within Aerospace specifications.