Comparison of refractory coatings based on talc, cordierite, zircon and mullite fillers for lost-foam casting

Abstract

This study presents the results of an investigation of high-temperature materials refractory coatings based on different refractory fillers including talc, cordierite, zircon and mullite applied in the lost-foam casting process. Design and optimization of a coating composition with controlled rheological properties and synthesis were achieved by applying different coating components, suspension agents and fillers and by altering the coating-production procedure. A morphological and microstructural analysis of the fillers was carried out with scanning electron microscopy. An X-ray diffraction analysis was applied to determine and monitor the phase-composition changes of the refractory fillers. The particle size and shape were assessed with the PC software application package OZARIA 2.5. To assess the effects of the applications of individual refractory coatings, a detailed investigation of the structural and mechanical properties of the mouldings obtained was performed. Highlight was placed on revealing and analyzing surface and volume defects present on the mouldings. Radiographic moulding tests were carried out with an X-ray device, SAIFORT type-S200. The attained results are essential for the synthesis of the refractory coatings based on high-temperature fillers and their applications in the lost-foam casting process for manufacturing the mouldings with in-advance-set properties.