Application of chromite in the production of refractory coatings

Abstract

This work investigated the possibility of developing new chromite-based refractory coatings for hot metal casting applications. The coating composition and rheological properties were optimized by careful choice of binding agents and addition of a suspension maintenance agent in the coating. Different solvents (water and isopropyl alcohol) and casting methods were used in the tests. Chromite was used as refractory filler in both the water- And alcohol-based coating compositions. The chromite was examined by X-ray diffraction analysis and scanning electron microscopy. The chromite shape and grain size were analysed visually with the aid of the OZARIA 2.5 PC image analysis package. Test samples were cast using sand moulds and by the method of expandable patterns using a polymer model, also known as the "lost foam" casting process. The investigation demonstrated that water- And alcohol-based coatings have positive influence on the surface quality, structural and mechanical properties of alloy castings made with both casting processes.