Desenvolvimento de uma casca cerâmica à base de silicato de sódio e alumina para o processo de espuma perdida

Abstract

The expanded polystyrene (EPS) casting process is widely used in the metallurgical industry to produce high precision parts. However, one of the main challenges of this process and the object of study of this work, carried out at the Foundry Laboratory of the Federal University of Ceará, is the development of a ceramic cover capable of resisting the high temperatures involved in casting and also having mechanical resistance so as not to break or warp, compared to the refractory cover process studied in a previous Capstone Project (CP). In this sense, alumina or aluminum oxide is a promising material in this sense, due to its thermal and mechanical properties. The objective of this CP was to develop an alumina-based shell for the casting process with expanded polystyrene (Styrofoam). The development process involved the selection of alumina with adequate granulometry, the correct formulation of the amount of oxide with sodium silicate, the performance of thermal resistance tests and the optimization of the formulation. The results of the tests indicated that the developed coating showed good results, and was able to resist the high temperatures of the process and to copy, with good precision, the details of the studied piece. In addition, the shell showed good adhesion to the surface of the castings and was easy to apply. In summary, the development of the aluminum oxide-based shell was successful and can be a viable alternative to the lost foam casting process. The coating can help reduce costs and improve the quality of castings produced in this process.