The analysis of gas evolved from casting powder during heating in the mold

Abstract

In this paper, the thermal stability of two commercial casting powders was assessed with respect to registered mass changes and evolved gas analysis using a combination of TG/DTA/EGA simultaneous thermal analysis methods. The experiments were conducted in a temperature range of 50 ÷ 1300 °C, in an oxidation atmosphere, with a heating rate of 10 K min−1. The results presented in the article perfectly fit into the research trend related to the emission of gases from powders, using for this purpose coupled TG/EGA techniques of thermal analysis. Thermogravimetric measurements together with simultaneous EGA analysis of gases released from the samples enable the identification of the main reactions responsible for mass disturbance. The main registered mass losses were associated with carbon oxidation and thermal decomposition of carbonates presented in investigated powders. Based on the DTA results, melting temperature, as well as other endo/exothermal effects of reactions taking place in the system, was elaborated. The possibility of FactSage usage, to elucidate the influence of selected components on the viscosity of investigated casting powders, is also presented. On the basis of the conducted research, it was found that recorded mass disturbance was not associated with the evaporation of components affecting the viscosity of casting powder.