MOISTURE DIFFUSION IN MOULDING MIXTURES FOR CORES OF FOUNDING

Moisture diffusion in moulding mixtures employed in foundry processes is described. Using gravimetric techniques, the humidification kinetic behaviour of different types of moulding mixtures for foundry cores was registered. The mixture hygroscopicity was compared using the percentage increase in wet mass. The kinetic study ended with calculations of effective coefficients of diffusion of atmospheric water in the mixtures in different weather conditions. For this goal, fitting by non-linear methods was used. The influences of the agglutinative and desanding materials on the hygroscopic properties were also analysed. 29 refs.