Effect of Metal Oxides Nanoparticles on Knocking Out Ability of Moulding Sands with Water Glass

摘要

This article presents the results of research on the effects of modifying the water glass with metal oxide nanoparticles on knocking out properties of moulding sands with sodium silicate hardened with liquid ester.Nanoparticles of ZnO, Al2O3 or MgO in propanol solutions were applied as modifiers of binding agents.3％ or 5％ of a modifier in the form of a nanoparticles colloidal solution in propanol was introduced to the water glass and subjected to a thorough homogenization.The verification of the technological properties of moulding sands with the modified water glass as the binder was performed on: tensile strength test and knock out tests.The study showed that the moulding sands with water glass modified with MgO nanoparticles have the best knocking out properties.The obtained improvement of the knock out coefficient in case of application of MgO as modifier was app.50％ in comparison with the moulding sand with not modified water glass.The performed investigations allowed selecting the water glass modifier-colloidal solution of MgO in propanol-providing the moulding sand with the best technological properties.In the case of the other two modifiers (ZnO and Al2O3) a better knocking out abilities were obtained but to a lesser extent.