Effect of Compound Additives on the Adhesive Performance of Sodium Silicate Binder for Core-making

In this paper, sodium silicate was the main component of the binder. In order to improve the flowability of the sand and the strength of the sand core, a composite additive containing polyvinyl alcohol, isopropanol, glucose and glucoside was added in the sand mixing process. The mass ratio of the composite additives was optimized by orthogonal test. In order to study the action mechanism of the composite additives on binder, the obtained additives were characterized using infrared spectroscopy and SEM. According to infrared spectroscopy data, the presence of additives can renew the chemical functional groups of the binder after hardening, generate the hydrophobic functional groups, and improve the strength and storage stability of the sand core. The SEM probing of the adhesive gel hardened by different ways reveals the significant structural changes along with the quality improvement of the adhesive film. Furthermore, the bridge bonding state of the hardened sand core is observed and analyzed by energy spectrum. The additives and the bonding agent obtained in this study were found to have the good fusion in combination with excellent strength characteristics.