Abstract

The model composition ZGV-1 produced by OJSC “Mining Wax Plant” (town of Svisloch, Belrus) has been modified with nanodiamond particles for precision investment casting of items made of ferrous and non-ferrous metals. A laboratory technology has been developed for introducing nanodiamond particles produced by Refinery “Sinta” (Minsk, Belarus) into the model composition ZGV-1 a diamondcontaining charge of the ASh-A grade and ultradispersed synthetic diamond of the UDA grade. The compatibility of nanoparticles with the model composition was evaluated depending on the method of administration. Model compositions were obtained with different concentrations of nanoparticles (wt. %): 0.005; 0.010; 0.050; 0.10. The heat resistance of the modified model compositions was determined by two independent parameters: the softening temperature (Tr) and the Ubbellode dropping point (TUB). The dependences of Tr and TUB on the concentration of nanoparticles were established, their nature was explained: a rapid increase in the heat resistance of model compositions at initial concentrations (0.005 wt. %) and a subsequent decrease in Tr and TUB with a further increase in the concentration of nanoparticles. A mechanism is proposed for increasing the heat resistance of the model composition ZGV-1 with nanodiamond particles, which consists in the following: as a result of the interaction of the energetically active surface of nanoparticles with the carboxyl and hydroxyl groups of the components that make up the model composition of ZGV-1, a system of interpenetrating nets of physical nature is formed, which disappears mainly when melting and re-recovering upon solidification of the model compositions.

This reversible process can be repeated many times. An increase in the heat resistance of the model composition ZGV-1 by an average of 10°C is of great practical importance.