Ramazanova G.   Assilbekov B.   Zhapbasbayev U.   Sattinova Z.  

Modeling of Beryllia Ceramics Formation Process

Reporter: Ramazanova G.

The technology of hot pressure molding remains the basic method for obtaining long-length, multi-channel, and complex shaped ceramics from non-plastic powders, despite the use of the isostatic pressing.
Obtaining ceramic fabrications by hot molding from particulates with anomalous physical properties, such as beryllium oxide (BeO), is complicated.
It is evident that without development of theoretical model of thermal flow control logics and mechanism on the basics of accumulated experience and knowledge it is impossible to overcome present technological limitations and problems of founding.
The slurry is a structured system where the mineral phase is a beryllium oxide powder and the liquid phase is an organic binder (paraffin, oleic acid and beeswax).
Experiments were carried out in the drawing-block for molding a circular tube with an outer diameter of 0.02 m and the inner diameter of 0.012 m.
Temperature distribution in the form-building cavity of the drawing-block depending on the molding speed and heat extraction conditions on the walls of form-building annular cavity was estimated during the experiments. It allows to determine the transition from viscous–plastic state to solid–plastic one.
Results of the experiment were analyzed and generalized using mathematical model of the thermoplastic slurry molding process. The latent heat of the phase change has been accounted by the apparent heat capacity.
The calculation results are in agreement with the experimental data, and they show physical validity of the proposed mathematical model of the BeO thermoplastic slurry solidification process.