Microporous refractory material based on ZrO 2 powder

Development of manufacturing conception of microporous refractory materials made from powders is based on the progress in area of effective preliminary densifi cation of ceramic powders. Vacuum granulation is a production technology, which allows us to obtain high level of preliminary densifi cation. In this paper, the effi ciency of vacuum granulation technology is shown and the infl uence of grain size distribution of the powder on granules densifi cation is determined. The research results are presented for manufacturing the microporous refractory material based on a ZrO2 powder. In the research, the cheap, low chemical purity and coarse ZrO2 powder, partially stabilized with CaO was used. The aim of this research was to obtain the material of microporous structure and with high densifi cation level. A vacuum granulation technology was used for the powder preparation in order to reduce shrinkage to minimum during sintering. This technology allows us to obtain green compacts with an apparent density of 78% TD and the very advantageous unimodal pore size distribution with an average diameter of 0,36 m. During sintering process, a very advantageous microstructure of the material was obtained with high densifi cation level at surface areas and small closed pores. This microstructure guarantees high resistance against infi ltration by liquid metals and slag.