Filler masses of zirconium dioxide based on ortho-phosphoric acid

The paper examines the effect of the content of monoclinal ZrO2 in ramming mass based on zirconium dioxide, and the quantity of orthophosphoric acid, on the properties of mass over a wide temperature range. The addition of monoclinal ZrO2 reduces the shrinkage of ramming mass and increases its strength in the range 300 - 1,0000C. The introduction of monoclinal ZrO2 into mass based on partly stabilized ZrO2 with a maximum grain size of 5 mm ensures a complete absence of shrinkage right up to 1,7500C. Such masses, however, have a more marked fall in strength at 1,2000C (destabilization temperature of ZrO2). Orthophosphoric acid acts as a surface active agent and improves the density of the samples; increasing its quantity from 2 to 5 % (by weight) increases the strength of ramming mass. (author)