| Autor: |
Karaulov, A., Zoz, E., Rudyak, I., Sudarkina, T. |
| Zdroj: |
Refractories; 1981, Vol. 22 Issue 9/10, p489-495, 7p |
| Abstrakt: |
The destabilization of solid solutions based on chemically pure technical ZrO and baddeleyite of various grades of purity has been compared after prolonged isothermal dwells (up to 240 h). It is established that the use of baddeleyite containing a higher amount of impurity, mainly in the form of anatite, lowers the degree of destabilization of the solid ZrO solutions. The presence of a monoclinic phase in solid solutions obtained from technical ZrO or baddeleyite strengthens the destabilization unlike the solid solutions based on chemically pure materials with minimum destabilization. In this case, the density and porosity of the material remains virtually unchanged and its ultimate compressive strength increases significantly. The solid solutions obtained from technical ZrO without any addition to the bonding of the monoclinic ZrO become looser after a prolonged isothermal dwell and their strength decreases. An addition of HfO leads to a slight increase in the stability of solid solutions in the ZrO-HfO-CaO system. The greatest intensity of the decomposition as in the ZrO-CaO system is observed in the region of 1400°C. A compound Ca(Zr, Hf)O is observed where 0≤x≤1 and this has been confirmed by x rays, IR spectroscopy, and by direct observation of the crystals using an electron microscope. In the case of the experimental compositions, when x=0.1 and x=0.3, the maximum of the formation of ordered zones is observed at 1200°C but at 1600°C these zones disappear. A cubic solid solution of the fluorite type has been observed using an x-ray method. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
| Externí odkaz: |
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