Creep-sintering of zinc oxide

The simultaneous creep and densification of zinc oxide powder compacts was studied, using a loading dilatometer, at 725° C subjected to uniaxial stresses of up to 0.25 M Pa. Between relative densities of 0.50 and 0.85, the dependence of the uniaxial creep rate on density can be described in terms of a stress intensification factor,, of the form exp (aP), wherea is constant equal to 5.0 andP is the porosity. Comparison of the creep and densification rates showed that the ratio of the linear densification rate to the creep rate is nearly constant over a density range between 0.55 and 0.85, and permitted the evaluation of the sintering effective stress, which is found to decrease with increasing density. The results are compared with those obtained earlier for cadmium oxide and a soda-lime glass powder.