A forced vibration method for measuring the frequency dispersion of internal friction under cyclic-tensile-compressive stress in a single axis was developed so that various mechanical tests could be conducted by using a specimen having the same shape, machining and sintering conditions. Using this new method, frequency dispersions of the internal friction for tetragonal and cubic zirconia polycrystals stabilized with yttria were measured. The activation energy for the relaxation time was determined. As a result of comparison with the activation energy for the relaxation time as measured by using a conventional method, it was concluded that the present results for the internal friction were valid. The activation energy for ionic conduction was determined, and was compared with that for the relaxation time. The activation energies for the relaxation time in 2.6% yttria-stabilized zirconia, 3% yttria-stabilized zirconia, and the lower-temperature peak of 10% yttria-stabilized zirconia were very similar to those for conductivity. It was concluded that the internal friction peaks of 2.6% yttria-stabilized zirconia and 3% yttria-stabilized zirconia, and the lower temperature peak of 10% yttria-stabilized zirconia arose from rearrangement of the point defects associated with O ion vacancies.

Frequency Dispersion of the Internal Friction in Tetragonal and Cubic Zirconia Polycrystals Stabilized with Yttria. J.Kondoh, H.Shiota: Journal of Materials Science, 2003, 38[17], 3689-94