Dependence of the sintering rate and related grain size of yttria-stabilized polycrystalline zirconia (3Y-TZP) on the strength of an applied DC electric field

The sintering rate of 3Y-TZP increased with increase in initial applied DC electric field strength up to 20 V/cm; no further effect however occurred at 50 V/cm. Analysis of the data confirmed the earlier finding that the increase in sintering rate by the field resulted mainly from a retardation of grain growth. It was further determined that the retardation resulted from a reduction in the grain boundary energy, which provides the driving force. The initial field of 20 V/cm reduced the grain boundary energy to essentially nil, thereby accounting for the fact that no further decrease in grain size occurred at the higher field strength. The reduction in the grain boundary energy by the field is attributed to the interaction of the field with the space charge.