Critical Sintering Temperature Research Articles

Effect of sintering conditions on the electrical properties of Ni1–xZnxLa0.05Fe1.95O4

Ferrite samples having the general formula Ni1–xZnxLa0.05Fe1.95O4 were prepared using the standard ceramic method. The effect of sintering temperature, heating rate, and sintering time on the structural and the electrical properties was studied. The data show that electrical conductivity ln σ as well as dielectric constant ε′ are highly dependent on both Zn content x and the sintering conditions. The data obtained show that 1250 °C is a critical sintering temperature. At this sintering temperature the grain growth is increased as the formation of spinel structure reaches its maximum value, and the volume diffusion is predominant. The critical heating rate is 4 °C/min where the full reaction and maximum densification occur simultaneously. The effect of sintering time was also studied at a constant heating rate of 4 °C/min and sintering temperature of 1250 °C. All the data obtained are nearly constant and begin to increase after 83 h. SEM and electrical properties confirmed the results obtained. (© 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)