Aging processes in the nanostructured temperature-sensitive ceramic materials

Abstract

Aging processes in the two types of temperature-sensitive Cu0.1Ni0.8Co0.2Mn1.9O4 ceramics (two-phase and with different amount of NiO phase) as well as thick films base on Cu0.1Ni0.1Co1.6Mn1.2O4 ceramics were investigated. It is shown for Cu0.1Ni0.8Co0.2Mn1.9O4 ceramics prepared at 1170 °C with addition treatment at 850 °C that the post-separation process of the second phase continue under heat at temperatures of 125 and 170 °C. It has been found that higher thermal aging leads to more pronounced changes in electrical resistance. Addition temperature influences contribute to the stabilization of ceramic parameters. The aging test at 170 °C results in a 7.5% reduction in electrical resistance, while at 125 °C this value is only 6%. It is shown that NiO phase additives formed during sintering of Cu0.1Ni0.1Co1.6Mn1.2O4 ceramics and located near the grain boundaries of ceramics inhibit the aging process in these materials. This effect is characteristic of fine-grained ceramics obtained by thermal energy converted during sintering. It is established that the kinetics of aging in Cu0.1Ni0.1Co1.6Mn1.2O4 ceramics is described by the relaxation function of DeBast-Gillard or Williams-Watts, regardless of the composition of the ceramics. The aging kinetics in thick films based on Cu0.1Ni0.1Co1.6Mn1.2O4 ceramics at 170 °C is also adequately described by the compression-exponential relaxation function.