Aging improvement in Ho-doped NTC ceramics prepared by high-energy ball mill method

High-energy ball milling is a widely used method in the lot production of nanostructure due to its economization and simplicity. Recently, a new application of this technology has been found as it can induce the structural changes of some crystals, nanoparticles fabricated from this application have a higher sintering activity. The mass nano-oxides are milled efficiently by Szegvari Attritor and combined with a solid-state reaction, we prepared negative temperature coefficient (NTC) thermistors based on a Ho-doped Mn2.05Co0.32Ni0.36Al0.27O4 ceramic. X-ray diffraction (XRD) results demonstrate that Pure spinel structure when Ho-doping within x = 0.01. As the Ho ion content increases, the resistivity of the experimental samples increases slightly, while B constant is essentially unchanged. It is notable that Ho-doped sample with x = 0.0025 has only a 0.19% shift in relative resistivity, meanwhile, the grain size of the sample is more uniform due to the Ho doping.