| Summary: | Here, we demonstrate that nano–sized Mn–Ni–Co–O powder can be prepared at a low temperature via a co–precipitation method. In this work, Mn<sup>2+</sup> was partially oxidized to Mn<sup>3+</sup> ions in an aqueous solution by adding an oxidizing agent (H<sub>2</sub>O<sub>2</sub>). The co-presence of Mn<sup>2+</sup> and Mn<sup>3+</sup> cations enabled the precipitated products to be well-crystallized at a calcining temperature as low as 650 °C, forming a pure cubic spinel structure. The pellets fabricated from this calcined powder showed a relative density of up to 97.1% at a moderate sintering temperature of 1100 °C. Moreover, these ceramics exhibited electrical performance suitable for use in industrial thermistors, i.e., a room temperature resistivity (<i>ρ</i><sub>25</sub>) of 1232 Ω cm, a thermistor constant (<i>B</i><sub>25/85</sub>) of 3676 K, and an aging coefficient (Δ<i>R</i>/<i>R</i>) of 1.43%. High sintering activity as well as the excellent electrical properties of the ceramics was attributed to the fine-sized particles of the synthesized powder.
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