Ink-jet printed new core@shell ceramic for high stability NTC thermistors

Mn1.95Co0.21Ni0.84O4-core@LaMnO3-shell microbeads were in-situ processed by an ink-jet printing method. The composition of the LaMnO3 on the electrical properties compared with the only core Mn1.95Co0.21Ni0.84O4 (MCN) ceramic were studied. X-ray diffraction analysis showed that the ceramics were composed mainly of cubic spinel NiMn2O4 with rhombohedral perovskite LaMnO3 phase. The X-ray photoelectron spectroscopy (XPS) results explained the ion migration occurred in the composite materials. These ceramics had negative temper ature coefficients and B25/50 and Ea values of 1456-5972 K and 0.0814-0.5148 eV, respectively. Moreover, the aging coefficients (oR/R) of the bilayer core@shell structure ceramics were <0.51%, which is much lower than that of uncoated Mn1.95Co0.21Ni0.84O4 microbeads (4.1%). The grain boundaries were verified to dominate important role in the electrical property of the Mn1.95Co0.21Ni0.84O4-core@LaMnO3-shell ceramics.

Automated summary

Mn1.95Co0.21Ni0.84O4-core@LaMnO3-shell microbeads were synthesized using ink-jet printing. The impact of LaMnO3 composition on the electrical properties was investigated. X-ray diffraction revealed a composition mainly composed of cubic spinel NiMn2O4 and rhombohedral perovskite LaMnO3. X-ray photoelectron spectroscopy confirmed ion migration in the composite material. These ceramics exhibited negative temperature coefficients and had low aging coefficients compared to uncoated microbeads.