NiMn₂O₄ Ceramic with Bi₂O₃ as Ablating Aid with Laser Melting Deposition

NiMn₂O₄ thermosensitive ceramics using Bi₂O₃ as a low-temperature ablating aid were prepared by laser melting deposition. Analyzing the structural, morphological, and electrical properties of the ceramics revealed important roles of Bi₂O₃. The room-temperature resistance decreased gradually with the increasing of the Bi₂O₃ content, the thermal constant of the ceramics varied from 2870.1 to 3853.2 K, and the activation energy varied from 0.2473 to 0.3320 eV. Furthermore, the alleviation of the aging issue was attributed to the grain growth and the densification of the ceramics due to the addition of Bi₂O₃ and the corresponding cationic redistribution. As a result, an optimized resistance drifting (∆R/R = 5.72%) of the ceramic was obtained with the addition of Bi₂O₃.