Novel thermal‐sensitive properties of NBT‐BZT composite ceramics for high‐temperature NTC thermistors

Abstract

We found for the first time that (1 − x) Na0.5Bi0.5TiO3‐xBiZn0.5Ti0.5O3 (NBT–BZT) composite ceramics showed negative temperature coefficient (NTC) at a high temperature. The NBT–BZT nanopowders were successfully prepared by Pechini method. Their ceramics were sintered at 1100°C. The NBT–BZT ceramic exhibited a good linear relationship between logarithm of electrical resistivity (Inρ) and reciprocal of absolute temperature (1000/T) at 250°C–1050°C. The obtained ρ600, ρ900, and B600/900 constants of the NBT–ZBT NTC thermistors are approximately 5.92 × 106 to 3.01 × 104 Ω cm, 7.03 × 103 to 7.60 × 102 Ω cm and 2.3 × 104‐1.3 × 104 K, respectively. The electrical characteristics can be tuned to the desired value by changing the Na0.5Bi0.5TiO3 content in the compound. The electrical conductivity in these compounds is due to the electron jumps between Ti3+ and Ti4+ and oxygen‐ion conductivity. Results demonstrate a tremendous potential of the studied system for perovskite materials with NTC performance.

Extremely enhanced thermal stability of Y2/3Cu3Ti4O12 ceramics by a Pechini method

“…In the second stage (259.11-526.73 • C), the mass loss reached 73.33%, which was attributed to the pyrolysis of residual nitrate with citric acid and the release of a large number of gases (such as H 2 O, CO 2 , and N 2 ). 34,37 This observation is confirmed by a sharp exothermic peak at 453.12 • C. There is almost no mass loss in the last stage (>526.73 • C), indicating the transformation from disorder to order. When the temperature rises to 731.41 • C, the DSC curve shows a heat absorption peak, indicating the formation of an oxide with a certain composition.…”

“…In the first stage (97.11–259.11°C), the TG curve decreases slowly and the initial mass loss (−9.95%) may be related to the evaporation of adsorbed water and the removal of crystalline water. In the second stage (259.11–526.73°C), the mass loss reached 73.33%, which was attributed to the pyrolysis of residual nitrate with citric acid and the release of a large number of gases (such as H 2 O, CO 2 , and N 2 ) 34,37 . This observation is confirmed by a sharp exothermic peak at 453.12°C.…”

Nonlinear electrical behaviors and conductivity mechanisms in Ca1‐xYbxCeNbWO8 ceramics

“…Therefore, the ES-VRH mechanism cannot be ignored. 15 Simultaneously, there occurs phonon-assisted carrier hopping in local states, 18,19 indicating that thermal activation is also one of the main mechanisms. When the Yb 3+ doping amount is large (x = 0.2), the carriers are mainly transported in the layered CeNbO 4 -rich phase.…”

High-stability solid solution perovskite (1-x) Bi0.2Sr0.5La0.3TiO3- xLaMnO3 (0.05≤ × ≤0.2) for wide-temperature NTC thermistors

“…The cations A and B of perovskite-type compounds are independent of temperature and are pinned at the lattice sites. Therefore, the cation migration hardly ever occurs between the dodecahedral A sites and the octahedrally coordinated smaller cations on B sites in perovskites, even at high temperatures (T. Liu et al, 2020). That is why perovskites exhibit stable electrical characteristics at high temperatures.…”